import * as Cesium from 'cesium'
import _, { cloneDeep, throttle } from 'lodash'
import * as turf from '@turf/turf'
import { boxTransformScale } from '@/utils/turfFunc'

/**
 * 多边形绘制与编辑工具类
 * 功能：
 *  - 绘制多边形
 *  - 拖动编辑端点
 *  - 删除端点、删除整个多边形
 *  - 多边形自交检查（避免非法几何）
 *  - 外部订阅/通知机制
 */
export class DrawPolygon {
	constructor() {
		// 是否绘制
		this.whetherToDraw =false
		// 图斑预览模式标记
		this.isPureSpotPreview = false
		// 是否删除测区
		this.isDeleteTheArea = true
		//是否可以编辑图斑
		this.isPreviewMode = true
		// Cesium 视图对象
		this.viewer = null
		// 当前绘制的多边形
		this.curPolygon = null
		// 绘制模式标识
		this.drawingMode = false
		// 编辑模式标识
		this.editingMode = false
		// 是否正在拖拽端点
		this.isDragging = false
		// 当前拖拽的点实体
		this.draggedEntity = null
		// 多边形实体
		this.polygonEntity = null
		// 存储端点的 DataSource
		this.editPolygonDataSource = null
		this.editPolygonPointDataSource = null
		// 鼠标事件处理器
		this.handler = null
		// 右键菜单 DOM
		this.menuPopup = null
		// 被右键选中的点
		this.delPolygonPoint = null
		// 是否显示警告提示（自交）
		this.isShowWaringTip = false
		// 当前拖拽点是否合法
		this.currentDragPointIsValid = false
		// 当前拖拽点的坐标
		this.currentDragPointPosition = null

		// 事件回调函数绑定 this
		this.handleLeftDown = this.handleLeftDown.bind(this)
		this.handleLeftUp = this.handleLeftUp.bind(this)
		this.handleMouseMove = this.handleMouseMove.bind(this)
		this.handleLeftClick = this.handleLeftClick.bind(this)
		this.handleRightClick = this.handleRightClick.bind(this)

		this.delPolygon = this.delPolygon.bind(this)
		this.delPoint = this.delPoint.bind(this)
		// 外部订阅者
		this.listeners = []
		
	}

	// 实体命名常量
	static ENTITY_NAMES = {
		POLYGON: '区域-面',
		POINT: '区域-端点',
		POLYGON_ID: 'planar-route-polygon',
		POINT_ID_PREFIX: 'planar-route-point',
	}

	// 颜色常量
	static COLORS = {
		DEFAULT_POLYGON: Cesium.Color.fromBytes(45, 140, 240, 99), // 默认面颜色
		DEFAULT_LINE: Cesium.Color.fromBytes(45, 140, 240, 255), // 默认边界线颜色
		ERROR_POLYGON: Cesium.Color.fromCssColorString('rgba(255, 0, 0, .3)'), // 错误（自交）面颜色
		ERROR_LINE: Cesium.Color.fromCssColorString('rgba(255, 0, 0, 1)'), // 错误（自交）线颜色
	}

	// ============ 发布订阅机制 ============

	// 外部订阅数据变化
	subscribe(key, listener) {
		this.listeners.push({ key, listener })
	}

	// 通知订阅者
	notify(key, data) {
		this.listeners.filter(subscriber => subscriber.key === key).forEach(subscriber => subscriber.listener(data))
	}

	// ============ 绘制相关 ============
	// 编辑图斑
	editThePatch(data) {
		this.isPreviewMode = data
	}
	// 绘制
	drawTheArea(data){
		this.whetherToDraw = data		
	}
	// 删除测区
	deleteTheArea(data) {
		this.isDeleteTheArea = data
	}

	// 开始绘制
	startDrawing() {
		if (!this.whetherToDraw) {
		
			return;
		  }
		 
		  
		this.drawingMode = true
		this.curPolygon = new Cesium.PolygonHierarchy()

