fix(compatibility): fix vim overwrite message and buffer clearing on exit (#98)

* fix(compatibility): fix vim overwrite message and buffer clearing on exit

* style(formatting): make rustfmt happy

9 files changed, 265 insertions, 24 deletions

diff --git a/src/terminal_pane/scroll.rs b/src/terminal_pane/scroll.rs
index e9801ef0..b6f66be9 100644
--- a/src/terminal_pane/scroll.rs
+++ b/src/terminal_pane/scroll.rs
@@ -248,7 +248,7 @@ impl Debug for WrappedFragment {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, Clone, Copy)]
 pub struct CursorPosition {
     line_index: (usize, usize), // (canonical line index, fragment index in line)
     column_index: usize,        // 0 is the first character from the pane edge
@@ -312,6 +312,8 @@ pub struct Scroll {
     viewport_bottom_offset: Option<usize>,
     scroll_region: Option<(usize, usize)>, // start line, end line (if set, this is the area the will scroll)
     show_cursor: bool,
+    lines_outside_of_scroll_region: Option<Vec<CanonicalLine>>,
+    cursor_position_outside_of_scroll_region: Option<CursorPosition>,
 }
 
 impl Scroll {
@@ -327,6 +329,8 @@ impl Scroll {
             viewport_bottom_offset: None,
             scroll_region: None,
             show_cursor: true,
+            lines_outside_of_scroll_region: None,
+            cursor_position_outside_of_scroll_region: None,
         }
     }
     pub fn as_character_lines(&self) -> Vec<Vec<TerminalCharacter>> {
@@ -393,7 +397,9 @@ impl Scroll {
     }
     pub fn add_canonical_line(&mut self) {
         let current_canonical_line_index = self.cursor_position.line_index.0;
-        if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
+        if let Some((scroll_region_top, scroll_region_bottom)) =
+            self.scroll_region_absolute_indices()
+        {
             if current_canonical_line_index == scroll_region_bottom {
                 // end of scroll region
                 // when we have a scroll region set and we're at its bottom
@@ -500,17 +506,15 @@ impl Scroll {
         self.cursor_position.move_up_by_canonical_lines(count);
     }
     pub fn change_size(&mut self, columns: usize, lines: usize) {
-        if self.scroll_region.is_none() {
-            for canonical_line in self.canonical_lines.iter_mut() {
-                canonical_line.change_width(columns);
-            }
-            let cursor_line = self
-                .canonical_lines
-                .get(self.cursor_position.line_index.0)
-                .expect("cursor out of bounds");
-            if cursor_line.wrapped_fragments.len() <= self.cursor_position.line_index.1 {
-                self.cursor_position.line_index.1 = cursor_line.wrapped_fragments.len() - 1;
-            }
+        for canonical_line in self.canonical_lines.iter_mut() {
+            canonical_line.change_width(columns);
+        }
+        let cursor_line = self
+            .canonical_lines
+            .get(self.cursor_position.line_index.0)
+            .expect("cursor out of bounds");
+        if cursor_line.wrapped_fragments.len() <= self.cursor_position.line_index.1 {
+            self.cursor_position.line_index.1 = cursor_line.wrapped_fragments.len() - 1;
         }
         self.lines_in_view = lines;
         self.total_columns = columns;
@@ -597,13 +601,18 @@ impl Scroll {
         self.cursor_position.reset();
     }
     pub fn move_cursor_to(&mut self, line: usize, col: usize) {
-        if self.canonical_lines.len() > line {
-            self.cursor_position.move_to_canonical_line(line);
+        let line_on_screen = if self.canonical_lines.len() > self.lines_in_view {
+            line + (self.canonical_lines.len() - self.lines_in_view)
+        } else {
+            line
+        };
+        if self.canonical_lines.len() > line_on_screen {
+            self.cursor_position.move_to_canonical_line(line_on_screen);
         } else {
-            for _ in self.canonical_lines.len()..=line {
+            for _ in self.canonical_lines.len()..=line_on_screen {
                 self.canonical_lines.push(CanonicalLine::new());
             }
-            self.cursor_position.move_to_canonical_line(line);
+            self.cursor_position.move_to_canonical_line(line_on_screen);
         }
         let (current_canonical_line_index, current_line_wrap_position) =
             self.cursor_position.line_index;
@@ -630,14 +639,48 @@ impl Scroll {
         self.move_cursor_to(line, current_column);
     }
     pub fn set_scroll_region(&mut self, top_line: usize, bottom_line: usize) {
+        if self.scroll_region.is_none() {
+            self.lines_outside_of_scroll_region = Some(self.canonical_lines.drain(..).collect());
+            self.cursor_position_outside_of_scroll_region = Some(self.cursor_position);
+        }
         self.scroll_region = Some((top_line, bottom_line));
-        // TODO: clear linewraps in scroll region?
