feat: flexible split panes with session persistence (#543)

.github/workflows/ci.yml

@@ -243,6 +243,7 @@ jobs:
               'SearchResultsView.swift',
               'SidebarView.swift',
               'StatusBarView.swift',
+              'PaneTreeView.swift',
               'TerminalBarView.swift',
               'TerminalSearchBar.swift',
               'WelcomeView.swift',
@@ -286,6 +287,7 @@ jobs:
               'QuickOpenView.swift',
               'RecoveryDialogView.swift',
               'RepresentedFileTracker.swift',
+              'PaneTreeView.swift',
               'SearchResultsView.swift',
               'SidebarView.swift',
               'StatusBarView.swift',

Pine/AccessibilityIdentifiers.swift

@@ -96,6 +96,11 @@ nonisolated enum AccessibilityID {
     static let symbolResultsList = "symbolResultsList"
     static func symbolItem(_ name: String) -> String { "symbolItem_\(name)" }
 
+    // MARK: - Split Panes
+    static let paneDivider = "paneDivider"
+    static let paneDropOverlay = "paneDropOverlay"
+    static func paneLeaf(_ id: String) -> String { "paneLeaf_\(id)" }
+
     // MARK: - Toast notifications
     static let toastNotification = "toastNotification"
 

Pine/ContentView+Helpers.swift

@@ -31,38 +31,46 @@ extension ContentView {
         // Restore editor tabs only if PM has no tabs (fresh or after restart)
         if tabManager.tabs.isEmpty {
             let disabledSet = Set(session.existingHighlightingDisabledPaths ?? [])
-            for url in session.existingFileURLs {
-                let disabled = disabledSet.contains(url.path)
-                tabManager.openTab(url: url, syntaxHighlightingDisabled: disabled)
-            }
-
-            // Restore preview modes for markdown tabs
-            if let previewModes = session.existingPreviewModes {
-                for index in tabManager.tabs.indices {
-                    let path = tabManager.tabs[index].url.path
-                    if let rawMode = previewModes[path],
-                       let mode = MarkdownPreviewMode(rawValue: rawMode) {
-                        tabManager.tabs[index].previewMode = mode
+            let previewModes = session.existingPreviewModes
+            let editorStates = session.existingEditorStates
+            let pinnedSet = session.existingPinnedPaths
+
+            // Try to restore pane layout if available
+            if let layoutData = session.paneLayoutData,
+               let restoredNode = try? JSONDecoder().decode(PaneNode.self, from: layoutData),
+               let assignments = session.paneTabAssignments,
+               restoredNode.leafCount > 1 {
+                let activePaneUUID = session.activePaneID.flatMap { UUID(uuidString: $0) }
+                paneManager.restoreLayout(from: restoredNode, activePaneUUID: activePaneUUID)
+
+                // Populate tabs into each pane's TabManager
+                for (paneID, tm) in paneManager.tabManagers {
+                    guard let paths = assignments[paneID.id.uuidString] else { continue }
+                    for path in paths {
+                        let url = URL(fileURLWithPath: path)
+                        guard FileManager.default.fileExists(atPath: path) else { continue }
+                        let disabled = disabledSet.contains(path)
+                        tm.openTab(url: url, syntaxHighlightingDisabled: disabled)
                     }
+                    Self.applyTabState(to: tm, previewModes: previewModes,
+                                       editorStates: editorStates, pinnedPaths: pinnedSet)
                 }
-            }
-
-            // Restore per-tab editor state (cursor, scroll, folds)
-            if let editorStates = session.existingEditorStates {
-                for index in tabManager.tabs.indices {
-                    let path = tabManager.tabs[index].url.path
-                    if let state = editorStates[path] {
-                        state.apply(to: &tabManager.tabs[index])
-                    }
+            } else {
+                // Single-pane restore (backwards compatible)
+                for url in session.existingFileURLs {
+                    let disabled = disabledSet.contains(url.path)
+                    tabManager.openTab(url: url, syntaxHighlightingDisabled: disabled)
                 }
+                Self.applyTabState(to: tabManager, previewModes: previewModes,
+                                   editorStates: editorStates, pinnedPaths: pinnedSet)
             }
 
             if let activeURL = session.activeFileURL,
                let tab = tabManager.tab(for: activeURL) {
                 tabManager.activeTabID = tab.id
             }
 
