feat(scroll): edit scrollback with default editor (#1456)

* initial commit for opening the current buffer in an editor

* fix(editor): take hidden panes into consideration when manipulating tiled grid

* when closing an edit buffer, take the geometry of the replaced buffer from the closed buffer

* if the floating panels are displayed, don't add to hidden panels the current buffer

* strategy changing - put the panels inside a suppressed_panels HashMap instead of hidden_panels

* Revert "strategy changing - put the panels inside a suppressed_panels HashMap instead of hidden_panels"

This reverts commit c52a203a20cf4c87c147be8b9c193ed6458c1038.

* remove the floating panes by moving them to the tiled_panes in hidden_panels

* feat(edit): open editor to correct line and don't crash when none is set

* formatting

* feat(edit): use suppressed panes

* style(fmt): rustfmt and logs

* style(fmt): clean up unused code

* test(editor): integration test for suppressing/closing suppressed pane

* test(e2e): editor e2e test

* style(fmt): rustfmt

* feat(edit): update ui and setup

* style(fmt): rustfmt

* feat(config): allow configuring scrollback_editor explicitly

* style(fmt): rustfmt

* chore(repo): build after merging

Co-authored-by: Aram Drevekenin <aram@poor.dev>

36 files changed, 978 insertions, 59 deletions

diff --git a/Cargo.lock b/Cargo.lock
index b7edee505..9f734a1e7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2727,6 +2727,16 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "936e4b492acfd135421d8dca4b1aa80a7bfc26e702ef3af710e0752684df5372"
 
 [[package]]
+name = "uuid"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bc5cf98d8186244414c848017f0e2676b3fcb46807f6668a97dfe67359a3c4b7"
+dependencies = [
+ "getrandom 0.2.6",
+ "serde",
+]
+
+[[package]]
 name = "value-bag"
 version = "1.0.0-alpha.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -3262,6 +3272,7 @@ dependencies = [
  "typetag",
  "unicode-width",
  "url",
+ "uuid",
  "wasmer",
  "wasmer-wasi",
  "zellij-tile",
diff --git a/docs/MANPAGE.md b/docs/MANPAGE.md
index 8f24bbc5b..877141b9a 100644
--- a/docs/MANPAGE.md
+++ b/docs/MANPAGE.md
@@ -152,6 +152,7 @@ ACTIONS
 * __MoveFocus: <Direction\>__ -  moves focus in the specified direction (Left,
   Right, Up, Down).
 * __DumpScreen: <File\>__ - dumps the screen in the specified file.
+* __EditScrollback__ - replaces the current pane with the scrollback buffer.
 * __ScrollUp__ - scrolls up 1 line in the focused pane.
 * __ScrollDown__ - scrolls down 1 line in the focused pane.
 * __PageScrollUp__ - scrolls up 1 page in the focused pane.
diff --git a/src/tests/e2e/cases.rs b/src/tests/e2e/cases.rs
index 92438525c..00cf27153 100644
--- a/src/tests/e2e/cases.rs
+++ b/src/tests/e2e/cases.rs
@@ -38,6 +38,7 @@ pub const SCROLL_UP_IN_SCROLL_MODE: [u8; 1] = [107]; // k
 pub const SCROLL_DOWN_IN_SCROLL_MODE: [u8; 1] = [106]; // j
 pub const SCROLL_PAGE_UP_IN_SCROLL_MODE: [u8; 1] = [2]; // ctrl-b
 pub const SCROLL_PAGE_DOWN_IN_SCROLL_MODE: [u8; 1] = [6]; // ctrl-f
+pub const EDIT_SCROLLBACK: [u8; 1] = [101]; // e
 
