ghostty/src/terminal/new/Screen.zig

const Screen = @This();

const std = @import("std");
const Allocator = std.mem.Allocator;
const assert = std.debug.assert;
const ansi = @import("../ansi.zig");
const charsets = @import("../charsets.zig");
const kitty = @import("../kitty.zig");
const sgr = @import("../sgr.zig");
const unicode = @import("../../unicode/main.zig");
const Selection = @import("../Selection.zig");
const PageList = @import("PageList.zig");
const pagepkg = @import("page.zig");
const point = @import("point.zig");
const size = @import("size.zig");
const style = @import("style.zig");
const Page = pagepkg.Page;
const Row = pagepkg.Row;
const Cell = pagepkg.Cell;

/// The general purpose allocator to use for all memory allocations.
/// Unfortunately some screen operations do require allocation.
alloc: Allocator,

/// The list of pages in the screen.
pages: PageList,

/// Special-case where we want no scrollback whatsoever. We have to flag
/// this because max_size 0 in PageList gets rounded up to two pages so
/// we can always have an active screen.
no_scrollback: bool = false,

/// The current cursor position
cursor: Cursor,

/// The saved cursor
saved_cursor: ?SavedCursor = null,

/// The selection for this screen (if any).
selection: ?Selection = null,

/// The charset state
charset: CharsetState = .{},

/// The current or most recent protected mode. Once a protection mode is
/// set, this will never become "off" again until the screen is reset.
/// The current state of whether protection attributes should be set is
/// set on the Cell pen; this is only used to determine the most recent
/// protection mode since some sequences such as ECH depend on this.
protected_mode: ansi.ProtectedMode = .off,

/// The kitty keyboard settings.
kitty_keyboard: kitty.KeyFlagStack = .{},

/// Kitty graphics protocol state.
kitty_images: kitty.graphics.ImageStorage = .{},

/// The cursor position.
pub const Cursor = struct {
    // The x/y position within the viewport.
    x: size.CellCountInt,
    y: size.CellCountInt,

    /// The "last column flag (LCF)" as its called. If this is set then the
    /// next character print will force a soft-wrap.
    pending_wrap: bool = false,

    /// The protected mode state of the cursor. If this is true then
    /// all new characters printed will have the protected state set.
    protected: bool = false,

    /// The currently active style. This is the concrete style value
    /// that should be kept up to date. The style ID to use for cell writing
    /// is below.
    style: style.Style = .{},

    /// The currently active style ID. The style is page-specific so when
    /// we change pages we need to ensure that we update that page with
    /// our style when used.
    style_id: style.Id = style.default_id,
    style_ref: ?*size.CellCountInt = null,

    /// The pointers into the page list where the cursor is currently
    /// located. This makes it faster to move the cursor.
    page_offset: PageList.RowOffset,
    page_row: *pagepkg.Row,
    page_cell: *pagepkg.Cell,
};

/// Saved cursor state.
pub const SavedCursor = struct {
    x: size.CellCountInt,
    y: size.CellCountInt,
    style: style.Style,
    protected: bool,
    pending_wrap: bool,
    origin: bool,
    charset: CharsetState,
};

/// State required for all charset operations.
pub const CharsetState = struct {
    /// The list of graphical charsets by slot
    charsets: CharsetArray = CharsetArray.initFill(charsets.Charset.utf8),

    /// GL is the slot to use when using a 7-bit printable char (up to 127)
    /// GR used for 8-bit printable chars.
    gl: charsets.Slots = .G0,
    gr: charsets.Slots = .G2,

    /// Single shift where a slot is used for exactly one char.
    single_shift: ?charsets.Slots = null,

    /// An array to map a charset slot to a lookup table.
    const CharsetArray = std.EnumArray(charsets.Slots, charsets.Charset);
};

/// Initialize a new screen.
///
/// max_scrollback is the amount of scrollback to keep in bytes. This
/// will be rounded UP to the nearest page size because our minimum allocation
/// size is that anyways.
///
/// If max scrollback is 0, then no scrollback is kept at all.
pub fn init(
    alloc: Allocator,
    cols: size.CellCountInt,
    rows: size.CellCountInt,
    max_scrollback: usize,
) !Screen {
    // Initialize our backing pages.
    var pages = try PageList.init(alloc, cols, rows, max_scrollback);
    errdefer pages.deinit();

    // The active area is guaranteed to be allocated and the first
    // page in the list after init. This lets us quickly setup the cursor.
    // This is MUCH faster than pages.rowOffset.
    const page_offset: PageList.RowOffset = .{
        .page = pages.pages.first.?,
        .row_offset = 0,
    };
    const page_rac = page_offset.rowAndCell(0);

    return .{
        .alloc = alloc,
        .pages = pages,
        .no_scrollback = max_scrollback == 0,
        .cursor = .{
            .x = 0,
            .y = 0,
            .page_offset = page_offset,
            .page_row = page_rac.row,
            .page_cell = page_rac.cell,
        },
    };
}

pub fn deinit(self: *Screen) void {
    self.kitty_images.deinit(self.alloc);
    self.pages.deinit();
}

/// Clone the screen.
///
/// This will copy:
///
///   - Screen dimensions
///   - Screen data (cell state, etc.) for the region
///
/// Anything not mentioned above is NOT copied. Some of this is for
/// very good reason:
///
///   - Kitty images have a LOT of data. This is not efficient to copy.
///     Use a lock and access the image data. The dirty bit is there for
///     a reason.
///   - Cursor location can be expensive to calculate with respect to the
///     specified region. It is faster to grab the cursor from the old
///     screen and then move it to the new screen.
///
/// If not mentioned above, then there isn't a specific reason right now
/// to not copy some data other than we probably didn't need it and it
/// isn't necessary for screen coherency.
///
/// Other notes:
///
///   - The viewport will always be set to the active area of the new
///     screen. This is the bottom "rows" rows.
///   - If the clone region is smaller than a viewport area, blanks will
///     be filled in at the bottom.
///
pub fn clone(
    self: *const Screen,
    alloc: Allocator,
    top: point.Point,
    bot: ?point.Point,
) !Screen {
    return try self.clonePool(alloc, null, top, bot);
}

/// Same as clone but you can specify a custom memory pool to use for
/// the screen.
pub fn clonePool(
    self: *const Screen,
    alloc: Allocator,
    pool: ?*PageList.MemoryPool,
    top: point.Point,
    bot: ?point.Point,
) !Screen {
    var pages = if (pool) |p|
        try self.pages.clonePool(p, top, bot)
    else
        try self.pages.clone(alloc, top, bot);
    errdefer pages.deinit();

    return .{
        .alloc = alloc,
        .pages = pages,
        .no_scrollback = self.no_scrollback,

        // TODO: let's make this reasonble
        .cursor = undefined,
    };
}

pub fn cursorCellRight(self: *Screen, n: size.CellCountInt) *pagepkg.Cell {
    assert(self.cursor.x + n < self.pages.cols);
    const cell: [*]pagepkg.Cell = @ptrCast(self.cursor.page_cell);
    return @ptrCast(cell + n);
}

pub fn cursorCellLeft(self: *Screen, n: size.CellCountInt) *pagepkg.Cell {
    assert(self.cursor.x >= n);
    const cell: [*]pagepkg.Cell = @ptrCast(self.cursor.page_cell);
    return @ptrCast(cell - n);
}

pub fn cursorCellEndOfPrev(self: *Screen) *pagepkg.Cell {
    assert(self.cursor.y > 0);

    const page_offset = self.cursor.page_offset.backward(1).?;
    const page_rac = page_offset.rowAndCell(self.pages.cols - 1);
    return page_rac.cell;
}

