/**
 * 镭射卡五图批量生成（Phase 1：纯客户端 Canvas，无后端接口）
 */

import { ref } from 'vue'
import {
	CASTLOVE_FORM_KEY,
	consumeGenerationFlowPayload,
	persistLaserPreviewImages,
} from '@/utils/castloveGenerationFlow.js'
import { generateLaserVariantBatch } from '@/utils/laser-card/laserBatchExport.js'

const DEFAULT_CANVAS_ID = 'laserBatchCanvas'
const DEFAULT_MIN_DURATION_MS = 1600

/**
 * @param {Object} [options]
 * @param {string} [options.canvasId]
 * @param {number} [options.minDurationMs]
 * @param {number} [options.flowStartedAt] 页面 onMounted 时的时间戳，用于最短展示时长
 */
export function useLaserBatchGenerate(options = {}) {
	const progress = ref(0)
	const running = ref(false)
	const error = ref(null)

	let progressTimer = null
	let flowStartedAt = options.flowStartedAt ?? Date.now()

	const canvasId = options.canvasId || DEFAULT_CANVAS_ID
	const minDurationMs = options.minDurationMs ?? DEFAULT_MIN_DURATION_MS

	const stopProgress = () => {
		if (progressTimer) {
			clearInterval(progressTimer)
			progressTimer = null
		}
	}

	const simulateProgress = () => {
		stopProgress()
		progressTimer = setInterval(() => {
			if (progress.value < 90) {
				const increment = Math.random() * 5 + 2
				progress.value = Math.min(90, progress.value + increment)
			}
		}, 500)
	}

	const completeProgress = () =>
		new Promise((resolve) => {
			stopProgress()
			const finalInterval = setInterval(() => {
				if (progress.value < 100) {
					progress.value = Math.min(100, progress.value + 5)
				} else {
					clearInterval(finalInterval)
					setTimeout(resolve, 500)
				}
			}, 50)
		})

	const waitMinDuration = async (minMs) => {
		if (!minMs || minMs <= 0) return
		const elapsed = Date.now() - flowStartedAt
		if (elapsed < minMs) {
			await new Promise((r) => setTimeout(r, minMs - elapsed))
		}
	}

	const readFormData = () => {
		const formStr = uni.getStorageSync(CASTLOVE_FORM_KEY)
		if (!formStr) {
			throw new Error('缺少表单数据')
		}
		return JSON.parse(formStr)
	}

	const resolveImagePath = (formData) => {
		const imagePath = formData?.image || formData?.uploadedImage || ''
		if (!imagePath) {
			throw new Error('缺少上传图片')
		}
		return imagePath
	}

	/**
	 * 执行五图合成并写入 Storage
	 * @param {Object} [runOptions]
	 * @param {Object} [runOptions.flow] consumeGenerationFlowPayload 结果；缺省则自动 consume
	 * @returns {Promise<string[]>} 本地临时 JPG 路径列表
	 */
	const run = async (runOptions = {}) => {
		if (running.value) {
			throw new Error('生成进行中')
		}
		running.value = true
		error.value = null
		simulateProgress()

		try {
			const flow = runOptions.flow ?? consumeGenerationFlowPayload()
			const minMs = flow?.minDurationMs ?? minDurationMs
			const formData = readFormData()
			const imagePath = resolveImagePath(formData)

			const paths = await generateLaserVariantBatch(imagePath, canvasId)
			await waitMinDuration(minMs)
			persistLaserPreviewImages(paths)
			await completeProgress()
			return paths
		} catch (e) {
			error.value = e
			stopProgress()
			throw e
		} finally {
			running.value = false
		}
	}

	const resetProgress = () => {
		stopProgress()
		progress.value = 0
	}

	const setFlowStartedAt = (ts) => {
		flowStartedAt = ts
	}

	return {
		progress,
		running,
		error,
		simulateProgress,
		completeProgress,
		stopProgress,
		resetProgress,
		setFlowStartedAt,
		run,
	}
}