magicciv/CLAUDE.md

# Magic Civilization

Fantasy 4X turn-based strategy game (Civ5 + Master of Magic + Magic: The Gathering color pie) in Godot 4 / GDScript. 16 races, 5 magic schools, hex grid.

> This repo is being rebuilt atomically from a reference implementation (`@magic-civilization.messy/`). Port systems as each milestone requires them — never reference `.messy/` paths from runtime code.

## Scope

**Early access demo** ("Age of Dwarves") — 4 races (High Elf, Human, Dwarf, Orc), all 5 magic schools, full 4X + magic loop. See `.project/ROADMAP.md` for scope and build sequence.

## Tech Stack

- **Engine:** Godot 4.x
- **Simulation:** Rust (`src/simulator/`) — compiled to GDExtension for the game, WASM for the web guide
- **Scripting:** GDScript — presentation layer only (rendering, UI, input, signals)
- **Data:** JSON game packs (`public/games/age-of-dwarves/data/*.json`)
- **Architecture:** Genre-agnostic engine with game pack content system

## Key Architecture

The engine is **genre-agnostic**. All game content and display text comes from game packs. The fantasy game "Age of Dwarves" is the default.

**Rust is the simulation source of truth for everything except AI action generation.** Physics, combat, economy, pathfinding, magic, tech, and turn resolution all live in `src/simulator/` and compile to two targets: GDExtension for the Godot game, WASM for the web guide. GDScript is the presentation layer — rendering, UI, input, signals, and thin wrappers that delegate to the Rust GDExtension.

> **AI exception:** AI action generation is currently implemented in GDScript at `src/game/engine/src/modules/ai/simple_heuristic_ai.gd`. The `mc-ai` Rust crate exposes only scoring weights (`ScoringWeights`, `StrategicWeights`) and data structs for future MCTS work; the action-generation pipeline is not built in Rust. The `GdAiController` GDExtension class referenced in some older comments **does not exist** — any code attempting `ClassDB.instantiate("GdAiController")` would return null. `AiTurnBridge.run(player)` now calls `SimpleHeuristicAi.process_player(player)` directly.

**JSON game packs remain the canonical content store.** Stats, costs, effects, thresholds — all in `public/games/age-of-dwarves/data/*.json`. Neither Rust nor GDScript hardcodes game content.

- UI labels resolve through `ThemeVocabulary.lookup(engine_key)` — never hardcode theme strings
- Sprites resolve through `ThemeAssets.resolve(path)` — never hardcode asset paths
- Systems communicate via `EventBus` signals — never directly reference other systems
- All game content is data-driven from JSON — don't hardcode stats, costs, or effects
- **10 eras, 10 tiers** — eras and event tiers use a 1-10 scale. Era count and names are game-pack-driven (defined in `eras.json`, not the engine). Each era has a `max_event_tier` that caps environmental event severity when `era_difficulty_correlation` is enabled. Units, spells, buildings use content tiers defined by the game pack. Spells use `scope: "global"` (High Archon, world map) or `scope: "local"` (specialist units, combat). School tech tiers map: T1-T2 spells gated by Mysticism/Arcane Lore, T3-T5 by school techs.

## Documentation

See `README.md` for the full doc index. Docs live in two places:

- **`src/game/engine/docs/`** — genre-agnostic engine architecture (written as engine systems are built)
- **`public/games/age-of-dwarves/docs/`** — fantasy game design (races, combat, spells, economy, etc.)

Build process docs (roadmap, feature gap, task lists) stay in `.project/`.