     }
     pub fn clear_scroll_region(&mut self) {
-        self.scroll_region = None;
+        if let Some(scroll_region) = self.scroll_region_absolute_indices() {
+            self.canonical_lines.drain(scroll_region.0..scroll_region.1);
+            self.cursor_position.reset();
+            self.scroll_region = None;
+        }
+        if let Some(lines_outside_of_scroll_region) = self.lines_outside_of_scroll_region.as_mut() {
+            self.canonical_lines = lines_outside_of_scroll_region.drain(..).collect();
+        }
+        if let Some(cursor_position_outside_of_scroll_region) =
+            self.cursor_position_outside_of_scroll_region
+        {
+            self.cursor_position = cursor_position_outside_of_scroll_region;
+        }
+        self.lines_outside_of_scroll_region = None;
+        self.cursor_position_outside_of_scroll_region = None;
+    }
+    pub fn set_scroll_region_to_screen_size(&mut self) {
+        self.scroll_region = Some((0, self.lines_in_view - 1)); // these are indices
+    }
+    fn scroll_region_absolute_indices(&mut self) -> Option<(usize, usize)> {
+        if self.scroll_region.is_none() {
+            return None;
+        };
+        if self.canonical_lines.len() > self.lines_in_view {
+            let absolute_top = self.canonical_lines.len() - 1 - self.lines_in_view;
+            let absolute_bottom = self.canonical_lines.len() - 1;
+            Some((absolute_top, absolute_bottom))
+        } else {
+            Some((self.scroll_region.unwrap().0, self.scroll_region.unwrap().1))
+        }
     }
     pub fn delete_lines_in_scroll_region(&mut self, count: usize) {
-        if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
+        if let Some((scroll_region_top, scroll_region_bottom)) =
+            self.scroll_region_absolute_indices()
+        {
             let current_canonical_line_index = self.cursor_position.line_index.0;
             if current_canonical_line_index >= scroll_region_top
                 && current_canonical_line_index <= scroll_region_bottom
@@ -655,7 +698,9 @@ impl Scroll {
         }
     }
     pub fn add_empty_lines_in_scroll_region(&mut self, count: usize) {
-        if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
+        if let Some((scroll_region_top, scroll_region_bottom)) =
+            self.scroll_region_absolute_indices()
+        {
             let current_canonical_line_index = self.cursor_position.line_index.0;
             if current_canonical_line_index >= scroll_region_top
                 && current_canonical_line_index <= scroll_region_bottom
@@ -673,7 +718,9 @@ impl Scroll {
         }
     }
     pub fn move_cursor_up_in_scroll_region(&mut self, count: usize) {
-        if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
+        if let Some((scroll_region_top, scroll_region_bottom)) =
+            self.scroll_region_absolute_indices()
+        {
             // the scroll region indices start at 1, so we need to adjust them
             for _ in 0..count {
                 let current_canonical_line_index = self.cursor_position.line_index.0;
@@ -694,7 +741,7 @@ impl Scroll {
     /// [scroll_up](https://github.com/alacritty/alacritty/blob/ec42b42ce601808070462111c0c28edb0e89babb/alacritty_terminal/src/grid/mod.rs#L261)
     /// This function takes the first line of the scroll region and moves it to the bottom (count times)
     pub fn rotate_scroll_region_up(&mut self, count: usize) {
-        if let Some((_, scroll_region_bottom)) = self.scroll_region {
+        if let Some((_, scroll_region_bottom)) = self.scroll_region_absolute_indices() {
             if self.show_cursor {
                 let scroll_region_bottom_index = scroll_region_bottom - 1;
                 self.cursor_position
@@ -714,7 +761,7 @@ impl Scroll {
     /// [scroll_down](https://github.com/alacritty/alacritty/blob/ec42b42ce601808070462111c0c28edb0e89babb/alacritty_terminal/src/grid/mod.rs#L221)
     /// This function takes the last line of the scroll region and moves it to the top (count times)
     pub fn rotate_scroll_region_down(&mut self, count: usize) {
-        if let Some((scroll_region_top, _)) = self.scroll_region {
+        if let Some((scroll_region_top, _)) = self.scroll_region_absolute_indices() {
             if self.show_cursor {
                 let scroll_region_top_index = scroll_region_top - 1;
                 self.cursor_position
diff --git a/src/terminal_pane/terminal_pane.rs b/src/terminal_pane/terminal_pane.rs
index a6b4b346..6754974c 100644
--- a/src/terminal_pane/terminal_pane.rs
+++ b/src/terminal_pane/terminal_pane.rs
@@ -443,6 +443,15 @@ impl vte::Perform for TerminalPane {
                     (params[0] as usize - 1, params[1] as usize - 1)
                 }
             };
+            if params.len() >= 1 && params[0] == 0 {
+                // this is a hack
+                //
+                // the logic should *probably* be:
+                // if we get an instruction to move outside the scroll region
+                // (which is 1 indexed, so if we get 0 it's always(?) outside)
+                // we need to set it to screen size
+                self.scroll.set_scroll_region_to_screen_size();
+            }
             self.scroll.move_cursor_to(row, col);
         } else if c == 'A' {
             // move cursor up until edge of screen
diff --git a/src/tests/fixtures/clear_scroll_region b/src/tests/fixtures/clear_scroll_region
new file mode 100644
index 00000000..d4741364
--- /dev/null
+++ b/src/tests/fixtures/clear_scroll_region
diff --git a/src/tests/fixtures/vim_overwrite b/src/tests/fixtures/vim_overwrite
new file mode 100644
index 00000000..3a804d64
