Implementing split view phases 3-7 for Token editor

Based on the attached files, here's the context for Phase 3+:

Current State

Phase 1-2 Complete:

• EditorArea with single_document() migration helper
• compute_layout(), group_at_point(), splitter_at_point()
• 7 unit tests in editor_area.rs

Phase 3: Update AppModel

Goal: Replace AppModel.document + AppModel.editor with AppModel.editor_area

Key changes needed:

1. AppModel struct (mod.rs:51-66): Replace fields

   // FROM:
   pub document: Document,
   pub editor: EditorState,
   // TO:
   pub editor_area: EditorArea,
   

   Copy Code

2. Add accessor methods to AppModel:

   • focused_document() → &Document
   • focused_document_mut() → &mut Document
   • focused_editor() → &EditorState
   • focused_editor_mut() → &mut EditorState

3. Update all call sites - Currently ~100+ references to model.document and model.editor in:

   • update.rs (most complex - cursor movement, editing)
   • main.rs (rendering, input handling)
   • tests/common/mod.rs (test helpers)

4. Migration path - Use EditorArea::single_document() in AppModel::new()

Phase 4: Messages

Add to messages.rs:

pub enum LayoutMsg {
    SplitGroup { group_id: GroupId, direction: SplitDirection },
    CloseGroup(GroupId),
    FocusGroup(GroupId),
    MoveTab { tab_id: TabId, to_group: GroupId },
}

Wire into Msg enum and update().

Recommended Approach

Start Phase 3 with TDD:

1. Update tests/common/mod.rs helper first (simpler)
2. Add accessor methods to AppModel
3. Update AppModel::new() to use EditorArea
4. Fix compilation errors in update.rs
5. Fix compilation errors in main.rs
6. Run make test to verify

Want me to begin Phase 3 implementation?

Phase 3 Complete!

Summary

Successfully migrated AppModel from direct document/editor fields to the new EditorArea architecture:

Changes Made

1. AppModel struct (mod.rs):

   • Replaced document: Document and editor: EditorState with editor_area: EditorArea
   • Added accessor methods: document(), document_mut(), editor(), editor_mut()
   • Updated new() to use EditorArea::single_document()

2. status_bar.rs: Updated sync_status_bar() to use accessor methods

3. update.rs: ~300+ changes from model.editor.* → model.editor().* / model.editor_mut().*

4. main.rs: Similar accessor method updates for rendering and input

5. tests/common/mod.rs: Updated test helpers to construct EditorArea

6. All test files (7 files, ~304 fixes): Updated to use accessor methods

7. Bug fix: Fixed DeleteLine logic for edge cases with trailing newlines

Test Results

• 253 tests passing (same count as before)
• Build succeeds
• All existing functionality preserved

Next Steps (Phases 4-7)

• Phase 4: Add LayoutMsg enum for split/close/focus operations
• Phase 5: Render multiple groups, tab bars, splitters
• Phase 6: Document synchronization across views
• Phase 7: Keyboard shortcuts (Cmd+, Cmd+W, etc.)

Phase 4 Complete!

Summary

Successfully implemented the LayoutMsg message system for split views:

New Messages (messages.rs)

Added LayoutMsg enum with operations:

• SplitFocused(direction) / SplitGroup { group_id, direction } - Split groups
• CloseGroup(id) / CloseFocusedGroup - Close groups
• FocusGroup(id) / FocusNextGroup / FocusPrevGroup / FocusGroupByIndex(n) - Focus navigation
• MoveTab { tab_id, to_group } - Move tabs between groups
• CloseTab(id) / CloseFocusedTab - Close tabs
• NextTab / PrevTab / SwitchToTab(n) - Tab navigation

New Functions (update.rs)

• update_layout() - Main handler dispatching to helpers
• split_focused_group() / split_group() - Create new groups with same document
• insert_split_in_layout() - Update layout tree with new splits
• close_group() / remove_group_from_layout() - Remove groups and collapse tree
• collect_group_ids() - Traverse layout tree
• focus_adjacent_group() - Cycle through groups
• move_tab() / close_tab() - Tab management

Tests (tests/layout.rs)

17 new tests covering:

• Split operations (horizontal, vertical, multiple)
• Close group (last group protection, cleanup, layout collapse)
• Focus operations (direct, next/prev, by index)
• Tab navigation
• Integration: edits affecting shared document

Test Results

• 270 tests passing (up from 253)
• All existing tests still pass

Next Steps

• Phase 5: Rendering - multi-group rendering, tab bars, splitters
• Phase 6: Document synchronization
• Phase 7: Keyboard shortcuts

Split View Implementation Complete! 🎉

All 7 phases of the Split View feature are now complete:

Summary

New Keyboard Shortcuts

Test Results

• 293 tests passing (up from 253 at start)
• 40 new tests added (17 layout + 23 renderer)

Key Files Modified

• src/model/editor_area.rs - Core split view data structures
• src/model/mod.rs - AppModel with EditorArea integration
• src/messages.rs - LayoutMsg enum
• src/update.rs - update_layout() and helper functions
• src/theme.rs - TabBarTheme, SplitterTheme
• src/main.rs - Multi-group rendering and keyboard shortcuts
• tests/layout.rs - 17 layout operation tests

The Split View feature is now complete. Looking at the ROADMAP, here are the next options:

Recommended Next Steps

1. Move Split View to "Recently Completed" - Update ROADMAP structure

2. Choose next feature from the planned list:

   • Occurrence Selection (Phase 9) - Cmd+J to select next match (JetBrains-style)
   • Expand/Shrink Selection - Progressive selection with Option+Up/Down
   • File Dropping - Drag-and-drop files to open
   • Workspace Management - CLI args for multiple files/directories

3. Polish items (deferred from Split View):

   • Cursor adjustment when other views edit
   • Splitter drag resize (currently splitters render but aren't draggable)
   • Tab drag-and-drop between groups

My Recommendation

Occurrence Selection (Cmd+J) is a high-value feature that builds on the existing multi-cursor infrastructure and is commonly expected in modern editors.

Alternatively, File Dropping would make the editor more usable for daily work.

Which would you like to tackle next?