Let the sidebar divider be dragged

src/app.rs

@@ -25,7 +25,7 @@ use crate::settings::{
     StreamingCacheBudget,
 };
 use iced::widget::{markdown, scrollable, text_input};
-use iced::{Size, Subscription, Task, keyboard, window};
+use iced::{Size, Subscription, Task, keyboard, mouse, window};
 use rfd::AsyncFileDialog;
 use std::collections::{HashMap, HashSet, VecDeque};
 use std::fs;
@@ -38,6 +38,8 @@ use std::time::{Duration, Instant};
 
 const APP_ID: &str = "de.rfc1437.ds4server";
 const METRICS_SAMPLE_INTERVAL: Duration = Duration::from_millis(200);
+pub(super) const MIN_SIDEBAR_WIDTH: i32 = 180;
+pub(super) const MAX_SIDEBAR_WIDTH: i32 = 520;
 
 pub(crate) struct App {
     main_window: window::Id,
@@ -64,6 +66,8 @@ pub(crate) struct App {
     session_rename: Option<(i32, String)>,
     /// Projects whose archived sessions are expanded in the sidebar.
     expanded_archives: HashSet<i32>,
+    /// True while the sidebar divider is being dragged.
+    sidebar_drag: bool,
     choosing_folder: bool,
     pending_project_path: Option<PathBuf>,
     project_name_input: String,
@@ -194,6 +198,9 @@ pub(crate) enum Message {
     ShowChat,
     ShowStats,
     ToggleSidebar,
+    StartSidebarDrag,
+    DragSidebar(f32),
+    EndSidebarDrag,
     MetricsTick,
 }
 
@@ -242,6 +249,7 @@ impl App {
                         session_menu: None,
                         session_rename: None,
                         expanded_archives: HashSet::new(),
+                        sidebar_drag: false,
                         choosing_folder: false,
                         pending_project_path: None,
                         project_name_input: String::new(),
@@ -323,6 +331,7 @@ impl App {
             session_menu: None,
             session_rename: None,
             expanded_archives: HashSet::new(),
+            sidebar_drag: false,
             choosing_folder: false,
             pending_project_path: None,
             project_name_input: String::new(),
@@ -414,6 +423,26 @@ impl App {
             }
             Message::ShowChat => self.detail_tab = DetailTab::Chat,
             Message::ShowStats => self.detail_tab = DetailTab::Stats,
+            // The sidebar starts at the window's left edge, so the cursor's x is
+            // the width the user is asking for. Only the final width is stored.
+            Message::StartSidebarDrag => self.sidebar_drag = true,
+            Message::DragSidebar(x) => {
+                if self.sidebar_drag {
+                    self.preferences.sidebar_width =
+                        (x.round() as i32).clamp(MIN_SIDEBAR_WIDTH, MAX_SIDEBAR_WIDTH);
+                }
+            }
+            Message::EndSidebarDrag => {
+                if self.sidebar_drag {
+                    self.sidebar_drag = false;
+                    if let Some(database) = self.database.as_mut()
+                        && let Err(error) =
+                            database.set_sidebar_width(self.preferences.sidebar_width)
+                    {
+                        self.error = Some(error);
+                    }
+                }
+            }
             Message::ToggleSidebar => {
                 let collapsed = !self.preferences.sidebar_collapsed;
                 self.preferences.sidebar_collapsed = collapsed;
@@ -969,6 +998,19 @@ impl App {
                 iced::time::every(Duration::from_millis(50)).map(|_| Message::GenerationTick),
             );
         }
+        // The cursor leaves the thin divider as soon as it moves, so the drag is
+        // followed through raw window events instead of the widget.
+        if self.sidebar_drag {
+            subscriptions.push(iced::event::listen_with(|event, _, _| match event {
+                iced::Event::Mouse(mouse::Event::CursorMoved { position }) => {
+                    Some(Message::DragSidebar(position.x))
+                }
+                iced::Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left)) => {
+                    Some(Message::EndSidebarDrag)
+                }
+                _ => None,
+            }));
+        }
         Subscription::batch(subscriptions)
     }