# `src/gui_2.py` — Main ImGui Application

[Top](../README.md) | [Architecture](guide_architecture.md) | [Testing](guide_testing.md)

---

## Overview

`src/gui_2.py` is the **largest file** in the project (~260KB, ~5400 lines). It contains the `App` class — the main ImGui application orchestrator — and ~90 module-level render functions that draw the GUI.

The file is divided into:

- **Module-level render functions** (~90 functions): pure `def render_xxx(app: App) -> None` functions that draw individual panels
- **`App` class** (~1500 lines): the main application with state, lifecycle, and the per-frame render loop in `_gui_func`

---

## Architecture

The file follows the project's **UI delegation pattern** (see [guide_architecture.md](guide_architecture.md)):

- Module-level functions do the drawing. They take `app: App` as their first parameter.
- The `App` class holds state and dispatches.
- Thin wrapper methods on `App` (e.g., `_render_message_panel(self)`) just call the module-level function.

This pattern enables:
- **Hot Reload**: module-level functions can be reloaded via `importlib.reload` without breaking the App class
- **Testability**: pure functions can be tested in isolation with a mock `App`
- **Consistency**: every render function follows the same calling convention

```
┌────────────────────────────────────────────────────┐
│ _gui_func (App method, ~50 lines)                  │
│ - Detects Ctrl+Shift+P, Ctrl+Alt+R, etc.          │
│ - Renders background shader                         │
│ - Renders custom title bar                          │
│ - Calls render_main_interface(self) ← thin wrapper  │
└──────────────────┬─────────────────────────────────┘
                   │ calls
                   ▼
┌────────────────────────────────────────────────────┐
│ render_main_interface(app)                          │
│ - Iterates over the major panels                    │
│ - Calls render_<hub>(app) for each hub              │
│ - Handles modal popups                              │
└──────────────────┬─────────────────────────────────┘
                   │ calls
                   ▼
┌────────────────────────────────────────────────────┐
│ render_<panel>(app) (~80 functions)                  │
│ - Each draws one panel (Context, AI, Discussion,    │
│   Operations, MMA Dashboard)                        │
│ - Reads from app state, writes to app state         │
│ - Returns nothing; mutates via side effects         │
└────────────────────────────────────────────────────┘
```

---

## The `App` Class

### `App.__init__`

The constructor (line 131) is long. It:

1. Creates the `AppController` (the headless counterpart)
2. Initializes `history.HistoryManager(max_capacity=100)` for undo/redo
3. Sets up UI state flags: `show_windows`, `show_*_modal` flags
4. Initializes the workspace manager
5. Starts services via `controller.start_services(self)`
6. Registers predefined callbacks on the controller for the Hook API:
   ```python
   self.controller._predefined_callbacks['save_context_preset'] = self.save_context_preset
   self.controller._predefined_callbacks['_toggle_command_palette'] = self._toggle_command_palette
   # ... ~10 more
   ```
7. Registers gettable fields for the Hook API:
   ```python
   self.controller._gettable_fields['show_command_palette'] = 'show_command_palette'
   ```

### Key State

The App holds dozens of state attributes. The most important:

| Attribute | Type | Purpose |
|---|---|---|
| `self.controller` | `AppController` | Headless counterpart; services and callbacks |
| `self.disc_entries` | `list[dict]` | Current discussion entries |
| `self.disc_roles` | `list[str]` | Roles per entry (User, AI, System, etc.) |
| `self.discussion_history` | `list` | Legacy alias for disc_entries |
| `self.context_files` | `list[FileItem]` | Files in the current context |
| `self.ui_file_paths` | `list[str]` | Tracked file paths |
| `self.ai_status` | `str` | Current AI state ("idle", "sending...", etc.) |
| `self.ai_response` | `str` | Latest AI response text |
| `self.last_md` | `str` | Last generated markdown (for MD-only mode) |
| `self.show_windows` | `dict[str, bool]` | Toggle state for each window |
| `self.workspace_profiles` | `dict` | Loaded workspace profiles |
| `self._comms_log` | `deque` | Communication log (in-memory) |
| `self._tool_log` | `deque` | Tool call log |
| `show_command_palette` | `bool` | Command palette visibility |

