#pragma once

#include <memory>
#include <random>
#include <vector>

#include "BeltSystem.h"
#include "BlueprintDropEvent.h"
#include "EntityId.h"
#include "FireEvent.h"
#include "GameConfig.h"
#include "Tick.h"

class BuildingSystem;

class Simulation
{
public:
    explicit Simulation(const GameConfig& config, unsigned int seed = 0);
    ~Simulation();

    // Advances the simulation by one tick. Tick order per architecture.md §Tick Order.
    void tick();

    // Returns all fire events accumulated since the last drain, clearing the
    // internal queue. Call once per rendered frame (REQ-SHP-FIRING-BEAM).
    std::vector<FireEvent> drainFireEvents();

    // Returns all blueprint drop events since the last drain.
    std::vector<BlueprintDropEvent> drainBlueprintDropEvents();

    Tick currentTick() const;
    int  buildingBlocksStock() const;

    BuildingSystem&       buildings();
    const BuildingSystem& buildings() const;
    BeltSystem&           belts();
    const BeltSystem&     belts() const;

private:
    EntityId allocateId();  // Strictly increasing; never returns kInvalidEntityId.

    const GameConfig& m_config;
    std::mt19937 m_rng;

    Tick     m_currentTick;
    EntityId m_nextId;
    int      m_buildingBlocksStock;

    BeltSystem                      m_beltSystem;
    std::unique_ptr<BuildingSystem> m_buildingSystem;

    std::vector<FireEvent>          m_fireEvents;
    std::vector<BlueprintDropEvent> m_blueprintDropEvents;
};