Allow saving current session for resurrection on demand (#4654)

* initial implementation

* session manager ui and plugin api

* remove event

* cleanups and formatting

* add pr

2 files changed, 154 insertions, 6 deletions

diff --git a/default-plugins/session-manager/src/main.rs b/default-plugins/session-manager/src/main.rs
index c89b0049..1a76fdb9 100644
--- a/default-plugins/session-manager/src/main.rs
+++ b/default-plugins/session-manager/src/main.rs
@@ -10,7 +10,7 @@ use new_session_info::NewSessionInfo;
 use ui::{
     components::{
         render_controls_line, render_error, render_new_session_block, render_prompt,
-        render_renaming_session_screen, render_screen_toggle, Colors,
+        render_renaming_session_screen, render_screen_toggle, render_unsaved_changes_line, Colors,
     },
     welcome_screen::{render_banner, render_welcome_boundaries},
     SessionUiInfo,
@@ -19,7 +19,7 @@ use ui::{
 use resurrectable_sessions::ResurrectableSessions;
 use session_list::SessionList;
 
-#[derive(Clone, Debug, Copy)]
+#[derive(Clone, Debug, Copy, PartialEq)]
 enum ActiveScreen {
     NewSession,
     AttachToSession,
@@ -47,6 +47,7 @@ struct State {
     show_kill_all_sessions_warning: bool,
     request_ids: Vec<String>,
     is_web_client: bool,
+    current_session_last_saved_time: Option<u64>,
 }
 
 register_plugin!(State);
@@ -61,11 +62,16 @@ impl ZellijPlugin for State {
             self.active_screen = ActiveScreen::NewSession;
         }
         self.new_session_info.is_welcome_screen = self.is_welcome_screen;
+
+        self.current_session_last_saved_time = current_session_last_saved_time();
+        set_timeout(1.0);
+
         subscribe(&[
             EventType::ModeUpdate,
             EventType::SessionUpdate,
             EventType::Key,
             EventType::RunCommandResult,
+            EventType::Timer,
         ]);
     }
 
@@ -94,6 +100,11 @@ impl ZellijPlugin for State {
     fn update(&mut self, event: Event) -> bool {
         let mut should_render = false;
         match event {
+            Event::Timer(_) => {
+                self.current_session_last_saved_time = current_session_last_saved_time();
+                set_timeout(1.0);
+                should_render = true;
+            },
             Event::ModeUpdate(mode_info) => {
                 self.colors = Colors::new(mode_info.style.colors);
                 self.is_web_client = mode_info.is_web_client.unwrap_or(false);
@@ -156,7 +167,8 @@ impl ZellijPlugin for State {
                     self.render_kill_all_sessions_warning(height, width, x, y);
                 } else {
                     render_prompt(&self.search_term, self.colors, x, y + 2);
-                    let room_for_list = height.saturating_sub(6); // search line and controls;
+                    let bottom_lines = 7;
+                    let room_for_list = height.saturating_sub(bottom_lines);
                     self.sessions.update_rows(room_for_list);
                     let list =
                         self.sessions
@@ -172,8 +184,25 @@ impl ZellijPlugin for State {
         }
         if let Some(error) = self.error.as_ref() {
             render_error(&error, height, width, x, y);
+        } else if self.active_screen == ActiveScreen::AttachToSession && !self.is_welcome_screen {
+            let help_offset = render_controls_line(
+                self.active_screen,
+                width,
+                self.colors,
+                x,
+                rows.saturating_sub(1),
+            );
+            // Adjust position and width based on whether controls line shows "Help: "
+            let adjusted_x = x + help_offset;
+            let adjusted_width = width.saturating_sub(help_offset);
+            render_unsaved_changes_line(
+                adjusted_width,
+                adjusted_x,
+                rows,
+                self.current_session_last_saved_time,
+            );
         } else {
-            render_controls_line(self.active_screen, width, self.colors, x + 1, rows);
+            let _ = render_controls_line(self.active_screen, width, self.colors, x, rows);
         }
         if self.is_welcome_screen {
             render_welcome_boundaries(rows, cols); // explicitly done in the end to override some
@@ -395,6 +424,14 @@ impl State {
                         hide_self();
                     }
                 },
+                BareKey::Char('a') if key.has_modifiers(&[KeyModifier::Ctrl]) => {
+                    if !self.is_welcome_screen {
+                        // we don't want to save welcome screen sessions
+                        if let Err(e) = save_session() {
+                            self.show_error(&format!("Couldn't save session: {}", e));
+                        }
+                    }
+                },
                 _ => {},
             }
         }
diff --git a/default-plugins/session-manager/src/ui/components.rs b/default-plugins/session-manager/src/ui/components.rs
index dede06d9..8310d2d3 100644
--- a/default-plugins/session-manager/src/ui/components.rs
+++ b/default-plugins/session-manager/src/ui/components.rs
@@ -1,4 +1,6 @@
+use humantime::format_duration;
 use std::path::PathBuf;
+use std::time::Duration;
 use unicode_width::UnicodeWidthChar;
 use unicode_width::UnicodeWidthStr;
 use zellij_tile::prelude::*;
@@ -927,13 +929,19 @@ pub fn render_controls_line(
     colors: Colors,
     x: usize,
     y: usize,
-) {
-    match active_screen {
+) -> usize {
+    const HELP_PREFIX_LEN: usize = 6;
+    let x = x + 1;
+
+    let shows_help_prefix = match active_screen {
         ActiveScreen::NewSession => {
             if max_cols >= 50 {
                 print!(
                     "\u{1b}[m\u{1b}[{y};{x}H\u{1b}[1mHelp: Fill in the form to start a new session."
                 );
+                true
+            } else {
+                false
             }
         },
         ActiveScreen::AttachToSession => {
@@ -950,8 +958,12 @@ pub fn render_controls_line(
                 print!(
                     "\u{1b}[m\u{1b}[{y};{x}HHelp: {rename} - {rename_text}, {disconnect} - {disconnect_text}, {kill} - {kill_text}, {kill_all} - {kill_all_text}"
                 );
+                true
             } else if max_cols >= 28 {
                 print!("\u{1b}[m\u{1b}[{y};{x}H{rename}/{disconnect}/{kill}/{kill_all}");
+                false
+            } else {
+                false
             }
         },
         ActiveScreen::ResurrectSession => {
@@ -968,13 +980,112 @@ pub fn render_controls_line(
                 print!(
                     "\u{1b}[m\u{1b}[{y};{x}HHelp: {arrows} - {navigate}, {enter} - {select}, {del} - {del_text}, {del_all} - {del_all_text}"
                 );
+                true
             } else if max_cols >= 28 {
                 print!("\u{1b}[m\u{1b}[{y};{x}H{arrows}/{enter}/{del}/{del_all}");
+                false
+            } else {
+                false
             }
         },
+    };
+
+    if shows_help_prefix {
+        HELP_PREFIX_LEN
+    } else {
+        0
+    }
+}
+
+fn format_elapsed_time(elapsed_millis: u64) -> String {
+    // Convert elapsed milliseconds to Duration
+    let elapsed_duration = Duration::from_millis(elapsed_millis);
+
+    // Use humantime to format the duration, same as in resurrectable_sessions.rs
+    let duration_str = format_duration(elapsed_duration).to_string();
+    let duration_parts = duration_str.split_whitespace();
+    let mut formatted_duration = String::new();
+    for part in duration_parts {
+        if !part.ends_with('s') {
+            if !formatted_duration.is_empty() {
+                formatted_duration.push(' ');
+            }
+            formatted_duration.push_str(part);
+        }
+    }
+    if formatted_duration.is_empty() {
+        format!("just now")
+    } else {
+        format!("{} ago", formatted_duration)
     }
 }
 
