import { TICK_RATE, BROADCAST_EVERY_N_TICKS, ENERGY_DECAY_PER_TICK, DAY_NIGHT_RATIO } from '@dflike/shared';
import { World } from '../ecs/World.js';
import { GameMap } from '../map/GameMap.js';
import { generateMap } from '../map/mapGenerator.js';
import { needsDecaySystem } from '../systems/needsDecaySystem.js';
import { npcBrainSystem } from '../systems/npcBrainSystem.js';
import { movementSystem } from '../systems/movementSystem.js';
import { socialSystem } from '../systems/socialSystem.js';
import { statModifierSystem } from '../systems/statModifierSystem.js';
import { relationshipSystem } from '../systems/relationshipSystem.js';
import { gatheringSystem } from '../systems/gatheringSystem.js';
import { createBondRegistry } from '../systems/bondRegistry.js';
import { ItemRegistry } from '../industry/itemRegistry.js';
import { industrySystem } from '../systems/industrySystem.js';
import { craftingSystem } from '../systems/craftingSystem.js';
import { buildingSystem } from '../systems/buildingSystem.js';
import { dropoffSystem } from '../systems/dropoffSystem.js';
import { pickupSystem } from '../systems/pickupSystem.js';
import { RecipeRegistry } from '../industry/recipeRegistry.js';
import { spawnNPC } from './spawner.js';
import { createLlmService, type LlmService } from '../llm/llmService.js';
import { generateBackstory } from '../llm/backstoryGenerator.js';
import { createNarrationService, type NarrationService } from '../llm/narrationService.js';
import { narrationEmitter } from '../systems/narrationEmitter.js';
import type { EntityId, InventionSummary, Position } from '@dflike/shared';
import type { StructureData } from '../systems/buildingSystem.js';
import { createThoughtSystem, type ThoughtSystem } from '../systems/thoughtSystem.js';
import { createEventMemoryService, type EventMemoryService } from '../llm/eventMemoryService.js';
import { createInventionSystem, type InventionSystem } from '../systems/inventionSystem.js';
import { createInventionTimeline } from '../industry/inventionTimeline.js';
import { createStockpileLog } from '../industry/stockpileLog.js';
import type { StockpileLogEntry } from '@dflike/shared';
import { SaveManager } from '../persistence/saveManager.js';
import { saveNarrationEvent, loadRecentNarrationEvents, saveMemoryEvent, loadAllRecentMemoryEvents, saveStockpileEntry, loadRecentStockpileEntries, saveInvention, loadAllInventions } from '../persistence/eventSerializer.js';
import type { StockpileLog } from '../industry/stockpileLog.js';
import type { InventionTimeline } from '../industry/inventionTimeline.js';

export class GameLoop {
  readonly world: World;
  readonly map: GameMap;
  readonly llmService: LlmService;
  readonly narrationService: NarrationService;
  readonly eventMemoryService: EventMemoryService;
  readonly thoughtSystem: ThoughtSystem;
  readonly inventionSystem: InventionSystem;
  public followedEntityIds: Set<EntityId> = new Set();
  public onInventionCreated: ((summary: InventionSummary) => void) | null = null;
  public onStockpileEvent: ((entry: StockpileLogEntry) => void) | null = null;
  private tick = 0;
  private interval: ReturnType<typeof setInterval> | null = null;
  private saveManager: SaveManager | null = null;
  private saveInterval: ReturnType<typeof setInterval> | null = null;
  private onBroadcast: (() => void) | null = null;

  constructor(options?: { newWorld?: boolean; savePath?: string }) {
    this.world = new World();
    this.map = new GameMap();
    this.llmService = createLlmService();
    this.narrationService = createNarrationService(this.llmService);
    this.eventMemoryService = createEventMemoryService();
    this.thoughtSystem = createThoughtSystem(this.llmService, this.narrationService, this.eventMemoryService);
    this.inventionSystem = createInventionSystem(
      this.llmService,
      this.narrationService,
      this.eventMemoryService,
      (summary) => this.onInventionCreated?.(summary),
    );

