terminal: Screen clone should preserve selection order

src/terminal/Screen.zig

@@ -263,12 +263,28 @@ pub fn clonePool(
     // Preserve our selection if we have one.
     const sel: ?Selection = if (self.selection) |sel| sel: {
         assert(sel.tracked());
-        const start_pin = pin_remap.get(sel.bounds.tracked.start) orelse start: {
+
+        const ordered: struct {
+            tl: *Pin,
+            br: *Pin,
+        } = switch (sel.order(self)) {
+            .forward, .mirrored_forward => .{
+                .tl = sel.bounds.tracked.start,
+                .br = sel.bounds.tracked.end,
+            },
+            .reverse, .mirrored_reverse => .{
+                .tl = sel.bounds.tracked.end,
+                .br = sel.bounds.tracked.start,
+            },
+        };
+
+        const start_pin = pin_remap.get(ordered.tl) orelse start: {
             // No start means it is outside the cloned area. We change it
             // to the top-left.
             break :start try pages.trackPin(.{ .page = pages.pages.first.? });
         };
-        const end_pin = pin_remap.get(sel.bounds.tracked.end) orelse end: {
+
+        const end_pin = pin_remap.get(ordered.br) orelse end: {
             // No end means it is outside the cloned area. We change it
             // to the bottom-right.
             break :end try pages.trackPin(pages.pin(.{ .active = .{
@@ -276,6 +292,7 @@ pub fn clonePool(
                 .y = pages.rows - 1,
             } }) orelse break :sel null);
         };
+
         break :sel .{
             .bounds = .{ .tracked = .{
                 .start = start_pin,
@@ -2877,6 +2894,43 @@ test "Screen: clone contains selection end cutoff" {
     }
 }
 
+test "Screen: clone contains selection end cutoff reversed" {
+    const testing = std.testing;
+    const alloc = testing.allocator;
+
+    var s = try init(alloc, 5, 3, 1);
+    defer s.deinit();
+    try s.testWriteString("1ABCD\n2EFGH\n3IJKL");
+
+    // Select a single line
+    try s.select(Selection.init(
+        s.pages.pin(.{ .active = .{ .x = 2, .y = 2 } }).?,
+        s.pages.pin(.{ .active = .{ .x = 0, .y = 1 } }).?,
+        false,
+    ));
+
+    // Clone
+    var s2 = try s.clone(
+        alloc,
+        .{ .active = .{ .y = 0 } },
+        .{ .active = .{ .y = 1 } },
+    );
+    defer s2.deinit();
+
+    // Our selection should remain valid
+    {
+        const sel = s2.selection.?;
+        try testing.expectEqual(point.Point{ .active = .{
+            .x = 0,
+            .y = 1,
+        } }, s2.pages.pointFromPin(.active, sel.start()).?);
+        try testing.expectEqual(point.Point{ .active = .{
+            .x = s2.pages.cols - 1,
+            .y = 2,
+        } }, s2.pages.pointFromPin(.active, sel.end()).?);
+    }
+}
+
 test "Screen: clone basic" {
     const testing = std.testing;
     const alloc = testing.allocator;