import * as Cesium from 'cesium'
import { MapTooltip } from '@ztzf/utils'
import { ToolBase } from '../ToolBase'

const POINT_ENTITY_NAME = 'draw-polygon-point'
const DEFAULT_STYLE = {
	fill: Cesium.Color.fromBytes(45, 140, 240, 99),
	outline: Cesium.Color.fromBytes(45, 140, 240, 255),
}
const resolveStyle = style => ({
	fill: style?.fill || DEFAULT_STYLE.fill,
	outline: style?.outline || DEFAULT_STYLE.outline,
})
const resolveColorWithAlpha = (baseColor, alphaSource) => {
	if (!baseColor) return alphaSource
	const alpha = typeof alphaSource?.alpha === 'number' ? alphaSource.alpha : 1
	return baseColor.withAlpha(alpha)
}

const normalizeRing = points => {
	if (!Array.isArray(points)) return []
	const ring = points.filter(Boolean)
	if (ring.length < 2) return ring
	const first = ring[0]
	const last = ring[ring.length - 1]
	if (Cesium.Cartesian3.equals(first, last)) {
		return ring.slice(0, -1)
	}
	return ring
}

const isSelfIntersecting = positions => {
	const ring = normalizeRing(positions)
	if (ring.length < 4) return false
	const epsilon = 1e-12
	const toPoint = cartesian => {
		const carto = Cesium.Cartographic.fromCartesian(cartesian)
		return { x: carto.longitude, y: carto.latitude }
	}
	const pts = ring.map(toPoint)
	const orientation = (a, b, c) => {
		const value = (b.y - a.y) * (c.x - b.x) - (b.x - a.x) * (c.y - b.y)
		if (Math.abs(value) < epsilon) return 0
		return value > 0 ? 1 : 2
	}
	const onSegment = (a, b, c) =>
		b.x <= Math.max(a.x, c.x) + epsilon &&
		b.x + epsilon >= Math.min(a.x, c.x) &&
		b.y <= Math.max(a.y, c.y) + epsilon &&
		b.y + epsilon >= Math.min(a.y, c.y)
	const segmentsIntersect = (p1, q1, p2, q2) => {
		const o1 = orientation(p1, q1, p2)
		const o2 = orientation(p1, q1, q2)
		const o3 = orientation(p2, q2, p1)
		const o4 = orientation(p2, q2, q1)
		if (o1 !== o2 && o3 !== o4) return true
		if (o1 === 0 && onSegment(p1, p2, q1)) return true
		if (o2 === 0 && onSegment(p1, q2, q1)) return true
		if (o3 === 0 && onSegment(p2, p1, q2)) return true
		if (o4 === 0 && onSegment(p2, q1, q2)) return true
		return false
	}
	const count = pts.length
	for (let i = 0; i < count; i += 1) {
		const p1 = pts[i]
		const q1 = pts[(i + 1) % count]
		for (let j = i + 1; j < count; j += 1) {
			const isAdjacent = j === i || j === i + 1 || (i === 0 && j === count - 1)
			if (isAdjacent) continue
			const p2 = pts[j]
			const q2 = pts[(j + 1) % count]
			if (segmentsIntersect(p1, q1, p2, q2)) return true
		}
	}
	return false
}

export class DrawPolygonTool extends ToolBase {
	constructor(viewer, options = {}) {
		super(viewer)
		this.tooltip = new MapTooltip(viewer)
		this.dataSource = null
		this.polygonEntity = null
		this.polylineEntity = null
		this.positions = []
		this.floatPosition = null
		this.isDrawing = false
		this.lastMousePosition = null
		this.isIntersecting = false
		this.style = resolveStyle(options?.style)
	}