### Render Entry Point: `_gui_func` (line 754)

The main render loop, called by imgui-bundle's Hello ImGui runner every frame:

```python
def _gui_func(self) -> None:
    io = imgui.get_io()

    # Keyboard shortcuts
    if io.key_ctrl and io.key_alt and imgui.is_key_down(imgui.Key.r):
        self._trigger_hot_reload()
    if (io.key_ctrl and io.key_shift
            and not io.key_alt and not io.key_super
            and imgui.is_key_pressed(imgui.Key.p)):
        self.show_command_palette = not self.show_command_palette
        # Reset per-open state...

    # Render background shader (if enabled)
    render_custom_title_bar(self)
    render_shader_live_editor(self)
    render_history_window(self)
    # ... background rendering ...

    # Main content
    render_main_interface(self)

    # Error tint on hot-reload failure
    render_error_tint(self)
```

### `render_main_interface` (line 1259)

The "main content" renderer. Iterates over the major panels and calls the right render function for each:

```python
def render_main_interface(app: App) -> None:
    # Background panels (always rendered if shown)
    render_history_window(app)
    render_track_proposal_modal(app)
    render_patch_modal(app)
    # ... all the modals ...

    # Hubs
    render_project_settings_hub(app)
    render_ai_settings_hub(app)
    render_files_and_media(app)
    render_discussion_hub(app)
    render_operations_hub(app)
    render_mma_dashboard(app)
    # ... etc
```

### Modal Helpers

- **`_render_window_if_open(name, render_func, flag_condition=True)`** (line 800): helper that renders a window only if its toggle is active. Uses `imscope.window` context manager.
- **`imscope`** from `src/imgui_scopes.py`: stack-style context managers for `imgui.begin/end`, `imgui.push_style/pop_style`, etc. — replaces the legacy push/pop pattern with Pythonic `with` statements.

---

## Keyboard Shortcuts

Implemented in `_gui_func`:

| Shortcut | Action |
|---|---|
| `Ctrl+Alt+R` | Hot Reload the GUI module |
| `Ctrl+Shift+P` | Toggle Command Palette |
| `Ctrl+L` | Clear AI input field |
| `Ctrl+Enter` | Generate + Send |
| `Escape` (in modals) | Close the modal |

Other shortcuts are handled in individual render functions (e.g., `Ctrl+S` in the project settings).

---

## Key Patterns

### Module-Level Render Functions

Every render function follows this signature:

```python
def render_<thing>(app: App) -> None:
    """One-line docstring describing what this draws."""
    if app.perf_profiling_enabled:
        app.perf_monitor.start_component("<thing>")
    # ... draw ImGui widgets, reading from and writing to app state ...
    if app.perf_profiling_enabled:
        app.perf_monitor.end_component("<thing>")
```

- Takes `app: App` as the only positional arg
- Returns `None`
- Defensive: checks `hasattr(app, "...")` before touching state, in case the state was never initialized

### Custom Title Bar

`render_custom_title_bar` (line 1358) draws a custom ImGui-drawn title bar (instead of the OS title bar) for the cross-platform PyOpenGL-backed window. The Windows-specific close/min/max/close buttons are added via ctypes in the same function (lines 858-865).

### Hot Reload Hook

The Hot Reload module (`src/hot_reloader.py`) registers `src.gui_2` as a hot-reloadable module. The `state_keys` list (line 155) tells the reloader which App attributes to snapshot and restore:

```python
state_keys=['active_discussion', 'show_windows', 'ui_file_paths',
           'ui_screenshot_paths', 'disc_entries', 'disc_roles']
```

`delegation_targets` (line 156) lists the module-level functions the App calls into:
```python
delegation_targets=['_render_main_interface', '_render_discussion_hub',
                    '_render_files_and_media', '_render_ai_settings_hub',
                    '_render_operations_hub', '_render_mma_dashboard']
```

The user presses `Ctrl+Alt+R` → `_trigger_hot_reload()` → `HotReloader.reload("src.gui_2", app)`. The module is re-imported, the App's state is restored, and the next frame uses the new render functions.

### Snapshots (Undo/Redo)

`App._take_snapshot` and `App._apply_snapshot` (lines 548, 567) capture and restore UI state for the undo/redo system. Used by the discussion view's edit-in-place operations.

Snapshots include: `ai_input`, `project_system_prompt`, `global_system_prompt`, `base_system_prompt`, `use_default_base_prompt`, `temperature`, `top_p`, `max_tokens`, `auto_add_history`, `disc_entries`, `files`, `screenshots`.

