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
		}

		plus.runtime.getProperty(plus.runtime.appid, (properties) => {
			resolve({
				appid: plus.runtime.appid,
				appVersion: String(plus.runtime.version || ''),
				appVersionCode: Number(plus.runtime.versionCode || 0),
				wgtVersion: String(properties?.version || plus.runtime.version || '')
			})
		})
	})
}

function normalizeUpdate(payload, runtime) {
	const value = payload && typeof payload === 'object' ? payload : {}
	if (value.update !== true) 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 installUpdate(filePath, update) {
	return new Promise((resolve, reject) => {
		plus.runtime.install(
			filePath,
			{ force: false },
			resolve,
			() => reject(new Error('更新包安装失败，请重新下载'))
		)
	})
}

function showFailure(error, mandatory) {
	const message = error?.message || '检查更新失败，请稍后重试'
	if (!mandatory) {
		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: '重新尝试',
			showCancel: false,
			complete: () => resolve(true)
		})
	})
}

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

	try {
		const filePath = await downloadUpdate(update)
		await installUpdate(filePath, update)
		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?.data ?? 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
	}
}