-            didRestoreTabs = !tabManager.tabs.isEmpty
+            didRestoreTabs = !projectManager.allTabs.isEmpty
         }
 
         // Restore terminal state
@@ -88,6 +96,28 @@ extension ContentView {
         return didRestoreTabs
     }
 
+    /// Applies preview modes, editor states, and pinned status to a TabManager's tabs.
+    private static func applyTabState(
+        to tm: TabManager,
+        previewModes: [String: String]?,
+        editorStates: [String: PerTabEditorState]?,
+        pinnedPaths: Set<String>?
+    ) {
+        for index in tm.tabs.indices {
+            let path = tm.tabs[index].url.path
+            if let rawMode = previewModes?[path],
+               let mode = MarkdownPreviewMode(rawValue: rawMode) {
+                tm.tabs[index].previewMode = mode
+            }
+            if let state = editorStates?[path] {
+                state.apply(to: &tm.tabs[index])
+            }
+            if pinnedPaths?.contains(path) == true {
+                tm.tabs[index].isPinned = true
+            }
+        }
+    }
+
     func checkForRecovery() {
         guard let entries = projectManager.recoveryManager?.pendingRecoveryEntries(),
               !entries.isEmpty else { return }
@@ -326,85 +356,20 @@ extension ContentView {
 
 extension ContentView {
 
-    /// Shows a confirmation dialog for bulk close operations when there are dirty tabs.
-    /// Returns `true` if the operation should proceed (user chose Save All or Don't Save),
-    /// `false` if cancelled. When the user chooses Save All, all dirty tabs are saved first.
-    private func confirmBulkClose(dirtyTabs: [EditorTab]) -> Bool {
-        guard !dirtyTabs.isEmpty else { return true }
-
-        let fileList = dirtyTabs.map { "  \u{2022} \($0.fileName)" }.joined(separator: "\n")
-        let alert = NSAlert()
-        alert.messageText = Strings.unsavedChangesTitle
-        alert.informativeText = Strings.unsavedChangesListMessage(fileList)
-        alert.addButton(withTitle: Strings.dialogSaveAll)
-        alert.addButton(withTitle: Strings.dialogDontSave)
-        alert.addButton(withTitle: Strings.dialogCancel)
-        alert.alertStyle = .warning
-
-        let response = alert.runModal()
-        switch response {
-        case .alertFirstButtonReturn:
-            // Save all dirty tabs; abort if any save fails
-            for tab in dirtyTabs {
-                guard let index = tabManager.tabs.firstIndex(where: { $0.id == tab.id }) else { continue }
-                guard tabManager.saveTab(at: index) else { return false }
-            }
-            Task { await workspace.gitProvider.refreshAsync() }
-            return true
-        case .alertSecondButtonReturn:
-            return true
-        default:
-            return false
-        }
-    }
-
-    /// Closes all tabs except the one with the given ID, with unsaved-changes protection.
     func closeOtherTabsWithConfirmation(keeping tabID: UUID) {
-        let dirty = tabManager.dirtyTabsForCloseOthers(keeping: tabID)
-        guard confirmBulkClose(dirtyTabs: dirty) else { return }
-        tabManager.closeOtherTabs(keeping: tabID, force: true)
+        TabCloseHelper.closeOtherTabs(keeping: tabID, in: tabManager, gitProvider: workspace.gitProvider)
     }
 
-    /// Closes all tabs to the right of the given tab, with unsaved-changes protection.
     func closeTabsToTheRightWithConfirmation(of tabID: UUID) {
-        let dirty = tabManager.dirtyTabsForCloseRight(of: tabID)
-        guard confirmBulkClose(dirtyTabs: dirty) else { return }
-        tabManager.closeTabsToTheRight(of: tabID, force: true)
+        TabCloseHelper.closeTabsToTheRight(of: tabID, in: tabManager, gitProvider: workspace.gitProvider)
     }
 
-    /// Closes all tabs with unsaved-changes protection.
     func closeAllTabsWithConfirmation() {
-        let dirty = tabManager.dirtyTabsForCloseAll()
-        guard confirmBulkClose(dirtyTabs: dirty) else { return }
-        tabManager.closeAllTabs(force: true)
+        TabCloseHelper.closeAllTabs(in: tabManager, gitProvider: workspace.gitProvider)
     }
 
