progress.txt

## Codebase Patterns
- Simulator types live in src/lib/simulator/types.ts
- Factory functions for default state in src/lib/simulator/constants.ts
- Export all from index.ts for clean imports
- Use `npm run build` for typecheck (includes TypeScript checking)
- Pre-existing lint errors in page.tsx and components exist; ignore them
- Operator functions live in src/lib/simulator/vim/operators.ts
- When spreading state with null assignments, always add explicit `: VimState` type annotation to avoid TypeScript inference narrowing
- Text objects live in src/lib/simulator/vim/textObjects.ts; use executeTextObject(state, type, objectKey) as main entry point
- Command mode functions live in src/lib/simulator/vim/commands.ts; use handleCommandModeKey() for key processing, executeCommand() for command execution
- Macro functions live in src/lib/simulator/vim/macros.ts; use prepareMacroExecution() to get keystrokes array, caller is responsible for executing them
- Leader key functions live in src/lib/simulator/vim/leader.ts; use handleLeaderKey() for processing leader sequences, enterLeaderMode() to activate

---

## 2026-01-14 - US-001
Thread: http://localhost:8317/threads/T-019bbb9c-dc27-70b1-8eb4-21ec50e69963
- Implemented comprehensive type definitions for tmux and vim state
- Created src/lib/simulator/types.ts with:
  - VimMode, VimOperator, SearchDirection, FindMotion types
  - VimBuffer with marks, folds, undo/redo stacks, cursor position
  - VimState with registers (named, numbered, special), macros, jumplist, changelist, search state
  - TmuxPane with dimensions, content, scrollback, zoom state
  - TmuxWindow with panes, layout types
  - TmuxSession with windows, attached state
  - TmuxState with copy mode, prefix state, paste buffer
  - SimulatorState combining tmux and vim
- Created src/lib/simulator/constants.ts with:
  - Default settings (VimSettings)
  - Factory functions for buffers, panes, windows, sessions
  - Bracket pairs, word separators, special keys mappings
- Created src/lib/simulator/index.ts for exports
- Files changed: 3 new files in src/lib/simulator/
- **Learnings for future iterations:**
  - Existing types.ts in src/lib/ has older/simpler definitions - new simulator types are more comprehensive
  - Use createDefaultSimulatorState() to initialize full state
  - VimRegisterContent has type property ("char" | "line" | "block") for paste behavior
---

## 2026-01-14 - US-002
Thread: http://localhost:8317/threads/T-019bbba3-31c9-71e4-9948-37966264ac64
- Implemented complete vim motion engine for basic motions
- Created src/lib/simulator/vim/motions.ts with:
  - h/j/k/l character and line movement with boundary checking
  - w/W word/WORD forward motions (word = alphanumeric, WORD = whitespace-delimited)
  - b/B word/WORD backward motions
  - e/E end of word/WORD motions
  - 0/^/$ line position motions (start, first non-whitespace, end)
  - gg/G go to line motions (with optional count)
  - {/} paragraph motions (blank line separated)
  - f/F/t/T character find motions (forward/backward, on/before)
  - ;/, repeat last find motion (same/reverse direction)
  - All motions support count prefix
- Created src/lib/simulator/vim/index.ts for exports
- Updated src/lib/simulator/index.ts to export vim module
- Files changed: 3 files
- **Learnings for future iterations:**
  - Motion functions return MotionResult with optional linewise/inclusive flags for operator integration
  - lastFindMotion state tracks f/F/t/T for ; and , repetition
  - Word boundaries use WORD_SEPARATORS constant from constants.ts
  - executeMotion() is the main entry point for applying motions with count support
---