 pub const RESIZE_MODE: [u8; 1] = [14]; // ctrl-n
 pub const RESIZE_DOWN_IN_RESIZE_MODE: [u8; 1] = [106]; // j
@@ -1804,3 +1805,51 @@ pub fn tmux_mode() {
     };
     assert_snapshot!(last_snapshot);
 }
+
+#[test]
+#[ignore]
+pub fn edit_scrollback() {
+    let fake_win_size = Size {
+        cols: 120,
+        rows: 24,
+    };
+
+    let mut test_attempts = 10;
+    let last_snapshot = loop {
+        RemoteRunner::kill_running_sessions(fake_win_size);
+        let mut runner = RemoteRunner::new(fake_win_size).add_step(Step {
+            name: "Split pane to the right",
+            instruction: |mut remote_terminal: RemoteTerminal| -> bool {
+                let mut step_is_complete = false;
+                if remote_terminal.status_bar_appears() && remote_terminal.cursor_position_is(3, 2)
+                {
+                    remote_terminal.send_key(&SCROLL_MODE);
+                    remote_terminal.send_key(&EDIT_SCROLLBACK);
+                    step_is_complete = true;
+                }
+                step_is_complete
+            },
+        });
+        runner.run_all_steps();
+        let last_snapshot = runner.take_snapshot_after(Step {
+            name: "Wait for editor to appear",
+            instruction: |remote_terminal: RemoteTerminal| -> bool {
+                let mut step_is_complete = false;
+                if remote_terminal.snapshot_contains(".dump") {
+                    // the .dump is an indication we get on the bottom line of vi when editing a
+                    // file
+                    // the temp file name is randomly generated, so we don't assert the whole snapshot
+                    step_is_complete = true;
+                }
+                step_is_complete
+            },
+        });
+        if runner.test_timed_out && test_attempts > 0 {
+            test_attempts -= 1;
+            continue;
+        } else {
+            break last_snapshot;
+        }
+    };
+    assert!(last_snapshot.contains(".dump"));
+}
diff --git a/src/tests/e2e/remote_runner.rs b/src/tests/e2e/remote_runner.rs
index 466b18052..564714bb7 100644
--- a/src/tests/e2e/remote_runner.rs
+++ b/src/tests/e2e/remote_runner.rs
@@ -17,6 +17,7 @@ use std::cell::RefCell;
 use std::rc::Rc;
 
 const ZELLIJ_EXECUTABLE_LOCATION: &str = "/usr/src/zellij/x86_64-unknown-linux-musl/release/zellij";
+const SET_ENV_VARIABLES: &str = "EDITOR=/usr/bin/vi";
 const ZELLIJ_LAYOUT_PATH: &str = "/usr/src/zellij/fixtures/layouts";
 const ZELLIJ_DATA_DIR: &str = "/usr/src/zellij/e2e-data";
 const CONNECTION_STRING: &str = "127.0.0.1:2222";
@@ -64,8 +65,8 @@ fn start_zellij(channel: &mut ssh2::Channel) {
     channel
         .write_all(
             format!(
-                "{} --session {} --data-dir {}\n",
-                ZELLIJ_EXECUTABLE_LOCATION, SESSION_NAME, ZELLIJ_DATA_DIR
+                "{} {} --session {} --data-dir {}\n",
+                SET_ENV_VARIABLES, ZELLIJ_EXECUTABLE_LOCATION, SESSION_NAME, ZELLIJ_DATA_DIR
             )
             .as_bytes(),
         )
@@ -78,8 +79,8 @@ fn start_zellij_mirrored_session(channel: &mut ssh2::Channel) {
     channel
         .write_all(
             format!(
-                "{} --session {} --data-dir {} options --mirror-session true\n",
-                ZELLIJ_EXECUTABLE_LOCATION, SESSION_NAME, ZELLIJ_DATA_DIR
+                "{} {} --session {} --data-dir {} options --mirror-session true\n",
+                SET_ENV_VARIABLES, ZELLIJ_EXECUTABLE_LOCATION, SESSION_NAME, ZELLIJ_DATA_DIR
             )
             .as_bytes(),
         )
@@ -92,8 +93,12 @@ fn start_zellij_in_session(channel: &mut ssh2::Channel, session_name: &str, mirr
     channel
         .write_all(
             format!(
-                "{} --session {} --data-dir {} options --mirror-session {}\n",
-                ZELLIJ_EXECUTABLE_LOCATION, session_name, ZELLIJ_DATA_DIR, mirrored
+                "{} {} --session {} --data-dir {} options --mirror-session {}\n",
+                SET_ENV_VARIABLES,
+                ZELLIJ_EXECUTABLE_LOCATION,
+                session_name,
+                ZELLIJ_DATA_DIR,
+                mirrored
             )
             .as_bytes(),
         )
@@ -103,7 +108,13 @@ fn start_zellij_in_session(channel: &mut ssh2::Channel, session_name: &str, mirr
 
