import { ref, onUnmounted } from 'vue'
import * as Cesium from 'cesium'
import { use3DTiles } from './use3DTiles'

/**
 * 双地图对比模式
 * 使用两个独立的Cesium Viewer实现并排对比
 * 左侧显示灾前场景，右侧显示灾后场景
 * 单向相机同步：右侧主地图驱动，左侧对比地图跟随
 */
export function useDualMapCompare() {
  /** 左侧Viewer引用 */
  const leftViewer = ref(null)

  /** 右侧Viewer引用 */
  const rightViewer = ref(null)

  /** 对比模式是否激活 */
  const isCompareMode = ref(false)

  /** 相机同步监听器移除函数 */
  let cameraSyncRemover = null

  /** 左侧3D Tileset（灾前） */
  let leftTileset = null

  /** 右侧3D Tileset（灾后，主地图的tileset） */
  let rightTileset = null

  const { load3DTileset } = use3DTiles()

  /**
   * 初始化左侧Viewer（灾前场景）
   * @param {HTMLElement} container - 容器元素
   * @returns {Cesium.Viewer}
   */
  const initLeftViewer = (container) => {
    if (!container) {
      console.error('[useDualMapCompare] 左侧容器元素不存在')
      return null
    }

    // 验证容器尺寸
    const { clientWidth, clientHeight } = container
    console.log(`[useDualMapCompare] 左侧容器尺寸: ${clientWidth}x${clientHeight}`)

    if (clientWidth <= 0 || clientHeight <= 0) {
      console.error(`[useDualMapCompare] 左侧容器尺寸无效 (width=${clientWidth}, height=${clientHeight})`)
      return null
    }

    // 创建左侧viewer
    const viewer = new Cesium.Viewer(container, {
      animation: false,
      baseLayerPicker: false,
      fullscreenButton: false,
      geocoder: false,
      homeButton: false,
      infoBox: false,
      sceneModePicker: false,
      selectionIndicator: false,
      timeline: false,
      navigationHelpButton: false,
      scene3DOnly: true,
      shouldAnimate: false,
    })

    // 移除默认的Cesium logo和版权信息
    viewer.cesiumWidget.creditContainer.style.display = 'none'

    // 完全禁用左侧Viewer的所有交互（只作为对比显示）
    // viewer.scene.screenSpaceCameraController.enableRotate = false
    // viewer.scene.screenSpaceCameraController.enableTranslate = false
    // viewer.scene.screenSpaceCameraController.enableZoom = false
    // viewer.scene.screenSpaceCameraController.enableTilt = false
    // viewer.scene.screenSpaceCameraController.enableLook = false

    leftViewer.value = viewer
    console.log('[useDualMapCompare] 左侧Viewer初始化成功（交互已启用）') // 关键修改

    return viewer
  }

  /**
   * 设置单向相机同步（右→左）
   * 右侧主地图驱动，左侧对比地图跟随
   * @param {Cesium.Viewer} rightViewerInstance - 右侧Viewer（主地图，驱动者）
   * @param {Cesium.Viewer} leftViewerInstance - 左侧Viewer（对比地图，跟随者）
   */
  const setupCameraSync = (rightViewerInstance, leftViewerInstance) => {
    if (!rightViewerInstance || !leftViewerInstance) {
      console.warn('[useDualMapCompare] Viewer未初始化，无法设置相机同步')
      return
    }

    console.log('[useDualMapCompare] 设置智能相机同步（右→左）...')

    /** 同步相机状态（带防抖） */
    let isSyncing = false
    const handleCameraSync = () => {
      if (isSyncing) return
      isSyncing = true

      requestAnimationFrame(() => {
        try {
          const rightCamera = rightViewerInstance.camera
          leftViewerInstance.camera.setView({
            destination: rightCamera.position.clone(),
            orientation: {
              heading: rightCamera.heading,
              pitch: rightCamera.pitch,
              roll: rightCamera.roll
            }
          })
        } catch (e) {
          console.warn('[useDualMapCompare] 同步异常:', e)
        } finally {
          isSyncing = false
        }
      })
    }

    const syncController = {
      _isUserInteracting: false,
      _interactionHandlers: [], // 存储 moveStart 监听器
      _moveEndHandler: null,
      _lastPosition: null,
      _interval: null,

      start: () => {
        const controller = rightViewerInstance.scene.screenSpaceCameraController

        if (!controller) {
          console.error('[useDualMapCompare] screenSpaceCameraController未初始化')
          return
        }

        // 1. 事件监听逻辑
        if (typeof rightViewerInstance.camera.moveStart?.addEventListener === 'function' &&
          typeof rightViewerInstance.camera.moveEnd?.addEventListener === 'function') {

          // 监听相机移动开始（替代所有操作类型监听）
          const moveStartHandler = rightViewerInstance.camera.moveStart.addEventListener(() => {
            syncController._isUserInteracting = true
            console.log('[useDualMapCompare] 捕获相机操作开始')