/// Move the cursor right. This is a specialized function that is very fast
/// if the caller can guarantee we have space to move right (no wrapping).
pub fn cursorRight(self: *Screen, n: size.CellCountInt) void {
    assert(self.cursor.x + n < self.pages.cols);

    const cell: [*]pagepkg.Cell = @ptrCast(self.cursor.page_cell);
    self.cursor.page_cell = @ptrCast(cell + n);
    self.cursor.x += n;
}

/// Move the cursor left.
pub fn cursorLeft(self: *Screen, n: size.CellCountInt) void {
    assert(self.cursor.x >= n);

    const cell: [*]pagepkg.Cell = @ptrCast(self.cursor.page_cell);
    self.cursor.page_cell = @ptrCast(cell - n);
    self.cursor.x -= n;
}

/// Move the cursor up.
///
/// Precondition: The cursor is not at the top of the screen.
pub fn cursorUp(self: *Screen, n: size.CellCountInt) void {
    assert(self.cursor.y >= n);

    const page_offset = self.cursor.page_offset.backward(n).?;
    const page_rac = page_offset.rowAndCell(self.cursor.x);
    self.cursor.page_offset = page_offset;
    self.cursor.page_row = page_rac.row;
    self.cursor.page_cell = page_rac.cell;
    self.cursor.y -= n;
}

pub fn cursorRowUp(self: *Screen, n: size.CellCountInt) *pagepkg.Row {
    assert(self.cursor.y >= n);

    const page_offset = self.cursor.page_offset.backward(n).?;
    const page_rac = page_offset.rowAndCell(self.cursor.x);
    return page_rac.row;
}

/// Move the cursor down.
///
/// Precondition: The cursor is not at the bottom of the screen.
pub fn cursorDown(self: *Screen, n: size.CellCountInt) void {
    assert(self.cursor.y + n < self.pages.rows);

    // We move the offset into our page list to the next row and then
    // get the pointers to the row/cell and set all the cursor state up.
    const page_offset = self.cursor.page_offset.forward(n).?;
    const page_rac = page_offset.rowAndCell(self.cursor.x);
    self.cursor.page_offset = page_offset;
    self.cursor.page_row = page_rac.row;
    self.cursor.page_cell = page_rac.cell;

    // Y of course increases
    self.cursor.y += n;
}

/// Move the cursor to some absolute horizontal position.
pub fn cursorHorizontalAbsolute(self: *Screen, x: size.CellCountInt) void {
    assert(x < self.pages.cols);

    const page_rac = self.cursor.page_offset.rowAndCell(x);
    self.cursor.page_cell = page_rac.cell;
    self.cursor.x = x;
}

/// Move the cursor to some absolute position.
pub fn cursorAbsolute(self: *Screen, x: size.CellCountInt, y: size.CellCountInt) void {
    assert(x < self.pages.cols);
    assert(y < self.pages.rows);

    const page_offset = if (y < self.cursor.y)
        self.cursor.page_offset.backward(self.cursor.y - y).?
    else if (y > self.cursor.y)
        self.cursor.page_offset.forward(y - self.cursor.y).?
    else
        self.cursor.page_offset;
    const page_rac = page_offset.rowAndCell(x);
    self.cursor.page_offset = page_offset;
    self.cursor.page_row = page_rac.row;
    self.cursor.page_cell = page_rac.cell;
    self.cursor.x = x;
    self.cursor.y = y;
}

/// Reloads the cursor pointer information into the screen. This is expensive
/// so it should only be done in cases where the pointers are invalidated
/// in such a way that its difficult to recover otherwise.
pub fn cursorReload(self: *Screen) void {
    const get = self.pages.getCell(.{ .active = .{
        .x = self.cursor.x,
        .y = self.cursor.y,
    } }).?;
    self.cursor.page_offset = .{ .page = get.page, .row_offset = get.row_idx };
    self.cursor.page_row = get.row;
    self.cursor.page_cell = get.cell;
}

/// Scroll the active area and keep the cursor at the bottom of the screen.
/// This is a very specialized function but it keeps it fast.
pub fn cursorDownScroll(self: *Screen) !void {
    assert(self.cursor.y == self.pages.rows - 1);

    // If we have no scrollback, then we shift all our rows instead.
    if (self.no_scrollback) {
        // Erase rows will shift our rows up
        self.pages.eraseRows(.{ .active = .{} }, .{ .active = .{} });

        // We need to reload our cursor because the pointers are now invalid.
        const page_offset = self.cursor.page_offset;
        const page_rac = page_offset.rowAndCell(self.cursor.x);
        self.cursor.page_offset = page_offset;
        self.cursor.page_row = page_rac.row;
        self.cursor.page_cell = page_rac.cell;

        // Erase rows does NOT clear the cells because in all other cases
        // we never write those rows again. Active erasing is a bit
        // different so we manually clear our one row.
        self.clearCells(
            &page_offset.page.data,
            self.cursor.page_row,
            page_offset.page.data.getCells(self.cursor.page_row),
        );
    } else {
        // Grow our pages by one row. The PageList will handle if we need to
        // allocate, prune scrollback, whatever.
        _ = try self.pages.grow();
        const page_offset = self.cursor.page_offset.forward(1).?;
        const page_rac = page_offset.rowAndCell(self.cursor.x);
        self.cursor.page_offset = page_offset;
        self.cursor.page_row = page_rac.row;
        self.cursor.page_cell = page_rac.cell;

        // Clear the new row so it gets our bg color. We only do this
        // if we have a bg color at all.
        if (self.cursor.style.bg_color != .none) {
            self.clearCells(
                &page_offset.page.data,
                self.cursor.page_row,
                page_offset.page.data.getCells(self.cursor.page_row),
            );
        }
    }

    // The newly created line needs to be styled according to the bg color
    // if it is set.
    if (self.cursor.style_id != style.default_id) {
        if (self.cursor.style.bgCell()) |blank_cell| {
            const cell_current: [*]pagepkg.Cell = @ptrCast(self.cursor.page_cell);
            const cells = cell_current - self.cursor.x;
            @memset(cells[0..self.pages.cols], blank_cell);
        }
    }
}

/// Move the cursor down if we're not at the bottom of the screen. Otherwise
/// scroll. Currently only used for testing.
fn cursorDownOrScroll(self: *Screen) !void {
    if (self.cursor.y + 1 < self.pages.rows) {
        self.cursorDown(1);
    } else {
        try self.cursorDownScroll();
    }
}

/// Options for scrolling the viewport of the terminal grid. The reason
/// we have this in addition to PageList.Scroll is because we have additional
/// scroll behaviors that are not part of the PageList.Scroll enum.
pub const Scroll = union(enum) {
    /// For all of these, see PageList.Scroll.
    active,
    top,
    delta_row: isize,
};

/// Scroll the viewport of the terminal grid.
pub fn scroll(self: *Screen, behavior: Scroll) void {
    // No matter what, scrolling marks our image state as dirty since
    // it could move placements. If there are no placements or no images
    // this is still a very cheap operation.
    self.kitty_images.dirty = true;

    switch (behavior) {
        .active => self.pages.scroll(.{ .active = {} }),
        .top => self.pages.scroll(.{ .top = {} }),
        .delta_row => |v| self.pages.scroll(.{ .delta_row = v }),
    }
}