---

## Window State Management

The `app.show_windows: dict[str, bool]` is the central toggle for all toggleable windows:

```python
self.show_windows.setdefault("Text Viewer", False)
self.show_windows.setdefault("Diagnostics", False)
self.show_windows.setdefault("Usage Analytics", False)
self.show_windows.setdefault("Context Preview", False)
self.show_windows.setdefault("Tier 1: Strategy", False)
self.show_windows.setdefault("Tier 2: Tech Lead", False)
self.show_windows.setdefault("Tier 3: Workers", False)
self.show_windows.setdefault("Tier 4: QA", False)
self.show_windows.setdefault('External Tools', False)
self.show_windows.setdefault('Shader Editor', False)
self.show_windows.setdefault('Undo/Redo History', False)
```

The Command Palette exposes all of these via the `toggle_*` commands (32 total in `src/commands.py`).

---

## Modal Pattern

Modals use `imgui.begin_popup_modal` or the `if imgui.begin(...): ... imgui.end()` pattern. The codebase has moved toward using `imscope.window` (line 800) for cleaner scoping:

```python
def _render_window_if_open(self, name, render_func, flag_condition=True):
    if not flag_condition or not self.show_windows.get(name, False):
        return
    with imscope.window(name, self.show_windows[name]) as (exp, opened):
        if not opened:
            self.show_windows[name] = False
        if exp:
            render_func(self)
```

Modals that need explicit state (e.g., "command palette" or "approve script") use `app.show_<thing>_modal: bool` directly.

---

## Public Methods Worth Knowing

| Method | Line | Purpose |
|---|---|---|
| `__init__` | 131 | Construct the App and all subsystems |
| `run` | ~1252 | Launch the ImGui render loop |
| `reset_session` | ~500 | Clear the AI session and discussion |
| `save_context_preset` / `load_context_preset` | varies | Preset CRUD |
| `_handle_generate_send` | 492 | The "Generate + Send" button handler |
| `_handle_md_only` | 499 | The "Generate MD Only" button handler |
| `_take_snapshot` / `_apply_snapshot` | 548 / 567 | Undo/redo snapshot system |
| `_capture_workspace_profile` | 602 | Capture the current layout as a profile |
| `_apply_workspace_profile` | 625 | Apply a saved profile |
| `_handle_undo` / `_handle_redo` | 632 / 652 | Undo/redo handlers |
| `_toggle_command_palette` | 732 | Test helper for opening the palette via the hook API |
| `_gui_func` | 754 | The main per-frame render function |
| `_show_menus` | 807 | The menu bar (File, Windows, Project, Layout) |

---

## Performance Considerations

- **Frame budget**: target 60 FPS (16.67ms/frame). Heavy panels like the MMA dashboard and tier stream panels use `imscope` to skip work when not visible.
- **Performance monitor**: `app.perf_monitor` tracks per-component timing. Set `app.perf_profiling_enabled = True` to enable.
- **Heavy text**: `render_heavy_text` (line 4589) is the wrapper for displaying large blocks of text (used by text viewer, logs).
- **Background rendering**: Background shader (`bg_shader.py`) and ImGui draw lists are batched per frame.

---

## Testing

The App class is the integration target for most `live_gui` tests. Common patterns:

### Pure Tests (no app)

```python
def test_my_helper():
    from src.gui_2 import render_some_thing
    # ... test the render function with a mock app ...
```

### Integration via `live_gui`

```python
def test_my_thing(live_gui):
    client = ApiHookClient()
    client.push_event("custom_callback", {
        "callback": "_my_method",
        "args": [],
    })
    time.sleep(0.5)
    assert client.get_value("my_field") == "expected"
```

### Mock App

```python
def test_with_mock(mock_app):
    mock_app.some_attr = "test"
    from src.gui_2 import render_main_interface
    render_main_interface(mock_app)
    # Assert on side effects
```

See [guide_testing.md](guide_testing.md) for the full test infrastructure.

