feature(mouse): forward mouse events (#1191)

* handle sgr mouse mode enable by applications

* forward mouse events

* fix scroll events not forwarded to floating panes

* improve mouse hold/release with floating panes

4 files changed, 132 insertions, 28 deletions

diff --git a/zellij-server/src/panes/grid.rs b/zellij-server/src/panes/grid.rs
index dedf93412..fe1a81ea0 100644
--- a/zellij-server/src/panes/grid.rs
+++ b/zellij-server/src/panes/grid.rs
@@ -306,6 +306,7 @@ pub struct Grid {
     pub link_handler: Rc<RefCell<LinkHandler>>,
     pub ring_bell: bool,
     scrollback_buffer_lines: usize,
+    pub mouse_mode: bool,
 }
 
 impl Debug for Grid {
@@ -363,6 +364,7 @@ impl Grid {
             link_handler,
             ring_bell: false,
             scrollback_buffer_lines: 0,
+            mouse_mode: false,
         }
     }
     pub fn render_full_viewport(&mut self) {
@@ -1773,6 +1775,9 @@ impl Perform for Grid {
                     Some(7) => {
                         self.disable_linewrap = true;
                     }
+                    Some(1006) => {
+                        self.mouse_mode = false;
+                    }
                     _ => {}
                 };
             } else if let Some(4) = params_iter.next().map(|param| param[0]) {
@@ -1826,6 +1831,9 @@ impl Perform for Grid {
                     Some(7) => {
                         self.disable_linewrap = false;
                     }
+                    Some(1006) => {
+                        self.mouse_mode = true;
+                    }
                     _ => {}
                 };
             } else if let Some(4) = params_iter.next().map(|param| param[0]) {
diff --git a/zellij-server/src/panes/plugin_pane.rs b/zellij-server/src/panes/plugin_pane.rs
index f5a11c845..8b21c8333 100644
--- a/zellij-server/src/panes/plugin_pane.rs
+++ b/zellij-server/src/panes/plugin_pane.rs
@@ -401,4 +401,7 @@ impl Pane for PluginPane {
             ))
             .unwrap();
     }
+    fn mouse_mode(&self) -> bool {
+        false
+    }
 }
diff --git a/zellij-server/src/panes/terminal_pane.rs b/zellij-server/src/panes/terminal_pane.rs
index eca769869..5ac94c4f3 100644
--- a/zellij-server/src/panes/terminal_pane.rs
+++ b/zellij-server/src/panes/terminal_pane.rs
@@ -472,6 +472,10 @@ impl Pane for TerminalPane {
     fn borderless(&self) -> bool {
         self.borderless
     }
+
+    fn mouse_mode(&self) -> bool {
+        self.grid.mouse_mode
+    }
 }
 
 impl TerminalPane {
diff --git a/zellij-server/src/tab/mod.rs b/zellij-server/src/tab/mod.rs
index d304aa61c..e33141f61 100644
--- a/zellij-server/src/tab/mod.rs
+++ b/zellij-server/src/tab/mod.rs
@@ -289,6 +289,7 @@ pub trait Pane {
     fn set_borderless(&mut self, borderless: bool);
     fn borderless(&self) -> bool;
     fn handle_right_click(&mut self, _to: &Position, _client_id: ClientId) {}
+    fn mouse_mode(&self) -> bool;
 }
 
 impl Tab {
@@ -975,6 +976,20 @@ impl Tab {
         };
         self.write_to_pane_id(input_bytes, pane_id);
     }
+    pub fn write_to_terminal_at(&mut self, input_bytes: Vec<u8>, position: &Position) {
+        if self.floating_panes.panes_are_visible() {
+            let pane_id = self.floating_panes.get_pane_id_at(position, false);
+            if let Some(pane_id) = pane_id {
+                self.write_to_pane_id(input_bytes, pane_id);
+                return;
+            }
+        }
+
+        let pane_id = self.get_pane_id_at(position, false);
+        if let Some(pane_id) = pane_id {
+            self.write_to_pane_id(input_bytes, pane_id);
+        }
+    }
     pub fn write_to_pane_id(&mut self, input_bytes: Vec<u8>, pane_id: PaneId) {
         match pane_id {
             PaneId::Terminal(active_terminal_id) => {
@@ -2288,15 +2303,35 @@ impl Tab {
     }
     pub fn scroll_terminal_up(&mut self, point: &Position, lines: usize, client_id: ClientId) {
         if let Some(pane) = self.get_pane_at(point, false) {
-            pane.scroll_up(lines, client_id);
+            if pane.mouse_mode() {
+                let relative_position = pane.relative_position(point);
+                let mouse_event = format!(
+                    "\u{1b}[<64;{:?};{:?}M",
+                    relative_position.column.0 + 1,
+                    relative_position.line.0 + 1
+                );
+                self.write_to_terminal_at(mouse_event.into_bytes(), point);
+            } else {
+                pane.scroll_up(lines, client_id);
+            }
         }
     }
     pub fn scroll_terminal_down(&mut self, point: &Position, lines: usize, client_id: ClientId) {
         if let Some(pane) = self.get_pane_at(point, false) {
-            pane.scroll_down(lines, client_id);
-            if !pane.is_scrolled() {
-                if let PaneId::Terminal(pid) = pane.pid() {
-                    self.process_pending_vte_events(pid);
+            if pane.mouse_mode() {
+                let relative_position = pane.relative_position(point);
+                let mouse_event = format!(
+                    "\u{1b}[<65;{:?};{:?}M",
+                    relative_position.column.0 + 1,
+                    relative_position.line.0 + 1
+                );
+                self.write_to_terminal_at(mouse_event.into_bytes(), point);
+            } else {
+                pane.scroll_down(lines, client_id);
+                if !pane.is_scrolled() {
+                    if let PaneId::Terminal(pid) = pane.pid() {
+                        self.process_pending_vte_events(pid);
+                    }
                 }
             }
         }
@@ -2348,8 +2383,18 @@ impl Tab {
 
