From 6fa4cb07c75ce5b02e535a48b9a63e86ccded623 Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <mitchell.hashimoto@gmail.com>
Date: Mon, 8 Aug 2022 13:56:09 -0700
Subject: [PATCH] more cursor reflow

---
 src/terminal/Screen.zig | 66 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 63 insertions(+), 3 deletions(-)

diff --git a/src/terminal/Screen.zig b/src/terminal/Screen.zig
index 2fa93deab..18f242eb0 100644
--- a/src/terminal/Screen.zig
+++ b/src/terminal/Screen.zig
@@ -539,8 +539,7 @@ pub fn resize(self: *Screen, alloc: Allocator, rows: usize, cols: usize) !void {
 
                         // If our cursor is in this line, then we have to move it
                         // onto the new line because it got unwrapped.
-                        if (cursor_pos.y == iter.value - 1) {
-                            assert(new_cursor == null); // should only happen once
+                        if (cursor_pos.y == iter.value - 1 and new_cursor == null) {
                             new_cursor = .{ .y = y, .x = cursor_pos.x + x };
                         }
 
@@ -570,7 +569,6 @@ pub fn resize(self: *Screen, alloc: Allocator, rows: usize, cols: usize) !void {
                     if (cursor_pos.y == iter.value - 1 and
                         cursor_pos.x < new_row.len)
                     {
-                        if (true) @panic("IN FLOW"); // TODO: to test
                         assert(new_cursor == null); // should only happen once
                         new_cursor = .{ .y = y, .x = x + cursor_pos.x };
                     }
@@ -619,6 +617,11 @@ pub fn resize(self: *Screen, alloc: Allocator, rows: usize, cols: usize) !void {
         alloc.free(self.storage);
         self.storage = storage;
 
+        // If our cursor was past the end of our old value, we pull it back.
+        if (self.cursor.y >= rows) {
+            self.cursor.y -= self.rows - rows;
+        }
+
         // Fix our row count
         self.rows = rows;
 
@@ -1365,6 +1368,11 @@ test "Screen: resize more cols with reflow that forces more wrapping" {
     const str = "1ABCD2EFGH\n3IJKL";
     s.testWriteString(str);
 
+    // Let's put our cursor on row 2, where the soft wrap is
+    s.cursor.x = 0;
+    s.cursor.y = 1;
+    try testing.expectEqual(@as(u32, '2'), s.getCell(s.cursor.y, s.cursor.x).char);
+
     // Verify we soft wrapped
     {
         var contents = try s.testString(alloc, .viewport);
@@ -1381,6 +1389,10 @@ test "Screen: resize more cols with reflow that forces more wrapping" {
         const expected = "1ABCD2E\nFGH\n3IJKL";
         try testing.expectEqualStrings(expected, 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 unwraps multiple times" {
@@ -1392,6 +1404,11 @@ test "Screen: resize more cols with reflow that unwraps multiple times" {
     const str = "1ABCD2EFGH3IJKL";
     s.testWriteString(str);
 
+    // Let's put our cursor on row 2, where the soft wrap is
+    s.cursor.x = 0;
+    s.cursor.y = 2;
+    try testing.expectEqual(@as(u32, '3'), s.getCell(s.cursor.y, s.cursor.x).char);
+
     // Verify we soft wrapped
     {
         var contents = try s.testString(alloc, .viewport);
@@ -1408,6 +1425,10 @@ test "Screen: resize more cols with reflow that unwraps multiple times" {
         const expected = "1ABCD2EFGH3IJKL";
         try testing.expectEqualStrings(expected, contents);
     }
+
+    // Our cursor should've moved
+    try testing.expectEqual(@as(usize, 10), s.cursor.x);
+    try testing.expectEqual(@as(usize, 0), s.cursor.y);
 }
 
 test "Screen: resize less rows no scrollback" {
@@ -1418,8 +1439,47 @@ test "Screen: resize less rows no scrollback" {
     defer s.deinit(alloc);
     const str = "1ABCD\n2EFGH\n3IJKL";
     s.testWriteString(str);
+    const cursor = s.cursor;
     try s.resize(alloc, 1, 5);
 
+    // Cursor should not move
+    try testing.expectEqual(cursor, s.cursor);
+
+    {
+        var contents = try s.testString(alloc, .viewport);
+        defer alloc.free(contents);
+        const expected = "3IJKL";
+        try testing.expectEqualStrings(expected, contents);
+    }
+    {
+        var contents = try s.testString(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, 3, 5, 0);
+    defer s.deinit(alloc);
+    const str = "1ABCD\n2EFGH\n3IJKL";
+    s.testWriteString(str);
+
+    // Put our cursor on the last line
+    s.cursor.x = 1;
+    s.cursor.y = 2;
+    try testing.expectEqual(@as(u32, 'I'), s.getCell(s.cursor.y, s.cursor.x).char);
+
+    // Resize
+    try s.resize(alloc, 1, 5);
+
+    // Cursor should be on the last line
+    try testing.expectEqual(@as(usize, 1), s.cursor.x);
+    try testing.expectEqual(@as(usize, 0), s.cursor.y);
+
     {
         var contents = try s.testString(alloc, .viewport);
         defer alloc.free(contents);