-    /// Closes a tab with unsaved-changes protection.
     func closeTabWithConfirmation(_ tab: EditorTab) {
-        if tab.isDirty {
-            let alert = NSAlert()
-            alert.messageText = Strings.unsavedChangesTitle
-            alert.informativeText = Strings.unsavedChangesMessage
-            alert.addButton(withTitle: Strings.dialogSave)
-            alert.addButton(withTitle: Strings.dialogDontSave)
-            alert.addButton(withTitle: Strings.dialogCancel)
-            alert.alertStyle = .warning
-
-            let response = alert.runModal()
-            switch response {
-            case .alertFirstButtonReturn:
-                guard let index = tabManager.tabs.firstIndex(where: { $0.id == tab.id }) else { return }
-                guard tabManager.saveTab(at: index) else { return }
-                Task { await workspace.gitProvider.refreshAsync() }
-                tabManager.closeTab(id: tab.id)
-            case .alertSecondButtonReturn:
-                tabManager.closeTab(id: tab.id)
-            default:
-                return
-            }
-        } else {
-            tabManager.closeTab(id: tab.id)
-        }
+        TabCloseHelper.closeTab(tab, in: tabManager, gitProvider: workspace.gitProvider)
     }
 
     func handleExternalChanges(_ result: TabManager.ExternalChangeResult) {

Pine/ContentView.swift

@@ -14,6 +14,7 @@ struct ContentView: View {
     @Environment(WorkspaceManager.self) var workspace
     @Environment(TerminalManager.self) var terminal
     @Environment(TabManager.self) var tabManager
+    @Environment(PaneManager.self) var paneManager
     @Environment(ProjectRegistry.self) var registry
     @Environment(\.openWindow) var openWindow
 
@@ -103,7 +104,7 @@ struct ContentView: View {
                 gitProvider: workspace.gitProvider,
                 isGitRepository: workspace.gitProvider.isGitRepository
             )
-            DocumentEditedTracker(isEdited: tabManager.hasUnsavedChanges)
+            DocumentEditedTracker(isEdited: projectManager.hasUnsavedChanges)
             RepresentedFileTracker(url: activeTab?.url ?? workspace.rootURL)
         }
         .task {
@@ -243,21 +244,25 @@ struct ContentView: View {
 
     @ViewBuilder
     var editorArea: some View {
-        EditorAreaView(
-            lineDiffs: $lineDiffs,
-            isDragTargeted: $isDragTargeted,
-            goToLineOffset: $goToLineOffset,
-            isBlameVisible: isBlameVisible,
-            blameLines: blameLines,
-            isMinimapVisible: isMinimapVisible,
-            isWordWrapEnabled: isWordWrapEnabled,
-            diffHunks: diffHunks,
-            onCloseTab: { closeTabWithConfirmation($0) },
-            onCloseOtherTabs: { closeOtherTabsWithConfirmation(keeping: $0) },
-            onCloseTabsToTheRight: { closeTabsToTheRightWithConfirmation(of: $0) },
-            onCloseAllTabs: { closeAllTabsWithConfirmation() },
-            onSaveSession: { projectManager.saveSession() }
-        )
+        if paneManager.root.leafCount > 1 {
+            PaneTreeView(node: paneManager.root)
+        } else {
+            EditorAreaView(
+                lineDiffs: $lineDiffs,
+                isDragTargeted: $isDragTargeted,
+                goToLineOffset: $goToLineOffset,
+                isBlameVisible: isBlameVisible,
+                blameLines: blameLines,
+                isMinimapVisible: isMinimapVisible,
+                isWordWrapEnabled: isWordWrapEnabled,
+                diffHunks: diffHunks,
+                onCloseTab: { closeTabWithConfirmation($0) },
+                onCloseOtherTabs: { closeOtherTabsWithConfirmation(keeping: $0) },
+                onCloseTabsToTheRight: { closeTabsToTheRightWithConfirmation(of: $0) },
+                onCloseAllTabs: { closeAllTabsWithConfirmation() },
+                onSaveSession: { projectManager.saveSession() }
+            )
+        }
     }
 
     @ViewBuilder
@@ -283,6 +288,7 @@ struct ContentView: View {
         .environment(projectManager.workspace)
         .environment(projectManager.terminal)
         .environment(projectManager.tabManager)
+        .environment(projectManager.paneManager)
         .environment(projectManager.toastManager)
         .environment(registry)
 }