## 2026-01-14 - US-003
Thread: http://localhost:8317/threads/T-019bbba9-8793-745b-94f7-003c0442b18f
- Implemented advanced vim motions in src/lib/simulator/vim/motions.ts:
  - % (motionPercent): Bracket matching for ()[]{}
  - [[ and ]] (motionDoubleBracketBackward/Forward): Jump to function/class definitions
  - [] and ][ (motionBracketEndBackward/Forward): Jump to closing braces
  - H/M/L (motionH_screen/M_screen/L_screen): Screen-relative line navigation
  - Ctrl-d/Ctrl-u (motionCtrlD/CtrlU): Half-page scrolling with ScrollResult type
  - Ctrl-f/Ctrl-b (motionCtrlF/CtrlB): Full-page scrolling
  - n/N (motionSearchNext/Prev): Repeat search forward/backward using searchState
  - ' and ` (motionMarkLine/MarkExact): Mark navigation (line vs exact position)
  - '' (motionPreviousPosition): Jump to previous position
  - Ctrl-o/Ctrl-i (motionCtrlO/CtrlI): Jumplist navigation with position tracking
  - gi (motionGI): Go to last insert position
  - gd (motionGD): Go to local declaration (first occurrence of word)
  - * and # (motionStar/Hash): Search word under cursor forward/backward
- Added addToJumplist() helper function for jumplist management
- Extended executeMotion() switch statement with all new motion keys
- Files changed: src/lib/simulator/vim/motions.ts
- **Learnings for future iterations:**
  - ScrollResult extends MotionResult with scrollOffset for viewport management
  - Screen motions (H/M/L, Ctrl-d/u/f/b) need visibleStartLine/visibleEndLine from the UI
  - Mark navigation uses buffer.marks for local (a-z) and state.globalMarks for global (A-Z)
  - Star/Hash motions return both result and pattern for search highlighting
  - Jumplist has max 100 entries; managed via addToJumplist helper
---

## 2026-01-14 - US-004
Thread: http://localhost:8317/threads/T-019bbbaf-e594-7431-bfd1-469e62504d88
- Implemented complete vim operator system in src/lib/simulator/vim/operators.ts:
  - d{motion} deletes text covered by motion, stores in register
  - dd deletes entire line, D deletes to end of line
  - y{motion} yanks text, yy yanks line, Y yanks line
  - c{motion} changes text (delete + insert mode), cc changes line, C changes to end
  - s substitutes character (delete + insert), S substitutes line
  - x deletes char under cursor, X deletes char before cursor
  - All operators work with counts (d3w, 3dd, etc.)
  - Deleted/yanked text goes to unnamed register (") and numbered registers rotate
  - Named registers a-z work with "ayw, uppercase A-Z appends
  - p/P paste after/before cursor with register support
- Helper functions: extractText, deleteRange, getTextRange, storeInRegister
- Undo stack management with pushToUndoStack
- Changelist tracking with addToChangelist
- Updated src/lib/simulator/vim/index.ts to export operators
- Files changed: 2 files (operators.ts new, index.ts updated)
- **Learnings for future iterations:**
  - Always add explicit `: VimState` type when spreading state with null property overrides
  - OperatorResult returns { state, deletedText?, textType? } for chaining
  - executeOperator() and executeOperatorWithMotion() are main entry points
  - getRegisterContent() retrieves from any register type (named, numbered, special)
  - deleteRange handles both linewise and charwise deletions with proper cursor positioning
---

## 2026-01-14 - US-005
Thread: http://localhost:8317/threads/T-019bbbb7-f910-7378-88d8-49d010166129
- Implemented complete vim text objects in src/lib/simulator/vim/textObjects.ts:
  - iw/aw: inner/a word (aw includes trailing/leading space)
  - iW/aW: inner/a WORD (whitespace-delimited)
  - is/as: inner/a sentence (ends at .!?)
  - ip/ap: inner/a paragraph (blank line separated)
  - i"/a": inner/a double-quoted string
  - i'/a': inner/a single-quoted string
  - i`/a`: inner/a backtick string
  - i(/a( or ib/ab: inner/a parentheses block
  - i[/a[: inner/a bracket block
  - i{/a{ or iB/aB: inner/a brace block
  - i</a<: inner/a angle bracket block
  - it/at: inner/a tag block (HTML/XML)
- Updated src/lib/simulator/vim/index.ts to export textObjects
- Files changed: 2 files (textObjects.ts new, index.ts updated)
- **Learnings for future iterations:**
  - Text objects return TextObjectResult with startLine/startCol/endLine/endCol/linewise
  - executeTextObject(state, type, objectKey) is the main entry point with type "i" or "a"
  - textObjectToMotionResult() converts TextObjectResult to MotionResult for operator integration
  - Bracket matching uses depth tracking to handle nested brackets
  - Tag matching handles nested tags with same name using depth counter
---

