import appManifest from '@/manifest.json'

const updateEndpoint = String(import.meta.env.VITE_PDA_UPDATE_URL || '').trim()

let checking = false

function request(options) {
	return new Promise((resolve, reject) => {
		uni.request({ ...options, success: resolve, fail: reject })
	})
}

function getRuntimeInfo() {
	return new Promise((resolve, reject) => {
		if (typeof plus === 'undefined' || !plus.runtime) {
			reject(new Error('当前环境不支持 App 在线更新'))
			return
		}

		// 标准真机基座的版本属于 HBuilderX；调试更新按当前工程版本模拟。
		const debugBase = import.meta.env.DEV || uni.getAppBaseInfo().packageName === 'io.dcloud.HBuilder'
		const runtime = {
			appid: String((debugBase ? appManifest.appid : plus.runtime.appid) || ''),
			appVersion: String((debugBase ? appManifest.versionName : plus.runtime.version) || ''),
			appVersionCode: Number(debugBase ? appManifest.versionCode : plus.runtime.versionCode)
		}
		if (!runtime.appid || !runtime.appVersion || !Number.isInteger(runtime.appVersionCode) || runtime.appVersionCode < 1) {
			reject(new Error('无法读取当前应用版本，请重新运行 App'))
			return
		}
		if (debugBase) {
			resolve({ ...runtime, wgtVersion: runtime.appVersion })
			return
		}

		// 正式 APK 始终保留原生基座版本码，WGT 升级只改变资源版本。
		plus.runtime.getProperty(plus.runtime.appid, (properties) => {
			resolve({ ...runtime, wgtVersion: String(properties?.version || runtime.appVersion) })
		})
	})
}

function normalizeUpdate(payload, runtime) {
	const value = payload && typeof payload === 'object' ? payload : {}
	if ('code' in value && String(value.code) !== '200') {
		const error = new Error(String(value.message || '检查更新失败，请稍后重试'))
		error.code = value.code
		error.requestId = value.requestId
		error.traceId = value.traceId
		throw error
	}
	if (typeof value.update !== 'boolean') throw new Error('更新服务返回了无效的版本信息')
	if (!value.update) return null

	if (value.appid !== runtime.appid) throw new Error('更新包与当前应用不匹配')
	const packageType = String(value.packageType || '').toLowerCase()
	const downloadUrl = String(value.downloadUrl || '').trim()
	const versionName = String(value.versionName || '').trim()
	if (!['apk', 'wgt'].includes(packageType) || !downloadUrl || !/^\d+(\.\d+)+$/.test(versionName)) {
		throw new Error('更新服务返回了无效的版本信息')
	}
	if (!/^https:\/\//i.test(downloadUrl)) throw new Error('更新包必须使用 HTTPS 地址')
	const minAppVersionCode = Number(value.minAppVersionCode)
	if (packageType === 'wgt' && (!Number.isInteger(minAppVersionCode) || minAppVersionCode < 1
		|| minAppVersionCode > runtime.appVersionCode)) {
		throw new Error('当前安装包不支持此热更新，请安装新版 APK')
	}

	return {
		packageType,
		downloadUrl,
		versionName,
		versionCode: Number(value.versionCode || 0),
		minAppVersionCode,
		mandatory: value.mandatory === true,
		releaseNotes: String(value.releaseNotes || '').trim()
	}
}

function compareVersions(left, right) {
	const leftParts = String(left).split('.').map(Number)
	const rightParts = String(right).split('.').map(Number)
	const length = Math.max(leftParts.length, rightParts.length)
	for (let index = 0; index < length; index += 1) {
		const difference = (leftParts[index] || 0) - (rightParts[index] || 0)
		if (difference !== 0) return difference
	}
	return 0
}

function isNewerUpdate(update, runtime) {
	if (update.packageType === 'apk') {
		return Number.isInteger(update.versionCode) && update.versionCode > runtime.appVersionCode
	}
	return compareVersions(update.versionName, runtime.wgtVersion) > 0
}

function confirmUpdate(update) {
	const notes = update.releaseNotes || '修复已知问题并提升作业稳定性。'
	return new Promise((resolve) => {
		uni.showModal({
			title: `${update.mandatory ? '必须' : '发现'}更新 ${update.versionName}`,
			content: notes,
			confirmText: '立即更新',
			cancelText: '稍后再说',
			showCancel: !update.mandatory,
			success: ({ confirm }) => resolve(Boolean(confirm)),
			fail: () => resolve(false)
		})
	})
}