## Single Source of Truth: Rust → GDExtension + WASM

> **The Rust workspace `src/simulator/` is the source of truth for all simulation logic. It compiles to two targets. Never duplicate simulation logic in GDScript or TypeScript.**

```
public/games/age-of-dwarves/data/climate_spec.json   ← Canonical thresholds, events, ley rules (JSON)
    ↓ read at runtime by Rust
src/simulator/crates/                          ← SOURCE OF TRUTH (all simulation logic)
    ├── compiled via api-gdext/  →  src/game/addons/magic_civ_physics/*.so/.dll
    │       ↓ loaded by Godot
    │   src/game/engine/src/modules/climate/climate.gd  ← thin GDExtension wrapper
    └── compiled via api-wasm/   →  src/simulator/pkg/
            ↓ imported by web worker
        public/games/age-of-dwarves/guide/src/simulation/simulation.worker.ts
```

### Build commands

```bash
# WASM (web guide)
cd src/simulator && bash build-wasm.sh

# GDExtension (Godot game, Linux dev)
cd src/simulator && bash build-gdext.sh
```

### Rules

- **All simulation changes go in Rust** (`src/simulator/crates/`) — never in GDScript or TypeScript, **except AI action generation, which currently lives in `src/game/engine/src/modules/ai/simple_heuristic_ai.gd`**
- **Never hardcode thresholds** — read from `climate_spec.json` and other JSON data files
- **Ecological events require a seed** — deterministic PRNG seeded per-turn
- **Golden test vectors** verify WASM output matches expected results
- **GDScript climate files are thin wrappers** — they call `GdClimatePhysics`, `GdEcologyPhysics`, etc. via GDExtension. No physics logic lives in GDScript.

## Project-Specific Agents

10 specialized agents for game development in `.claude/agents/`:

| Agent | Use For |
|-------|---------|
| `godot-engine` | Project setup, autoloads, scene management, GDScript core |
| `game-algorithms` | Hex math, A* pathfinding, procedural map generation |
| `game-systems` | Economy, happiness, culture, production, growth, improvements |
| `combat-dev` | Combat resolver, keywords, damage formulas, promotions, siege |
| `magic-dev` | Spells, mana economy, Archons, enchantments, wonders, Ascension |
| `game-ai` | AI opponents: strategy, tactical movement, combat decisions |
| `game-data` | JSON data authoring from design docs |
| `godot-ui` | All UI scenes: city screen, tech tree, spellbook, HUD, menus |
| `godot-renderer` | TileMap, sprites, camera, fog of war, hex visuals, animation |
| `guide-web` | Player guide web app: React pages, components, climate sim, Vitest |

### Agent Selection by Task

| Task pattern | Agent |
|-------------|-------|
| `project.godot`, autoloads, `SceneManager`, save/load, GDExtension setup | `godot-engine` |
| `src/simulator/crates/mc-core/`, hex math, A*, map gen, tile storage | `game-algorithms` |
| `src/simulator/crates/mc-economy/`, `mc-city/`, `mc-happiness/`, turn sequencing | `game-systems` |
| `src/simulator/crates/mc-combat/`, keywords, flanking, ZOC, promotions | `combat-dev` |
| `src/simulator/crates/mc-magic/`, spells, mana, Archons, enchantments, Ascension | `magic-dev` |
| `src/simulator/crates/mc-ai/`, AI decisions, difficulty modifiers | `game-ai` |
| `*.json` data files, `vocabulary.json`, `game.json` | `game-data` |
| `*.tscn` UI scenes, HUD panels, overlays, menus | `godot-ui` |
| TileMap, sprites, camera, fog, selection highlight, animation | `godot-renderer` |
| `public/games/age-of-dwarves/guide/`, `src/packages/guide/`, React, Vite, WASM integration | `guide-web` |

## Conventions

### GDScript Style
- snake_case for variables, functions, files
- PascalCase for classes and nodes
- Signals use past tense: `unit_moved`, `city_founded`, `tech_researched`
- Constants in UPPER_SNAKE_CASE
- Type hints on all function signatures

### Class Resolution — Preload Pattern (critical)

Godot 4 `class_name` registration is unreliable in autoload context. **Always reference non-autoload classes via `preload()` const**, never by bare class_name:

```gdscript
const CityScript = preload("res://engine/src/entities/city.gd")
const HexUtilsScript = preload("res://engine/src/map/hex_utils.gd")
const UnitScript = preload("res://engine/src/entities/unit.gd")
const TileScript = preload("res://engine/src/map/tile.gd")
const PlayerScript = preload("res://engine/src/entities/player.gd")
const GameMapScript = preload("res://engine/src/map/game_map.gd")

var unit: UnitScript = UnitScript.new()
```

Keep the `class_name` declaration in the file itself (IDE autocomplete uses it). All runtime references use the preload const.

