Ferrous-Solitaire/CLAUDE.md

Solitaire Quest — Claude Code Instructions

See @ARCHITECTURE.md for full project design, crate responsibilities, data models, and API reference.

---

Project Layout

solitaire_core/    # Pure Rust game logic — NO Bevy, NO network, NO I/O
solitaire_sync/    # Shared API types — NO Bevy, serde/uuid/chrono only
solitaire_data/    # Persistence + SyncProvider trait + server client
solitaire_engine/  # Bevy ECS systems, components, plugins
solitaire_server/  # Axum sync server binary
solitaire_gpgs/    # Google Play Games bridge — STUB ONLY until Android phase
solitaire_app/     # Thin binary entry point
assets/            # Loaded at runtime via Bevy AssetServer only

---

Build & Test Commands

# Dev run (fast compile via dynamic linking)
cargo run -p solitaire_app --features bevy/dynamic_linking

# Release build
cargo build --workspace --release

# All tests — MUST pass before any commit
cargo test --workspace

# Lint — MUST pass clean (zero warnings)
cargo clippy --workspace -- -D warnings

# Run sync server locally
cargo run -p solitaire_server

# Check a single crate
cargo test -p solitaire_core
cargo clippy -p solitaire_core -- -D warnings

---

Hard Rules

• solitaire_core and solitaire_sync must never gain Bevy or network dependencies.
• No unwrap() or panic!() in game logic. All state transitions return Result<_, MoveError>.
• No hardcoded bytes in source. All assets go through Bevy's AssetServer.
• Atomic file writes only: write to filename.json.tmp, then rename().
• Passwords and tokens are stored in the OS keychain via the keyring crate — never in plaintext files or logs.
• Sync runs on AsyncComputeTaskPool — never block the Bevy main thread.
• All sync backends implement the SyncProvider trait. The SyncPlugin is backend-agnostic — never match on SyncBackend inside a Bevy system.
• solitaire_gpgs is a stub until Android work begins. Do not write JNI bindings yet; keep the compile-time stub so the trait contract is enforced from day one.
• cargo clippy --workspace -- -D warnings must pass clean after every change.
• cargo test --workspace must pass after every change.

---

Code Style

• Use thiserror for error types. Never Box<dyn Error> in library crates.
• Prefer Into<T> over concrete types in public API function parameters.
• All public items must have doc comments (///). Private items: comment only when non-obvious.
• Derive order convention: #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
• Bevy systems: one responsibility per system. Use Events for cross-system communication, never shared mutable state.
• SQL queries: use sqlx::query! macros (compile-time checked), not raw string queries.
• No clone() calls in hot paths (game loop systems). Profile before optimising elsewhere.

---

Bevy Conventions

• One Plugin per major feature: CardPlugin, AudioPlugin, AchievementPlugin, UIPlugin, SyncPlugin.
• Resources own shared state. Events communicate between systems. Components own per-entity data.
• All egui screens live in solitaire_engine::ui. Never mix egui and Bevy spawn logic in the same system.
• Layout is recomputed on WindowResized — never assume a fixed window size.

---

Git Workflow

• Commit after each passing phase, not after every file change.
• Commit message format: type(scope): description
  • feat(core): add draw-three mode validation
  • fix(engine): card z-order during drag
  • test(core): undo stack boundary conditions
  • chore(server): add sqlx migration 002
• Never commit with failing tests or clippy warnings.
• Never commit secrets, .env files, or *.db files.

---

Ask Before Doing

• Adding a new crate dependency (discuss alternatives first).
• Changing a type in solitaire_sync (breaking change on both client and server).
• Altering the database schema (requires a new sqlx migration).
• Introducing unsafe code anywhere.
• Changing the merge strategy in solitaire_sync::merge().

---

Lessons Learned

Add entries here when Claude makes a mistake so it isn't repeated.

• Bevy's Time resource uses f32 seconds; convert to u64 only when writing to StatsSnapshot.
• sqlx::migrate!() macro path is relative to the crate root, not the workspace root.
• keyring on Linux requires a running secret service (e.g. GNOME Keyring or KWallet) — handle Error::NoStorageAccess gracefully and fall back to prompting the user.
• dirs::data_dir() returns None on some minimal Linux environments — always handle the None case explicitly, do not unwrap.