 fn attach_to_existing_session(channel: &mut ssh2::Channel, session_name: &str) {
     channel
-        .write_all(format!("{} attach {}\n", ZELLIJ_EXECUTABLE_LOCATION, session_name).as_bytes())
+        .write_all(
+            format!(
+                "{} {} attach {}\n",
+                SET_ENV_VARIABLES, ZELLIJ_EXECUTABLE_LOCATION, session_name
+            )
+            .as_bytes(),
+        )
         .unwrap();
     channel.flush().unwrap();
 }
@@ -113,8 +124,8 @@ fn start_zellij_without_frames(channel: &mut ssh2::Channel) {
     channel
         .write_all(
             format!(
-                "{} --session {} --data-dir {} options --no-pane-frames\n",
-                ZELLIJ_EXECUTABLE_LOCATION, SESSION_NAME, ZELLIJ_DATA_DIR
+                "{} {} --session {} --data-dir {} options --no-pane-frames\n",
+                SET_ENV_VARIABLES, ZELLIJ_EXECUTABLE_LOCATION, SESSION_NAME, ZELLIJ_DATA_DIR
             )
             .as_bytes(),
         )
@@ -127,8 +138,12 @@ fn start_zellij_with_layout(channel: &mut ssh2::Channel, layout_path: &str) {
     channel
         .write_all(
             format!(
-                "{} --layout {} --session {} --data-dir {}\n",
-                ZELLIJ_EXECUTABLE_LOCATION, layout_path, SESSION_NAME, ZELLIJ_DATA_DIR
+                "{} {} --layout {} --session {} --data-dir {}\n",
+                SET_ENV_VARIABLES,
+                ZELLIJ_EXECUTABLE_LOCATION,
+                layout_path,
+                SESSION_NAME,
+                ZELLIJ_DATA_DIR
             )
             .as_bytes(),
         )
diff --git a/src/tests/e2e/snapshots/zellij__tests__e2e__cases__scrolling_inside_a_pane.snap b/src/tests/e2e/snapshots/zellij__tests__e2e__cases__scrolling_inside_a_pane.snap
index 664e881b4..422a5616c 100644
--- a/src/tests/e2e/snapshots/zellij__tests__e2e__cases__scrolling_inside_a_pane.snap
+++ b/src/tests/e2e/snapshots/zellij__tests__e2e__cases__scrolling_inside_a_pane.snap
@@ -1,7 +1,7 @@
 ---
 source: src/tests/e2e/cases.rs
+assertion_line: 295
 expression: last_snapshot
-
 ---
  Zellij (e2e-test)  Tab #1                                                                                            
 ┌ Pane #1 ─────────────────────────────────────────────────┐┌ Pane #2 ─────────────────────────────────── SCROLL:  1/1 ┐
@@ -26,4 +26,4 @@ expression: last_snapshot
 │                                                          ││line19 00000000000000000000000000000000000000000000000000█│
 └──────────────────────────────────────────────────────────┘└──────────────────────────────────────────────────────────┘
  Ctrl + <g> LOCK  <p> PANE  <t> TAB  <n> RESIZE  <h> MOVE  <s> SCROLL  <o> SESSION  <q> QUIT           
- <↓↑> Scroll / <PgUp/PgDn> Scroll Page / <u/d> Scroll Half Page / <ENTER> Select pane                                   
+ <↓↑> Scroll / <PgUp/PgDn> Scroll / <u/d> Scroll / <e> Edit / <ENTER> Select pane                                       
diff --git a/zellij-server/Cargo.toml b/zellij-server/Cargo.toml
index d1cf9eb25..74767439d 100644
--- a/zellij-server/Cargo.toml
+++ b/zellij-server/Cargo.toml
@@ -28,6 +28,7 @@ typetag = "0.1.7"
 chrono = "0.4.19"
 close_fds = "0.3.2"
 sysinfo = "0.22.5"
+uuid = { version = "0.8.2", features = ["serde", "v4"] }
 
