# The Chaos — Game Architecture

This document describes the system architecture for developers and AI agents
working on the codebase.

## Design Principle

The Chaos is a **self-contained terminal game**. The TUI owns the full game
loop — including LLM calls — so there is no split between a "DM agent" in chat
and a "dashboard" in the terminal. The player runs one command:

```bash
python3 tools/run.py
```

Everything — narrative, choices, character sheet, log, archive, ambience — lives
in that process.

## Project Layout

```
the-chaos/
├── rules/                    # LOCKED — game rules, do not modify
│   ├── deck/                 # Card tables
│   └── mechanics.md          # Core mechanics reference
├── tools/                    # Game system code
│   ├── __init__.py
│   ├── engine.py             # Game engine (prompt builder, LLM client, parser, state)
│   ├── run.py                # TUI (Textual app, game loop, narrative, input)
│   ├── ambience.py           # CLI shortcut for ambience switching
│   ├── draw.py               # Card drawing tool
│   ├── music-fetch.py        # YouTube audio downloader
│   ├── roll.py               # Dice rolling tool
│   └── store_turn.py         # DEPRECATED — use engine.py archive_turn instead
├── scripts/                  # UNLOCKED — helper scripts
├── run.sh                    # Entry point (just calls tools/run.py)
└── session/                  # Game state (read/write by engine)
    ├── config.json           # LLM provider config
    ├── character.md          # Player character sheet
    ├── world.md              # Keep & Realm state
    ├── book.md               # Story book (append-only turn archive)
    ├── journal.md            # TODO / DONE tracking
    ├── ambience.md           # Current ambience name
    ├── ambience_options.md   # Ambience → file mapping
    ├── ambience_sources.md   # Track source URLs
    ├── tweaks.md             # House rules log
    ├── audio/                # Music files
    └── log/                  # Session logs by date
```

## How It Works

### Tools

| Tool | Role |
|------|------|
| `tools/engine.py` | Game engine. Owns the LLM interaction, prompt assembly, response parsing, and state persistence. Can be used standalone from the CLI for debugging. |
| `tools/run.py` | TUI (Textual app). Owns the game loop: display narrative → get player input → call engine → display result. |

### The Game Loop (run.py)

1. **Mount**: Load engine, build system prompt (rules + character + world + log).
2. **Scene**: Call `engine.generate()` → receive narrative + choices.
3. **Display**: Show narrative in main pane, render choice buttons.
4. **Input**: Player clicks a choice or types free text, presses Enter.
5. **Resolve**: Call `engine.generate(player_action)` → receive outcome + state changes.
6. **Archive**: Append the full turn (scene + action + outcome) to `book.md`.
7. **Apply**: Write state changes to `character.md`, `world.md`, `log/`, `ambience.md`, `journal.md`.
8. **Loop**: Display the next scene → go to step 3.

### The Engine (engine.py)

- `GameEngine` class loads config from `session/config.json`.
- `build_system_prompt()` assembles the DM prompt from game rules + current state.
- `build_user_message()` builds the per-turn message with player action context.
- `generate()` calls litellm, returns parsed `GenerationResult`.
- `parse_response()` extracts the JSON block from the LLM response.
- `apply_state()` writes state changes to session files.
- `archive_turn()` appends the narrative to `book.md`.

### LLM Output Format

The LLM must end every response with a JSON fenced code block:

```json
{
  "choices": ["Choice 1", "Choice 2"],
  "log_entry": "- **time** — description.",
  "ambience": "ambience_name_or_null",
  "character_updates": null,
  "world_updates": null,
  "journal_add": [],
  "journal_done": []
}
```

- `choices`: 2-4 action options for the player.
- `log_entry`: Single-line summary appended to today's log.
- `ambience`: One of: silence, calm, combat, dungeon, forest, tavern, tension, town, wilds.
- `character_updates`: Full character sheet markdown only if HP/cash/gear/stats changed.
- `world_updates`: Full world markdown only if NPCs/locations/threads changed.
- `journal_add` / `journal_done`: TODO list management.

### Session Config

```json
{
  "llm": {
    "model": "ollama/llama3.1",
    "api_key": null,
    "api_base": null,
    "temperature": 0.8
  }
}
```

The `model` field accepts any litellm provider string: `openai/gpt-4`,
`anthropic/claude-sonnet-4-20250514`, `ollama/llama3.1`, `groq/llama3-70b-8192`,
etc. Set `api_key` for remote providers.

## Files Still Used By Tools

| File | Purpose | Written By |
|------|---------|------------|
| `session/config.json` | LLM provider config | Manual edit |
| `session/character.md` | PC state | engine.py |
| `session/world.md` | Realm state | engine.py |
| `session/book.md` | Story archive | engine.py |
| `session/journal.md` | TODO/DONE | engine.py |
| `session/ambience.md` | Current ambience | engine.py |
| `session/log/<date>.md` | Session log | engine.py |
| `session/tweaks.md` | House rules | Manual edit |

## Running

```bash
# Start the game
./run.sh

# Or directly
python3 tools/run.py

# No music
python3 tools/run.py --no-music

# Test a generation from CLI (no TUI)
python3 tools/engine.py --action "I head to the market"
```