Dojo Architecture

1. Types (Enum Dispatch)

Location: contracts/src/types/

Types are enums that serve as entry points, dispatching to element implementations via match.

// types/power.cairo
pub enum Power {
    None, Reroll, High, Low, Swap, DoubleUp, Halve, Mirror,
}

#[generate_trait]
pub impl PowerImpl of PowerTrait {
    fn apply(self: Power, ref game: Game, ref rand: Random) {
        match self {
            Power::None => {},
            Power::Reroll => powers::reroll::Reroll::apply(ref game, ref rand),
            Power::High => powers::high::High::apply(ref game, ref rand),
            Power::Low => powers::low::Low::apply(ref game, ref rand),
            Power::Swap => powers::swap::Swap::apply(ref game, ref rand),
            Power::DoubleUp => powers::double_up::DoubleUp::apply(ref game, ref rand),
            Power::Halve => powers::halve::Halve::apply(ref game, ref rand),
            Power::Mirror => powers::mirror::Mirror::apply(ref game, ref rand),
        }
    }
}

Pattern: Enum variant → match → concrete element module call.

Conventions:

• Into<Power, u8> and Into<u8, Power> for serialization
• Each type defines dispatch traits: apply, rescue, index, draw, generate, etc.

2. Elements (Trait Implementations)

Location: contracts/src/elements/

Elements implement traits defined in interface.cairo files. Each element is a single-responsibility implementation.

Element Categories

Power Element Example

// elements/powers/interface.cairo — trait definition
pub trait PowerTrait {
    fn apply(ref game: Game, ref rand: Random);
    fn rescue(game: @Game, slots: @Array<u16>) -> bool;
}

// elements/powers/double_up.cairo — concrete implementation
pub impl DoubleUp of PowerTrait {
    #[inline]
    fn apply(ref game: Game, ref rand: Random) {
        game.number = double(game.number);
    }

    #[inline]
    fn rescue(game: @Game, slots: @Array<u16>) -> bool {
        let mut game = *game;
        game.number = double(game.number);
        !game.is_over(slots)
    }
}

Trap Element Example

// elements/traps/interface.cairo
pub trait TrapTrait {
    fn apply(ref game: Game, slot_index: u8, ref rand: Random);
}

// elements/traps/bomb.cairo
pub impl Bomb of TrapTrait {
    #[inline]
    fn apply(ref game: Game, slot_index: u8, ref rand: Random) {
        let slots = game.slots();
        // Complex logic: find nearest numbers, shuffle them
        // ...
        game.force(new_slots);
    }
}

Achievement Element Example

// elements/achievements/interface.cairo
pub trait AchievementTrait {
    fn identifier(level: u8) -> felt252;
    fn hidden(level: u8) -> bool;
    fn index(level: u8) -> u8;
    fn points(level: u8) -> u16;
    fn group() -> felt252;
    fn icon(level: u8) -> felt252;
    fn title(level: u8) -> felt252;
    fn description(level: u8) -> ByteArray;
    fn tasks(level: u8) -> Span<AchievementTask>;
}

// elements/achievements/claimer.cairo — pure metadata
pub impl Claimer of AchievementTrait {
    fn identifier(level: u8) -> felt252 { 'CLAIMER_I' }
    fn hidden(level: u8) -> bool { false }
    fn points(level: u8) -> u16 { match level { 0 => 10, _ => 0 } }
    fn group() -> felt252 { 'Claimer' }
    fn icon(level: u8) -> felt252 { match level { 0 => 'fa-shrimp', _ => '' } }
    fn title(level: u8) -> felt252 { ... }
    fn description(level: u8) -> ByteArray { ... }
    fn tasks(level: u8) -> Span<AchievementTask> { ... }
}

Conventions:

• Trait defined in interface.cairo, implementations in individual files
• All element methods are #[inline]
• Powers/Traps modify Game state via ref game
• Achievements/Tasks/Quests return metadata (stateless)

3. Models (Persistent State)

Location: contracts/src/models/

Models are Dojo models with #[dojo::model] and trait implementations for lifecycle and validation.

// models/index.cairo — struct definitions
#[derive(Copy, Drop, Serde)]
#[dojo::model]
pub struct Game {
    #[key] pub id: u64,
    pub claimed: bool,
    pub multiplier: u16,
    pub level: u8,
    pub number: u16,
    pub next_number: u16,
    pub reward: u64,
    pub over: u64,
    pub slots: felt252,    // Packed via Packer helper
    pub traps: u128,       // Packed via Packer helper
    // ... more fields
}

// models/game.cairo — logic and validation
#[generate_trait]
pub impl GameImpl of GameTrait {
    fn new(...) -> Game { ... }
    fn start(ref self: Game, ref rand: Random) { ... }
    fn place(ref self: Game, number: u16, index: u8, ref rand: Random) { ... }
    fn apply(ref self: Game, index: u8, ref rand: Random) { ... }
    fn select(ref self: Game, index: u8) { ... }
    fn update(ref self: Game, ref rand: Random, target_supply: u256) { ... }
    fn claim(ref self: Game) -> u64 { ... }
    fn slots(self: @Game) -> Array<u16> { ... }
}