 [dev-dependencies]
 insta = "1.6.0"
diff --git a/zellij-server/src/lib.rs b/zellij-server/src/lib.rs
index 81b66801e..0a587d7c6 100644
--- a/zellij-server/src/lib.rs
+++ b/zellij-server/src/lib.rs
@@ -620,6 +620,7 @@ fn init_session(
                     Some(os_input.clone()),
                 ),
                 opts.debug,
+                config_options.scrollback_editor.clone(),
             );
 
             move || pty_thread_main(pty, layout)
diff --git a/zellij-server/src/os_input_output.rs b/zellij-server/src/os_input_output.rs
index 1e43e47fa..b757ad460 100644
--- a/zellij-server/src/os_input_output.rs
+++ b/zellij-server/src/os_input_output.rs
@@ -145,6 +145,7 @@ fn handle_openpty(
 ///
 fn handle_terminal(
     cmd: RunCommand,
+    failover_cmd: Option<RunCommand>,
     orig_termios: termios::Termios,
     quit_cb: Box<dyn Fn(PaneId) + Send>,
 ) -> (RawFd, RawFd) {
@@ -152,9 +153,12 @@ fn handle_terminal(
     // parent.
     match openpty(None, Some(&orig_termios)) {
         Ok(open_pty_res) => handle_openpty(open_pty_res, cmd, quit_cb),
-        Err(e) => {
-            panic!("failed to start pty{:?}", e);
-        }
+        Err(e) => match failover_cmd {
+            Some(failover_cmd) => handle_terminal(failover_cmd, None, orig_termios, quit_cb),
+            None => {
+                panic!("failed to start pty{:?}", e);
+            }
+        },
     }
 }
 
@@ -174,19 +178,40 @@ pub fn spawn_terminal(
     terminal_action: TerminalAction,
     orig_termios: termios::Termios,
     quit_cb: Box<dyn Fn(PaneId) + Send>,
-) -> (RawFd, RawFd) {
+    default_editor: Option<PathBuf>,
+) -> Result<(RawFd, RawFd), &'static str> {
+    let mut failover_cmd_args = None;
     let cmd = match terminal_action {
-        TerminalAction::OpenFile(file_to_open) => {
-            if env::var("EDITOR").is_err() && env::var("VISUAL").is_err() {
-                panic!("Can't edit files if an editor is not defined. To fix: define the EDITOR or VISUAL environment variables with the path to your editor (eg. /usr/bin/vim)");
+        TerminalAction::OpenFile(file_to_open, line_number) => {
+            if default_editor.is_none()
+                && env::var("EDITOR").is_err()
+                && env::var("VISUAL").is_err()
+            {
+                return Err(
+                    "No Editor found, consider setting a path to one in $EDITOR or $VISUAL",
+                );
             }
-            let command =
-                PathBuf::from(env::var("EDITOR").unwrap_or_else(|_| env::var("VISUAL").unwrap()));
+            let command = default_editor.unwrap_or_else(|| {
+                PathBuf::from(env::var("EDITOR").unwrap_or_else(|_| env::var("VISUAL").unwrap()))
+            });
 
-            let args = vec![file_to_open
+            let mut args = vec![];
+            let file_to_open = file_to_open
                 .into_os_string()
                 .into_string()
-                .expect("Not valid Utf8 Encoding")];
+                .expect("Not valid Utf8 Encoding");
+            if let Some(line_number) = line_number {
+                if command.ends_with("vim")
+                    || command.ends_with("nvim")
+                    || command.ends_with("emacs")
+                    || command.ends_with("nano")
+                    || command.ends_with("kak")
+                {
+                    failover_cmd_args = Some(vec![file_to_open.clone()]);
+                    args.push(format!("+{}", line_number));
+                }
+            }
+            args.push(file_to_open);
             RunCommand {
                 command,
                 args,
@@ -195,8 +220,15 @@ pub fn spawn_terminal(
         }
         TerminalAction::RunCommand(command) => command,
     };
+    let failover_cmd = if let Some(failover_cmd_args) = failover_cmd_args {
+        let mut cmd = cmd.clone();
+        cmd.args = failover_cmd_args;
+        Some(cmd)
+    } else {
+        None
+    };
 