/// See PageList.scrollClear. In addition to that, we reset the cursor
/// to be on top.
pub fn scrollClear(self: *Screen) !void {
    try self.pages.scrollClear();
    self.cursorReload();

    // No matter what, scrolling marks our image state as dirty since
    // it could move placements. If there are no placements or no images
    // this is still a very cheap operation.
    self.kitty_images.dirty = true;
}

/// Erase the region specified by tl and br, inclusive. This will physically
/// erase the rows meaning the memory will be reclaimed (if the underlying
/// page is empty) and other rows will be shifted up.
pub fn eraseRows(
    self: *Screen,
    tl: point.Point,
    bl: ?point.Point,
) void {
    // Erase the rows
    self.pages.eraseRows(tl, bl);

    // Just to be safe, reset our cursor since it is possible depending
    // on the points that our active area shifted so our pointers are
    // invalid.
    self.cursorReload();
}

// Clear the region specified by tl and bl, inclusive. Cleared cells are
// colored with the current style background color. This will clear all
// cells in the rows.
//
// If protected is true, the protected flag will be respected and only
// unprotected cells will be cleared. Otherwise, all cells will be cleared.
pub fn clearRows(
    self: *Screen,
    tl: point.Point,
    bl: ?point.Point,
    protected: bool,
) void {
    var it = self.pages.pageIterator(tl, bl);
    while (it.next()) |chunk| {
        for (chunk.rows()) |*row| {
            const cells_offset = row.cells;
            const cells_multi: [*]Cell = row.cells.ptr(chunk.page.data.memory);
            const cells = cells_multi[0..self.pages.cols];

            // Clear all cells
            if (protected) {
                self.clearUnprotectedCells(&chunk.page.data, row, cells);
            } else {
                self.clearCells(&chunk.page.data, row, cells);
            }

            // Reset our row to point to the proper memory but everything
            // else is zeroed.
            row.* = .{ .cells = cells_offset };
        }
    }
}

/// Clear the cells with the blank cell. This takes care to handle
/// cleaning up graphemes and styles.
pub fn clearCells(
    self: *Screen,
    page: *Page,
    row: *Row,
    cells: []Cell,
) void {
    // If this row has graphemes, then we need go through a slow path
    // and delete the cell graphemes.
    if (row.grapheme) {
        for (cells) |*cell| {
            if (cell.hasGrapheme()) page.clearGrapheme(row, cell);
        }
    }

    if (row.styled) {
        for (cells) |*cell| {
            if (cell.style_id == style.default_id) continue;

            // Fast-path, the style ID matches, in this case we just update
            // our own ref and continue. We never delete because our style
            // is still active.
            if (cell.style_id == self.cursor.style_id) {
                self.cursor.style_ref.?.* -= 1;
                continue;
            }

            // Slow path: we need to lookup this style so we can decrement
            // the ref count. Since we've already loaded everything, we also
            // just go ahead and GC it if it reaches zero, too.
            if (page.styles.lookupId(page.memory, cell.style_id)) |prev_style| {
                // Below upsert can't fail because it should already be present
                const md = page.styles.upsert(page.memory, prev_style.*) catch unreachable;
                assert(md.ref > 0);
                md.ref -= 1;
                if (md.ref == 0) page.styles.remove(page.memory, cell.style_id);
            }
        }

        // If we have no left/right scroll region we can be sure that
        // the row is no longer styled.
        if (cells.len == self.pages.cols) row.styled = false;
    }

    @memset(cells, self.blankCell());
}

/// Clear cells but only if they are not protected.
pub fn clearUnprotectedCells(
    self: *Screen,
    page: *Page,
    row: *Row,
    cells: []Cell,
) void {
    for (cells) |*cell| {
        if (cell.protected) continue;
        const cell_multi: [*]Cell = @ptrCast(cell);
        self.clearCells(page, row, cell_multi[0..1]);
    }
}

/// Returns the blank cell to use when doing terminal operations that
/// require preserving the bg color.
fn blankCell(self: *const Screen) Cell {
    if (self.cursor.style_id == style.default_id) return .{};
    return self.cursor.style.bgCell() orelse .{};
}

/// Resize the screen. The rows or cols can be bigger or smaller.
///
/// This will reflow soft-wrapped text. If the screen size is getting
/// smaller and the maximum scrollback size is exceeded, data will be
/// lost from the top of the scrollback.
///
/// If this returns an error, the screen is left in a likely garbage state.
/// It is very hard to undo this operation without blowing up our memory
/// usage. The only way to recover is to reset the screen. The only way
/// this really fails is if page allocation is required and fails, which
/// probably means the system is in trouble anyways. I'd like to improve this
/// in the future but it is not a priority particularly because this scenario
/// (resize) is difficult.
pub fn resize(
    self: *Screen,
    cols: size.CellCountInt,
    rows: size.CellCountInt,
) !void {
    if (self.pages.cols == cols) {
        // No resize necessary
        if (self.pages.rows == rows) return;

        // No matter what we mark our image state as dirty
        self.kitty_images.dirty = true;

        // If we have the same number of columns, text can't possibly
        // reflow in any way, so we do the quicker thing and do a resize
        // without reflow checks.
        try self.resizeWithoutReflow(cols, rows);
        return;
    }

    // No matter what we mark our image state as dirty
    self.kitty_images.dirty = true;

    var cursor: PageList.Resize.Cursor = .{
        .x = self.cursor.x,
        .y = self.cursor.y,
    };

    const old_cols = self.pages.cols;
    try self.pages.resize(.{
        .rows = rows,
        .cols = cols,
        .reflow = true,
        .cursor = &cursor,
    });

    // If we have no scrollback and we shrunk our rows, we must explicitly
    // erase our history. This is beacuse PageList always keeps at least
    // a page size of history.
    if (self.no_scrollback and cols < old_cols) {
        self.pages.eraseRows(.{ .history = .{} }, null);
    }

    if (cursor.x != self.cursor.x or cursor.y != self.cursor.y) {
        self.cursor.x = cursor.x;
        self.cursor.y = cursor.y;
        self.cursorReload();
    }
}

/// Resize the screen without any reflow. In this mode, columns/rows will
/// be truncated as they are shrunk. If they are grown, the new space is filled
/// with zeros.
pub fn resizeWithoutReflow(
    self: *Screen,
    cols: size.CellCountInt,
    rows: size.CellCountInt,
) !void {
    var cursor: PageList.Resize.Cursor = .{
        .x = self.cursor.x,
        .y = self.cursor.y,
    };

    const old_rows = self.pages.rows;

    try self.pages.resize(.{
        .rows = rows,
        .cols = cols,
        .reflow = false,
        .cursor = &cursor,
    });

    // If we have no scrollback and we shrunk our rows, we must explicitly
    // erase our history. This is beacuse PageList always keeps at least
    // a page size of history.
    if (self.no_scrollback and rows < old_rows) {
        self.pages.eraseRows(.{ .history = .{} }, null);
    }

    if (cursor.x != self.cursor.x or cursor.y != self.cursor.y) {
        self.cursor.x = cursor.x;
        self.cursor.y = cursor.y;
        self.cursorReload();
    }
}