		// 如果还没有 DataSource，就新建一个
		if (!this.editPolygonDataSource) {
			this.editPolygonDataSource = new Cesium.CustomDataSource('editPolygonDataSource')
			this.viewer?.dataSources.add(this.editPolygonDataSource)
		}

		if (!this.editPolygonPointDataSource) {
			this.editPolygonPointDataSource = new Cesium.CustomDataSource('editPolygonPointDataSource')
			this.viewer?.dataSources.add(this.editPolygonPointDataSource)
		}

		// 清空之前的点
		this.editPolygonDataSource?.entities.removeAll()
		this.editPolygonPointDataSource?.entities.removeAll()
	}

	// 创建多边形实体（含边界线）
	createPolygonEntity() {
		this.polygonEntity = this.editPolygonDataSource.entities.add({
			name: DrawPolygon.ENTITY_NAMES.POLYGON,
			id: DrawPolygon.ENTITY_NAMES.POLYGON_ID,
			polygon: {
				hierarchy: new Cesium.CallbackProperty(() => this.curPolygon, false),
				material: DrawPolygon.COLORS.DEFAULT_POLYGON,
				outline: false,
				outlineWidth: 2,
				heightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
			},
			polyline: {
				width: 2,
				material: DrawPolygon.COLORS.DEFAULT_LINE,
				clampToGround: true,
				positions: new Cesium.CallbackProperty(
					() => [...this.curPolygon.positions, this.curPolygon.positions[0]], // 闭合线
					false
				),
			},
		})
	}

	// 创建端点实体
	createPointEntity(position, isAdd) {
		const pointIndex = isAdd ? this.curPolygon.positions.length - 2 : this.curPolygon.positions.length - 1

		this.editPolygonPointDataSource.entities.add({
			name: DrawPolygon.ENTITY_NAMES.POINT,
			id: `${DrawPolygon.ENTITY_NAMES.POINT_ID_PREFIX}${pointIndex}`,
			position: position.clone(),
			point: {
				pixelSize: 14,
				color: Cesium.Color.WHITE,
				heightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
				disableDepthTestDistance: Number.POSITIVE_INFINITY,
			},
			customData: {
				ind: pointIndex, // 索引记录
			},
		})
	
		
	}

	// 添加一个点
	addPosition(position, isAdd = true) {
		// 第一个点要重复压入一次，形成动态绘制效果
		if (this.curPolygon.positions.length === 0 && isAdd) {
			this.curPolygon.positions.push(position.clone())
		}

		this.curPolygon.positions.push(position.clone())

		// 如果没有实体则创建
		if (!this.polygonEntity) {
			this.createPolygonEntity()
		}

		// 创建端点实体
		if (this.isPreviewMode) {
			this.createPointEntity(position, isAdd)
		}

		this.notify('getPoints', position)
	}

	// ============ 鼠标事件 ============

	// 鼠标左键按下（选中端点拖动）
	handleLeftDown(movement) {
		if (!this.editingMode) return

		const pickedEntity = this.viewer.scene.pick(movement.position)?.id
		const isPoint = pickedEntity?.name === DrawPolygon.ENTITY_NAMES.POINT

		if (pickedEntity && isPoint) {
			this.isDragging = true
			this.draggedEntity = pickedEntity
			this.currentDragPointPosition = this.curPolygon.positions[this.draggedEntity?.customData.ind]
			this.disableMapControl() // 禁止地图交互
		}
	}

	// 鼠标左键抬起（拖拽结束）
	handleLeftUp() {
		if (!(this.editingMode && this.curPolygon?.positions && this.draggedEntity)) return

		if (this.currentDragPointIsValid && this.isDragging) {
			// 更新点位置
			this.draggedEntity.position = this.currentDragPointPosition
			this.curPolygon.positions[this.draggedEntity?.customData.ind] = this.currentDragPointPosition

			// 校验多边形是否自交
			if (!this.curDragPointIsValid(this.curPolygon.positions)) {
				this.isShowWaringTip = true
				this.currentDragPointIsValid = true
				this.updatePolygonAppearance(DrawPolygon.COLORS.ERROR_POLYGON, DrawPolygon.COLORS.ERROR_LINE)
			} else {
				this.isShowWaringTip = false
				this.currentDragPointIsValid = false
				this.updatePolygonAppearance(DrawPolygon.COLORS.DEFAULT_POLYGON, DrawPolygon.COLORS.DEFAULT_LINE)
			}

			this.notify('getShowWaringTip', this.isShowWaringTip)
		}

		// 拖拽结束，恢复交互
		if (this.isDragging) {
			this.notify('getPolygonPositions', this.curPolygon.positions)
			this.isDragging = false
			this.draggedEntity = null
			this.enableMapControl()
		}
	}