    this.saveManager = new SaveManager(options?.savePath ?? 'saves/default.db');

    if (!options?.newWorld && this.saveManager.saveExists()) {
      this.loadFromSave();
    } else {
      this.initNewWorld();
    }
  }

  private initNewWorld(): void {
    this.world.setSingleton('bondRegistry', createBondRegistry());
    this.world.setSingleton('itemRegistry', ItemRegistry.createDefault());
    this.world.setSingleton('recipeRegistry', RecipeRegistry.createDefault());
    this.world.setSingleton('inventionTimeline', createInventionTimeline());
    this.world.setSingleton('stockpileLog', createStockpileLog());

    this.setupMap();
    this.spawnDefaultStockpiles();
    this.spawnInitialNPCs(8);

    if (this.saveManager) {
      this.saveManager.initNewWorld(this.world, this.map, {
        terrain: this.map.terrain,
        decorations: this.map.decorations,
        trunkDecorations: this.map.trunkDecorations,
        resourceTiles: this.map.resourceTiles,
        obstacles: new Set(this.map.getObstacles().map(p => `${p.x},${p.y}`)),
        foodPositions: this.map.getPointsOfInterest('food').map(p => p.position),
        restPositions: this.map.getPointsOfInterest('rest').map(p => p.position),
      });
      this.saveManager.saveEntityState(this.world, 0);
      this.wirePersistenceCallbacks();
    }
    console.log('Created new world');
  }

  private loadFromSave(): void {
    this.saveManager!.openExistingSave();

    // Load map
    this.saveManager!.loadMapState(this.map);

    // Set non-entity singletons
    this.world.setSingleton('itemRegistry', ItemRegistry.createDefault());
    this.world.setSingleton('recipeRegistry', RecipeRegistry.createDefault());

    // Load entities (also restores bondRegistry singleton)
    this.tick = this.saveManager!.loadEntityState(this.world);

    // Create and load inventionTimeline
    const inventionTimeline = createInventionTimeline();
    const inventions = loadAllInventions();
    inventionTimeline.loadFromPersistence(inventions);
    this.world.setSingleton('inventionTimeline', inventionTimeline);

    // Create and load stockpileLog
    const stockpileLog = createStockpileLog();
    const stockEntries = loadRecentStockpileEntries(50);
    stockpileLog.loadFromPersistence(stockEntries);
    this.world.setSingleton('stockpileLog', stockpileLog);

    // Load event history into services
    const narrationEvents = loadRecentNarrationEvents(50);
    this.narrationService.loadFromPersistence(narrationEvents);

    const memoryEvents = loadAllRecentMemoryEvents(50);
    this.eventMemoryService.loadFromPersistence(memoryEvents);

    this.wirePersistenceCallbacks();

    console.log(`Loaded save: tick ${this.tick}, ${this.world.getAllEntities().length} entities`);
  }

  private wirePersistenceCallbacks(): void {
    this.narrationService.setPersistence(saveNarrationEvent);
    this.eventMemoryService.setPersistence(saveMemoryEvent);

    const stockpileLog = this.world.getSingleton<StockpileLog>('stockpileLog')!;
    stockpileLog.setPersistence(saveStockpileEntry);

    const inventionTimeline = this.world.getSingleton<InventionTimeline>('inventionTimeline')!;
    inventionTimeline.setPersistence(saveInvention);
  }

  private setupMap(): void {
    const generated = generateMap(this.map.width, this.map.height);

    // Load terrain and decorations
    this.map.terrain = generated.terrain;
    this.map.decorations = generated.decorations;
    this.map.trunkDecorations = generated.trunkDecorations;
    this.map.loadObstacles(generated.obstacles);

    // Load resource tiles
    this.map.resourceTiles = generated.resourceTiles;

    // Points of interest from generator
    for (const pos of generated.foodPositions) {
      this.map.addPointOfInterest({ type: 'food', position: pos });
    }
    for (const pos of generated.restPositions) {
      this.map.addPointOfInterest({ type: 'rest', position: pos });
    }
  }

  private spawnDefaultStockpiles(): void {
    const cx = Math.floor(this.map.width / 2);
    const cy = Math.floor(this.map.height / 2);