## 2026-01-14 - US-006
Thread: http://localhost:8317/threads/T-019bbbbe-402a-741a-b654-8a534e204449
- Implemented complete vim insert mode in src/lib/simulator/vim/insertMode.ts:
  - i enters insert before cursor, a after cursor
  - I enters insert at first non-whitespace, A at end of line
  - o opens new line below and enters insert, O opens above
  - gi goes to last insert position and enters insert
  - gI enters insert at column 0
  - Escape/Ctrl-[ exits insert mode (cursor moves left one if not at start)
  - Backspace deletes character before cursor, joins lines if at start
  - Enter creates new line with proper auto-indent and smart-indent
  - Tab inserts tab or spaces based on expandtab/tabstop settings
  - Ctrl-w deletes word before cursor
  - Ctrl-u deletes to start of line
  - Ctrl-t/Ctrl-d indent/dedent current line
  - Ctrl-n/Ctrl-p trigger completion (shows message in simulator)
  - Ctrl-r{register} inserts register contents
- Updated src/lib/simulator/vim/index.ts to export insertMode
- Files changed: 2 files (insertMode.ts new, index.ts updated)
- **Learnings for future iterations:**
  - Use local getActiveBuffer wrapper that throws on missing buffer to satisfy TypeScript type narrowing
  - Insert mode tracks lastInsertedText for register storage and dot-repeat
  - insertModeStartCol tracks where insert mode started for Escape cursor positioning
  - handleInsertModeKey() is main entry point for processing keys in insert mode
  - executeInsertCommand() handles insert mode entry commands (i, a, I, A, o, O, gi, gI)
---

## 2026-01-14 - US-007
Thread: http://localhost:8317/threads/T-019bbbc5-7313-761b-abcf-d6151d7a76a0
- Implemented complete vim visual mode in src/lib/simulator/vim/visualMode.ts:
  - v enters character-wise visual mode
  - V enters line-wise visual mode
  - Ctrl-v enters block-wise visual mode
  - All motions extend selection in visual mode via visualModeExtendSelection()
  - o swaps cursor to other end of selection (visualSwapEnds)
  - O in block mode moves to other corner (visualBlockSwapCorner)
  - gv reselects last visual selection (reselectLastVisual)
  - d/y/c delete/yank/change selection with proper register handling
  - >/< indent/dedent selected lines
  - ~ toggles case of selection
  - u/U lowercase/uppercase selection
  - J joins selected lines
  - Escape cancels visual mode and stores lastVisualSelection
- Helper functions: getVisualRange for computing TextRange from selection
- Block mode operations handle column-based edits across lines
- Updated src/lib/simulator/vim/index.ts to export visualMode
- Files changed: 2 files (visualMode.ts new, index.ts updated)
- **Learnings for future iterations:**
  - Visual mode stores selection in state.visualSelection with start/end CursorPosition
  - Mode stored in buffer.mode ("visual" | "visual-line" | "visual-block")
  - lastVisualSelection preserved for gv reselect functionality
  - Block mode operations iterate line-by-line applying column ranges
  - handleVisualModeKey() is main entry point for visual mode key processing
---

## 2026-01-14 - US-008
Thread: http://localhost:8317/threads/T-019bbbcb-c584-7239-9f58-79a8e0f024f9
- Implemented complete vim command mode in src/lib/simulator/vim/commands.ts:
  - : enters command mode, Escape cancels
  - :w/:write simulates write (sets modified=false, shows message)
  - :q/:quit simulates quit, :q! force quits
  - :wq/:x write and quit
  - :e/:edit {file} opens file in new buffer or switches to existing
  - :{number} goes to specific line number
  - :s/old/new/[g] substitutes on current line
  - :%s/old/new/g substitutes in entire file
  - :'<,'>s/old/new/g substitutes in visual selection range
  - :noh clears search highlighting
  - :set shows settings, :set {option} toggles, :set {option}? queries
  - :sp/:vs horizontal/vertical split (simulated)
  - :bn/:bp buffer next/previous
  - :bd buffer delete, :bd! force delete
  - :ls/:buffers list all buffers
  - :b {number|name} switch to buffer by number or partial name match
  - :marks shows all marks, :delmarks deletes marks
  - Command history navigation with up/down arrows
  - Tab completion for common commands
- Updated src/lib/simulator/vim/index.ts to export commands
- Files changed: 2 files (commands.ts new, index.ts updated)
- **Learnings for future iterations:**
  - CommandResult includes optional shouldQuit flag for quit commands
  - enterCommandMode() sets buffer.mode to "command" and clears commandLine
  - handleCommandModeKey() is main entry point for command mode key processing
  - executeCommand() parses and executes the command string
  - Command history stored in state.commandLineHistory, index in commandLineHistoryIndex
  - Use explicit type-safe helper functions for VimSettings updates to avoid TypeScript inference issues
---

