kte/ROADMAP.md

kte ROADMAP — from skeleton to a working editor

Scope for “working editor” v0.1

• Runs in a terminal; opens files passed on the CLI or an empty buffer.
• Basic navigation, insert/delete, newline handling.
• Status line and message area; shows filename, dirty flag, cursor position.
• Save file(s) to disk safely; quit/confirm on dirty buffers.
• Core ke key chords: C-g (cancel), C-k s/x/q/C-q, C-l, basic arrows, Enter/Backspace, C-s (simple find).

Guiding principles

• Keep the core small and understandable; evolve incrementally.
• Separate model (Buffer/Editor), control (Input/Command), and view (Renderer).
• Favor terminal first; GUI hooks arrive later behind interfaces.

✓ Milestone 0 — Wire up a minimal app shell

1. main.cpp
   • Replace demo printing with real startup using Editor.
   • Parse CLI args; open each path into a buffer (create empty if none). ✓ when kte file1 file2 loads buffers and exits cleanly.
2. Editor integration
   • Ensure Editor can open/switch/close buffers and hold status messages.
   • Add a temporary “headless loop” to prove open/save calls work.

✓ Milestone 1 — Command model

1. Command vocabulary
   • Flesh out Command.h/.cpp: enums/struct for operations and data (e.g., InsertChar, MoveCursor, Save, Quit, FindNext, etc.).
   • Provide a dispatcher entry point callable from the input layer to mutate Editor/Buffer.
   • Definition of done: commands exist for minimal edit/navigation/save/quit; no rendering yet.

✓ Milestone 2 — Terminal input

1. Input interfaces
   • Add InputHandler.h interface plus TerminalInputHandler implementation.
   • Terminal input via ncurses (getch, keypad, non‑blocking with nodelay), basic key decoding (arrows, Ctrl, ESC sequences).
2. Keymap
   • Map ke chords to Command (C-k prefix handling, C-g cancel, C-l refresh, C-k s/x/q/C-q, C-s find start, text input → InsertChar).
3. Event loop
   • Introduce the core loop in main: read key → translate to Command → dispatch → trigger render.

✓ Milestone 3 — Terminal renderer

1. View interfaces
   • Add Renderer.h with TerminalRenderer implementation (ncurses‑based).
2. Minimal draw
   • Render viewport lines from current buffer; draw status bar (filename, dirty, row:col, message).
   • Handle scrolling when cursor moves past edges; support window resize (SIGWINCH).
3. Cursor
   • Place terminal cursor at logical buffer location (account for tabs later; start with plain text).

Milestone 4 — Buffer fundamentals to support editing

1. GapBuffer
   • Ensure GapBuffer supports insert char, backspace, delete, newline, and efficient cursor moves.
2. Buffer API
   • File I/O (open/save), dirty tracking, encoding/line ending kept simple (UTF‑8, LF) for v0.1.
   • Cursor state, mark (optional later), and viewport bookkeeping.
3. Basic motions
   • Left/Right/Up/Down, Home/End, PageUp/PageDown; word f/b (optional in v0.1).

Milestone 5 — Core editing loop complete

1. Tighten loop timing
   • Ensure keystroke→update→render latency is reliably low; avoid unnecessary redraws.
2. Status/messages
   • Editor::SetStatus() shows transient messages; C-l forces full refresh.
3. Prompts
   • Minimal prompt line for save‑as/confirm quit; blocking read in prompt mode is acceptable for v0.1.

Milestone 6 — Search (minimal)

1. Incremental search (C-s)
   • Simple forward substring search with live highlight of current match; arrow keys navigate matches while in search mode (ke‑style quirk acceptable).
   • ESC/C-g exits search; Enter confirms and leaves cursor on match.

Milestone 7 — Safety and polish for v0.1

1. Safe writes
   • Write to temp file then rename; preserve permissions where possible.
2. Dirty/quit logic
   • Confirm on quit when any buffer is dirty; C-k C-q bypasses confirmation.
3. Resize/terminal quirks
   • Handle small terminals gracefully; no crashes on narrow widths.
4. Basic tests
   • Unit tests for GapBuffer, Buffer open/save round‑trip, and command mapping.

Out of scope for v0.1 (tracked, not blocking)

• Undo/redo, regex search, kill ring, word motions, tabs/render width, syntax highlighting, piece table selection, GUI.

Implementation notes (files to add)

• Input: InputHandler.h, TerminalInputHandler.cc/h (ncurses).
• Rendering: Renderer.h, TerminalRenderer.cc/h (ncurses).
• Prompt helpers: minimal utility for line input in raw mode.
• Platform: small termios wrapper; SIGWINCH handler.

Acceptance checklist for v0.1

• Start: ./kte [files] opens files or an empty buffer.
• Edit: insert text, backspace, newlines; move cursor; content scrolls.
• Save: C-k s writes file atomically; dirty flag clears; status shows bytes written.
• Quit: C-k q confirms if dirty; C-k C-q exits without confirm; C-k x save+exit.
• Refresh: C-l redraws.
• Search: C-s finds next while typing; ESC cancels.

Next concrete step

• Stabilize cursor placement and scrolling logic; add resize handling and begin minimal prompt for save‑as.