/// Set a style attribute for the current cursor.
///
/// This can cause a page split if the current page cannot fit this style.
/// This is the only scenario an error return is possible.
pub fn setAttribute(self: *Screen, attr: sgr.Attribute) !void {
    switch (attr) {
        .unset => {
            self.cursor.style = .{};
        },

        .bold => {
            self.cursor.style.flags.bold = true;
        },

        .reset_bold => {
            // Bold and faint share the same SGR code for this
            self.cursor.style.flags.bold = false;
            self.cursor.style.flags.faint = false;
        },

        .italic => {
            self.cursor.style.flags.italic = true;
        },

        .reset_italic => {
            self.cursor.style.flags.italic = false;
        },

        .faint => {
            self.cursor.style.flags.faint = true;
        },

        .underline => |v| {
            self.cursor.style.flags.underline = v;
        },

        .reset_underline => {
            self.cursor.style.flags.underline = .none;
        },

        .underline_color => |rgb| {
            self.cursor.style.underline_color = .{ .rgb = .{
                .r = rgb.r,
                .g = rgb.g,
                .b = rgb.b,
            } };
        },

        .@"256_underline_color" => |idx| {
            self.cursor.style.underline_color = .{ .palette = idx };
        },

        .reset_underline_color => {
            self.cursor.style.underline_color = .none;
        },

        .blink => {
            self.cursor.style.flags.blink = true;
        },

        .reset_blink => {
            self.cursor.style.flags.blink = false;
        },

        .inverse => {
            self.cursor.style.flags.inverse = true;
        },

        .reset_inverse => {
            self.cursor.style.flags.inverse = false;
        },

        .invisible => {
            self.cursor.style.flags.invisible = true;
        },

        .reset_invisible => {
            self.cursor.style.flags.invisible = false;
        },

        .strikethrough => {
            self.cursor.style.flags.strikethrough = true;
        },

        .reset_strikethrough => {
            self.cursor.style.flags.strikethrough = false;
        },

        .direct_color_fg => |rgb| {
            self.cursor.style.fg_color = .{
                .rgb = .{
                    .r = rgb.r,
                    .g = rgb.g,
                    .b = rgb.b,
                },
            };
        },

        .direct_color_bg => |rgb| {
            self.cursor.style.bg_color = .{
                .rgb = .{
                    .r = rgb.r,
                    .g = rgb.g,
                    .b = rgb.b,
                },
            };
        },

        .@"8_fg" => |n| {
            self.cursor.style.fg_color = .{ .palette = @intFromEnum(n) };
        },

        .@"8_bg" => |n| {
            self.cursor.style.bg_color = .{ .palette = @intFromEnum(n) };
        },

        .reset_fg => self.cursor.style.fg_color = .none,

        .reset_bg => self.cursor.style.bg_color = .none,

        .@"8_bright_fg" => |n| {
            self.cursor.style.fg_color = .{ .palette = @intFromEnum(n) };
        },

        .@"8_bright_bg" => |n| {
            self.cursor.style.bg_color = .{ .palette = @intFromEnum(n) };
        },

        .@"256_fg" => |idx| {
            self.cursor.style.fg_color = .{ .palette = idx };
        },

        .@"256_bg" => |idx| {
            self.cursor.style.bg_color = .{ .palette = idx };
        },

        .unknown => return,
    }

    try self.manualStyleUpdate();
}

/// Call this whenever you manually change the cursor style.
pub fn manualStyleUpdate(self: *Screen) !void {
    var page = &self.cursor.page_offset.page.data;

    // Remove our previous style if is unused.
    if (self.cursor.style_ref) |ref| {
        if (ref.* == 0) {
            page.styles.remove(page.memory, self.cursor.style_id);
        }
    }

    // If our new style is the default, just reset to that
    if (self.cursor.style.default()) {
        self.cursor.style_id = 0;
        self.cursor.style_ref = null;
        return;
    }

    // After setting the style, we need to update our style map.
    // Note that we COULD lazily do this in print. We should look into
    // if that makes a meaningful difference. Our priority is to keep print
    // fast because setting a ton of styles that do nothing is uncommon
    // and weird.
    const md = try page.styles.upsert(page.memory, self.cursor.style);
    self.cursor.style_id = md.id;
    self.cursor.style_ref = &md.ref;
}

/// Dump the screen to a string. The writer given should be buffered;
/// this function does not attempt to efficiently write and generally writes
/// one byte at a time.
pub fn dumpString(
    self: *const Screen,
    writer: anytype,
    tl: point.Point,
) !void {
    var blank_rows: usize = 0;

    var iter = self.pages.rowIterator(tl, null);
    while (iter.next()) |row_offset| {
        const rac = row_offset.rowAndCell(0);
        const cells = cells: {
            const cells: [*]pagepkg.Cell = @ptrCast(rac.cell);
            break :cells cells[0..self.pages.cols];
        };

        if (!pagepkg.Cell.hasTextAny(cells)) {
            blank_rows += 1;
            continue;
        }
        if (blank_rows > 0) {
            for (0..blank_rows) |_| try writer.writeByte('\n');
            blank_rows = 0;
        }

        // TODO: handle wrap
        blank_rows += 1;

        var blank_cells: usize = 0;
        for (cells) |*cell| {
            // Skip spacers
            switch (cell.wide) {
                .narrow, .wide => {},
                .spacer_head, .spacer_tail => continue,
            }

            // If we have a zero value, then we accumulate a counter. We
            // only want to turn zero values into spaces if we have a non-zero
            // char sometime later.
            if (!cell.hasText()) {
                blank_cells += 1;
                continue;
            }
            if (blank_cells > 0) {
                for (0..blank_cells) |_| try writer.writeByte(' ');
                blank_cells = 0;
            }

            switch (cell.content_tag) {
                .codepoint => {
                    try writer.print("{u}", .{cell.content.codepoint});
                },

                .codepoint_grapheme => {
                    try writer.print("{u}", .{cell.content.codepoint});
                    const cps = row_offset.page.data.lookupGrapheme(cell).?;
                    for (cps) |cp| {
                        try writer.print("{u}", .{cp});
                    }
                },

                else => unreachable,
            }
        }
    }
}

pub fn dumpStringAlloc(
    self: *const Screen,
    alloc: Allocator,
    tl: point.Point,
) ![]const u8 {
    var builder = std.ArrayList(u8).init(alloc);
    defer builder.deinit();
    try self.dumpString(builder.writer(), tl);
    return try builder.toOwnedSlice();
}

/// This is basically a really jank version of Terminal.printString. We
/// have to reimplement it here because we want a way to print to the screen
/// to test it but don't want all the features of Terminal.
fn testWriteString(self: *Screen, text: []const u8) !void {
    const view = try std.unicode.Utf8View.init(text);
    var iter = view.iterator();
    while (iter.nextCodepoint()) |c| {
        // Explicit newline forces a new row
        if (c == '\n') {
            try self.cursorDownOrScroll();
            self.cursorHorizontalAbsolute(0);
            self.cursor.pending_wrap = false;
            continue;
        }

        const width: usize = if (c <= 0xFF) 1 else @intCast(unicode.table.get(c).width);
        if (width == 0) {
            @panic("zero-width todo");
        }

        if (self.cursor.pending_wrap) {
            assert(self.cursor.x == self.pages.cols - 1);
            self.cursor.pending_wrap = false;
            self.cursor.page_row.wrap = true;
            try self.cursorDownOrScroll();
            self.cursorHorizontalAbsolute(0);
            self.cursor.page_row.wrap_continuation = true;
        }

        assert(width == 1 or width == 2);
        switch (width) {
            1 => {
                self.cursor.page_cell.* = .{
                    .content_tag = .codepoint,
                    .content = .{ .codepoint = c },
                    .style_id = self.cursor.style_id,
                };