	start() {
		if (!this.tooltip) {
			this.tooltip = new MapTooltip(this.viewer)
		}
		this.dataSource = new Cesium.CustomDataSource('draw-polygon')
		this.viewer.dataSources.add(this.dataSource)
		this.handler = new Cesium.ScreenSpaceEventHandler(this.viewer.scene.canvas)
		this.handler.setInputAction(click => this.handleLeftClick(click), Cesium.ScreenSpaceEventType.LEFT_CLICK)
		this.handler.setInputAction(click => this.handleRightClick(click), Cesium.ScreenSpaceEventType.RIGHT_CLICK)
		this.handler.setInputAction(movement => this.handleMouseMove(movement), Cesium.ScreenSpaceEventType.MOUSE_MOVE)
		this.isDrawing = true
		this.tooltip.hide()
	}

	handleLeftClick(click) {
		if (!this.isDrawing) return

		const pickedEntity = this.viewer.scene.pick(click.position)?.id
		if (this.isFinishTrigger(pickedEntity)) {
			this.finishDrawing()
			return
		}
		if (pickedEntity?.name === POINT_ENTITY_NAME) return

		const position = this.getPositionFromScreen(click.position)
		if (!position) return

		const preview = [...this.positions, position]
		if (isSelfIntersecting(preview)) {
			this.isIntersecting = true
			this.tooltip.show(this.getTipText(), click.position)
			return
		}

		this.addPoint(position)
		this.tooltip.show(this.getTipText(), click.position)
	}

	handleRightClick(click) {
		if (!this.isDrawing) return
		const pickedEntity = this.viewer.scene.pick(click.position)?.id
		if (!pickedEntity || pickedEntity.name !== POINT_ENTITY_NAME) return
		const index = pickedEntity.customData?.index
		if (typeof index !== 'number') return
		this.removePoint(index)
		this.tooltip.show(this.getTipText(), click.position)
	}

	handleMouseMove(movement) {
		if (!this.isDrawing) return
		const tipText = this.getTipText()
		if (!this.tooltip?.isVisible) {
			this.tooltip?.show(tipText, movement.endPosition)
		} else {
			this.tooltip?.show(tipText)
			this.tooltip?.move(movement.endPosition)
		}
		if (this.positions.length === 0) return
		const position = this.getPositionFromScreen(movement.endPosition)
		if (!position) return
		this.lastMousePosition = position
		this.floatPosition = position
	}

	getTipText() {
		const preview = this.getPreviewPositions()
		this.isIntersecting = isSelfIntersecting(preview)
		if (this.isIntersecting) {
			return '区域存在交叉，请调整位置'
		}
		const count = this.positions.length
		if (count === 0) {
			return '单击增加点'
		}
		if (count < 3) {
			return '单击增加点，右击删除点'
		}
		return '单击增加点，右击删除点，双击结束绘制'
	}

	isFinishTrigger(pickedEntity) {
		if (!pickedEntity || pickedEntity.name !== POINT_ENTITY_NAME) return false
		if (this.positions.length < 3) return false
		const index = pickedEntity.customData?.index
		return index === this.positions.length - 1
	}

	addPoint(position) {
		this.positions.push(position)
		if (!this.polygonEntity) {
			this.createEntities()
		}
		this.rebuildPointEntities()
	}

	removePoint(index) {
		if (index < 0 || index >= this.positions.length) return
		this.positions.splice(index, 1)
		this.rebuildPointEntities()
		if (this.positions.length === 0) {
			this.floatPosition = null
			this.lastMousePosition = null
			return
		}
		if (this.lastMousePosition) {
			this.floatPosition = this.lastMousePosition
		} else {
			this.floatPosition = this.positions[this.positions.length - 1]
		}
	}

	getPreviewPositions() {
		if (this.positions.length === 0) return []
		if (!this.isDrawing || !this.floatPosition) return this.positions
		return [...this.positions, this.floatPosition]
	}

	createEntities() {
		const getIntersecting = () => {
			const preview = this.getPreviewPositions()
			this.isIntersecting = isSelfIntersecting(preview)
			return this.isIntersecting
		}