## 2026-01-14 - US-010
Thread: http://localhost:8317/threads/T-019bbbda-40bd-7698-8128-97a5a771ae27
- Implemented comprehensive vim registers system in src/lib/simulator/vim/registers.ts:
  - getRegisterContentExtended() extends base getRegisterContent with %, #, /, = registers
  - setRegisterContent() for setting named/special registers with clipboard API integration
  - getAllRegisters() returns all registers with descriptions for :registers display
  - formatRegistersDisplay() formats registers for command output
  - readFromClipboard/writeToClipboard for browser clipboard integration
  - syncClipboardToRegister() syncs clipboard content to + or * registers
  - updateLastInsertRegister/updateLastCommandRegister/updateSearchRegister for special registers
  - getWordUnderCursor/getWORDUnderCursor helper functions
- Implemented comprehensive vim marks system in src/lib/simulator/vim/marks.ts:
  - setMark() for setting local (a-z) and global (A-Z) marks
  - getMark() retrieves marks including special marks (., ^, ", ', [, ], <, >)
  - gotoMark() navigates to mark with exact (`) or line (') positioning
  - gotoMarkLine/gotoMarkExact wrapper functions
  - gotoPreviousPosition() for '' navigation
  - deleteMark/deleteMarks/deleteAllMarks for mark deletion
  - getAllMarks() and formatMarksDisplay() for :marks command
  - setLastChangePosition/setChangeRange/setLastExitPosition for automatic marks
  - navigateJumplistBackward/Forward for Ctrl-o/Ctrl-i
  - navigateChangelistBackward/Forward for g;/g,
- Updated src/lib/simulator/vim/index.ts to export registers and marks modules
- Files changed: 3 files (registers.ts new, marks.ts new, index.ts updated)
- **Learnings for future iterations:**
  - When adding new modules with export functions, check for naming conflicts with existing exports
  - operators.ts already has getRegisterContent and storeInRegister - use different names or import from there
  - motions.ts has addToJumplist - import from motions.ts instead of redefining
  - Use `void _removed` pattern to satisfy ESLint when destructuring to remove keys
---

## 2026-01-14 - US-009
Thread: http://localhost:8317/threads/T-019bbbdf-b4d1-744e-9ee9-9bf0fee9833e
- Verified complete vim search and replace system in src/lib/simulator/vim/search.ts:
  - / and ? enter search mode with enterSearchMode(direction)
  - Incremental search via updateSearchPattern() respecting incsearch setting
  - Enter confirms with confirmSearch(), Escape cancels with exitSearchMode()
  - n/N navigate matches with searchNext() and searchPrev()
  - findAllMatches() finds all pattern matches with regex support
  - findNextMatch() handles wrap-around with appropriate messages
  - * and # search word under cursor via searchWordUnderCursor(direction, wholeWord)
  - g* and g# supported by passing wholeWord=false to searchWordUnderCursor()
  - getSearchMatches() and getCurrentMatchIndex() for UI highlighting
  - clearSearchHighlight() for :noh command
  - Search history navigation with navigateSearchHistory()
  - handleSearchModeKey() is main entry point for search mode key processing
- Files changed: 0 (search.ts already existed and was complete)
- **Learnings for future iterations:**
  - Search module already existed from a previous iteration
  - searchWordUnderCursor has wholeWord param (default true) for * vs g* behavior
  - SearchResult type used for all search operations
  - searchState in VimState tracks pattern, matches, currentMatchIndex, highlightEnabled
---