                // If we have a ref-counted style, increase.
                if (self.cursor.style_ref) |ref| {
                    ref.* += 1;
                    self.cursor.page_row.styled = true;
                }

                if (self.cursor.x + 1 < self.pages.cols) {
                    self.cursorRight(1);
                } else {
                    self.cursor.pending_wrap = true;
                }
            },

            2 => @panic("todo double-width"),
            else => unreachable,
        }
    }
}

test "Screen read and write" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();
    try testing.expectEqual(@as(style.Id, 0), s.cursor.style_id);

    try s.testWriteString("hello, world");
    const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
    defer alloc.free(str);
    try testing.expectEqualStrings("hello, world", str);
}

test "Screen read and write newline" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();
    try testing.expectEqual(@as(style.Id, 0), s.cursor.style_id);

    try s.testWriteString("hello\nworld");
    const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
    defer alloc.free(str);
    try testing.expectEqualStrings("hello\nworld", str);
}

test "Screen read and write scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 2, 1000);
    defer s.deinit();

    try s.testWriteString("hello\nworld\ntest");
    {
        const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("hello\nworld\ntest", str);
    }
    {
        const str = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("world\ntest", str);
    }
}

test "Screen read and write no scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 2, 0);
    defer s.deinit();

    try s.testWriteString("hello\nworld\ntest");
    {
        const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("world\ntest", str);
    }
    {
        const str = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("world\ntest", str);
    }
}

test "Screen read and write no scrollback large" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 2, 0);
    defer s.deinit();

    for (0..1_000) |i| {
        var buf: [128]u8 = undefined;
        const str = try std.fmt.bufPrint(&buf, "{}\n", .{i});
        try s.testWriteString(str);
    }
    try s.testWriteString("1000");

    {
        const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("999\n1000", str);
    }
}

test "Screen style basics" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();
    const page = s.cursor.page_offset.page.data;
    try testing.expectEqual(@as(usize, 0), page.styles.count(page.memory));

    // Set a new style
    try s.setAttribute(.{ .bold = {} });
    try testing.expect(s.cursor.style_id != 0);
    try testing.expectEqual(@as(usize, 1), page.styles.count(page.memory));
    try testing.expect(s.cursor.style.flags.bold);

    // Set another style, we should still only have one since it was unused
    try s.setAttribute(.{ .italic = {} });
    try testing.expect(s.cursor.style_id != 0);
    try testing.expectEqual(@as(usize, 1), page.styles.count(page.memory));
    try testing.expect(s.cursor.style.flags.italic);
}

test "Screen style reset to default" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();
    const page = s.cursor.page_offset.page.data;
    try testing.expectEqual(@as(usize, 0), page.styles.count(page.memory));

    // Set a new style
    try s.setAttribute(.{ .bold = {} });
    try testing.expect(s.cursor.style_id != 0);
    try testing.expectEqual(@as(usize, 1), page.styles.count(page.memory));

    // Reset to default
    try s.setAttribute(.{ .reset_bold = {} });
    try testing.expect(s.cursor.style_id == 0);
    try testing.expectEqual(@as(usize, 0), page.styles.count(page.memory));
}

test "Screen style reset with unset" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();
    const page = s.cursor.page_offset.page.data;
    try testing.expectEqual(@as(usize, 0), page.styles.count(page.memory));

    // Set a new style
    try s.setAttribute(.{ .bold = {} });
    try testing.expect(s.cursor.style_id != 0);
    try testing.expectEqual(@as(usize, 1), page.styles.count(page.memory));

    // Reset to default
    try s.setAttribute(.{ .unset = {} });
    try testing.expect(s.cursor.style_id == 0);
    try testing.expectEqual(@as(usize, 0), page.styles.count(page.memory));
}

test "Screen clearRows active one line" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();

    try s.testWriteString("hello, world");
    s.clearRows(.{ .active = .{} }, null, false);
    const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
    defer alloc.free(str);
    try testing.expectEqualStrings("", str);
}

test "Screen clearRows active multi line" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();

    try s.testWriteString("hello\nworld");
    s.clearRows(.{ .active = .{} }, null, false);
    const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
    defer alloc.free(str);
    try testing.expectEqualStrings("", str);
}

test "Screen clearRows active styled line" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 80, 24, 1000);
    defer s.deinit();

    try s.setAttribute(.{ .bold = {} });
    try s.testWriteString("hello world");
    try s.setAttribute(.{ .unset = {} });

    // We should have one style
    const page = s.cursor.page_offset.page.data;
    try testing.expectEqual(@as(usize, 1), page.styles.count(page.memory));

    s.clearRows(.{ .active = .{} }, null, false);

    // We should have none because active cleared it
    try testing.expectEqual(@as(usize, 0), page.styles.count(page.memory));

    const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
    defer alloc.free(str);
    try testing.expectEqualStrings("", str);
}

test "Screen eraseRows history" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 5, 5, 1000);
    defer s.deinit();

    try s.testWriteString("1\n2\n3\n4\n5\n6");

    {
        const str = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("2\n3\n4\n5\n6", str);
    }
    {
        const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("1\n2\n3\n4\n5\n6", str);
    }

    s.eraseRows(.{ .history = .{} }, null);

    {
        const str = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("2\n3\n4\n5\n6", str);
    }
    {
        const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("2\n3\n4\n5\n6", str);
    }
}

test "Screen eraseRows history with more lines" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try Screen.init(alloc, 5, 5, 1000);
    defer s.deinit();

    try s.testWriteString("A\nB\nC\n1\n2\n3\n4\n5\n6");

    {
        const str = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("2\n3\n4\n5\n6", str);
    }
    {
        const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("A\nB\nC\n1\n2\n3\n4\n5\n6", str);
    }

    s.eraseRows(.{ .history = .{} }, null);

    {
        const str = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("2\n3\n4\n5\n6", str);
    }
    {
        const str = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(str);
        try testing.expectEqualStrings("2\n3\n4\n5\n6", str);
    }
}

test "Screen: scrolling" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    try s.setAttribute(.{ .direct_color_bg = .{ .r = 155 } });
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL");

    // Scroll down, should still be bottom
    try s.cursorDownScroll();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }
    {
        const list_cell = s.pages.getCell(.{ .active = .{ .x = 0, .y = 2 } }).?;
        const cell = list_cell.cell;
        try testing.expect(cell.content_tag == .bg_color_rgb);
        try testing.expectEqual(Cell.RGB{
            .r = 155,
            .g = 0,
            .b = 0,
        }, cell.content.color_rgb);
    }

    // Scrolling to the bottom does nothing
    s.scroll(.{ .active = {} });

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }
}

test "Screen: scroll down from 0" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL");

    // Scrolling up does nothing, but allows it
    s.scroll(.{ .delta_row = -1 });
    try testing.expect(s.pages.viewport == .active);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }
}

test "Screen: scrollback various cases" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 1);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL");
    try s.cursorDownScroll();