--- /dev/null
+++ b/src/tests/fixtures/vim_overwrite
diff --git a/src/tests/integration/compatibility.rs b/src/tests/integration/compatibility.rs
index 114c10d2..1df46583 100644
--- a/src/tests/integration/compatibility.rs
+++ b/src/tests/integration/compatibility.rs
@@ -260,3 +260,60 @@ pub fn htop_right_scrolling() {
         assert_snapshot!(snapshot);
     }
 }
+
+#[test]
+pub fn vim_overwrite() {
+    // this tests the vim overwrite message
+    // to recreate:
+    // * open a file in vim
+    // * open the same file in another window
+    // * change the file in the other window and save
+    // * change the file in the original vim window and save
+    // * confirm you would like to change the file by pressing 'y' and then ENTER
+    // * if everything looks fine, this test passed :)
+    let fake_win_size = PositionAndSize {
+        columns: 116,
+        rows: 28,
+        x: 0,
+        y: 0,
+    };
+    let fixture_name = "vim_overwrite";
+    let mut fake_input_output = get_fake_os_input(&fake_win_size, fixture_name);
+    fake_input_output.add_terminal_input(&[&COMMAND_TOGGLE, &COMMAND_TOGGLE, &QUIT]);
+    start(Box::new(fake_input_output.clone()), Opt::default());
+    let output_frames = fake_input_output
+        .stdout_writer
+        .output_frames
+        .lock()
+        .unwrap();
+    let snapshots = get_output_frame_snapshots(&output_frames, &fake_win_size);
+    for snapshot in snapshots {
+        assert_snapshot!(snapshot);
+    }
+}
+
+#[test]
+pub fn clear_scroll_region() {
+    // this tests the scroll region used by eg. vim is cleared properly
+    // this means that when vim exits, we get back the previous scroll
+    // buffer
+    let fake_win_size = PositionAndSize {
+        columns: 116,
+        rows: 28,
+        x: 0,
+        y: 0,
+    };
+    let fixture_name = "clear_scroll_region";
+    let mut fake_input_output = get_fake_os_input(&fake_win_size, fixture_name);
+    fake_input_output.add_terminal_input(&[&COMMAND_TOGGLE, &COMMAND_TOGGLE, &QUIT]);
+    start(Box::new(fake_input_output.clone()), Opt::default());
+    let output_frames = fake_input_output
+        .stdout_writer
+        .output_frames
+        .lock()
+        .unwrap();
+    let snapshots = get_output_frame_snapshots(&output_frames, &fake_win_size);
+    for snapshot in snapshots {
+        assert_snapshot!(snapshot);
+    }
+}
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__clear_scroll_region-2.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__clear_scroll_region-2.snap
new file mode 100644
index 00000000..8c309266
--- /dev/null
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__clear_scroll_region-2.snap
@@ -0,0 +1,32 @@
+---
+source: src/tests/integration/compatibility.rs
+expression: snapshot
+---
+⋊> ~/c/mosaic on main ⨯ vim some-file                                                                       15:07:22
+⋊> ~/c/mosaic on main ⨯                                                                                     15:07:29
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+Bye from Mosaic!█                                                                                                   
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__clear_scroll_region.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__clear_scroll_region.snap
new file mode 100644
index 00000000..3a7b2d5e
--- /dev/null
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__clear_scroll_region.snap
@@ -0,0 +1,32 @@
+---
+source: src/tests/integration/compatibility.rs
+expression: snapshot
+---
+Welcome to fish, the friendly interactive shell                                                                     
+⋊> ~/c/mosaic on main ⨯ vim some-file                                                                       15:07:22
+⋊> ~/c/mosaic on main ⨯ █                                                                                   15:07:29
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
+                                                                                                                    
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__vim_overwrite-2.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__vim_overwrite-2.snap
new file mode 100644
index 00000000..7edfc74d
--- /dev/null
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__vim_overwrite-2.snap
@@ -0,0 +1,32 @@
+---
+source: src/tests/integration/compatibility.rs
+expression: snapshot
+---
+  1 line 1                                                                                                          
+  2 line 2                                                                                                          
+  3 line 3                                                                                                          
+  4 line 4                                                                                                          
+  5 line 5                                                                                                          
+  6 line 6                                                                                                          
+  7 line 7                                                                                                          
+  8 line 8                                                                                                          
+  9 line 9                                                                                                          
+ 10 line 10                                                                                                         
