/**
 * 共享相机 composable (H5 only)
 *
 * 用法: const { captured, errorMsg, startCamera, flipCamera, takePhoto, retake, confirm } = useCamera('my-video-id')
 *
 * - 自动在 onMounted 启动摄像头
 * - 自动在 onBeforeUnmount 停止摄像头
 * - 返回 ref 和方法,业务页只需负责 UI 布局
 */
import { ref, onMounted, onBeforeUnmount } from 'vue'
import {
	openCamera,
	stopCamera,
	captureFrame,
	captureFrameWithBlur,
	describeCameraError,
	type Facing,
} from '@/utils/camera'
import { uploadCameraPhoto } from '@/utils/upload'

/** 条带高斯模糊配置 (签到表脱敏用): 对截图竖直 [start, end] 比例区间做高斯模糊 */
export type BlurConfig = {
	start: number
	end: number
	radius: number
}

export function useCamera(videoId: string, blur?: BlurConfig) {
	const facing = ref<Facing>('environment')
	const captured = ref<string>('')
	const blurred = ref<string>('')
	const errorMsg = ref<string>('')

	function getVideoEl(): HTMLVideoElement | null {
		const el = document.getElementById(videoId) as HTMLElement | null
		if (!el) return null
		// uni-app H5 把 <video> 编译成 <uni-video> Vue 组件时, getElementById
		// 拿到的是 wrapper, 它的 srcObject setter 会透传给内部原生 <video>,
		// 但 readyState / play() 不一定透传. 用 readyState 是否 number 判断是否原生.
		if (el.tagName === 'VIDEO' && typeof (el as any).readyState === 'number') {
			return el as HTMLVideoElement
		}
		// wrapper 场景: 内部包了一个原生 <video>
		const inner = el.querySelector('video') as HTMLVideoElement | null
		if (inner && typeof inner.readyState === 'number') {
			console.log('[camera] 穿透 uni-app wrapper, 找到内部原生 <video>')
			return inner
		}
		// 最后一搏: 找页面上第一个原生 <video>
		const fallback = document.querySelector('video') as HTMLVideoElement | null
		if (fallback) {
			console.log('[camera] 全局兜底找到第一个原生 <video>')
			return fallback
		}
		return null
	}

	async function startCamera() {
		errorMsg.value = ''
		const video = getVideoEl()
		if (!video) {
			errorMsg.value = '视频元素未找到'
			return
		}
		try {
			await openCamera(video, facing.value)
		} catch (err) {
			errorMsg.value = describeCameraError(err)
			console.error('[camera]', err)
		}
	}

	function flipCamera() {
		facing.value = facing.value === 'environment' ? 'user' : 'environment'
		startCamera()
	}

	async function takePhoto() {
		const video = getVideoEl()
		if (!video) return
		try {
			if (blur) {
				const r = captureFrameWithBlur(video, blur.start, blur.end, blur.radius)
				captured.value = r.sharp
				blurred.value = r.blurred
			} else {
				captured.value = captureFrame(video)
				blurred.value = ''
			}
		} catch (err) {
			uni.showToast({
				title: (err as Error).message || '截图失败',
				icon: 'none',
			})
		}
	}

	function retake() {
		captured.value = ''
		blurred.value = ''
	}

	async function confirm() {
		if (!captured.value) return
		uni.showLoading({ title: '上传中...' })
		try {
			// 直传 OSS + 回传 URL 到后端 (公开端点, 无需登录)
			// 签到表额外上传一张高斯模糊版 (blurred) 作为 extraOssUrl, sponsor 只看这个
			await uploadCameraPhoto(captured.value, blurred.value || '')
			uni.hideLoading()
			uni.showToast({
				title: '已上传',
				icon: 'success',
				duration: 1500,
			})
			captured.value = ''
			blurred.value = ''
		} catch (err) {
			uni.hideLoading()
			uni.showToast({
				title: (err as Error).message || '上传失败',
				icon: 'none',
				duration: 2500,
			})
		}
	}

	onMounted(() => {
		startCamera()
	})

	onBeforeUnmount(() => {
		const video = getVideoEl()
		if (video) {
			stopCamera(video)
		}
	})

	return {
		facing,
		captured,
		errorMsg,
		startCamera,
		flipCamera,
		takePhoto,
		retake,
		confirm,
	}
}