Add PDF state persistence

src-tauri/src/commands/config.rs

@@ -2,7 +2,9 @@
 
 use std::path::Path;
 
-use crate::config::{GlobalConfig, ProjectConfig};
+use crate::config::{GlobalConfig, ProjectConfig, SessionConfig};
+use crate::state::AppState;
+use tauri::State;
 
 /// Load the global config from `~/.config/brittle/config.toml`.
 /// Returns the default config if the file does not yet exist.
@@ -80,6 +82,32 @@ pub fn get_layout_config() -> Result<crate::config::LayoutConfig, String> {
         .map_err(|e| e.to_string())
 }
 
+/// Return the session state for the currently open project.
+///
+/// Returns `Default` if no session has been saved yet.
+/// Errors if no repository is open.
+#[tauri::command]
+pub fn get_session(state: State<AppState>) -> Result<SessionConfig, String> {
+    let guard = state.brittle.lock().map_err(|_| "lock poisoned".to_string())?;
+    let brittle = guard.as_ref().ok_or_else(|| "no repository open".to_string())?;
+    ProjectConfig::load(brittle.repository_root())
+        .map(|c| c.session)
+        .map_err(|e| e.to_string())
+}
+
+/// Persist the session state for the currently open project.
+///
+/// Errors if no repository is open.
+#[tauri::command]
+pub fn save_session(state: State<AppState>, session: SessionConfig) -> Result<(), String> {
+    let guard = state.brittle.lock().map_err(|_| "lock poisoned".to_string())?;
+    let brittle = guard.as_ref().ok_or_else(|| "no repository open".to_string())?;
+    let root = brittle.repository_root();
+    let mut config = ProjectConfig::load(root).map_err(|e| e.to_string())?;
+    config.session = session;
+    config.save(root).map_err(|e| e.to_string())
+}
+
 /// Return the user's keybinding overrides from the global config.
 ///
 /// Map keys are action names in snake_case (e.g. `"tab_next"`); values are

src-tauri/src/config/mod.rs

@@ -10,7 +10,7 @@ mod global;
 mod project;
 
 pub use global::GlobalConfig;
-pub use project::ProjectConfig;
+pub use project::{PdfTabEntry, PdfTabState, ProjectConfig, SessionConfig};
 
 use std::collections::HashMap;
 
@@ -104,8 +104,8 @@ pub struct MergedConfig {
     pub appearance: AppearanceConfig,
     pub layout: LayoutConfig,
     pub keybindings: KeybindingsConfig,
-    /// Reference IDs of tabs that should be restored on launch.
-    pub open_tabs: Vec<String>,
+    /// Tabs that should be restored on launch.
+    pub open_tabs: Vec<PdfTabEntry>,
 }
 
 impl MergedConfig {
@@ -157,7 +157,7 @@ pub enum ConfigError {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::config::project::SessionConfig;
+    use crate::config::project::{PdfTabEntry, SessionConfig};
 
     // ── AppearanceConfig ──────────────────────────────────────────────────────
 
@@ -273,12 +273,18 @@ mod tests {
         let global = GlobalConfig::default();
         let project = ProjectConfig {
             session: SessionConfig {
-                open_tabs: vec!["tab-a".to_string(), "tab-b".to_string()],
+                open_tabs: vec![
+                    PdfTabEntry { ref_id: "tab-a".to_string(), title: "a2024".to_string() },
+                    PdfTabEntry { ref_id: "tab-b".to_string(), title: "b2024".to_string() },
+                ],
+                ..Default::default()
             },
             ..Default::default()
         };
         let merged = MergedConfig::merge(&global, Some(&project));
-        assert_eq!(merged.open_tabs, ["tab-a", "tab-b"]);
+        assert_eq!(merged.open_tabs.len(), 2);
+        assert_eq!(merged.open_tabs[0].ref_id, "tab-a");
+        assert_eq!(merged.open_tabs[1].ref_id, "tab-b");
     }
 
     #[test]

src-tauri/src/config/project.rs

@@ -1,16 +1,37 @@
 //! Per-project configuration.
 
+use std::collections::HashMap;
 use std::path::{Path, PathBuf};
 
 use serde::{Deserialize, Serialize};
 
 use super::{AppearanceOverride, ConfigError};
 
-/// Reference IDs of tabs to restore when the project is next opened.
+/// Persisted zoom and scroll state for a single PDF tab.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
+#[serde(default)]
+pub struct PdfTabState {
+    pub zoom: f64,
+    pub scroll_top: f64,
+}
+
+/// A PDF tab to restore on next launch.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
+pub struct PdfTabEntry {
+    pub ref_id: String,
+    pub title: String,
+}
+
+/// Session state restored when a project is next opened.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
 #[serde(default)]
 pub struct SessionConfig {
-    pub open_tabs: Vec<String>,
+    /// PDF tabs to reopen, in order (Library tab is implicit).
+    pub open_tabs: Vec<PdfTabEntry>,
+    /// Index into [Library, ...open_tabs] of the tab that was active.
+    pub active_tab: usize,
+    /// Per-reference zoom and scroll position, keyed by ref_id.
+    pub pdf_states: HashMap<String, PdfTabState>,
 }
 
 /// Per-project configuration, stored at `{repo}/.brittle/config.toml`.
@@ -77,6 +98,8 @@ mod tests {
         let cfg = ProjectConfig::default();
         assert!(cfg.appearance.is_none());
         assert!(cfg.session.open_tabs.is_empty());
+        assert_eq!(cfg.session.active_tab, 0);
+        assert!(cfg.session.pdf_states.is_empty());
     }
 
     #[test]
@@ -87,7 +110,13 @@ mod tests {
                 font_size: Some(16),
             }),
             session: SessionConfig {
-                open_tabs: vec!["abc-123".to_string()],
+                open_tabs: vec![PdfTabEntry {
+                    ref_id: "abc-123".to_string(),
+                    title: "smith2024".to_string(),
+                }],
+                active_tab: 1,
+                pdf_states: [("abc-123".to_string(), PdfTabState { zoom: 1.5, scroll_top: 320.0 })]
+                    .into_iter().collect(),
             },
         };
         let s = toml::to_string_pretty(&cfg).unwrap();
@@ -130,7 +159,8 @@ mod tests {
                 font_size: None,
             }),
             session: SessionConfig {
-                open_tabs: vec!["ref-1".to_string()],
+                open_tabs: vec![PdfTabEntry { ref_id: "ref-1".to_string(), title: "ref2024".to_string() }],
+                ..Default::default()
             },
         };
         original.save_to(&path).unwrap();
@@ -146,7 +176,8 @@ mod tests {
 
         let original = ProjectConfig {
             session: SessionConfig {
-                open_tabs: vec!["x".to_string()],
+                open_tabs: vec![PdfTabEntry { ref_id: "x".to_string(), title: "x2024".to_string() }],
+                ..Default::default()
             },
             ..Default::default()
         };

src-tauri/src/lib.rs

@@ -32,6 +32,8 @@ pub fn run() {
             commands::config::get_keybindings,
             commands::config::get_layout_config,
             commands::config::get_last_project,
+            commands::config::get_session,
+            commands::config::save_session,
             // repository
             commands::repository::create_repository,
             commands::repository::open_repository,