// Separate assertion impl
#[generate_trait]
pub impl GameAssert of AssertTrait {
    fn assert_does_exist(self: @Game) { ... }
    fn assert_has_started(self: @Game) { ... }
    fn assert_not_over(self: @Game) { ... }
    fn assert_is_valid(self: @Game) { ... }
}

Conventions:

• Struct definition in index.cairo, logic in dedicated files
• Separate AssertTrait impl for validation (keeps logic clean)
• Uses #[generate_trait] for impl-defined traits
• Packed fields use Packer/Bitmap helpers for storage efficiency

4. Store (Data Access Layer)

Location: contracts/src/store.cairo

Single centralized struct wrapping WorldStorage with typed accessors for all models, dispatchers, and events.

#[derive(Copy, Drop)]
pub struct Store {
    pub world: WorldStorage,
}

#[generate_trait]
pub impl StoreImpl of StoreTrait {
    fn new(world: WorldStorage) -> Store {
        Store { world }
    }

    // Dispatchers (external contracts)
    fn token_disp(self: @Store) -> ITokenDispatcher {
        let config = self.config();
        ITokenDispatcher { contract_address: config.token }
    }
    fn vrf_disp(self: @Store) -> IVrfProviderDispatcher {
        let config = self.config();
        IVrfProviderDispatcher { contract_address: config.vrf }
    }

    // Model access
    fn config(self: @Store) -> Config { self.world.read_model(WORLD_RESOURCE) }
    fn set_config(mut self: Store, config: Config) { self.world.write_model(@config) }
    fn game(self: @Store, game_id: u64) -> Game { self.world.read_model(game_id) }
    fn set_game(mut self: Store, game: @Game) { self.world.write_model(game) }

    // Event emission
    fn purchased(mut self: Store, player_id: felt252, ...) {
        let event = PurchasedTrait::new(player_id, ...);
        self.world.emit_event(@event);
    }
}

Rule: All model access flows through Store. Never call world.read_model() directly in components or systems.

5. Components (Orchestration)

Location: contracts/src/components/

Starknet components that compose models (via Store) and external components. This is where business logic lives.

#[starknet::component]
pub mod PlayableComponent {
    // External component dependencies
    component!(path: AchievableComponent, ...);
    component!(path: QuestableComponent, ...);
    component!(path: RankableComponent, ...);

    #[generate_trait]
    pub impl InternalImpl<TContractState, +HasComponent<TContractState>, ...> of InternalTrait<TContractState> {
        fn set(ref self: ComponentState<TContractState>, world: WorldStorage, game_id: u64, index: u8) -> u16 {
            let mut store = StoreImpl::new(world);

            // Read model
            let mut game = store.game(game_id);
            game.assert_does_exist();
            game.assert_has_started();

            // Execute game logic
            let mut rand = RandomImpl::new_vrf(store.vrf_disp());
            game.place(game.number, index, ref rand);
            game.assert_is_valid();

            // Update state
            game.update(ref rand, store.config().target_supply);
            store.set_game(@game);

            // Update external systems
            if game.over != 0 {
                let mut rankable = get_dep_component_mut!(ref self, Rankable);
                rankable.submit(world, LEADERBOARD_ID, game.id, player.into(), game.level.into(), time, true);
            }

            // Track achievements
            let achievable = get_dep_component!(@self, Achievable);
            achievable.progress(world, player.into(), Task::FillerOne.identifier(), 1, true);

            game.number
        }
    }
}

Conventions:

• Use StoreImpl::new(world) to access models
• Call model assertions before mutating state
• Use get_dep_component! / get_dep_component_mut! for external components
• Multiple impl blocks per component (InternalImpl, StarterpackImpl, QuestRewarderImpl)

6. Systems (Entry Points)

Location: contracts/src/systems/

Dojo contracts that embed components and expose public interfaces.

#[starknet::interface]
pub trait IPlay<T> {
    fn set(ref self: T, game_id: u64, index: u8) -> u16;
    fn select(ref self: T, game_id: u64, index: u8);
    fn apply(ref self: T, game_id: u64, index: u8) -> u16;
    fn claim(ref self: T, game_id: u64);
}

#[dojo::contract]
pub mod Play {
    // Embed components
    component!(path: PlayableComponent, storage: playable, event: PlayableEvent);
    component!(path: AchievableComponent, storage: achievable, event: AchievableEvent);
    component!(path: QuestableComponent, storage: questable, event: QuestableEvent);
    component!(path: RankableComponent, storage: rankable, event: RankableEvent);

    // Wire component impls
    impl PlayableInternalImpl = PlayableComponent::InternalImpl<ContractState>;

    #[storage]
    struct Storage {
        #[substorage(v0)]
        playable: PlayableComponent::Storage,
        #[substorage(v0)]
        achievable: AchievableComponent::Storage,
        // ...
    }

    #[event]
    #[derive(Drop, starknet::Event)]
    enum Event {
        #[flat] PlayableEvent: PlayableComponent::Event,
        #[flat] AchievableEvent: AchievableComponent::Event,
        // ...
    }

    #[abi(embed_v0)]
    impl PlayImpl of IPlay<ContractState> {
        fn set(ref self: ContractState, game_id: u64, index: u8) -> u16 {
            let world = self.world(@NAMESPACE());
            self.playable.set(world, game_id, index)
        }
    }
}

Conventions:

• Define #[starknet::interface] trait first
• Embed components via component!() macro
• Delegate all logic to components — systems are thin wrappers
• Each component needs #[substorage(v0)] in Storage and #[flat] in Event enum

7. Helpers (Stateless Utilities)

Location: contracts/src/helpers/

Pure functions with no game state. Generic implementations with trait bounds.