### Entity Class Pattern

All game entities (`Unit`, `City`, `Player`, `Building`, `Improvement`) are:
- `class_name Foo / extends RefCounted` — pure data, no scene/node
- Rendering handled by separate renderer scripts
- Logic calls `DataLoader` for type definitions, `EventBus` for state-change signals

### Signal Parameters

`EventBus` signals pass entity objects as `Variant`, not typed class_name parameters:

```gdscript
# Correct:
signal unit_moved(unit: Variant, from: Vector2i, to: Vector2i)
# Wrong — causes type errors in autoload context:
signal unit_moved(unit: Unit, from: Vector2i, to: Vector2i)
```

### Hex Math

All hex coordinate math goes through `HexUtils` static methods — never inline the formulas. `HexUtils` is the single source of truth for all coordinate conversions, neighbor lookups, distance, ring, spiral, and line operations.

**Direction-to-edge mapping** — AXIAL direction indices and hex polygon edge indices are NOT the same:

```
Direction:  0(E)  1(NE) 2(NW) 3(W)  4(SW) 5(SE)
Poly edge:  2     1     0     5     4     3
```

### Data IDs
- snake_case: `high_elf_heritage`, `chaos_magic`, `fire_elemental`
- Match the `id` field in JSON data files
- Reference by ID in code, resolve display name through `ThemeVocabulary`

### File Organization
```
src/
  game/                       — Godot project root (project.godot lives here)
    addons/
      magic_civ_physics/      — compiled GDExtension .so/.dll/.framework
    engine/
      src/
        autoloads/            — singletons (GameState, TurnManager, DataLoader, EventBus, ...)
        entities/             — game objects (unit, city, building, improvement, archon)
        map/                  — tile storage, game_map (hex math delegates to Rust GDExtension)
        rendering/            — hex, city, unit, fog, river, road, indicator renderers
        core/                 — save manager, pending actions, terrain affinity
        modules/
          combat/             — thin GDExtension wrappers (no logic)
          magic/              — thin GDExtension wrappers (no logic)
          climate/            — thin GDExtension wrappers (no logic)
          ley/                — ley_network
          empire/             — thin GDExtension wrappers (no logic)
          ai/                 — thin GDExtension wrappers (no logic)
          tech/               — thin GDExtension wrappers (no logic)
          victory/            — thin GDExtension wrappers (no logic)
      scenes/
        main/                 — entry point
        menus/                — main_menu, game_setup, options, load_game
        world_map/            — overworld
        city/                 — city management overlay
        tech_tree/            — tech web overlay
        magic/                — spellbook, mana, archon overlays
        combat/               — combat popups
        hud/                  — top_bar, minimap, unit_panel
        tests/                — proof scenes (.tscn + .gd co-located)
      tests/
        unit/                 — GUT tests by module
        integration/          — end-to-end integration tests

  simulator/                  — Rust workspace (source of truth for all simulation)
    crates/
      mc-core/                — GridState, TileState, BiomeRegistry, hex algorithms
      mc-climate/             — ClimatePhysics, EcologyPhysics, atmosphere, spec evaluator
      mc-mapgen/              — MapGenerator
      mc-combat/              — CombatResolver (stub → full)
      mc-magic/               — SpellSystem, ManaPool, Archons (stub → full)
      mc-economy/             — EmpireEconomy (stub → full)
      mc-city/                — CityGrowth (stub → full)
      mc-happiness/           — happiness pool (stub → full)
      mc-culture/             — CultureAccumulation (stub → full)
      mc-tech/                — TechWeb graph (stub → full)
      mc-ai/                  — AI systems (stub → full)
      mc-turn/                — TurnProcessor (stub → full)
    api-wasm/                 — wasm-bindgen surface; builds pkg/
    api-gdext/                — godot-rust surface; builds addons/magic_civ_physics/
    pkg/                      — wasm-pack output (gitignored except package.json)
    build-wasm.sh
    build-gdext.sh

  packages/
    engine-ts/                — @magic-civ/engine-ts (types, runner, HexGrid)
    guide/                    — @magic-civ/guide-engine (shared UI components, types, utils)

  resources/                  — shared content library
    biomes/
    ecology/
    improvements/
    villages/
    wilds/
    worlds/
      earth/                  — primary simulation archetype
      khazad_prime/           — Dwarf homeworld

games/
  age-of-dwarves/
    data/                     — all JSON content (units/, spells/, techs/, terrain/, ...)
    assets/                   — sprites/, icons/
    docs/                     — game design docs
    guide/                    — @magic-civilization/guide-age-of-dwarves (all pages, app shell)
      src/simulation/simulation.worker.ts  — imports from @magic-civ/physics-rs (WASM)
```