---

## Common Operations

### Adding a New Toggleable Window

1. Add the key to `show_windows` in `__init__`:
   ```python
   self.show_windows.setdefault("My Window", False)
   ```
2. Add a render function:
   ```python
   def render_my_window(app: App) -> None:
       if not app.show_windows.get("My Window", False):
           return
       with imscope.window("My Window", app.show_windows["My Window"]) as (exp, opened):
           if not opened:
               app.show_windows["My Window"] = False
           if exp:
               # ... draw the window ...
   ```
3. Call it from `render_main_interface`.
4. Add a command in `src/commands.py` for keyboard access:
   ```python
   @registry.register
   def toggle_my_window(app: "App") -> None:
       from src.commands import _toggle_window
       _toggle_window(app, "My Window")
   ```

### Adding a New Modal

1. Add a state flag in `__init__`:
   ```python
   self.show_my_modal: bool = False
   ```
2. Add a render function that uses `imgui.begin_popup_modal` or the begin/end pattern.
3. Call it from `render_main_interface`.
4. Optionally add a Hook API gettable field for testing.

### Exposing a New Method via the Hook API

In `__init__`:
```python
self.controller._predefined_callbacks['_my_method'] = self._my_method
self.controller._gettable_fields['show_my_thing'] = 'show_my_thing'
```

The test can then invoke via:
```python
client.push_event("custom_callback", {"callback": "_my_method", "args": []})
value = client.get_value("show_my_thing")
```

### Theme Color-Callable Pattern

Theme color helpers in `src/theme_2.py` (`C_LBL`, `C_VAL`, `C_OUT`, `C_IN`, `C_OK`, `C_ERR`, etc.) are **callable functions, not `ImVec4` values**. This is intentional: it lets the active theme be swapped at runtime and have the new colors take effect on the next render frame, instead of capturing stale colors at module import time.

**Correct usage** — call the function at the use site:
```python
imgui.text_colored(C_LBL(), "Completed:")
imgui.text_colored(C_VAL(), str(value))
```

**Common bug** — storing the function in a dict keyed by name, then passing the function (not its result) to `imgui.text_colored`:
```python
DIR_COLORS = {
    "request": C_OUT,
    "response": C_IN,
}
# ... later ...
d_col_fn = DIR_COLORS.get(direction, C_VAL)  # WRONG: stores the function
imgui.text_colored(d_col_fn(), direction)     # CORRECT: calls it
```

This pattern is used in `src/gui_2.py:3705-3707` (the `render_comms_history_panel` `DIR_COLORS`/`KIND_COLORS` dicts). The bug shipped in the multi-themes track commit `7ea52cbb` and was caught by `1469ecac` — `imgui.text_colored` was being passed a callable instead of an `ImVec4`, raising `TypeError` on every render frame.

When writing tests that assert theme color usage, **patch `src.theme_2.imgui`** so `theme.get_color()` returns the mock's `ImVec4`, and assert with `C_LBL()` (called), not `C_LBL` (the function).

### Workspace Profile Defer-Not-Catch

`_capture_workspace_profile` (line 601) calls `imgui.save_ini_settings_to_memory()` to serialize the current ImGui layout. This C function **crashes the Python process with `0xc0000005` access violation** when called in the first few render frames because ImGui's internal state (Fonts, DisplaySize, Settings) isn't yet fully initialized. The crash is **not catchable from Python** — it's a native access violation, not a Python exception.

The fix uses a **defer-not-catch** pattern: a one-shot `_ini_capture_ready` flag in the instance state. The first call (during initial startup) returns an empty profile and flips the flag; subsequent calls (when the user actually clicks "Save Profile") invoke the C function. The user's workflow is unaffected because the first call is non-blocking and the user cannot have clicked "Save Profile" before the GUI was fully rendered.

This pattern unblocks 4-5 live_gui tests that were crashing the GUI subprocess during the first render frames after a `save_workspace_profile` Hook API callback. See [guide_testing.md](guide_testing.md#known-gotchas-2026-06-05) for the broader pattern and how to recognize these crashes.

**Sentinel type contract.** When implementing a defer-not-catch guard, the early-return sentinel value must match the type contract of the downstream consumer. For `WorkspaceProfile.ini_content: str` (in this codebase), the sentinel must be `""` (str), not `b""` (bytes) — `tomli_w` rejects bytes (`TypeError: Object of type 'bytes' is not TOML serializable`), and `imgui.load_ini_settings_from_memory(ini_data: str, ...)` also expects `str`. A previous version of this fix used `b""` and silently broke the save flow via a `TypeError` raised by `tomli_w.dump`; tests passed unit-test-wise but failed in the live_gui save+load round-trip. The fix was a 1-character change (`b""` → `""`). The regression test in `tests/test_workspace_profile_serialization.py` encodes this contract.