    // Find two walkable positions near the center for wood and stone stockpiles
    const positions: Position[] = [];
    outer:
    for (let r = 0; positions.length < 2; r++) {
      for (let dx = -r; dx <= r; dx++) {
        for (let dy = -r; dy <= r; dy++) {
          if (r > 0 && Math.abs(dx) !== r && Math.abs(dy) !== r) continue;
          const x = cx + dx;
          const y = cy + dy;
          if (this.map.isWalkable(x, y) && !positions.some(p => p.x === x && p.y === y)) {
            positions.push({ x, y });
            if (positions.length >= 2) break outer;
          }
        }
      }
    }

    const subtypes = ['wood', 'stone'];
    for (let i = 0; i < positions.length; i++) {
      const entity = this.world.createEntity();
      this.world.addComponent<Position>(entity, 'position', positions[i]);
      this.world.addComponent<StructureData>(entity, 'structure', {
        type: 'stockpile',
        subtype: subtypes[i],
        inventory: new Map(),
      });
    }
  }

  generateNpcBackstory(entityId: number): void {
    generateBackstory(this.world, entityId, this.llmService);
  }

  private spawnInitialNPCs(count: number): void {
    for (let i = 0; i < count; i++) {
      const entity = spawnNPC(this.world, this.map, undefined, this.eventMemoryService);
      this.generateNpcBackstory(entity);
    }
  }

  setBroadcastHandler(handler: () => void): void {
    this.onBroadcast = handler;
  }

  start(): void {
    const tickInterval = 1000 / TICK_RATE;
    this.interval = setInterval(() => this.update(), tickInterval);
    console.log(`Game loop started at ${TICK_RATE} ticks/sec`);

    // Periodic save every 30 seconds
    this.saveInterval = setInterval(() => {
      if (this.saveManager) {
        this.saveManager.saveEntityState(this.world, this.tick);
        console.log(`Autosaved at tick ${this.tick}`);
      }
    }, 30_000);
  }

  stop(): void {
    if (this.interval) {
      clearInterval(this.interval);
      this.interval = null;
    }
    if (this.saveInterval) {
      clearInterval(this.saveInterval);
      this.saveInterval = null;
    }
    // Final save on shutdown
    if (this.saveManager) {
      this.saveManager.saveEntityState(this.world, this.tick);
      this.saveManager.close();
      console.log(`Final save at tick ${this.tick}`);
    }
  }

  private update(): void {
    this.tick++;

    // Run systems in order
    statModifierSystem(this.world);
    needsDecaySystem(this.world, this.eventMemoryService);
    npcBrainSystem(this.world, this.map, this.eventMemoryService);
    socialSystem(this.world, this.eventMemoryService);
    narrationEmitter(this.world, this.narrationService, this.followedEntityIds, this.eventMemoryService);
    relationshipSystem(this.world, this.eventMemoryService);
    industrySystem(this.world, this.map);
    pickupSystem(this.world, this.tick, (entry) => this.onStockpileEvent?.(entry));
    gatheringSystem(this.world, this.map);
    craftingSystem(this.world);
    buildingSystem(this.world, this.map);
    dropoffSystem(this.world, this.map, this.tick, (entry) => this.onStockpileEvent?.(entry));
    movementSystem(this.world);
    this.thoughtSystem.update(this.world, this.followedEntityIds, this.tick);
    this.inventionSystem.update(this.world, this.tick);

    // Broadcast state periodically
    if (this.tick % BROADCAST_EVERY_N_TICKS === 0 && this.onBroadcast) {
      this.onBroadcast();
    }
  }

  getTick(): number {
    return this.tick;
  }

  getGameTime(): number {
    const dayTicks = 100 / ENERGY_DECAY_PER_TICK;
    const nightTicks = dayTicks / DAY_NIGHT_RATIO;
    const cycleTicks = Math.round(dayTicks + nightTicks);
    return (this.tick % cycleTicks) / cycleTicks;
  }
}