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }

    // Scrolling to the bottom
    s.scroll(.{ .active = {} });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }

    // Scrolling back should make it visible again
    s.scroll(.{ .delta_row = -1 });
    try testing.expect(s.pages.viewport != .active);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }

    // Scrolling back again should do nothing
    s.scroll(.{ .delta_row = -1 });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }

    // Scrolling to the bottom
    s.scroll(.{ .active = {} });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }

    // Scrolling forward with no grow should do nothing
    s.scroll(.{ .delta_row = 1 });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }

    // Scrolling to the top should work
    s.scroll(.{ .top = {} });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }

    // Should be able to easily clear active area only
    s.clearRows(.{ .active = .{} }, null, false);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD", contents);
    }

    // Scrolling to the bottom
    s.scroll(.{ .active = {} });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }
}

test "Screen: scrollback with multi-row delta" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 3);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH\n6IJKL");

    // Scroll to top
    s.scroll(.{ .top = {} });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }

    // Scroll down multiple
    s.scroll(.{ .delta_row = 5 });
    try testing.expect(s.pages.viewport == .active);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("4ABCD\n5EFGH\n6IJKL", contents);
    }
}

test "Screen: scrollback empty" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 50);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL");
    s.scroll(.{ .delta_row = 1 });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }
}

test "Screen: scrollback doesn't move viewport if not at bottom" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 3);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH");

    // First test: we scroll up by 1, so we're not at the bottom anymore.
    s.scroll(.{ .delta_row = -1 });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL\n4ABCD", contents);
    }

    // Next, we scroll back down by 1, this grows the scrollback but we
    // shouldn't move.
    try s.cursorDownScroll();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL\n4ABCD", contents);
    }

    // Scroll again, this clears scrollback so we should move viewports
    // but still see the same thing since our original view fits.
    try s.cursorDownScroll();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL\n4ABCD", contents);
    }
}

test "Screen: scroll and clear full screen" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 5);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL");

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }

    try s.scrollClear();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }
}

test "Screen: scroll and clear partial screen" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 5);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH");

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH", contents);
    }

    try s.scrollClear();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH", contents);
    }
}

test "Screen: scroll and clear empty screen" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 5);
    defer s.deinit();
    try s.scrollClear();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }
}

test "Screen: scroll and clear ignore blank lines" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 10);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH");
    try s.scrollClear();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }

    // Move back to top-left
    s.cursorAbsolute(0, 0);

    // Write and clear
    try s.testWriteString("3ABCD\n");
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("3ABCD", contents);
    }

    try s.scrollClear();
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }

    // Move back to top-left
    s.cursorAbsolute(0, 0);
    try s.testWriteString("X");

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3ABCD\nX", contents);
    }
}

test "Screen: clone" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 10);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH");
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH", contents);
    }

    // Clone
    var s2 = try s.clone(alloc, .{ .active = .{} }, null);
    defer s2.deinit();
    {
        const contents = try s2.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH", contents);
    }

    // Write to s1, should not be in s2
    try s.testWriteString("\n34567");
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n34567", contents);
    }
    {
        const contents = try s2.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH", contents);
    }
}

test "Screen: clone partial" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 10);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH");
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH", contents);
    }

    // Clone
    var s2 = try s.clone(alloc, .{ .active = .{ .y = 1 } }, null);
    defer s2.deinit();
    {
        const contents = try s2.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH", contents);
    }
}

test "Screen: clone basic" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL");

    {
        var s2 = try s.clone(
            alloc,
            .{ .active = .{ .y = 1 } },
            .{ .active = .{ .y = 1 } },
        );
        defer s2.deinit();

        // Test our contents rotated
        const contents = try s2.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH", contents);
    }

    {
        var s2 = try s.clone(
            alloc,
            .{ .active = .{ .y = 1 } },
            .{ .active = .{ .y = 2 } },
        );
        defer s2.deinit();

        // Test our contents rotated
        const contents = try s2.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }
}

test "Screen: clone empty viewport" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();

    {
        var s2 = try s.clone(
            alloc,
            .{ .viewport = .{ .y = 0 } },
            .{ .viewport = .{ .y = 0 } },
        );
        defer s2.deinit();

        // Test our contents rotated
        const contents = try s2.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }
}

test "Screen: clone one line viewport" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    try s.testWriteString("1ABC");

    {
        var s2 = try s.clone(
            alloc,
            .{ .viewport = .{ .y = 0 } },
            .{ .viewport = .{ .y = 0 } },
        );
        defer s2.deinit();

        // Test our contents
        const contents = try s2.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABC", contents);
    }
}

test "Screen: clone empty active" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();

    {
        var s2 = try s.clone(
            alloc,
            .{ .active = .{ .y = 0 } },
            .{ .active = .{ .y = 0 } },
        );
        defer s2.deinit();

        // Test our contents rotated
        const contents = try s2.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("", contents);
    }
}

test "Screen: clone one line active with extra space" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    try s.testWriteString("1ABC");

    {
        var s2 = try s.clone(
            alloc,
            .{ .active = .{ .y = 0 } },
            null,
        );
        defer s2.deinit();

        // Test our contents rotated
        const contents = try s2.dumpStringAlloc(alloc, .{ .active = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABC", contents);
    }
}

test "Screen: clear history with no history" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 3);
    defer s.deinit();
    try s.testWriteString("4ABCD\n5EFGH\n6IJKL");
    try testing.expect(s.pages.viewport == .active);
    s.eraseRows(.{ .history = .{} }, null);
    try testing.expect(s.pages.viewport == .active);
    {
        // Test our contents rotated
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("4ABCD\n5EFGH\n6IJKL", contents);
    }
    {
        // Test our contents rotated
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("4ABCD\n5EFGH\n6IJKL", contents);
    }
}

test "Screen: clear history" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 3);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH\n6IJKL");
    try testing.expect(s.pages.viewport == .active);

    // Scroll to top
    s.scroll(.{ .top = {} });
    {
        // Test our contents rotated
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL", contents);
    }

    s.eraseRows(.{ .history = .{} }, null);
    try testing.expect(s.pages.viewport == .active);
    {
        // Test our contents rotated
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("4ABCD\n5EFGH\n6IJKL", contents);
    }
    {
        // Test our contents rotated
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("4ABCD\n5EFGH\n6IJKL", contents);
    }
}

test "Screen: clear above cursor" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 10, 3);
    defer s.deinit();
    try s.testWriteString("4ABCD\n5EFGH\n6IJKL");
    s.clearRows(
        .{ .active = .{ .y = 0 } },
        .{ .active = .{ .y = s.cursor.y - 1 } },
        false,
    );
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("\n\n6IJKL", contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("\n\n6IJKL", contents);
    }

    try testing.expectEqual(@as(usize, 5), s.cursor.x);
    try testing.expectEqual(@as(usize, 2), s.cursor.y);
}

test "Screen: clear above cursor with history" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 3);
    defer s.deinit();
    try s.testWriteString("1ABCD\n2EFGH\n3IJKL\n");
    try s.testWriteString("4ABCD\n5EFGH\n6IJKL");
    s.clearRows(
        .{ .active = .{ .y = 0 } },
        .{ .active = .{ .y = s.cursor.y - 1 } },
        false,
    );
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("\n\n6IJKL", contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD\n2EFGH\n3IJKL\n\n\n6IJKL", contents);
    }

    try testing.expectEqual(@as(usize, 5), s.cursor.x);
    try testing.expectEqual(@as(usize, 2), s.cursor.y);
}

test "Screen: resize (no reflow) more rows" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);

