/// Prompt-to-game compilation pipeline
pub struct GameCompiler {
    parser: PromptParser,
    planner: MechanicPlanner,
    codegen: BytecodeEmitter,
    renderer: RenderGraph,
    physics: PhysicsConfig,
}

impl GameCompiler {
    /// Takes a natural language description and produces a shippable game binary.
    /// The pipeline is deterministic -- same prompt, same output, every time.
    pub fn compile(&self, prompt: &str) -> Result<GameBinary, CompileError> {
        let intent = self.parser.extract_intent(prompt)?;
        let mechanics = self.planner.resolve_mechanics(&intent)?;
        let bytecode = self.codegen.emit(&mechanics, &self.physics)?;
        let render_bindings = self.renderer.bind(&mechanics)?;

        Ok(GameBinary {
            bytecode,
            render_bindings,
            metadata: intent.metadata(),
        })
    }
}

/// Every game entity is a composition of components.
/// No inheritance. No virtual dispatch. Just data.
pub struct Entity {
    pub id: u64,
    pub position: Vec2,
    pub velocity: Vec2,
    pub sprite: SpriteHandle,
    pub collider: ColliderShape,
    pub behavior: BehaviorTree,
}

/// Fixed 60Hz physics step. Decoupled from render framerate.
/// Gravity, boundary clamping, and bounce are handled here.
pub fn physics_step(world: &mut World, dt: f32) {
    for entity in world.entities.iter_mut() {
        entity.velocity += world.gravity * dt;
        entity.position += entity.velocity * dt;

        if entity.position.y <= 0.0 || entity.position.y >= WORLD_HEIGHT {
            entity.velocity.y *= -BOUNCE_DAMPING;
            entity.position.y = entity.position.y.clamp(0.0, WORLD_HEIGHT);
        }
    }

    // Broad-phase collision sweep
    world.collision_grid.rebuild(&world.entities);
    for (a, b) in world.collision_grid.candidate_pairs() {
        if intersects(&world.entities[a].collider, &world.entities[b].collider) {
            world.event_queue.push(CollisionEvent { a, b });
        }
    }
}