function downloadUpdate(update) {
	return new Promise((resolve, reject) => {
		uni.showLoading({ title: '正在下载 0%', mask: true })
		const task = uni.downloadFile({
			url: update.downloadUrl,
			success: (result) => {
				if (result.statusCode === 200 && result.tempFilePath) {
					resolve(result.tempFilePath)
					return
				}
				reject(new Error(`更新包下载失败（${result.statusCode || '未知状态'}）`))
			},
			fail: () => reject(new Error('更新包下载失败，请检查网络后重试')),
			complete: () => uni.hideLoading()
		})

		task.onProgressUpdate?.(({ progress }) => {
			uni.showLoading({ title: `正在下载 ${progress}%`, mask: true })
		})
	})
}

function prepareUpdateFile(filePath, update) {
	return new Promise((resolve, reject) => {
		const fail = (cause) => {
			const error = new Error('更新包文件准备失败，请重新下载')
			error.stage = 'prepare'
			error.code = cause?.code
			reject(error)
		}
		// 下载接口以 /package 结尾，临时文件可能没有安装器要求的扩展名。
		const filename = `overseas-pda-${update.versionName}-${Date.now()}.${update.packageType}`
		plus.io.resolveLocalFileSystemURL(filePath, (entry) => {
			entry.getParent((parent) => {
				entry.moveTo(parent, filename, (file) => resolve(file.toLocalURL()), fail)
			}, fail)
		}, fail)
	})
}

function installUpdate(filePath) {
	return new Promise((resolve, reject) => {
		plus.runtime.install(
			filePath,
			{ force: false },
			resolve,
			(cause) => {
				const code = cause?.code == null ? '' : `（${cause.code}）`
				const reason = String(cause?.message || '请重新下载后重试')
				const error = new Error(`更新包安装失败${code}：${reason}`)
				error.stage = 'install'
				error.code = cause?.code
				reject(error)
			}
		)
	})
}

function showFailure(error, mandatory) {
	const message = error?.message || '检查更新失败，请稍后重试'
	if (!mandatory && error?.stage !== 'install' && error?.stage !== 'prepare') {
		uni.showToast({ title: message, icon: 'none', duration: 3000 })
		return Promise.resolve(false)
	}

	return new Promise((resolve) => {
		uni.showModal({
			title: '更新失败',
			content: message,
			confirmText: mandatory ? '重新尝试' : '知道了',
			showCancel: false,
			complete: () => resolve(mandatory)
		})
	})
}

async function runUpdate(update) {
	const accepted = await confirmUpdate(update)
	if (!accepted) return

	try {
		const filePath = await downloadUpdate(update)
		const installPath = await prepareUpdateFile(filePath, update)
		await installUpdate(installPath)
		if (update.packageType === 'wgt') {
			uni.showModal({
				title: '更新完成',
				content: '应用将立即重启以启用新版本。',
				showCancel: false,
				complete: () => plus.runtime.restart()
			})
		}
	} catch (error) {
		const retry = await showFailure(error, update.mandatory)
		if (retry) await runUpdate(update)
	}
}

export async function checkForAppUpdate({ manual = false } = {}) {
	if (checking) return
	if (!updateEndpoint) {
		if (manual) uni.showToast({ title: '未配置更新服务', icon: 'none' })
		return
	}

	checking = true
	try {
		if (!/^https:\/\//i.test(updateEndpoint)) throw new Error('更新服务必须使用 HTTPS 地址')
		const runtime = await getRuntimeInfo()
		const response = await request({
			url: updateEndpoint,
			method: 'GET',
			data: {
				appid: runtime.appid,
				platform: 'android',
				appVersion: runtime.appVersion,
				appVersionCode: runtime.appVersionCode,
				wgtVersion: runtime.wgtVersion
			}
		})
		if (response.statusCode !== 200) throw new Error('更新服务暂时不可用')

		const update = normalizeUpdate(response.data, runtime)
		if (update && isNewerUpdate(update, runtime)) {
			await runUpdate(update)
		} else if (manual) {
			uni.showToast({ title: '当前已是最新版本', icon: 'none' })
		}
	} catch (error) {
		if (manual) await showFailure(error, false)
	} finally {
		checking = false
	}
}