		this.polygonEntity = this.dataSource.entities.add({
			polygon: {
				hierarchy: new Cesium.CallbackProperty(
					() => new Cesium.PolygonHierarchy(this.getPreviewPositions()),
					false
				),
				material: new Cesium.ColorMaterialProperty(
					new Cesium.CallbackProperty(() => {
						if (getIntersecting()) return resolveColorWithAlpha(Cesium.Color.RED, this.style.fill)
						return this.style.fill
					}, false)
				),
				outline: false,
				heightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
				show: new Cesium.CallbackProperty(() => this.getPreviewPositions().length >= 3, false),
			},
		})

		this.polylineEntity = this.dataSource.entities.add({
			polyline: {
				positions: new Cesium.CallbackProperty(() => {
					const positions = this.getPreviewPositions()
					if (positions.length < 2) return positions
					if (positions.length >= 3) {
						return [...positions, positions[0]]
					}
					return positions
				}, false),
				clampToGround: true,
				width: 2,
				material: new Cesium.ColorMaterialProperty(
					new Cesium.CallbackProperty(() => {
						if (getIntersecting()) return resolveColorWithAlpha(Cesium.Color.RED, this.style.outline)
						return this.style.outline
					}, false)
				),
				show: new Cesium.CallbackProperty(() => this.getPreviewPositions().length >= 2, false),
			},
		})
	}

	rebuildPointEntities() {
		this.dataSource.entities.values
			.slice()
			.filter(entity => entity?.name === POINT_ENTITY_NAME)
			.forEach(entity => this.dataSource.entities.remove(entity))

		this.positions.forEach((position, index) => {
			this.dataSource.entities.add({
				name: POINT_ENTITY_NAME,
				position: position.clone ? position.clone() : position,
				point: {
					pixelSize: 12,
					color: Cesium.Color.WHITE,
					outlineColor: this.style.outline,
					outlineWidth: 2,
					heightReference: Cesium.HeightReference.CLAMP_TO_GROUND,
					disableDepthTestDistance: Number.POSITIVE_INFINITY,
				},
				customData: {
					index,
				},
			})
		})
	}

	finishDrawing() {
		if (this.positions.length < 3) return
		this.isDrawing = false
		this.floatPosition = null
		this.isIntersecting = false
		this.notify('getPolygonPositions', this.positions)
		this.tooltip?.hide()
		this.clearPreviewEntities()
	}

	setStyle(style) {
		this.style = resolveStyle(style)
		if (this.dataSource) {
			this.dataSource.entities.values
				.filter(entity => entity?.name === POINT_ENTITY_NAME)
				.forEach(entity => {
					if (entity?.point) {
						entity.point.outlineColor = this.style.outline
					}
				})
		}
	}

	clearPreviewEntities() {
		if (!this.dataSource) return
		this.dataSource.entities.removeAll()
		this.polygonEntity = null
		this.polylineEntity = null
		this.isIntersecting = false
	}

	getPositionFromScreen(screenPosition) {
		const scene = this.viewer.scene
		const ray = scene.camera.getPickRay(screenPosition)
		const cartesian = ray ? scene.globe.pick(ray, scene) : null
		if (cartesian) return cartesian
		return scene.camera.pickEllipsoid(screenPosition, scene.globe.ellipsoid)
	}

	destroy() {
		if (this.dataSource) {
			this.dataSource.entities.removeAll()
			this.viewer.dataSources.remove(this.dataSource)
			this.dataSource = null
		}
		if (this.handler) {
			this.handler.removeInputAction(Cesium.ScreenSpaceEventType.LEFT_CLICK)
			this.handler.removeInputAction(Cesium.ScreenSpaceEventType.RIGHT_CLICK)
			this.handler.removeInputAction(Cesium.ScreenSpaceEventType.MOUSE_MOVE)
			this.handler.destroy()
			this.handler = null
		}
		this.tooltip?.destroy()
		this.tooltip = null
		this.positions = []
		this.floatPosition = null
		this.isDrawing = false
		this.lastMousePosition = null
		this.isIntersecting = false
	}
}