	// 鼠标移动
	handleMouseMove(movement) {
		if (!this.drawingMode && !this.editingMode) return

		const cartesian = this.viewer.scene.pickPosition(movement.endPosition)
		if (!cartesian) return

		// 编辑模式下，拖拽点实时更新
		if (this.editingMode && this.draggedEntity?.customData) {
			this.draggedEntity.position = cartesian
			this.curPolygon.positions[this.draggedEntity?.customData.ind] = cartesian			
		}

		// 绘制模式下，实时更新最后一个点
		if (this.drawingMode && this.polygonEntity && this.curPolygon.positions.length >= 1) {
			this.curPolygon.positions.pop()
			this.curPolygon.positions.push(cartesian)
		}

		// 实时检查是否自交
		if (
			(this.editingMode && this.draggedEntity?.customData) ||
			(this.drawingMode && this.polygonEntity && this.curPolygon.positions.length >= 3)
		) {
			if (!this.curDragPointIsValid(this.curPolygon.positions)) {
				this.isShowWaringTip = true
				this.currentDragPointIsValid = true
				this.updatePolygonAppearance(DrawPolygon.COLORS.ERROR_POLYGON, DrawPolygon.COLORS.ERROR_LINE)
			} else {
				this.isShowWaringTip = false
				this.currentDragPointIsValid = false
				this.updatePolygonAppearance(DrawPolygon.COLORS.DEFAULT_POLYGON, DrawPolygon.COLORS.DEFAULT_LINE)
			}

			this.notify('getShowWaringTip', this.isShowWaringTip)
		}
	}

	// 鼠标左键点击
	handleLeftClick(click) {
		this.removeMenuPopup()
		const pickedAllEntity = this.viewer.scene.drillPick(click.position).filter(i => i.id)
		const isPolygonPoint = pickedAllEntity.find(i => i.id.name === DrawPolygon.ENTITY_NAMES.POINT)
		const isPolygon = pickedAllEntity.find(i => i.id.name === DrawPolygon.ENTITY_NAMES.POLYGON)
		if (this.drawingMode && !this.whetherToDraw) {
		
			return; // 阻断后续绘制逻辑
		  }
		// 如果不是绘制模式
		if (!this.drawingMode) {
			if (!isPolygon) {
				
				
				this.editingMode = false
				this.editPolygonPointDataSource.entities.show = false
				return
			}

			if (isPolygon) {
			
				this.editingMode = true
				this.editPolygonPointDataSource.entities.show = true
			}
			return
		}

		// 点击闭合多边形
		if (this.curPolygon.positions.length < 4 && isPolygonPoint) {
			return
		}

		if (this.curPolygon.positions.length >= 4 && isPolygonPoint) {
			if (!this.drawingMode) return

			this.finishDrawing()
			return
		}

		// 添加新的点
		const cartesian = this.viewer.scene.pickPosition(click.position)
		if (!cartesian) return

		this.addPosition(cartesian)
	}

	// 鼠标右键点击（弹出菜单）
	handleRightClick(click) {		
		const that = this
		if (that.drawingMode) return
		that.removeMenuPopup()

		const pickedAllEntity = that.viewer.scene.drillPick(click.position).filter(i => i.id)
		const isPolygon = pickedAllEntity.find(i => i.id.name === DrawPolygon.ENTITY_NAMES.POLYGON)
		const isEditPoint = pickedAllEntity.find(i => i.id.name === DrawPolygon.ENTITY_NAMES.POINT)
		const {
			position: { x, y },
		} = click

		let pickedEntity, tooltipEvent, menuType
		if (isPolygon) {
			pickedEntity = isPolygon
			tooltipEvent = that.delPolygon
			menuType = 'polygon'
		