    // Resize
    try s.resizeWithoutReflow(10, 10);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

test "Screen: resize (no reflow) less rows" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);
    try testing.expectEqual(5, s.cursor.x);
    try testing.expectEqual(2, s.cursor.y);
    try s.resizeWithoutReflow(10, 2);

    // Since we shrunk, we should adjust our cursor
    try testing.expectEqual(5, s.cursor.x);
    try testing.expectEqual(1, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2EFGH\n3IJKL", contents);
    }
}

test "Screen: resize (no reflow) less rows trims blank lines" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    const str = "1ABCD";
    try s.testWriteString(str);

    // Write only a background color into the remaining rows
    for (1..s.pages.rows) |y| {
        const list_cell = s.pages.getCell(.{ .active = .{ .x = 0, .y = y } }).?;
        list_cell.cell.* = .{
            .content_tag = .bg_color_rgb,
            .content = .{ .color_rgb = .{ .r = 0xFF, .g = 0, .b = 0 } },
        };
    }

    const cursor = s.cursor;
    try s.resizeWithoutReflow(6, 2);

    // Cursor should not move
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD", contents);
    }
}

test "Screen: resize (no reflow) more rows trims blank lines" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    const str = "1ABCD";
    try s.testWriteString(str);

    // Write only a background color into the remaining rows
    for (1..s.pages.rows) |y| {
        const list_cell = s.pages.getCell(.{ .active = .{ .x = 0, .y = y } }).?;
        list_cell.cell.* = .{
            .content_tag = .bg_color_rgb,
            .content = .{ .color_rgb = .{ .r = 0xFF, .g = 0, .b = 0 } },
        };
    }

    const cursor = s.cursor;
    try s.resizeWithoutReflow(10, 7);

    // Cursor should not move
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD", contents);
    }
}

test "Screen: resize (no reflow) more cols" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);
    try s.resizeWithoutReflow(20, 3);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

test "Screen: resize (no reflow) less cols" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 10, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);
    try s.resizeWithoutReflow(4, 3);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1ABC\n2EFG\n3IJK";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize (no reflow) more rows with scrollback cursor end" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 7, 3, 2);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH";
    try s.testWriteString(str);
    try s.resizeWithoutReflow(7, 10);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

test "Screen: resize (no reflow) less rows with scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 7, 3, 2);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH";
    try s.testWriteString(str);
    try s.resizeWithoutReflow(7, 2);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }
}

// https://github.com/mitchellh/ghostty/issues/1030
test "Screen: resize (no reflow) less rows with empty trailing" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 5);
    defer s.deinit();
    const str = "1\n2\n3\n4\n5\n6\n7\n8";
    try s.testWriteString(str);
    try s.scrollClear();
    s.cursorAbsolute(0, 0);
    try s.testWriteString("A\nB");

    const cursor = s.cursor;
    try s.resizeWithoutReflow(5, 2);
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("A\nB", contents);
    }
}

test "Screen: resize (no reflow) more rows with soft wrapping" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 2, 3, 3);
    defer s.deinit();
    const str = "1A2B\n3C4E\n5F6G";
    try s.testWriteString(str);

    // Every second row should be wrapped
    for (0..6) |y| {
        const list_cell = s.pages.getCell(.{ .screen = .{ .x = 0, .y = y } }).?;
        const row = list_cell.row;
        const wrapped = (y % 2 == 0);
        try testing.expectEqual(wrapped, row.wrap);
    }

    // Resize
    try s.resizeWithoutReflow(2, 10);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1A\n2B\n3C\n4E\n5F\n6G";
        try testing.expectEqualStrings(expected, contents);
    }

    // Every second row should be wrapped
    for (0..6) |y| {
        const list_cell = s.pages.getCell(.{ .screen = .{ .x = 0, .y = y } }).?;
        const row = list_cell.row;
        const wrapped = (y % 2 == 0);
        try testing.expectEqual(wrapped, row.wrap);
    }
}

test "Screen: resize more rows no scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);
    const cursor = s.cursor;
    try s.resize(5, 10);

    // Cursor should not move
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

test "Screen: resize more rows with empty scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 10);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);
    const cursor = s.cursor;
    try s.resize(5, 10);

    // Cursor should not move
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

test "Screen: resize more rows with populated scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 5);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH";
    try s.testWriteString(str);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL\n4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }

    // Set our cursor to be on the "4"
    s.cursorAbsolute(0, 1);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '4'), list_cell.cell.content.codepoint);
    }

    // Resize
    try s.resize(5, 10);

    // Cursor should still be on the "4"
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '4'), list_cell.cell.content.codepoint);
    }

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL\n4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize more cols no reflow" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);

    const cursor = s.cursor;
    try s.resize(10, 3);

    // Cursor should not move
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

// https://github.com/mitchellh/ghostty/issues/272#issuecomment-1676038963
test "Screen: resize more cols perfect split" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD2EFGH3IJKL";
    try s.testWriteString(str);
    try s.resize(10, 3);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("1ABCD2EFGH\n3IJKL", contents);
    }
}

// https://github.com/mitchellh/ghostty/issues/1159
test "Screen: resize (no reflow) more cols with scrollback scrolled up" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 5);
    defer s.deinit();
    const str = "1\n2\n3\n4\n5\n6\n7\n8";
    try s.testWriteString(str);

    // Cursor at bottom
    try testing.expectEqual(@as(size.CellCountInt, 1), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 2), s.cursor.y);

    s.scroll(.{ .delta_row = -4 });
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings("2\n3\n4", contents);
    }

    try s.resize(8, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }

    // Cursor remains at bottom
    try testing.expectEqual(@as(size.CellCountInt, 1), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 2), s.cursor.y);
}

test "Screen: resize more cols with reflow that fits full width" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD2EFGH\n3IJKL";
    try s.testWriteString(str);

    // Verify we soft wrapped
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1ABCD\n2EFGH\n3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }

    // Let's put our cursor on row 2, where the soft wrap is
    s.cursorAbsolute(0, 1);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '2'), list_cell.cell.content.codepoint);
    }

    // Resize and verify we undid the soft wrap because we have space now
    try s.resize(10, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }

    // Our cursor should've moved
    try testing.expectEqual(@as(usize, 5), s.cursor.x);
    try testing.expectEqual(@as(usize, 0), s.cursor.y);
}

test "Screen: resize more cols with reflow that ends in newline" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 6, 3, 0);
    defer s.deinit();
    const str = "1ABCD2EFGH\n3IJKL";
    try s.testWriteString(str);

    // Verify we soft wrapped
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1ABCD2\nEFGH\n3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }

    // Let's put our cursor on the last row
    s.cursorAbsolute(0, 2);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '3'), list_cell.cell.content.codepoint);
    }

    // Resize and verify we undid the soft wrap because we have space now
    try s.resize(10, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }

    // Our cursor should still be on the 3
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '3'), list_cell.cell.content.codepoint);
    }
}

test "Screen: resize more cols with reflow that forces more wrapping" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD2EFGH\n3IJKL";
    try s.testWriteString(str);