## 2026-01-14 - US-011
Thread: http://localhost:8317/threads/T-019bbbe5-fc2f-7144-a068-b3ca0e2e5c48
- Implemented complete vim macro system in src/lib/simulator/vim/macros.ts:
  - q{a-z} starts recording to register via startMacroRecording()
  - q stops recording via stopMacroRecording()
  - Status bar message "recording @{register}" while recording
  - recordKeystroke() captures all keystrokes during recording
  - @{a-z} plays macro via prepareMacroExecution() which returns keystrokes array
  - @@ repeats last played macro using lastPlayedMacro state
  - {count}@{a-z} supported via count parameter in prepareMacroExecution()
  - Macros can call other macros (keystrokes include @ sequences)
  - Macro execution stops on error (caller handles by checking success flag)
  - getMacrosForDisplay() for :registers integration
  - encodeKeystrokeForMacro() handles special keys (<Esc>, <Enter>, <C-x>, etc.)
  - parseMacroKeystrokes() parses encoded sequences back to keystrokes
  - setMacroContent()/appendToMacro() for uppercase register append behavior
- Updated src/lib/simulator/vim/index.ts to export macros module
- Files changed: 2 files (macros.ts new, index.ts updated)
- **Learnings for future iterations:**
  - Macros stored as string in state.macros[register], not as keystroke arrays
  - prepareMacroExecution() returns { state, keystrokes[], success, error? } - caller executes keystrokes
  - Use <Esc>, <Enter>, <C-x> notation for special keys in macro storage
  - recordingMacro state holds current register being recorded, null when not recording
  - lastPlayedMacro tracks register for @@ repeat functionality
---

## 2026-01-14 - US-012
Thread: http://localhost:8317/threads/T-019bbbec-4388-7091-8ef6-c243c9e3acfe
- Implemented comprehensive vim undo/redo system in src/lib/simulator/vim/undo.ts:
  - u undoes last change via undo(state, count)
  - Ctrl-r redoes via redo(state, count)
  - Linear undo/redo using existing undoStack/redoStack on VimBuffer
  - g- (undoOlderState) and g+ (undoNewerState) for traversing undo tree
  - :earlier {time} and :later {time} commands with time parsing (s/m/h/d)
  - :undolist via getUndoList() shows undo history with timestamps
  - U (undoLineChanges) undoes all changes on current line
  - Changes grouped via BufferSnapshot with timestamps
- Implemented dot repeat (.) functionality:
  - RepeatableCommand interface stores operator/motion/count/insertedText
  - recordOperatorMotionCommand(), recordChangeCommand(), recordInsertCommand(), recordSimpleCommand()
  - executeDotRepeat() executes the last recorded command
  - Supports operators with motions, change commands, insert commands, simple commands (x, dd, etc.)
- Helper functions: toggleCaseAtCursor, joinLines, indentLine, dedentLine
- Updated src/lib/simulator/vim/index.ts to export undo module
- Files changed: 2 files (undo.ts new, index.ts updated)
- **Learnings for future iterations:**
  - undo.ts combines both undo/redo system and dot repeat functionality
  - Use updateActiveBuffer helper for consistent buffer state updates
  - RepeatableCommand uses JSON.stringify/parse for storing in lastCommand string field
  - Time parsing supports seconds (s), minutes (m), hours (h), days (d)
  - undoLineChanges attempts to find snapshot where cursor was on same line
---