// helpers/bitmap.cairo — generic bit manipulation
pub trait BitmapTrait<T> {
    fn popcount(x: T) -> u8;
    fn get(x: T, index: u8) -> u8;
    fn set(x: T, index: u8) -> T;
    fn unset(x: T, index: u8) -> T;
}

pub impl Bitmap<T, +Into<u8, T>, +Into<T, u256>, ...> of BitmapTrait<T> {
    #[inline]
    fn get(x: T, index: u8) -> u8 {
        let x: u256 = x.into();
        let offset: u256 = TwoPower::pow(index);
        (x / offset % 2).try_into().unwrap()
    }
}

// helpers/random.cairo — seeded RNG
#[derive(Copy, Drop, Serde)]
pub struct Random { pub seed: felt252, pub nonce: usize }

#[generate_trait]
pub impl RandomImpl of RandomTrait {
    fn new(salt: felt252) -> Random { Random { seed: seed(salt), nonce: 0 } }
    fn new_vrf(vrf_provider_disp: IVrfProviderDispatcher) -> Random { ... }
    fn between<T, ...>(ref self: Random, min: T, max: T) -> T { ... }
    fn bool(ref self: Random) -> bool { ... }
}

Conventions:

• Generic traits with trait bounds for type flexibility
• #[inline] on all methods
• No self or ref self on static helpers (e.g., Rewarder::amount(...))
• ref self for stateful helpers (e.g., Random with nonce)

8. Events (Dojo Events)

Location: contracts/src/events/

Dojo events with factory traits for construction.

// events/index.cairo — struct definitions
#[derive(Copy, Drop, Serde)]
#[dojo::event]
pub struct Started {
    #[key] pub player_id: felt252,
    #[key] pub game_id: u64,
    pub multiplier: u16,
    pub time: u64,
}

// events/started.cairo — factory trait
#[generate_trait]
pub impl StartedImpl of StartedTrait {
    fn new(player_id: felt252, game_id: u64, multiplier: u16) -> Started {
        Started {
            player_id, game_id, multiplier,
            time: starknet::get_block_timestamp(),
        }
    }
}

Conventions:

• Struct definition in index.cairo, factory in dedicated file (mirrors models pattern)
• Factory traits add computed fields (e.g., time from block timestamp)
• Events emitted via Store::purchased(...) — never directly

9. Interfaces (External Contracts)

Location: contracts/src/interfaces/

ABIs for external contract calls (tokens, VRF, registries).

// interfaces/token.cairo
#[starknet::interface]
pub trait IToken<T> {
    fn reward(ref self: T, recipient: ContractAddress, amount: u256);
    fn burn(ref self: T, from: ContractAddress, amount: u256);
}

// interfaces/vrf.cairo
#[starknet::interface]
pub trait IVrfProvider<T> {
    fn consume_random(ref self: T, source: Source) -> felt252;
}

Data Flow

User calls System (Play::set)
  → System delegates to Component (PlayableComponent::set)
    → Component reads via Store (store.game(game_id))
      → Model validates state (game.assert_does_exist())
      → Model executes logic (game.place(number, index, ref rand))
        → Type dispatches to Element (Power::apply → DoubleUp::apply)
          → Element modifies Model state (game.number = double(game.number))
          → Helpers used throughout (Random, Packer, Bitmap)
      → Model validates result (game.assert_is_valid())
    → Component writes via Store (store.set_game(@game))
    → Component updates external systems (achievements, quests, leaderboard)
    → Store emits Events (store.started(...))

Adding New Game Mechanics

New Power

1. Add variant to Power enum in types/power.cairo
2. Create elements/powers/my_power.cairo implementing PowerTrait
3. Add match arm in PowerImpl::apply() and other dispatch methods
4. Add module declaration in lib.cairo
5. Update Into<Power, u8> / Into<u8, Power> conversions

New Trap

1. Add variant to Trap enum in types/trap.cairo
2. Create elements/traps/my_trap.cairo implementing TrapTrait
3. Add match arm in TrapImpl::apply() and other dispatch methods
4. Add module declaration in lib.cairo

New Model

1. Define struct with #[dojo::model] in models/index.cairo
2. Create models/my_model.cairo with MyModelTrait and AssertTrait
3. Add read/write methods to store.cairo

New System

1. Define #[starknet::interface] trait
2. Create systems/my_system.cairo with #[dojo::contract]
3. Embed required components, delegate logic to them

Naming Conventions

External Dependencies