+pub fn render_unsaved_changes_line(
+    max_cols: usize,
+    x: usize,
+    y: usize,
+    last_saved_timestamp: Option<u64>,
+) {
+    // Declare all text components
+    let shortcut_text = "<Ctrl a>";
+    let full_action_text = "Save current session for resurrection";
+    let medium_action_text = "Save session";
+    let short_action_text = "Save";
+    let separator = " - ";
+    let space = " ";
+
+    let time_text = match last_saved_timestamp {
+        Some(timestamp) => {
+            let elapsed = format_elapsed_time(timestamp);
+            format!("(saved {})", elapsed)
+        },
+        None => "(not saved)".to_string(),
+    };
+
+    // Calculate component widths
+    let shortcut_width = shortcut_text.width();
+    let separator_width = separator.width();
+    let space_width = space.width();
+    let time_width = time_text.width();
+
+    // Calculate total widths for each display mode
+    // Format: "{shortcut}{separator}{action}{space}{time}"
+    let full_width =
+        shortcut_width + separator_width + full_action_text.width() + space_width + time_width;
+    let medium_width =
+        shortcut_width + separator_width + medium_action_text.width() + space_width + time_width;
+    let short_width =
+        shortcut_width + separator_width + short_action_text.width() + space_width + time_width;
+    let minimal_width = shortcut_width + space_width + time_width;
+
+    // Select appropriate message based on available width
+    let msg = if max_cols >= full_width {
+        format!(
+            "{}{}{}{}{}",
+            shortcut_text, separator, full_action_text, space, time_text
+        )
+    } else if max_cols >= medium_width {
+        format!(
+            "{}{}{}{}{}",
+            shortcut_text, separator, medium_action_text, space, time_text
+        )
+    } else if max_cols >= short_width {
+        format!(
+            "{}{}{}{}{}",
+            shortcut_text, separator, short_action_text, space, time_text
+        )
+    } else if max_cols >= minimal_width {
+        format!("{}{}{}", shortcut_text, space, time_text)
+    } else {
+        return; // Not enough space to render
+    };
+
+    let text = Text::new(&msg)
+        .color_substring(3, shortcut_text)
+        .color_substring(2, &time_text);
+    print_text_with_coordinates(text, x, y, None, None);
+}
+
 // Maps the various prompts and UI elements to the colors to present them with
 //
 // Since this plugin predates the UI components, this is a developer