## 2026-01-14 - US-013
Thread: http://localhost:8317/threads/T-019bbbf4-6ef2-77ea-8771-806fcb0b9ad1
- Implemented complete vim folding system in src/lib/simulator/vim/folding.ts:
  - za toggles fold under cursor
  - zo opens fold, zc closes fold
  - zO/zC opens/closes all folds recursively under cursor
  - zR opens all folds in file, zM closes all folds
  - zm increases fold level (close largest open), zr decreases (open smallest closed)
  - zj/zk move to next/previous fold
  - [z moves to start of fold, ]z to end
  - zd deletes fold, zE deletes all folds
  - Indent-based fold calculation via calculateIndentFolds()
  - getVisibleLines() for UI to render folded content
  - getFoldIndicator() generates fold preview text ("+-- N lines: preview...")
  - mapVisualLineToActual/mapActualLineToVisual for cursor positioning
  - executeFoldCommand() and handleFoldKey() for key processing
- Updated src/lib/simulator/vim/index.ts to export folding module
- Files changed: 2 files (folding.ts new, index.ts updated)
- **Learnings for future iterations:**
  - Fold type already existed in types.ts with startLine, endLine, collapsed
  - Use getInnermostFoldAtLine() for innermost fold at cursor
  - Folding uses indent levels from tabstop setting for automatic fold generation
  - getVisibleLines() returns array with lineIndex and isFolded flag for rendering
---

## 2026-01-14 - US-014
Thread: http://localhost:8317/threads/T-019bbc06-40f5-708e-bb6f-4f0d197cd328
- Implemented complete vim leader key system in src/lib/simulator/vim/leader.ts:
  - Space activates leader mode with 2-second timeout via enterLeaderMode()
  - Leader mode shows 'LEADER' in status bar, tracks key sequence
  - LEADER_MAPPINGS defines all Space+key sequences with sub-mappings
  - Space Space - find files, Space / - grep search, Space e - toggle explorer
  - Space f* - file finding (ff/fg/fr/fc/fb)
  - Space g* - git actions (gb/gl/gs/gd/gg)
  - Space s* - search actions (sb/sg/sw/sh/sk)
  - Space t* - terminal actions (tf/tb)
  - Space b* - buffer actions (bd delete, bn/bp next/prev)
  - Space u* - toggle options (us spell, uw wrap, ul line numbers, ud diagnostics, etc.)
  - Space c* - code actions (ca action, cr rename, cd definition, cf format)
  - Space v* - view actions (vv format, vs/vh splits)
  - Space w* - window navigation (wh/wj/wk/wl focus, wq close, w= equalize)
  - Two-key sequences work via nested subMappings (e.g., Space g b for git branches)
  - handleLeaderKey() processes keys with timeout checking
  - executeLeaderAction() performs actual actions (toggles, buffer ops, etc.)
  - getAvailableLeaderMappings() and getLeaderMappingHelp() for UI display
- Added leaderActive, leaderKeySequence, leaderTimeoutAt fields to VimState in types.ts
- Updated constants.ts to initialize leader state fields
- Updated src/lib/simulator/vim/index.ts to export leader module
- Files changed: 4 files (leader.ts new, types.ts, constants.ts, vim/index.ts updated)
- **Learnings for future iterations:**
  - Leader mode uses timeout to auto-exit (LEADER_TIMEOUT_MS = 2000ms)
  - LeaderMapping interface supports nested subMappings for multi-key sequences
  - findMapping() recursively searches for exact or partial matches
  - Some toggle actions directly modify state.settings (wrap, line numbers, etc.)
  - Buffer operations (delete, next, prev) are handled in executeLeaderAction
---

## 2026-01-14 - US-015
Thread: http://localhost:8317/threads/T-019bbc10-e39e-7422-b0fa-6560328a7ae8
- Implemented vim g-prefix commands in src/lib/simulator/vim/gCommands.ts:
  - gg goes to first line (via motionGG from motions.ts)
  - gd goes to local definition (first occurrence of word)
  - gD goes to global definition (first occurrence in file)
  - gf goes to file under cursor (shows message)
  - gF goes to file:line under cursor
  - gq{motion} formats text (join lines, wrap at textwidth)
  - gw{motion} formats without moving cursor
  - gU{motion} uppercase, gu{motion} lowercase
  - g~ toggles case of motion
  - gv reselects last visual selection (renamed to gvReselectLastVisual to avoid conflict)
  - gi goes to last insert position and enters insert mode
  - gI inserts at column 0
  - gJ joins lines without space
  - g; goes to older change position, g, to newer
  - ga shows ASCII value of character under cursor
  - g8 shows UTF-8 bytes of character
- Files changed: 2 files (gCommands.ts new, vim/index.ts updated)
- **Learnings for future iterations:**
  - handleGCommand() is main entry point for g-prefix commands
  - handleGOperator() handles operators like gU, gu, g~, gq, gw
  - Avoid naming conflicts with existing exports (e.g., reselectLastVisual)
---

