From 0a27e5a58b70ceebd4f58fb9c9ad569e5740f58a Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Sun, 18 Feb 2024 22:11:21 -0800
Subject: [PATCH] terminal/new: print some characters (test string)

---
 src/terminal/new/Screen.zig | 71 +++++++++++++++++++++++++++++++++++--
 src/terminal/new/page.zig   | 39 +++++++++++++++++++-
 2 files changed, 106 insertions(+), 4 deletions(-)

diff --git a/src/terminal/new/Screen.zig b/src/terminal/new/Screen.zig
index fbef50aef..fe5cd660c 100644
--- a/src/terminal/new/Screen.zig
+++ b/src/terminal/new/Screen.zig
@@ -3,6 +3,7 @@ const Screen = @This();
 const std = @import("std");
 const Allocator = std.mem.Allocator;
 const assert = std.debug.assert;
+const unicode = @import("../../unicode/main.zig");
 const pagepkg = @import("page.zig");
 const Page = pagepkg.Page;
 
@@ -46,16 +47,31 @@ pages: PageList,
 viewport: *PageList.Node,
 viewport_row: usize,
 
+/// The current cursor position
+cursor: Cursor,
+
+/// The current desired screen dimensions. I say "desired" because individual
+/// pages may still be a different size and not yet reflowed since we lazily
+/// reflow text.
+cols: usize,
+rows: usize,
+
 /// The cursor position.
 const Cursor = struct {
     // The x/y position within the viewport.
-    x: usize = 0,
-    y: usize = 0,
+    x: usize,
+    y: usize,
+
+    /// 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 page that the cursor is on and the offset into that page that
     // the current y exists.
     page: *PageList.Node,
     page_row: usize,
+    page_row_ptr: *pagepkg.Row,
+    page_cell_ptr: *pagepkg.Cell,
 };
 
 /// Initialize a new screen.
@@ -88,12 +104,27 @@ pub fn init(
     var page_list: PageList = .{};
     page_list.prepend(page);
 
+    const cursor_row_ptr, const cursor_cell_ptr = ptr: {
+        const rac = page.data.getRowAndCell(0, 0);
+        break :ptr .{ rac.row, rac.cell };
+    };
+
     return .{
         .alloc = alloc,
+        .cols = cols,
+        .rows = rows,
         .page_pool = pool,
         .pages = page_list,
         .viewport = page,
         .viewport_row = 0,
+        .cursor = .{
+            .x = 0,
+            .y = 0,
+            .page = page,
+            .page_row = 0,
+            .page_row_ptr = cursor_row_ptr,
+            .page_cell_ptr = cursor_cell_ptr,
+        },
     };
 }
 
@@ -104,10 +135,44 @@ pub fn deinit(self: *Screen) void {
     self.page_pool.deinit();
 }
 
-test {
+fn testWriteString(self: *Screen, text: []const u8) !void {
+    const view = try std.unicode.Utf8View.init(text);
+    var iter = view.iterator();
+    while (iter.nextCodepoint()) |c| {
+        if (self.cursor.x == self.cols) {
+            @panic("wrap not implemented");
+        }
+
+        const width: usize = if (c <= 0xFF) 1 else @intCast(unicode.table.get(c).width);
+        if (width == 0) {
+            @panic("zero-width todo");
+        }
+
+        assert(width == 1 or width == 2);
+        switch (width) {
+            1 => {
+                self.cursor.page_cell_ptr.codepoint = c;
+                self.cursor.x += 1;
+                if (self.cursor.x < self.cols) {
+                    const cell_ptr: [*]pagepkg.Cell = @ptrCast(self.cursor.page_cell_ptr);
+                    self.cursor.page_cell_ptr = @ptrCast(cell_ptr + 1);
+                } else {
+                    @panic("wrap not implemented");
+                }
+            },
+
+            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 s.testWriteString("hello, world");
 }
diff --git a/src/terminal/new/page.zig b/src/terminal/new/page.zig
index 273bfa19c..ad9d49326 100644
--- a/src/terminal/new/page.zig
+++ b/src/terminal/new/page.zig
@@ -107,6 +107,21 @@ pub const Page = struct {
         self.* = undefined;
     }
 
+    /// Get the row and cell for the given X/Y within this page.
+    pub fn getRowAndCell(self: *const Page, x: usize, y: usize) struct {
+        row: *Row,
+        cell: *Cell,
+    } {
+        assert(y < self.capacity.rows);
+        assert(x < self.capacity.cols);
+
+        const rows = self.rows.ptr(self.memory);
+        const row = &rows[y];
+        const cell = &row.cells.ptr(self.memory)[x];
+
+        return .{ .row = row, .cell = cell };
+    }
+
     const Layout = struct {
         total_size: usize,
         rows_start: usize,
@@ -184,7 +199,7 @@ pub const Cell = packed struct(u32) {
 //     });
 // }
 
-test "Page" {
+test "Page init" {
     const testing = std.testing;
     const alloc = testing.allocator;
     var page = try Page.init(alloc, .{
@@ -194,3 +209,25 @@ test "Page" {
     });
     defer page.deinit(alloc);
 }
+
+test "Page read and write cells" {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+    var page = try Page.init(alloc, .{
+        .cols = 10,
+        .rows = 10,
+        .styles = 8,
+    });
+    defer page.deinit(alloc);
+
+    for (0..page.capacity.rows) |y| {
+        const rac = page.getRowAndCell(1, y);
+        rac.cell.codepoint = @intCast(y);
+    }
+
+    // Read it again
+    for (0..page.capacity.rows) |y| {
+        const rac = page.getRowAndCell(1, y);
+        try testing.expectEqual(@as(u21, @intCast(y)), rac.cell.codepoint);
+    }
+}