    // Let's put our cursor on row 2, where the soft wrap is
    s.cursorAbsolute(0, 1);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '2'), list_cell.cell.content.codepoint);
    }

    // Verify we soft wrapped
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1ABCD\n2EFGH\n3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }

    // Resize and verify we undid the soft wrap because we have space now
    try s.resize(7, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1ABCD2E\nFGH\n3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }

    // Our cursor should've moved
    try testing.expectEqual(@as(size.CellCountInt, 5), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 0), s.cursor.y);
}

test "Screen: resize more cols with reflow that unwraps multiple times" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD2EFGH3IJKL";
    try s.testWriteString(str);

    // Let's put our cursor on row 2, where the soft wrap is
    s.cursorAbsolute(0, 2);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '3'), list_cell.cell.content.codepoint);
    }

    // Verify we soft wrapped
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1ABCD\n2EFGH\n3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }

    // Resize and verify we undid the soft wrap because we have space now
    try s.resize(15, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1ABCD2EFGH3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }

    // Our cursor should've moved
    try testing.expectEqual(@as(size.CellCountInt, 10), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 0), s.cursor.y);
}

test "Screen: resize more cols with populated scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 5);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL\n4ABCD5EFGH";
    try s.testWriteString(str);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL\n4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }

    // // Set our cursor to be on the "5"
    s.cursorAbsolute(0, 2);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '5'), list_cell.cell.content.codepoint);
    }

    // Resize
    try s.resize(10, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "2EFGH\n3IJKL\n4ABCD5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }

    // Cursor should still be on the "5"
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u21, '5'), list_cell.cell.content.codepoint);
    }
}

test "Screen: resize more cols with reflow" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 2, 3, 5);
    defer s.deinit();
    const str = "1ABC\n2DEF\n3ABC\n4DEF";
    try s.testWriteString(str);

    // Let's put our cursor on row 2, where the soft wrap is
    s.cursorAbsolute(0, 2);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u32, 'E'), list_cell.cell.content.codepoint);
    }

    // Verify we soft wrapped
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "BC\n4D\nEF";
        try testing.expectEqualStrings(expected, contents);
    }

    // Resize and verify we undid the soft wrap because we have space now
    try s.resize(7, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "1ABC\n2DEF\n3ABC\n4DEF";
        try testing.expectEqualStrings(expected, contents);
    }

    // Our cursor should've moved
    try testing.expectEqual(@as(size.CellCountInt, 2), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 2), s.cursor.y);
}

test "Screen: resize more rows and cols with wrapping" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 2, 4, 0);
    defer s.deinit();
    const str = "1A2B\n3C4D";
    try s.testWriteString(str);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1A\n2B\n3C\n4D";
        try testing.expectEqualStrings(expected, contents);
    }

    try s.resize(5, 10);

    // Cursor should move due to wrapping
    try testing.expectEqual(@as(size.CellCountInt, 3), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 1), s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

test "Screen: resize less rows no scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);

    s.cursorAbsolute(0, 0);
    const cursor = s.cursor;
    try s.resize(5, 1);

    // Cursor should not move
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize less rows moving cursor" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);

    // Put our cursor on the last line
    s.cursorAbsolute(1, 2);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u32, 'I'), list_cell.cell.content.codepoint);
    }

    // Resize
    try s.resize(5, 1);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }

    // Cursor should be on the last line
    try testing.expectEqual(@as(size.CellCountInt, 1), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 0), s.cursor.y);
}

test "Screen: resize less rows with empty scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 10);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL";
    try s.testWriteString(str);
    try s.resize(5, 1);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize less rows with populated scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 5);
    defer s.deinit();
    const str = "1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH";
    try s.testWriteString(str);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL\n4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }

    // Resize
    try s.resize(5, 1);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize less rows with full scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 3);
    defer s.deinit();
    const str = "00000\n1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH";
    try s.testWriteString(str);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL\n4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }

    try testing.expectEqual(@as(size.CellCountInt, 4), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 2), s.cursor.y);

    // Resize
    try s.resize(5, 2);

    // Cursor should stay in the same relative place (bottom of the
    // screen, same character).
    try testing.expectEqual(@as(size.CellCountInt, 4), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 1), s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "00000\n1ABCD\n2EFGH\n3IJKL\n4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize less cols no reflow" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "1AB\n2EF\n3IJ";
    try s.testWriteString(str);

    s.cursorAbsolute(0, 0);
    const cursor = s.cursor;
    try s.resize(3, 3);

    // Cursor should not move
    try testing.expectEqual(cursor.x, s.cursor.x);
    try testing.expectEqual(cursor.y, s.cursor.y);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        try testing.expectEqualStrings(str, contents);
    }
}

test "Screen: resize less cols with reflow but row space" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 1);
    defer s.deinit();
    const str = "1ABCD";
    try s.testWriteString(str);

    // Put our cursor on the end
    s.cursorAbsolute(4, 0);
    {
        const list_cell = s.pages.getCell(.{ .active = .{
            .x = s.cursor.x,
            .y = s.cursor.y,
        } }).?;
        try testing.expectEqual(@as(u32, 'D'), list_cell.cell.content.codepoint);
    }

    try s.resize(3, 3);
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "1AB\nCD";
        try testing.expectEqualStrings(expected, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "1AB\nCD";
        try testing.expectEqualStrings(expected, contents);
    }

    // Cursor should be on the last line
    try testing.expectEqual(@as(size.CellCountInt, 1), s.cursor.x);
    try testing.expectEqual(@as(size.CellCountInt, 1), s.cursor.y);
}

test "Screen: resize less cols with reflow with trimmed rows" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "3IJKL\n4ABCD\n5EFGH";
    try s.testWriteString(str);
    try s.resize(3, 3);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "CD\n5EF\nGH";
        try testing.expectEqualStrings(expected, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "CD\n5EF\nGH";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize less cols with reflow with trimmed rows and scrollback" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 1);
    defer s.deinit();
    const str = "3IJKL\n4ABCD\n5EFGH";
    try s.testWriteString(str);
    try s.resize(3, 3);

    {
        const contents = try s.dumpStringAlloc(alloc, .{ .viewport = .{} });
        defer alloc.free(contents);
        const expected = "CD\n5EF\nGH";
        try testing.expectEqualStrings(expected, contents);
    }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "3IJ\nKL\n4AB\nCD\n5EF\nGH";
        try testing.expectEqualStrings(expected, contents);
    }
}

test "Screen: resize less cols with reflow previously wrapped" {
    const testing = std.testing;
    const alloc = testing.allocator;

    var s = try init(alloc, 5, 3, 0);
    defer s.deinit();
    const str = "3IJKL4ABCD5EFGH";
    try s.testWriteString(str);

    // Check
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "3IJKL\n4ABCD\n5EFGH";
        try testing.expectEqualStrings(expected, contents);
    }

    try s.resize(3, 3);

    // {
    //     const contents = try s.testString(alloc, .viewport);
    //     defer alloc.free(contents);
    //     const expected = "CD\n5EF\nGH";
    //     try testing.expectEqualStrings(expected, contents);
    // }
    {
        const contents = try s.dumpStringAlloc(alloc, .{ .screen = .{} });
        defer alloc.free(contents);
        const expected = "ABC\nD5E\nFGH";
        try testing.expectEqualStrings(expected, contents);
    }
}