Add mode switching.

PLAN.md

@@ -1,77 +1,40 @@
 # Implementation Plan
 
-## Phase 1: Minimal Conversation Loop
-
-**Done when:** Multi-turn streaming conversation with Claude works in terminal
-
-### 1.1 Project Scaffolding
-- `Cargo.toml` with initial dependencies:
-  - `ratatui`, `crossterm` — TUI
-  - `tokio` (full features) — async runtime
-  - `serde`, `serde_json` — serialization
-  - `thiserror` — error types
-  - `tracing`, `tracing-subscriber` — structured logging
-  - `reqwest` (with `stream` feature) — HTTP client for SSE
-  - `futures` — stream combinators
-- Establish `src/{app,tui,core,provider}/mod.rs` stubs
-- `cargo build` passes; `cargo clippy -- -D warnings` passes on empty stubs
-
-### 1.2 Shared Types (`src/core/types.rs`)
-- `StreamEvent` enum: `TextDelta(String)`, `InputTokens(u32)`, `OutputTokens(u32)`, `Done`, `Error(String)`
-- `UserAction` enum (TUI → core channel): `SendMessage(String)`, `Quit`
-- `UIEvent` enum (core → TUI channel): `StreamDelta(String)`, `TurnComplete`, `Error(String)`
-- `ConversationMessage` struct: `role: Role`, `content: String`
-- All types derive `Debug`; all public types have doc comments
-
-### 1.3 Provider: `ModelProvider` Trait + Claude SSE (`src/provider/`)
-- `ModelProvider` trait: `async fn stream(&self, messages: &[ConversationMessage]) -> impl Stream<Item = StreamEvent>`
-- `ClaudeProvider` struct: API key from env, `reqwest` HTTP client
-- Serialize messages to Anthropic Messages API JSON format
-- Parse SSE byte stream → `StreamEvent` (handle `content_block_delta`, `message_delta` for tokens, `message_stop`)
-- Unit tests: SSE parsing from hardcoded byte fixtures in `#[cfg(test)]`
-
-### 1.4 Core: Conversation State + Orchestrator Loop (`src/core/`)
-- `ConversationHistory`: `Vec<ConversationMessage>` with `push` and `messages()` (flat list, no tree yet)
-- `Orchestrator` struct holding history, provider, channel senders/receivers
-- Orchestrator loop:
-  1. Await `UserAction` from TUI channel
-  2. On `SendMessage`: append user message, call `provider.stream()`
-  3. Forward each `StreamEvent` as `UIEvent` to TUI
-  4. Accumulate deltas into assistant message; append to history on `Done`
-  5. On `Quit`: break loop
-
-### 1.5 TUI: Layout + Input + Streaming Display (`src/tui/`)
-- `AppState` struct: `messages: Vec<(Role, String)>`, `input: String`, `scroll: u16`
-- Ratatui layout: full-height `Paragraph` output area (scrollable) + single-line `Paragraph` input
-- Insert mode only — printable chars append to `input`, Enter sends `UserAction::SendMessage`, Backspace deletes
-- On `UIEvent::StreamDelta`: append to last assistant message in `messages`, re-render
-- On `UIEvent::TurnComplete`: finalize assistant message
-- Crossterm raw mode enter/exit; restore terminal on panic or clean exit
-
-### 1.6 App Wiring + Entry Point (`src/app/`, `src/main.rs`)
-- `main.rs`: parse `--project-dir <path>` CLI arg
-- Initialize `tracing_subscriber` (log to file, not stdout — avoids TUI interference)
-- Create `tokio::sync::mpsc` channel pair for `UserAction` and `UIEvent`
-- Spawn `Orchestrator::run()` as a tokio task
-- Run TUI event loop on main thread (Ratatui requires main thread for crossterm)
-- On `UserAction::Quit` or Ctrl-C: signal orchestrator shutdown, restore terminal, exit cleanly
-
-### 1.7 Phase 1 Unit Tests
-- Provider: SSE byte fixture → correct `StreamEvent` sequence
-- Provider: `ConversationMessage` vec → correct Anthropic API JSON shape
-- Core: `ConversationHistory` push/read roundtrip
-- Core: Orchestrator state transitions against mock `StreamEvent` sequence (no real API)
-
 ## Phase 2: Vim Modes and Navigation
-- Normal, Insert, Command modes with visual indicator
-- `j`/`k` scroll in Normal mode
-- `:quit`, `:clear` commands
-- **Done when:** Fluid mode switching and scrolling feels vim-native
+
+**Done when:** Fluid mode switching and scrolling feels vim-native
+
+### 2.3 Command Parser + Execution
+- Parse command buffer on enter: `:quit` -> `Quit`, `:clear` -> clear messages and history, `:q` alias for `:quit`
+- Return appropriate `LoopControl` or mutate `AppState` directly for display-only commands
+- Unknown commands -> show error in a transient status area
+
+### 2.4 Status Bar + Command Overlay
+- Add a status bar row at the bottom of the layout (below input pane)
+- Status bar shows: current mode (`-- NORMAL --`, `-- INSERT --`), token totals (placeholder for now)
+- Style: bold, color-coded per mode (following vim convention)
+- Command input renders as a floating bar near the top of the screen (overlay on the output pane), not in the status bar
+- Command overlay: shows `:` prefix + partial command buffer, only visible in Command mode
+- Overlay dismisses on Esc or Enter
+
+### 2.6 Input Pane Behavior by Mode
+- Normal mode: input pane shows last draft (unsent) message or is empty, not editable
+- Insert mode: input pane is editable (current behavior)
+- Command mode: floating overlay near top shows `:` prefix + command buffer; input pane unchanged
+- Cursor visibility: show cursor in Insert and Command modes, hide in Normal
+
+### 2.7 Phase 2 Unit Tests
+- Mode transitions: Normal->Insert->Normal, Normal->Command->Normal, Command execute
+- Key dispatch: correct handler called per mode
+- Command parser: `:quit`, `:clear`, `:q`, unknown command
+- Scroll clamping: j/k at boundaries, G/gg
+- `insta` snapshot tests: mode indicator rendering for each mode, layout with status bar
+- Existing Phase 1 input tests still pass (insert mode behavior unchanged)
 
 ## Phase 3: Tool Execution
 - `Tool` trait, `ToolRegistry`, core tools (`read_file`, `write_file`, `shell_exec`)
 - Tool definitions in API requests, parse tool-use responses
-- Approval gate: core → TUI pending event → user approve/deny → result back
+- Approval gate: core -> TUI pending event -> user approve/deny -> result back
 - Working directory confinement + path validation (no Landlock yet)
 - **Done when:** Claude can read, modify files, and run commands with user approval
 
@@ -81,8 +44,3 @@
 - `:net on/off` toggle, state in status bar
 - Graceful degradation on older kernels
 - **Done when:** Writes outside project dir fail; network toggle works
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