		} else if (isEditPoint) {
			pickedEntity = isEditPoint
			tooltipEvent = that.delPoint
			menuType = 'edit-point'
			
		}

		if (pickedEntity && this.isDeleteTheArea) {
			that.delPolygonPoint = pickedEntity.id
			that.menuPopup = that.createMenuPopup(menuType)
			that.menuPopup.style.transform = `translate3d(${x - 10}px, ${y - 10}px, 0)`
			that.viewer.container.appendChild(that.menuPopup)
			that.menuPopup.addEventListener('click', tooltipEvent)
		}
	}

	// ============ 删除相关 ============

	// 删除所有实体
	removeEntities() {
		if (this.editPolygonDataSource) {
			this.editPolygonDataSource.entities.removeAll()
			this.editPolygonDataSource = null
		}

		if (this.editPolygonPointDataSource) {
			this.editPolygonPointDataSource.entities.removeAll()
			this.editPolygonPointDataSource = null
		}
		this.editingMode = false
		this.polygonEntity = null
		this.curPolygon = null
	}

	// 完成绘制
	finishDrawing() {
		this.curPolygon.positions.pop()

		if (this.curPolygon.positions.length >= 3) {
			this.drawingMode = false
			this.editingMode = true
			this.editPolygonPointDataSource.entities.show = true

			if (!this.curDragPointIsValid(this.curPolygon.positions)) {
				this.isShowWaringTip = true
				this.currentDragPointIsValid = true
				this.updatePolygonAppearance(DrawPolygon.COLORS.ERROR_POLYGON, DrawPolygon.COLORS.ERROR_LINE)
			} else {
				this.isShowWaringTip = false
				this.currentDragPointIsValid = false
				this.updatePolygonAppearance(DrawPolygon.COLORS.DEFAULT_POLYGON, DrawPolygon.COLORS.DEFAULT_LINE)
			}

			this.notify('getShowWaringTip', this.isShowWaringTip)
			this.notify('getPolygonPositions', this.curPolygon.positions)
		}
	}

	// 删除多边形
	delPolygon() {
		this.removeEntities()
		this.removeMenuPopup()
		this.notify('getPolygonPositions', [])
		this.startDrawing()
	}

	// 删除端点
	delPoint() {
		if (this.curPolygon.positions.length <= 3) {
			this.removeMenuPopup()
			return ElMessage.warning('端点不可少于3个')
		}
		if (!this.delPolygonPoint) return

		this.curPolygon.positions.splice(this.delPolygonPoint.customData.ind, 1)
		this.editPolygonPointDataSource.entities.remove(this.delPolygonPoint)
		this.removeMenuPopup()

		// 更新剩余点索引
		this.editPolygonPointDataSource.entities.values.forEach((item, index) => {
			item.customData.ind = index
		})

		this.notify('getPolygonPositions', this.curPolygon.positions)
	}

	// ============ 工具方法 ============

	// 创建右键菜单
	createMenuPopup(type = 'polygon') {
		const menuPopupVBox = document.createElement('div')
		menuPopupVBox.id = 'planarPolygonEdit'
		menuPopupVBox.className = 'planar-polygon-edit-tooltip'

		const menuPopup = document.createElement('div')
		menuPopup.id = 'planarPolygonEditMenu'
		menuPopup.className = 'planar-polygon-edit-menu'


		const menuItems =
			type === 'polygon'
				? [{ title: '删除测区', class: 'del-planar-polygon' }]
				: [{ title: '删除端点', class: 'del-planar-point' }]

		menuItems.forEach(item => {
			const titleDiv = document.createElement('div')
			titleDiv.innerText = item.title
			titleDiv.className = item.class
			menuPopup.appendChild(titleDiv)
		})
	
		this.isPreviewMode = true
		menuPopupVBox.appendChild(menuPopup)
		return menuPopupVBox
	}

	// 移除菜单
	removeMenuPopup() {
		const that = this
		if (that.menuPopup) {
			that.menuPopup.removeEventListener('click', that.delPolygon)
			that.menuPopup.removeEventListener('click', that.delPoint)
			that.viewer.container.removeChild(that.menuPopup)
			that.menuPopup = null
		}
		that.delPolygonPoint = null
	}