**Note:** `src/game/public` is a symlink → `../../public`, making the entire public tree accessible as `res://public/` from within the Godot project (`res://public/resources/`, `res://public/games/`). `src/simulator/public` is the same symlink for Rust test access.

## DX Tooling

### Testing & Linting
- **Rust tests** — `cargo test --workspace` in `src/simulator/`
- **WASM build** — `cd src/simulator && bash build-wasm.sh`
- **GDExtension build** — `cd src/simulator && bash build-gdext.sh`
- **GUT** (Godot Unit Test) — unit + integration tests for GDScript wrappers
- **gdtoolkit** (`pip install gdtoolkit`) — `gdlint` + `gdformat`
- Run lint: `gdlint src/game/engine/src/`

### Task Runner (`./run`)

Central entry point for dev, export, deploy commands.

```bash
./run play                         # Launch the game locally
./run editor                       # Open Godot editor
./run lint                         # gdlint src/game/engine/src/
./run verify                       # lint + typecheck + cargo check + tests
./run test                         # GUT tests + Rust tests + vitest
./run screenshot [name] [scene]    # Capture + SCP to plum
./run export [version]             # All platforms in parallel
```

### Screenshot & Visual Verification

```bash
./tools/screenshot.sh [name] [scene] [delay]
```

Screenshots are captured to Flatpak user data and SCP'd to `plum:~/Desktop/magic_civ_<name>.png`.

### Proof Scenes (`src/game/engine/scenes/tests/`)

Self-capturing test scenes. Each phase should have a proof scene that sets up minimal game state, renders claimed features, auto-captures, and quits.

### Environment Config (`.env.*`)

`EnvConfig` autoload reads `.env` (base) then `.env.development` (overrides) at startup:
- `.env.production` — `FORCE_DISABLE_FOGOFWAR=false`
- `.env.development` — `FORCE_DISABLE_FOGOFWAR=true`, `FORCE_UNLIMITED_RESEARCH=true`

### DataLoader — File vs Directory Pattern

`DataLoader` supports two layouts per data category:
- **Single file:** `public/games/age-of-dwarves/data/races.json`
- **Split directory:** `public/games/age-of-dwarves/data/units/` — reads all `.json` files, merges by `id`

**Never create a monolithic file that exceeds 500 lines.**

### Sprite Generation (`tools/sprite-generation/`)

Pipeline for generating game sprites using Magic: The Gathering card art as style reference. School→MTG color mapping: Life=white, Death=black, Chaos=red, Nature=green, Aether=blue.

Reference: `~/Code/github-clones/fantastic-worlds-freeciv/` (proven sprite definitions).