            // 新增拖动持续监听
            const onDragFrame = () => {
              if (syncController._isUserInteracting) {
                console.log('[useDualMapCompare] 主同步触发')
                handleCameraSync()
                requestAnimationFrame(onDragFrame)
              }
            }
            requestAnimationFrame(onDragFrame)
          })

          // 2. 同步逻辑
          syncController._moveEndHandler = rightViewerInstance.camera.moveEnd.addEventListener(() => {
            if (syncController._isUserInteracting) {
              console.log('[useDualMapCompare] 主同步触发')
              handleCameraSync()
              syncController._isUserInteracting = false
            }
          })

        } else {
          console.warn(`[useDualMapCompare] 相机事件不可用，当前Cesium版本: ${Cesium.VERSION}`)
          return
        }

        // 3. 保险同步逻辑
        syncController._lastPosition = new Cesium.Cartesian3()
        syncController._interval = setInterval(() => {
          const isMoving = controller.isMoving
          const currentPosition = rightViewerInstance.camera.position

          if (syncController._isUserInteracting) {
            if (isMoving) {
              Cesium.Cartesian3.clone(currentPosition, syncController._lastPosition)
            } else {
              const positionChanged = !Cesium.Cartesian3.equalsEpsilon(
                currentPosition, 
                syncController._lastPosition,
                0.1
              )
              if (positionChanged) {
                console.log('[useDualMapCompare] 保险同步触发')
                handleCameraSync()
              }
              if (!controller.isMoving) {
                syncController._isUserInteracting = false 
              }
              Cesium.Cartesian3.clone(currentPosition, syncController._lastPosition)
            }
          }
        }, 300)

        console.log('[useDualMapCompare] 智能同步设置完成')
      },

      stop: () => {
        const controller = rightViewerInstance.scene.screenSpaceCameraController

        // 移除 moveStart 监听
        syncController._interactionHandlers.forEach(handler => {
          if (typeof rightViewerInstance.camera.moveStart?.removeEventListener === 'function') {
            rightViewerInstance.camera.moveStart.removeEventListener(handler)
          }
        })
        syncController._interactionHandlers = []

        // 移除 moveEnd 监听
        if (syncController._moveEndHandler &&
          typeof rightViewerInstance.camera.moveEnd?.removeEventListener === 'function') {
          rightViewerInstance.camera.moveEnd.removeEventListener(syncController._moveEndHandler)
        }

        // 清除保险同步
        if (syncController._interval) {
          clearInterval(syncController._interval)
          syncController._interval = null
        }

        syncController._isUserInteracting = false
        syncController._lastPosition = null
        console.log('[useDualMapCompare] 智能同步已移除')
      }
    }


    // 启动监听
    syncController.start()

    // 保存移除函数
    cameraSyncRemover = () => {
      syncController.stop()
      console.log('[useDualMapCompare] 智能同步已移除')
    }

    console.log('[useDualMapCompare] 智能同步设置完成')
  }

  /**
   * 启用对比模式
   * @param {Cesium.Viewer} rightViewerInstance - 右侧Viewer实例（主地图，灾后场景）
   * @param {Object} options - 配置选项
   * @param {boolean} options.skipLeftModelLoad - 是否跳过左侧模型加载
   * @param {boolean} options.loadLeftModel - 是否仅加载左侧模型（不重新初始化Viewer）
   */
  const enableCompareMode = async (rightViewerInstance, options = {}) => {
    const { skipLeftModelLoad = false, loadLeftModel = false } = options

    // 前置检查: viewer
    if (!rightViewerInstance) {
      const error = new Error('右侧主地图Viewer未初始化')
      console.error('[useDualMapCompare]', error.message)
      throw error
    }

    // 如果只是加载左侧模型（Viewer已存在）
    if (loadLeftModel && leftViewer.value) {
      console.log('[useDualMapCompare] 加载左侧灾前模型...')
      try {
        const tileset = await load3DTileset(leftViewer.value, 'before', false)
        if (tileset) {
          leftTileset = tileset
          console.log('[useDualMapCompare] 左侧灾前模型加载完成')
        }
      } catch (error) {
        console.error('[useDualMapCompare] 左侧模型加载失败:', error)
      }
      return
    }

    console.log('[useDualMapCompare] 启用对比模式...')

    rightViewer.value = rightViewerInstance

    // 查找左侧容器（容器已存在于DOM中）
    const leftContainer = document.getElementById('leftCesiumContainer')
    if (!leftContainer) {
      const error = new Error('找不到左侧容器元素 #leftCesiumContainer')
      console.error('[useDualMapCompare]', error.message)
      throw error
    }

    // 先设置状态，触发CSS动画
    isCompareMode.value = true

    // 增强型布局等待策略
    await new Promise(resolve => {
      // 1. 基础等待 → 2. 强制重绘 → 3. 循环检查
      setTimeout(() => {
        // 强制触发浏览器重绘
        void leftContainer.offsetWidth