+ 11 line 11                                                                                                         
+ 12 line 12                                                                                                         
+ 13 line 13                                                                                                         
+ 14 line 14                                                                                                         
+ 15 line 15                                                                                                         
+ 16 line 16                                                                                                         
+ 17 line 17                                                                                                         
+ 18 line 18                                                                                                         
+ 19 line 19                                                                                                         
+ 20 line 20                                                                                                         
+ 21 line 21                                                                                                         
+ 22 line 22                                                                                                         
+ 23 line 23                                                                                                         
+ 24 line 24                                                                                                         
+ 25 line 25                                                                                                         
+ NORMAL  some-file                                                               unix | utf-8 | no ft    1%    1:1  
+                                                                                                                    
+Bye from Mosaic!█                                                                                                   
diff --git a/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__vim_overwrite.snap b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__vim_overwrite.snap
new file mode 100644
index 00000000..406b5b31
--- /dev/null
+++ b/src/tests/integration/snapshots/mosaic__tests__integration__compatibility__vim_overwrite.snap
@@ -0,0 +1,32 @@
+---
+source: src/tests/integration/compatibility.rs
+expression: snapshot
+---
+1   █                                                                                                               
+  1 line 1                                                                                                          
+  2 line 2                                                                                                          
+  3 line 3                                                                                                          
+  4 line 4                                                                                                          
+  5 line 5                                                                                                          
+  6 line 6                                                                                                          
+  7 line 7                                                                                                          
+  8 line 8                                                                                                          
+  9 line 9                                                                                                          
+ 10 line 10                                                                                                         
+ 11 line 11                                                                                                         
+ 12 line 12                                                                                                         
+ 13 line 13                                                                                                         
+ 14 line 14                                                                                                         
+ 15 line 15                                                                                                         
+ 16 line 16                                                                                                         
+ 17 line 17                                                                                                         
+ 18 line 18                                                                                                         
+ 19 line 19                                                                                                         
+ 20 line 20                                                                                                         
+ 21 line 21                                                                                                         
+ 22 line 22                                                                                                         
+ 23 line 23                                                                                                         
+ 24 line 24                                                                                                         
+ 25 line 25                                                                                                         
+ NORMAL  some-file                                                               unix | utf-8 | no ft    1%    1:1  
+