-    handle_terminal(cmd, orig_termios, quit_cb)
+    Ok(handle_terminal(cmd, failover_cmd, orig_termios, quit_cb))
 }
 
 #[derive(Clone)]
@@ -245,7 +277,8 @@ pub trait ServerOsApi: Send + Sync {
         &self,
         terminal_action: TerminalAction,
         quit_cb: Box<dyn Fn(PaneId) + Send>,
-    ) -> (RawFd, RawFd);
+        default_editor: Option<PathBuf>,
+    ) -> Result<(RawFd, RawFd), &'static str>;
     /// Read bytes from the standard output of the virtual terminal referred to by `fd`.
     fn read_from_tty_stdout(&self, fd: RawFd, buf: &mut [u8]) -> Result<usize, nix::Error>;
     /// Creates an `AsyncReader` that can be used to read from `fd` in an async context
@@ -284,9 +317,15 @@ impl ServerOsApi for ServerOsInputOutput {
         &self,
         terminal_action: TerminalAction,
         quit_cb: Box<dyn Fn(PaneId) + Send>,
-    ) -> (RawFd, RawFd) {
+        default_editor: Option<PathBuf>,
+    ) -> Result<(RawFd, RawFd), &'static str> {
         let orig_termios = self.orig_termios.lock().unwrap();
-        spawn_terminal(terminal_action, orig_termios.clone(), quit_cb)
+        spawn_terminal(
+            terminal_action,
+            orig_termios.clone(),
+            quit_cb,
+            default_editor,
+        )
     }
     fn read_from_tty_stdout(&self, fd: RawFd, buf: &mut [u8]) -> Result<usize, nix::Error> {
         unistd::read(fd, buf)
diff --git a/zellij-server/src/panes/floating_panes/mod.rs b/zellij-server/src/panes/floating_panes/mod.rs
index e4925c365..f8bd46bc3 100644
--- a/zellij-server/src/panes/floating_panes/mod.rs
+++ b/zellij-server/src/panes/floating_panes/mod.rs
@@ -101,6 +101,49 @@ impl FloatingPanes {
         self.panes.insert(pane_id, pane);
         self.z_indices.push(pane_id);
     }
+    pub fn replace_active_pane(
+        &mut self,
+        pane: Box<dyn Pane>,
+        client_id: ClientId,
+    ) -> Option<Box<dyn Pane>> {
+        self.active_panes
+            .get(&client_id)
+            .copied()
+            .and_then(|active_pane_id| self.replace_pane(active_pane_id, pane))
+    }
+    pub fn replace_pane(
+        &mut self,
+        pane_id: PaneId,
+        mut with_pane: Box<dyn Pane>,
+    ) -> Option<Box<dyn Pane>> {
+        let with_pane_id = with_pane.pid();
+        with_pane.set_content_offset(Offset::frame(1));
+        let removed_pane = self.panes.remove(&pane_id).map(|removed_pane| {
+            let removed_pane_id = removed_pane.pid();
+            let with_pane_id = with_pane.pid();
+            let removed_pane_geom = removed_pane.current_geom();
+            with_pane.set_geom(removed_pane_geom);
+            self.panes.insert(with_pane_id, with_pane);
+            let z_index = self
+                .z_indices
+                .iter()
+                .position(|pane_id| pane_id == &removed_pane_id)
+                .unwrap();
+            self.z_indices.remove(z_index);
+            self.z_indices.insert(z_index, with_pane_id);
+            removed_pane
+        });
+
+        // update the desired_pane_positions to relate to the new pane
+        if let Some(desired_pane_position) = self.desired_pane_positions.remove(&pane_id) {
+            self.desired_pane_positions
+                .insert(with_pane_id, desired_pane_position);
+        }
+
+        // move clients from the previously active pane to the new pane we just inserted
+        self.move_clients_between_panes(pane_id, with_pane_id);
+        removed_pane
+    }
     pub fn rem