        // 3. 循环验证容器尺寸
        const startTime = Date.now()
        const checkLayout = () => {
          if (leftContainer.clientWidth > 0 && leftContainer.clientHeight > 0) {
            resolve()
          } else if (Date.now() - startTime < 2000) { // 总等待不超过2秒
            setTimeout(checkLayout, 50)
          } else {
            console.error('左侧容器最终尺寸：',
              `width: ${leftContainer.clientWidth}px, height: ${leftContainer.clientHeight}px`)
            throw new Error('左侧容器布局超时')
          }
        }
        checkLayout()
      }, 350) // 原等待时间保持
    })

    // 初始化左侧Viewer
    const leftViewerInstance = initLeftViewer(leftContainer)
    if (!leftViewerInstance) {
      const error = new Error('左侧Viewer初始化失败')
      console.error('[useDualMapCompare]', error.message)
      isCompareMode.value = false  // 回滚状态
      throw error
    }

    // 立即同步右侧相机的当前位置到左侧
    console.log('[useDualMapCompare] 同步初始相机位置...')
    const rightCamera = rightViewerInstance.camera
    leftViewerInstance.camera.setView({
      destination: rightCamera.position.clone(),
      orientation: {
        heading: rightCamera.heading,
        pitch: rightCamera.pitch,
        roll: rightCamera.roll
      }
    })

    // 设置相机同步（单向：右→左）
    setupCameraSync(rightViewerInstance, leftViewerInstance)

    // 根据选项决定是否加载左侧模型
    if (!skipLeftModelLoad) {
      // 异步加载灾前模型到左侧（不阻塞对比模式启用）
      console.log('[useDualMapCompare] 开始异步加载左侧灾前模型...')
      load3DTileset(leftViewerInstance, 'before', false)
        .then(tileset => {
          if (tileset) {
            leftTileset = tileset
            console.log('[useDualMapCompare] 左侧灾前模型加载完成')
          }
        })
        .catch(error => {
          console.error('[useDualMapCompare] 左侧模型加载失败:', error)
        })
    } else {
      console.log('[useDualMapCompare] 跳过左侧模型加载（将延迟加载）')
    }

    // 右侧保持灾后模型（已加载）

    // 触发左侧viewer resize
    setTimeout(() => {
      if (leftViewerInstance && leftViewerInstance.canvas) {
        leftViewerInstance.resize()
        leftViewerInstance.camera.changed.raiseEvent()
      }
      // 同时触发右侧viewer resize
      if (rightViewerInstance && rightViewerInstance.canvas) {
        rightViewerInstance.resize()
      }
    }, 350)

    console.log('[useDualMapCompare] 对比模式已启用')
  }

  /**
   * 禁用对比模式
   */
  const disableCompareMode = () => {
    console.log('[useDualMapCompare] 禁用对比模式...')

    // 移除相机同步
    if (cameraSyncRemover) {
      cameraSyncRemover()
      cameraSyncRemover = null
    }

    // 销毁左侧Viewer
    if (leftViewer.value && !leftViewer.value.isDestroyed()) {
      // 清理左侧tileset
      if (leftTileset) {
        leftViewer.value.scene.primitives.remove(leftTileset)
        leftTileset = null
      }

      leftViewer.value.destroy()
      leftViewer.value = null
      console.log('[useDualMapCompare] 左侧Viewer已销毁')
    }

    // 触发右侧viewer resize恢复全屏
    if (rightViewer.value && !rightViewer.value.isDestroyed()) {
      setTimeout(() => {
        if (rightViewer.value && rightViewer.value.canvas) {
          rightViewer.value.resize()
        }
      }, 350)
    }

    isCompareMode.value = false
    console.log('[useDualMapCompare] 对比模式已禁用')
  }

  /**
   * 切换对比模式
   * @param {boolean} active - true启用，false禁用
   * @param {Cesium.Viewer} rightViewerInstance - 右侧Viewer实例（主地图）
   * @param {Object} options - 配置选项（传递给 enableCompareMode）
   * @throws {Error} 当切换失败时抛出错误
   */
  const toggleCompareMode = async (active, rightViewerInstance, options) => {
    try {
      console.log(`[useDualMapCompare] 切换对比模式: ${active}`)

      if (active) {
        // 前置检查
        if (!rightViewerInstance) {
          throw new Error('右侧Viewer未初始化,无法启用对比模式')
        }

        await enableCompareMode(rightViewerInstance, options)
      } else {
        disableCompareMode()
      }

      console.log(`[useDualMapCompare] 对比模式切换成功: ${active}`)
    } catch (error) {
      console.error('[useDualMapCompare] 切换对比模式失败:', error)

      // 确保状态回滚
      isCompareMode.value = !active

      // 向上层传播错误
      throw error
    }
  }

  // 清理
  onUnmounted(() => {
    disableCompareMode()
  })

  return {
    leftViewer,
    rightViewer,
    isCompareMode,
    enableCompareMode,
    disableCompareMode,
    toggleCompareMode
  }
}

export default useDualMapCompare