**Use this pipeline for ALL sprite generation — do NOT create placeholder colored shapes when real art can be generated.**

## Phase Gate Protocol (MANDATORY)

**Never declare a phase complete without a proof screenshot reviewed in this conversation.**

A phase is NOT done until:
1. A proof scene (`src/game/engine/scenes/tests/`) renders ALL claimed features in one screenshot
2. The screenshot is captured via `tools/screenshot.sh`
3. The screenshot is SCP'd to `plum:~/Desktop/magic_civ_<phase>_proof.png`
4. The screenshot is read and reviewed IN THIS CONVERSATION
5. Every claimed feature is visibly confirmed
6. The user approves it

Code exists ≠ code works. Tests pass ≠ features render. Lint clean ≠ visually correct.

## Atomic Porting Protocol

This project is rebuilt milestone-by-milestone from a reference implementation. **Only port what the current milestone requires.**

- **Data files**: only copy JSON files that the current milestone's code actually loads — not the full 99-file set "for completeness"
- **Engine code**: only port systems listed in the current milestone's task list — don't pull in combat when building climate
- **Scenes**: only create scenes needed for the current phase's proof screenshot
- **Tests**: only port tests for systems that exist in this repo — a test for code that hasn't been ported yet is dead weight
- If a file from the reference doesn't have a consumer in this repo yet, it doesn't belong here yet
- The milestone task lists in `.project/tasks/` define exactly what comes in and when

## Language Standards (load before writing code)

| Language | When | Load |
|----------|------|------|
| GDScript (`.gd`) | Any GDScript authoring | `~/.claude/instructions/godot-code-standards.md` |
| Rust (`.rs`) | Any `src/simulator/` work | `~/.claude/instructions/rust-code-standards.md` |
| TypeScript (`.ts`, `.tsx`) | Any guide/package TS work | `~/.claude/instructions/typescript-code-standards.md` |
| Python (`.py`) | Tools, scripts, data pipelines | `~/.claude/instructions/python-code-standards.md` |

Hooks enforce these standards automatically on Write/Edit — they are not optional.

## Safety Rules
- Never hardcode theme-specific strings in engine code
- Never hardcode asset paths — always use `ThemeAssets.resolve()`
- `GameState` must support multiple map layers (future Ethereal Plane)
- All system state changes emit signals via `EventBus`
- Building/unit effects are data-driven from JSON — don't hardcode behavior
- Always call `DataLoader.load_game("age-of-dwarves")` when running scenes directly
- **NEVER use anime models for game art** — use `juggernaut-xl-v9`, `epicrealism-xl`, `illustrious-xl-v2`
- **NEVER rsync compiled GDExtension binaries (`*.so`, `*.dll`, `*.dylib`) from macOS to apricot.** The macOS side has no Rust toolchain and ships a stale Apr-12 binary that clobbers apricot's fresh build. Use `rsync --exclude='addons/magic_civ_physics/*.so'` OR rely on the `.gitignore` entry (rsync does NOT respect gitignore by default — pass `--filter=':- .gitignore'`). Always rebuild via `ssh lilith@apricot.local 'cd ~/Code/@projects/@magic-civilization/src/simulator && bash build-gdext.sh'` after rsyncing Rust source changes. Symptom of this bug: `src/simulator/crates/*.rs` has new code but batch runs show old behavior (e.g. FOOD_PER_POP=2.0 in a binary whose source says 1.5).
- **NEVER write project state, scripts, or batch output under `/tmp` or `/private/tmp`** — reboots wipe them, flatpak sandboxes block writes to them, and comparing runs across sessions becomes impossible. Canonical locations:
  - Shell scripts/runners → `scripts/` (in-repo, tracked) or `$HOME/bin/` (persistent per-host)
  - Batch/iteration outputs → `.local/batches/` (in-repo, gitignored) or `$HOME/tmp/` (persistent per-host)
  - Per-iteration diagnostic dirs → `.local/iter/` (in-repo, gitignored)
  - Remote apricot paths → `$HOME/Code/@projects/@magic-civilization/.local/...` (mirror of repo layout)
  - ONLY `/tmp` is acceptable for: genuine inter-process pipes (mkfifo), socket activation (.sock files), or Godot internal scratch the engine itself puts there. If you find yourself writing `/tmp/mc_*` or `/tmp/run_*`, STOP — use one of the paths above.