### The `__getattr__` / `__setattr__` State Delegation Pattern

The `App` class (around line 478-487) defines two descriptor hooks that delegate state to the `AppController`:

```python
def __getattr__(self, name: str) -> Any:
 if name == 'controller':
  raise AttributeError(name)
 return getattr(self.controller, name)

def __setattr__(self, name: str, value: Any) -> None:
 if name != 'controller' and hasattr(self, 'controller') and hasattr(self.controller, name):
  setattr(self.controller, name, value)
 else:
  object.__setattr__(self, name, value)
```

**Why this matters:**
- The `Controller` is the single source of truth for settable state (e.g. `ui_ai_input`, `ui_separate_tier1`, `show_windows`, `temperature`).
- The `App` is a thin view layer that delegates reads (`__getattr__`) and writes (`__setattr__`) to the Controller.
- This means: **do NOT add `self.ui_ai_input = ""` in `App.__init__` for fields that the Controller owns.** The Controller initializes them via its own `__init__`. If the App initializes them too, the App's value shadows the Controller's (and `__getattr__` returns the App's value, not the Controller's).

**Safe App-only state (no Controller counterpart):**
- `ui_separate_context_preview`, `ui_separate_message_panel`, `ui_separate_response_panel`, `ui_separate_tool_calls_panel`, `ui_separate_external_tools`, `ui_discussion_split_h` — these are NOT in the Controller's `_settable_fields`, so `__setattr__` falls through to `object.__setattr__` and stores them on the App.
- Private App state (`_ini_capture_ready`, `_pending_gui_tasks`, etc.) is also App-only.

**Subtle gotcha:** the `hasattr(self.controller, name)` check in `__setattr__` returns `False` for App-only fields on the **first** write (because the Controller doesn't have the attribute yet). The write goes to the App. The Controller never gets the attribute. This is the **correct** behavior for App-only fields, but **wrong** for Controller-owned fields that haven't been initialized in the Controller's `__init__`. Always make sure Controller-owned fields are initialized in `AppController.__init__` (or in `init_state` called from there) so `__setattr__`'s `hasattr` check returns `True`.

### Indentation Gotcha (CRITICAL)

**The bug:** A class method defined with the right intent (2-space indent) may be parsed as **nested inside the previous function** if indentation is off by even one space. The file "passes" syntactically (imports OK) but the method is **not** on the class. `hasattr(App, 'method_name')` returns `False`. Any production code that calls `app.method_name` falls through to `__getattr__`, delegates to the Controller (which also doesn't have the method), and a cryptic `AttributeError` is raised at runtime.

**How to detect:** Use AST to list all App methods. The skeleton via `manual-slop_py_get_skeleton` should show the method as a class member. If the AST walk doesn't find the method, it's nested.

```bash
uv run python -c "import ast; tree = ast.parse(open('src/gui_2.py').read()); [print(item.name) for n in ast.walk(tree) if isinstance(n, ast.ClassDef) and n.name == 'App' for item in n.body if isinstance(item, ast.FunctionDef)]"
```

**How to fix:** Re-indent the affected method to 2-space class level. This bit the project in 2026-06-05 during a cleanup commit: `_capture_workspace_profile` was being parsed as nested inside `_apply_snapshot` due to a 1-space indentation drift, breaking 3 live_gui tests (test_auto_switch_sim, test_workspace_profiles_restoration, test_undo_redo_lifecycle).

---



---

## See Also

- **[guide_architecture.md](guide_architecture.md#the-task-pipeline-producer-consumer-synchronization)** — Threading model that the App respects
- **[guide_command_palette.md](guide_command_palette.md)** — The 32 commands accessible via Ctrl+Shift+P
- **[guide_testing.md](guide_testing.md)** — Test infrastructure for GUI tests
- **[guide_hot_reload.md](guide_hot_reload.md)** — How Ctrl+Alt+R reloads this file
- **[guide_themes.md](guide_themes.md)** — TOML theme system; defines the `C_*` callable color helpers used throughout `gui_2.py`
- **[conductor/product-guidelines.md](../../conductor/product-guidelines.md)** — The UI delegation pattern rules