         if let Some(pane) = self.get_pane_at(position, false) {
             let relative_position = pane.relative_position(position);
-            pane.start_selection(&relative_position, client_id);
-            self.selecting_with_mouse = true;
+
+            if pane.mouse_mode() {
+                let mouse_event = format!(
+                    "\u{1b}[<0;{:?};{:?}M",
+                    relative_position.column.0 + 1,
+                    relative_position.line.0 + 1
+                );
+                self.write_to_active_terminal(mouse_event.into_bytes(), client_id);
+            } else {
+                pane.start_selection(&relative_position, client_id);
+                self.selecting_with_mouse = true;
+            }
         };
     }
     pub fn handle_right_click(&mut self, position: &Position, client_id: ClientId) {
@@ -2357,7 +2402,16 @@ impl Tab {
 
         if let Some(pane) = self.get_pane_at(position, false) {
             let relative_position = pane.relative_position(position);
-            pane.handle_right_click(&relative_position, client_id);
+            if pane.mouse_mode() {
+                let mouse_event = format!(
+                    "\u{1b}[<2;{:?};{:?}M",
+                    relative_position.column.0 + 1,
+                    relative_position.line.0 + 1
+                );
+                self.write_to_active_terminal(mouse_event.into_bytes(), client_id);
+            } else {
+                pane.handle_right_click(&relative_position, client_id);
+            }
         };
     }
     fn focus_pane_at(&mut self, point: &Position, client_id: ClientId) {
@@ -2392,38 +2446,73 @@ impl Tab {
         }
     }
     pub fn handle_mouse_release(&mut self, position: &Position, client_id: ClientId) {
-        if self.selecting_with_mouse {
-            let mut selected_text = None;
-            let active_pane = self.get_active_pane_or_floating_pane_mut(client_id);
-            if let Some(active_pane) = active_pane {
-                let relative_position = active_pane.relative_position(position);
+        if self.floating_panes.panes_are_visible()
+            && self.floating_panes.pane_is_being_moved_with_mouse()
+        {
+            self.floating_panes.stop_moving_pane_with_mouse(*position);
+            return;
+        }
+
+        let selecting = self.selecting_with_mouse;
+        let active_pane = self.get_active_pane_or_floating_pane_mut(client_id);
+
+        if let Some(active_pane) = active_pane {
+            let relative_position = active_pane.relative_position(position);
+            if active_pane.mouse_mode() {
+                // ensure that coordinates are valid
+                let col = (relative_position.column.0 + 1)
+                    .max(1)
+                    .min(active_pane.get_content_columns());
+
+                let line = (relative_position.line.0 + 1)
+                    .max(1)
+                    .min(active_pane.get_content_rows() as isize);
+                let mouse_event = format!("\u{1b}[<0;{:?};{:?}m", col, line);
+                self.write_to_active_terminal(mouse_event.into_bytes(), client_id);
+            } else if selecting {
                 active_pane.end_selection(&relative_position, client_id);
-                selected_text = active_pane.get_selected_text();
+                let selected_text = active_pane.get_selected_text();
                 active_pane.reset_selection();
+                if let Some(selected_text) = selected_text {
+                    self.write_selection_to_clipboard(&selected_text);
+                }
+                self.selecting_with_mouse = false;
             }
-
-            if let Some(selected_text) = selected_text {
-                self.write_selection_to_clipboard(&selected_text);
-            }
-            self.selecting_with_mouse = false;
-        } else if self.floating_panes.panes_are_visible() {
-            self.floating_panes.stop_moving_pane_with_mouse(*position);
         }
     }
     pub fn handle_mouse_hold(&mut self, position_on_screen: &Position, client_id: ClientId) {
         let search_selectable = true;
-        if self.selecting_with_mouse {
-            let active_pane = self.get_active_pane_or_floating_pane_mut(client_id);
-            if let Some(active_pane) = active_pane {
-                let relative_position = active_pane.relative_position(position_on_screen);
-                active_pane.update_selection(&relative_position, client_id);
-            }
-        } else if self.floating_panes.panes_are_visible()
+
+        if self.floating_panes.panes_are_visible()
+            && self.floating_panes.pane_is_being_moved_with_mouse()
             && self
                 .floating_panes
                 .move_pane_with_mouse(*position_on_screen, search_selectable)
         {
             self.set_force_render();
+            return;
+        }
+
+        let selecting = self.selecting_with_mouse;
+        let active_pane = self.get_active_pane_or_floating_pane_mut(client_id);
+
+        if let Some(active_pane) = active_pane {
+            let relative_position = active_pane.relative_position(position_on_screen);
+            if active_pane.mouse_mode() {
+                // ensure that coordinates are valid
+                let col = (relative_position.column.0 + 1)
+                    .max(1)
+                    .min(active_pane.get_content_columns());
+
+                let line = (relative_position.line.0 + 1)
+                    .max(1)
+                    .min(active_pane.get_content_rows() as isize);
+
+                let mouse_event = format!("\u{1b}[<32;{:?};{:?}M", col, line);
+                self.write_to_active_terminal(mouse_event.into_bytes(), client_id);
+            } else if selecting {
+                active_pane.update_selection(&relative_position, client_id);
+            }
         }
     }