From 20ab4ec01fef4098364404010d552082a5550acd Mon Sep 17 00:00:00 2001
From: Qwerasd <qwerasd205@users.noreply.github.com>
Date: Fri, 29 Mar 2024 13:12:52 -0400
Subject: [PATCH] fix(terminal): correct wrap logic in insert/deleteLines

Appropriately handles clearing spacer heads if shifted lines include rightmost column, and centralizes clearing of row wrap state for full width scrolling regions.
---
 src/terminal/Terminal.zig | 73 +++++++++++++++++++++++++++------------
 1 file changed, 50 insertions(+), 23 deletions(-)

diff --git a/src/terminal/Terminal.zig b/src/terminal/Terminal.zig
index 0c91cb428..6dbe2345a 100644
--- a/src/terminal/Terminal.zig
+++ b/src/terminal/Terminal.zig
@@ -1359,8 +1359,31 @@ pub fn insertLines(self: *Terminal, count: usize) void {
         var it = bot.rowIterator(.left_up, top);
         while (it.next()) |p| {
             const dst_p = p.down(adjusted_count).?;
-            const src: *Row = p.rowAndCell().row;
-            const dst: *Row = dst_p.rowAndCell().row;
+            const src_rac = p.rowAndCell();
+            const dst_rac = dst_p.rowAndCell();
+            const src: *Row = src_rac.row;
+            const dst: *Row = dst_rac.row;
+
+            // If our scrolling region includes the rightmost column then we
+            // need to turn any spacer heads in to normal empty cells, since
+            // once we move them they no longer correspond with soft-wrapped
+            // wide characters.
+            if (self.scrolling_region.right == self.cols - 1) {
+                const src_end_cell: *Cell = @ptrCast(@as([*]Cell, @ptrCast(src_rac.cell)) + p.page.data.size.cols - 1);
+                const dst_end_cell: *Cell = @ptrCast(@as([*]Cell, @ptrCast(dst_rac.cell)) + dst_p.page.data.size.cols - 1);
+                if (dst_end_cell.wide == .spacer_head) {
+                    dst_end_cell.wide = .narrow;
+                }
+                if (src_end_cell.wide == .spacer_head) {
+                    src_end_cell.wide = .narrow;
+                }
+
+                // If our scrolling region is full width, then we unset wrap.
+                if (self.scrolling_region.left == 0) {
+                    dst.wrap = false;
+                    src.wrap = false;
+                }
+            }
 
             // If our page doesn't match, then we need to do a copy from
             // one page to another. This is the slow path.
@@ -1376,9 +1399,6 @@ pub fn insertLines(self: *Terminal, count: usize) void {
                     @panic("TODO");
                 };
 
-                // Row never is wrapped if we're full width.
-                if (!left_right) dst.wrap = false;
-
                 continue;
             }
 
@@ -1389,10 +1409,6 @@ pub fn insertLines(self: *Terminal, count: usize) void {
                 dst.* = src.*;
                 src.* = dst_row;
 
-                // Row never is wrapped
-                dst.wrap = false;
-                src.wrap = false;
-
                 // Ensure what we did didn't corrupt the page
                 p.page.data.assertIntegrity();
                 continue;
@@ -1407,9 +1423,6 @@ pub fn insertLines(self: *Terminal, count: usize) void {
                 self.scrolling_region.left,
                 (self.scrolling_region.right - self.scrolling_region.left) + 1,
             );
-
-            // Row never is wrapped
-            dst.wrap = false;
         }
 
         // The operations above can prune our cursor style so we need to
@@ -1498,8 +1511,31 @@ pub fn deleteLines(self: *Terminal, count_req: usize) void {
         var it = top.rowIterator(.right_down, bot);
         while (it.next()) |p| {
             const src_p = p.down(count).?;
-            const src: *Row = src_p.rowAndCell().row;
-            const dst: *Row = p.rowAndCell().row;
+            const src_rac = src_p.rowAndCell();
+            const dst_rac = p.rowAndCell();
+            const src: *Row = src_rac.row;
+            const dst: *Row = dst_rac.row;
+
+            // If our scrolling region includes the rightmost column then we
+            // need to turn any spacer heads in to normal empty cells, since
+            // once we move them they no longer correspond with soft-wrapped
+            // wide characters.
+            if (self.scrolling_region.right == self.cols - 1) {
+                const src_end_cell: *Cell = @ptrCast(@as([*]Cell, @ptrCast(src_rac.cell)) + src_p.page.data.size.cols - 1);
+                const dst_end_cell: *Cell = @ptrCast(@as([*]Cell, @ptrCast(dst_rac.cell)) + p.page.data.size.cols - 1);
+                if (dst_end_cell.wide == .spacer_head) {
+                    dst_end_cell.wide = .narrow;
+                }
+                if (src_end_cell.wide == .spacer_head) {
+                    src_end_cell.wide = .narrow;
+                }
+
+                // If our scrolling region is full width, then we unset wrap.
+                if (self.scrolling_region.left == 0) {
+                    dst.wrap = false;
+                    src.wrap = false;
+                }
+            }
 
             if (src_p.page != p.page) {
                 p.page.data.clonePartialRowFrom(
@@ -1513,9 +1549,6 @@ pub fn deleteLines(self: *Terminal, count_req: usize) void {
                     @panic("TODO");
                 };
 
-                // Row never is wrapped if we're full width.
-                if (!left_right) dst.wrap = false;
-
                 continue;
             }
 
@@ -1526,9 +1559,6 @@ pub fn deleteLines(self: *Terminal, count_req: usize) void {
                 dst.* = src.*;
                 src.* = dst_row;
 
-                // Row never is wrapped
-                dst.wrap = false;
-
                 // Ensure what we did didn't corrupt the page
                 p.page.data.assertIntegrity();
                 continue;
@@ -1543,9 +1573,6 @@ pub fn deleteLines(self: *Terminal, count_req: usize) void {
                 self.scrolling_region.left,
                 (self.scrolling_region.right - self.scrolling_region.left) + 1,
             );
-
-            // Row never is wrapped
-            dst.wrap = false;
         }
 
         // The operations above can prune our cursor style so we need to