import Phaser from 'phaser'
import { TILE_SIZE, BUILDING_COSTS } from '../config'
import { TileType, IMPASSABLE } from '../types'
import type { BuildingType } from '../types'
import { stateManager } from '../StateManager'
import type { LocalAdapter } from '../NetworkAdapter'

const BUILDING_TILE: Partial<Record<BuildingType, TileType>> = {
  floor: TileType.FLOOR,
  wall:  TileType.WALL,
  chest: TileType.FLOOR,   // chest placed on floor tile
  // bed and stockpile_zone do NOT change the underlying tile
}

export class BuildingSystem {
  private scene: Phaser.Scene
  private adapter: LocalAdapter
  private active = false
  private selectedBuilding: BuildingType = 'floor'
  private ghost!: Phaser.GameObjects.Rectangle
  private ghostLabel!: Phaser.GameObjects.Text
  private buildKey!: Phaser.Input.Keyboard.Key
  private cancelKey!: Phaser.Input.Keyboard.Key

  onModeChange?: (active: boolean, building: BuildingType) => void
  onPlaced?: (msg: string) => void

  constructor(scene: Phaser.Scene, adapter: LocalAdapter) {
    this.scene = scene
    this.adapter = adapter
  }

  create(): void {
    this.ghost = this.scene.add.rectangle(0, 0, TILE_SIZE, TILE_SIZE, 0x00FF00, 0.35)
    this.ghost.setDepth(1000)
    this.ghost.setVisible(false)
    this.ghost.setStrokeStyle(2, 0x00FF00, 0.8)

    this.ghostLabel = this.scene.add.text(0, 0, '', {
      fontSize: '10px', color: '#ffffff', fontFamily: 'monospace',
      backgroundColor: '#000000aa', padding: { x: 3, y: 2 }
    })
    this.ghostLabel.setDepth(1001)
    this.ghostLabel.setVisible(false)
    this.ghostLabel.setOrigin(0.5, 1)

    this.buildKey  = this.scene.input.keyboard!.addKey(Phaser.Input.Keyboard.KeyCodes.B)
    this.cancelKey = this.scene.input.keyboard!.addKey(Phaser.Input.Keyboard.KeyCodes.ESC)

    // Click to place
    this.scene.input.on('pointerdown', (ptr: Phaser.Input.Pointer) => {
      if (!this.active) return
      if (ptr.rightButtonDown()) {
        this.deactivate()
        return
      }
      this.tryPlace(ptr)
    })
  }

  /** Select a building type and activate build mode */
  selectBuilding(kind: BuildingType): void {
    this.selectedBuilding = kind
    this.activate()
  }

  private activate(): void {
    this.active = true
    this.ghost.setVisible(true)
    this.ghostLabel.setVisible(true)
    this.onModeChange?.(true, this.selectedBuilding)
  }

  deactivate(): void {
    this.active = false
    this.ghost.setVisible(false)
    this.ghostLabel.setVisible(false)
    this.onModeChange?.(false, this.selectedBuilding)
  }

  isActive(): boolean { return this.active }

  update(): void {
    if (Phaser.Input.Keyboard.JustDown(this.buildKey)) {
      if (this.active) this.deactivate()
      // If not active, UIScene opens build menu
    }
    if (Phaser.Input.Keyboard.JustDown(this.cancelKey)) {
      this.deactivate()
    }

    if (!this.active) return

    // Update ghost to follow mouse (snapped to tile grid)
    const ptr    = this.scene.input.activePointer
    const worldX = ptr.worldX
    const worldY = ptr.worldY
    const tileX = Math.floor(worldX / TILE_SIZE)
    const tileY = Math.floor(worldY / TILE_SIZE)
    const snapX = tileX * TILE_SIZE + TILE_SIZE / 2
    const snapY = tileY * TILE_SIZE + TILE_SIZE / 2

    this.ghost.setPosition(snapX, snapY)
    this.ghostLabel.setPosition(snapX, snapY - TILE_SIZE / 2 - 2)

    // Color ghost based on can-build
    const canBuild = this.canBuildAt(tileX, tileY)
    const color = canBuild ? 0x00FF00 : 0xFF4444
    this.ghost.setFillStyle(color, 0.35)
    this.ghost.setStrokeStyle(2, color, 0.9)

    const costs = BUILDING_COSTS[this.selectedBuilding] ?? {}
    const costStr = Object.entries(costs).map(([k, v]) => `${v}${k[0].toUpperCase()}`).join(' ')
    this.ghostLabel.setText(`${this.selectedBuilding} [${costStr}]`)
  }

  private canBuildAt(tileX: number, tileY: number): boolean {
    const state = stateManager.getState()
    const tile = state.world.tiles[tileY * 512 + tileX] as TileType  // 512 = WORLD_TILES

    // Can only build on passable ground tiles (not water, not existing buildings)
    if (IMPASSABLE.has(tile)) return false

    // Check no resource node on this tile
    for (const res of Object.values(state.world.resources)) {
      if (res.tileX === tileX && res.tileY === tileY) return false
    }

    // Check no existing building of any kind on this tile
    for (const b of Object.values(state.world.buildings)) {
      if (b.tileX === tileX && b.tileY === tileY) return false
    }

    // Check have enough resources
    const costs = BUILDING_COSTS[this.selectedBuilding] ?? {}
    for (const [item, qty] of Object.entries(costs)) {
      const have = state.world.stockpile[item as keyof typeof state.world.stockpile] ?? 0
      if (have < qty) return false
    }

    return true
  }

  private tryPlace(ptr: Phaser.Input.Pointer): void {
    const worldX = ptr.worldX
    const worldY = ptr.worldY
    const tileX = Math.floor(worldX / TILE_SIZE)
    const tileY = Math.floor(worldY / TILE_SIZE)

    if (!this.canBuildAt(tileX, tileY)) {
      this.onPlaced?.('Cannot build here!')
      return
    }

    const costs = BUILDING_COSTS[this.selectedBuilding] ?? {}
    const building = {
      id: `building_${tileX}_${tileY}_${Date.now()}`,
      tileX,
      tileY,
      kind: this.selectedBuilding,
      ownerId: stateManager.getState().player.id,
    }

    this.adapter.send({ type: 'PLACE_BUILDING', building, costs })
    // Only change the tile type for buildings that have a floor/wall tile mapping
    const tileMapped = BUILDING_TILE[this.selectedBuilding]
    if (tileMapped !== undefined) {
      this.adapter.send({
        type: 'CHANGE_TILE',
        tileX,
        tileY,
        tile: tileMapped,
      })
    }
    this.onPlaced?.(`Placed ${this.selectedBuilding}!`)
  }

  destroy(): void {
    this.ghost.destroy()
    this.ghostLabel.destroy()
  }
}