import * as Cesium from 'cesium'

// 获取正射影像4至点
export function getOrthoImageBoundaryPoints (data) {
	const arr = JSON.parse(data)

	if (arr.length !== 4) return undefined

	const west = Math.min(arr[0], arr[2])
	const east = Math.max(arr[0], arr[2])
	const south = Math.min(arr[1], arr[3])
	const north = Math.max(arr[1], arr[3])

	return Cesium.Rectangle.fromDegrees(
		west,
		south,
		east,
		north
	)
}

/**
 * 飞到中心点并且所有点在可视范围
 *  @param positionsData 二维数组，每项为 [lon, lat] 或 三维数组 [lon, lat, height]
 *  @param viewer Cesium.Viewer 实例
 *  @param multiple 缩放倍数-默认为4
 *  @param pitch 俯仰角-默认为-90
 */
export function flyVisual({ positionsData, viewer, multiple = 4, pitch = -90 }) {
	if (!Array.isArray(positionsData) || positionsData.length === 0) return

	// 如果是一个点，加两个点方便后续生成外包围盒
	if (positionsData.length === 1) {
		const [lon, lat, height = 0] = positionsData[0]
		positionsData = [
			[lon + 0.001, lat + 0.001, height],
			[lon - 0.001, lat - 0.001, height],
			[lon, lat, height],
		]
	}
	const positions = positionsData.map(([lon, lat, height = 0]) =>
		Cesium.Cartesian3.fromDegrees(Number(lon), Number(lat), Number(height || 0))
	)

	// 计算最高高度和中心点经纬度
	let maxHeight = -Infinity
	let sumLon = 0,
		sumLat = 0
	for (const [lon, lat, height] of positionsData) {
		sumLon += Number(lon)
		sumLat += Number(lat)
		maxHeight = Math.max(maxHeight, Number(height || 0))
	}
	const centerLon = sumLon / positionsData.length
	const centerLat = sumLat / positionsData.length
	const boundingSphere = Cesium.BoundingSphere.fromPoints(positions)
	// 暂时飞向 BoundingSphere
	viewer.camera.flyToBoundingSphere(Cesium.BoundingSphere.fromPoints(positions), {
		duration: 0,
		offset: {
			heading: Cesium.Math.toRadians(0),
			pitch: Cesium.Math.toRadians(pitch),
			range: boundingSphere.radius * multiple,
		},
		complete: () => {
			// 飞行完成后检查相机高度是否小于最高点
			const cameraHeight = Cesium.Cartographic.fromCartesian(viewer.camera.position).height
			if (cameraHeight < maxHeight) {
				viewer.camera.flyTo({
					destination: Cesium.Cartesian3.fromDegrees(centerLon, centerLat, maxHeight + 100), // 加100米缓冲
					duration: 1.5,
					orientation: {
						heading: viewer.camera.heading,
						pitch: viewer.camera.pitch,
						roll: viewer.camera.roll,
					},
				})
			}
		},
	})
}