	// 更新多边形样式（正常/错误）
	updatePolygonAppearance(polygonColor, lineColor) {
		this.polygonEntity.polygon.material = polygonColor
		this.polygonEntity.polyline.material = lineColor
	}

	// 禁用地图交互
	disableMapControl() {
		const controller = this.viewer.scene.screenSpaceCameraController
		controller.enableRotate = false
		controller.enableTranslate = false
		controller.enableZoom = false
	}

	// 启用地图交互
	enableMapControl() {
		const controller = this.viewer.scene.screenSpaceCameraController
		controller.enableRotate = true
		controller.enableTranslate = true
		controller.enableZoom = true
	}

	// 检查多边形是否自交
	curDragPointIsValid(positions) {
		if (positions.length < 3) return true

		const cartographics = Cesium.Ellipsoid.WGS84.cartesianArrayToCartographicArray(positions)
		const latLngPoints = cartographics.map(cartographic => [
			Cesium.Math.toDegrees(cartographic.longitude),
			Cesium.Math.toDegrees(cartographic.latitude),
		])

		// 用 turf.js 检查自交
		const poly = turf.polygon([[...latLngPoints, latLngPoints[0]]])
		const intersections = turf.kinks(poly)

		return intersections.features.length === 0
	}

	// 初始化已有多边形
	initPolygon(viewer, positions, isPurePreview = false) {
		this.initHandler(viewer)
	
		if (this.whetherToDraw) {
			this.startDrawing();
		  } else {
			// 新增：不允许绘制时，确保绘制模式为 false，避免误触发
			this.drawingMode = false;
		
		  }
		
		let newPosition = positions.map(item => {
			return Cesium.Cartesian3.fromDegrees(Number(item.lng), Number(item.lat), Number(item.height))
		})
		

		newPosition.forEach(item => {
			this.addPosition(item, false)
		})

		// 视角飞入区域
		const newBox = boxTransformScale(
			positions.map(item => [item.lng, item.lat]),
			5
		)
		viewer.camera.flyTo({
			destination: Cesium.Rectangle.fromDegrees(...newBox),
			offset: new Cesium.HeadingPitchRange(0, Cesium.Math.toRadians(-90), 0),
			duration: 0.5,
		})

		this.drawingMode = false
		this.editingMode = true
	}

	// 初始化事件处理器
	initHandler(viewer) {
		this.viewer = viewer

		if(this.whetherToDraw){
			this.startDrawing()
		}

		if (!this.handler) {
			this.handler = new Cesium.ScreenSpaceEventHandler(viewer.scene.canvas)

			// 注册鼠标事件
			const events = [
				[Cesium.ScreenSpaceEventType.LEFT_DOWN, this.handleLeftDown],
				[Cesium.ScreenSpaceEventType.LEFT_UP, this.handleLeftUp],
				[Cesium.ScreenSpaceEventType.MOUSE_MOVE, this.handleMouseMove],
				[Cesium.ScreenSpaceEventType.LEFT_CLICK, this.handleLeftClick],
				[Cesium.ScreenSpaceEventType.RIGHT_CLICK, this.handleRightClick],
			]

			events.forEach(([type, handler]) => {
				this.handler.setInputAction(handler, type)
			})
		}
	}

	// 移除事件处理器
	removeHandler() {
		if (this.handler) {
			const eventTypes = [
				Cesium.ScreenSpaceEventType.LEFT_DOWN,
				Cesium.ScreenSpaceEventType.LEFT_UP,
				Cesium.ScreenSpaceEventType.MOUSE_MOVE,
				Cesium.ScreenSpaceEventType.LEFT_CLICK,
				Cesium.ScreenSpaceEventType.RIGHT_CLICK,
			]

			eventTypes.forEach(type => {
				this.handler.removeInputAction(type)
			})

			this.handler = null
		}
	}

	/**
	 * 销毁实例，释放资源
	 */
	destroy() {
		if (!this.viewer) return

		this.removeMenuPopup()
		this.removeEntities()
		this.removeHandler()
		this.enableMapControl()
	}
}