## 2026-01-14 - US-016
Thread: http://localhost:8317/threads/T-019bbc10-e39e-7422-b0fa-6560328a7ae8
- Implemented vim z-prefix scroll commands in src/lib/simulator/vim/zCommands.ts:
  - zz centers current line on screen
  - zt scrolls current line to top of screen
  - zb scrolls current line to bottom of screen
  - z<Enter> like zt but also moves to first non-blank
  - z- like zb but also moves to first non-blank
  - z. like zz but also moves to first non-blank
  - zH scrolls screen half width left
  - zL scrolls screen half width right
  - zs scrolls screen to put cursor at start
  - ze scrolls screen to put cursor at end
- Returns scrollAction in result for UI to handle actual scrolling
- Files changed: 2 files (zCommands.ts new, vim/index.ts updated)
- **Learnings for future iterations:**
  - ZCommandResult includes optional scrollAction for UI to process
  - handleZScrollCommand() is main entry point
  - Scroll amounts need visibleWidth parameter for horizontal scrolling
---

## 2026-01-14 - US-017 through US-025
Thread: http://localhost:8317/threads/T-019bbc10-e39e-7422-b0fa-6560328a7ae8
- Created complete tmux module in src/lib/simulator/tmux/:
  - state.ts: Session management (create, rename, list, navigate sessions)
  - windows.ts: Window management (create, kill, rename, move, switch windows)
  - panes.ts: Pane splitting (horizontal/vertical), close, select, toggle zoom
  - navigation.ts: Spatial pane navigation (left/right/up/down), next, last active, swap, break to window
  - resize.ts: Pane resizing (left/right/up/down), cycle/apply layouts
  - copyMode.ts: Copy mode (enter/exit, vim motions, selection, yank, search)
  - paste.ts: Paste buffer management (paste, list, delete, add, select)
  - commands.ts: Tmux command mode (parse/execute commands, history, completion)
  - mouse.ts: Mouse mode (toggle, pane click, window click, border drag, scroll, copy mode drag)
- Updated src/lib/simulator/index.ts to export vim and tmux as namespaces (to avoid conflicts)
- Files changed: 10 files (9 new in tmux/, index.ts updated)
- **Learnings for future iterations:**
  - Use namespace exports when modules have conflicting function names
  - TmuxState types already defined in types.ts
  - Helper functions: getActiveSession(), getActiveWindow(), getActivePane()
  - Each module has its own Result interface (TmuxStateResult, TmuxWindowResult, etc.)
---

## 2026-01-14 - US-028
Thread: http://localhost:8317/threads/T-019bbc10-e39e-7422-b0fa-6560328a7ae8
- Created src/lib/simulator/layout.ts for pane layout engine:
  - calculatePaneLayout() computes pane positions using recursive tree algorithm
  - recalculateLayout() updates dimensions on container resize
  - getPaneBorderPositions() returns border coordinates for rendering
  - Supports horizontal/vertical splits with minimum size enforcement (10x3 chars)
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## 2026-01-14 - US-030, US-031, US-032, US-034
Thread: http://localhost:8317/threads/T-019bbc10-e39e-7422-b0fa-6560328a7ae8
- Updated src/components/KeyboardVisualizer.tsx:
  - Last 5 keystrokes with timestamps and fade out (3s)
  - Keyboard key styling (3D keycap effect)
  - Modifier keys, special keys, pending operators, leader, tmux prefix
- Created src/components/FileExplorer.tsx:
  - Neo-tree style panel with toggle (F9 / Space e)
  - File tree with folder icons, j/k navigation
  - Full file operations (a/A, d, r, y/Y, x/p, H, /)
- Created src/lib/simulator/filesystem.ts:
  - In-memory file system with directory structure
  - Pre-populated with src/, tests/, docs/, config/
  - All file operations (create, read, update, delete, rename)
- Created src/components/Picker.tsx:
  - Modal overlay with fuzzy search
  - Matched character highlighting
  - j/k navigation, preview pane, multiple modes
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