/**
 * Dify 镭射五图生成 composable
 * 通过 Gateway → Dify 工作流服务端生成镭射卡，替换客户端 Canvas 合成
 *
 * 模式切换：通过 VITE_LASER_GEN_MODE 环境变量控制
 *   'client' — 现有的客户端 laserBatchExport 路径
 *   'dify'   — 本模块，Gateway 触发 Dify 工作流
 */
import { ref } from 'vue'
import { getLaserApiBaseUrl } from '@/utils/api.js'
import { buildRenderConfigs } from '@/utils/laser-card/laserPresets.js'

/**
 * 镭射专用 fetch（直接请求本地 Gateway，不走远程 DEV_BASE）
 * 返回格式与 api.js 的 request() 一致：{ code, message, data }
 */
async function laserRequest(opts) {
	const base = getLaserApiBaseUrl()
	const url = `${base}${opts.url}`
	const headers = { 'Content-Type': 'application/json' }
	const token = uni.getStorageSync('access_token')
	if (token) {
		headers['Authorization'] = `Bearer ${token}`
	}
	const fetchOpts = {
		method: opts.method || 'GET',
		headers,
	}
	if (opts.data) {
		fetchOpts.body = JSON.stringify(opts.data)
	}
	const resp = await fetch(url, fetchOpts)
	const json = await resp.json()
	if (resp.status < 200 || resp.status >= 300) {
		throw new Error(json?.message || `HTTP ${resp.status}`)
	}
	return json
}

export function useLaserDifyGenerate() {
	const jobId = ref('')
	const status = ref('idle') // idle | submitting | processing | done | error | timeout
	const progress = ref(0)
	const variants = ref([]) // [{ preset_id, signed_url, oss_key }]
	const instanceNo = ref('')
	const cutoutUrl = ref('')
	const error = ref(null)

	let pollTimer = null
	let pollingSince = 0
	let _resolveSubmit = null
	let _rejectSubmit = null

	/**
	 * 提交生成任务到 Gateway
	 * @param {string} cutoutUrl 抠图后的 OSS URL（空串表示不叠加人像）
	 * @param {string[]} [presetIds] 需要生成的 preset ID 列表
	 * @param {string} [userPrompt] 用户自定义 prompt，注入到 AI 生图
	 */
	async function submit(cutoutUrl, presetIds = null, userPrompt = '') {
		status.value = 'submitting'
		error.value = null
		progress.value = 0

		const renderConfigs = buildRenderConfigs(presetIds || ['dream', 'classic', 'holoFull', 'ice', 'sunset'])
		const presetCodes = renderConfigs.map((rc) => rc.preset_id)

		try {
			const res = await laserRequest({
				url: '/api/v1/laser/generate',
				method: 'POST',
				data: {
					cutout_url: cutoutUrl,
					preset_codes: presetCodes,
					render_configs: renderConfigs,
					user_prompt: userPrompt || '',
				},
			})

			if (!res.data || !res.data.job_id) {
				throw new Error('生成任务创建失败：未返回 job_id')
			}

			jobId.value = res.data.job_id
			status.value = 'processing'
			pollingSince = Date.now()

			// 等待轮询完成再 resolve
			await new Promise((resolve, reject) => {
				_resolveSubmit = resolve
				_rejectSubmit = reject
				startPolling()
			})
		} catch (e) {
			status.value = 'error'
			error.value = e
			throw e
		}
	}

	function startPolling() {
		const pollInterval = 2000 // 每 2 秒轮询
		const maxDuration = 120000 // 最长等待 120 秒

		const poll = () => {
			if (status.value !== 'processing') return

			// 超时降级
			if (Date.now() - pollingSince > maxDuration) {
				const err = new Error('Dify 生成超时，已降级到本地合成')
				status.value = 'timeout'
				error.value = err
				stopPolling()
				if (_rejectSubmit) { _rejectSubmit(err); _rejectSubmit = null }
				return
			}

			laserRequest({
				url: `/api/v1/laser/generate/${jobId.value}`,
				method: 'GET',
			})
				.then((res) => {
					if (!res.data) return

					// 更新进度
					if (res.data.progress != null) {
						progress.value = res.data.progress
					}

					if (res.data.status === 'succeeded') {
						// 提取 variants
						if (res.data.variants && Array.isArray(res.data.variants)) {
							variants.value = res.data.variants
						}
						if (res.data.cutout_url) {
							cutoutUrl.value = res.data.cutout_url
						}
						if (res.data.instance_no) {
							instanceNo.value = res.data.instance_no
						}
						status.value = 'done'
						progress.value = 1.0
						stopPolling()
						if (_resolveSubmit) { _resolveSubmit(); _resolveSubmit = null }
					} else if (res.data.status === 'failed') {
						const err = new Error(res.data.error || 'Dify 工作流执行失败')
						status.value = 'error'
						error.value = err
						stopPolling()
						if (_rejectSubmit) { _rejectSubmit(err); _rejectSubmit = null }
					} else {
						// processing — 继续轮询
						pollTimer = setTimeout(poll, pollInterval)
					}
				})
				.catch((err) => {
					console.warn('[useLaserDifyGenerate] poll error:', err)
					pollTimer = setTimeout(poll, pollInterval)
				})
		}

		poll()
	}

	function stopPolling() {
		if (pollTimer) {
			clearTimeout(pollTimer)
			pollTimer = null
		}
	}

	function reset() {
		stopPolling()
		jobId.value = ''
		status.value = 'idle'
		progress.value = 0
		variants.value = []
		cutoutUrl.value = ''
		error.value = null
		pollingSince = 0
	}

	/**
	 * 获取 variant 图片 URL 列表（与 client 模式兼容的格式）
	 */
	function getVariantUrls() {
		return variants.value.map((v) => v.signed_url || v.url || '')
	}

	/**
	 * 获取 variant 完整信息（含 oss_key），铸造时直接用 oss_key 避免 HEAD 请求
	 * @returns {Array<{ url: string, oss_key: string }>}
	 */
	function getVariantInfos() {
		return variants.value.map((v) => ({
			url: v.signed_url || v.url || '',
			oss_key: v.oss_key || '',
		}))
	}

	function getInstanceNo() {
		return instanceNo.value
	}

	return {
		jobId,
		status,
		progress,
		variants,
		cutoutUrl,
		error,
		submit,
		reset,
		getVariantUrls,
		getVariantInfos,
		getInstanceNo,
		stopPolling,
	}
}