From 76bbb7c361166964de43422c749c67f56eb08e04 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Sun, 8 Oct 2023 20:51:00 -0700
Subject: [PATCH] terminal: insert lines (IL) handles left/right scroll regions

---
 src/terminal/Screen.zig   | 21 ++++++++++++++++
 src/terminal/Terminal.zig | 50 ++++++++++++++++++++-------------------
 2 files changed, 47 insertions(+), 24 deletions(-)

diff --git a/src/terminal/Screen.zig b/src/terminal/Screen.zig
index 6fd50b54e..93194393b 100644
--- a/src/terminal/Screen.zig
+++ b/src/terminal/Screen.zig
@@ -498,6 +498,27 @@ pub const Row = struct {
         }
     }
 
+    /// Copy a single cell from column x in src to column x in this row.
+    pub fn copyCell(self: Row, src: Row, x: usize) !void {
+        const dst_cell = self.getCellPtr(x);
+        const src_cell = src.getCellPtr(x);
+
+        // If our destination has graphemes, we have to clear them.
+        if (dst_cell.attrs.grapheme) self.clearGraphemes(x);
+        dst_cell.* = src_cell.*;
+
+        // If the source doesn't have any graphemes, then we can just copy.
+        if (!src_cell.attrs.grapheme) return;
+
+        // Source cell has graphemes. Copy them.
+        const src_key = src.getId() + x + 1;
+        const src_data = src.screen.graphemes.get(src_key) orelse return;
+        const dst_key = self.getId() + x + 1;
+        const dst_gop = try self.screen.graphemes.getOrPut(self.screen.alloc, dst_key);
+        dst_gop.value_ptr.* = try src_data.copy(self.screen.alloc);
+        self.storage[0].header.flags.grapheme = true;
+    }
+
     /// Copy the row src into this row. The row can be from another screen.
     pub fn copyRow(self: Row, src: Row) !void {
         // If we have graphemes, clear first to unset them.
diff --git a/src/terminal/Terminal.zig b/src/terminal/Terminal.zig
index cdf044be4..b09ca943e 100644
--- a/src/terminal/Terminal.zig
+++ b/src/terminal/Terminal.zig
@@ -1590,7 +1590,9 @@ pub fn insertLines(self: *Terminal, count: usize) !void {
     while (y > top) : (y -= 1) {
         const src = self.screen.getRow(.{ .active = y - adjusted_count });
         const dst = self.screen.getRow(.{ .active = y });
-        try dst.copyRow(src);
+        for (self.scrolling_region.left..self.scrolling_region.right + 1) |x| {
+            try dst.copyCell(src, x);
+        }
     }
 
     // Insert count blank lines
@@ -2730,29 +2732,29 @@ test "Terminal: insertLines top/bottom scroll region" {
     }
 }
 
-// test "Terminal: insertLines left/right scroll region" {
-//     const alloc = testing.allocator;
-//     var t = try init(alloc, 10, 10);
-//     defer t.deinit(alloc);
-//
-//     try t.printString("ABC123");
-//     t.carriageReturn();
-//     try t.linefeed();
-//     try t.printString("DEF456");
-//     t.carriageReturn();
-//     try t.linefeed();
-//     try t.printString("GHI789");
-//     t.scrolling_region.left = 1;
-//     t.scrolling_region.right = 3;
-//     t.setCursorPos(2, 2);
-//     try t.insertLines(1);
-//
-//     {
-//         var str = try t.plainString(testing.allocator);
-//         defer testing.allocator.free(str);
-//         try testing.expectEqualStrings("ABC123\nD   56\nGEF489\n HI7", str);
-//     }
-// }
+test "Terminal: insertLines left/right scroll region" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 10, 10);
+    defer t.deinit(alloc);
+
+    try t.printString("ABC123");
+    t.carriageReturn();
+    try t.linefeed();
+    try t.printString("DEF456");
+    t.carriageReturn();
+    try t.linefeed();
+    try t.printString("GHI789");
+    t.scrolling_region.left = 1;
+    t.scrolling_region.right = 3;
+    t.setCursorPos(2, 2);
+    try t.insertLines(1);
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("ABC123\nD   56\nGEF489\n HI7", str);
+    }
+}
 
 test "Terminal: insertLines" {
     const alloc = testing.allocator;