'use strict';

const platformAndroid = 'Android';
const platformIOS = 'iOS';
const platformHarmony = 'Harmony';
const packageApp = 'native_app';
const packageWgt = 'wgt';
const appVersionDbName = 'opendb-app-versions';

function errorResult(code, message) {
	return { code, message };
}

function isNonEmptyString(value) {
	return typeof value === 'string' && value.trim().length > 0;
}

function isValidVersion(value) {
	return isNonEmptyString(value) && /^\d+(?:\.\d+)*$/.test(value.trim());
}

function parseHttpEvent(event) {
	if (!event || typeof event !== 'object' || Array.isArray(event)) {
		return { error: errorResult(-102, '请求参数必须是对象') };
	}
	if (!event.headers) return { data: event, isHttp: false };

	const method = String(event.httpMethod || 'GET').toLowerCase();
	let body;
	try {
		if (method === 'get') {
			body = event.queryStringParameters || {};
			if (typeof body === 'string') body = JSON.parse(body || '{}');
		} else if (event.body && typeof event.body === 'object') {
			body = event.body;
		} else {
			body = JSON.parse(event.body || '{}');
		}
	} catch (e) {
		return { error: errorResult(-102, '请求参数格式错误') };
	}
	if (!body || typeof body !== 'object' || Array.isArray(body)) {
		return { error: errorResult(-102, '请求参数必须是对象') };
	}

	return {
		data: { ...event, ...body },
		isHttp: true
	};
}

function detectPlatform(event, context, isHttp) {
	if (isHttp) {
		const headers = typeof event.headers === 'string' ?
			event.headers : JSON.stringify(event.headers || {});
		if (/iPhone|iPad/i.test(headers)) return platformIOS;
		if (/Android/i.test(headers)) return platformAndroid;
		if (/HarmonyOS|Harmony/i.test(headers)) return platformHarmony;
	}

	const os = context && typeof context.OS === 'string' ? context.OS.toLowerCase() : '';
	if (os === 'ios') return platformIOS;
	if (os === 'harmonyos') return platformHarmony;
	return platformAndroid;
}

module.exports = async (event, context) => {
	const parsed = parseHttpEvent(event);
	if (parsed.error) return parsed.error;

	const request = parsed.data;
	const appid = request.appid;
	const appVersion = request.appVersion;
	const wgtVersion = request.wgtVersion;
	const isUniappX = request.is_uniapp_x === undefined ? false : request.is_uniapp_x;
	if (!isNonEmptyString(appid) || !isValidVersion(appVersion) || !isValidVersion(wgtVersion)) {
		return errorResult(-102, '请检查appid、appVersion、wgtVersion是否填写正确');
	}
	if (isUniappX !== true && isUniappX !== false) {
		return errorResult(-102, 'is_uniapp_x必须是布尔值');
	}

	const platform = detectPlatform(request, context, parsed.isHttp);
	try {
		const collection = uniCloud.database().collection(appVersionDbName);
		const record = await collection.where({
			appid: appid.trim(),
			platform,
			stable_publish: true
		}).orderBy('create_date', 'desc').get();

		if (!record || !Array.isArray(record.data) || record.data.length === 0) {
			return errorResult(-101, '暂无更新或检查appid是否填写正确');
		}

		const appVersionInDb = record.data.find(item => item && item.type === packageApp) || {};
		const wgtVersionInDb = record.data.find(item => item && item.type === packageWgt) || {};
		const hasAppPackage = isValidVersion(appVersionInDb.version);
		const hasWgtPackage = isValidVersion(wgtVersionInDb.version);

		let stablePublishDb = {};
		if (isUniappX === true && platform === platformAndroid) {
			if (hasAppPackage) stablePublishDb = appVersionInDb;
		} else if (hasAppPackage && hasWgtPackage) {
			stablePublishDb = compare(wgtVersionInDb.version, appVersionInDb.version) >= 0 ?
				wgtVersionInDb : appVersionInDb;
		} else if (hasAppPackage) {
			stablePublishDb = appVersionInDb;
		} else if (hasWgtPackage) {
			stablePublishDb = wgtVersionInDb;
		}

		if (Object.keys(stablePublishDb).length > 0) {
			const { version, min_uni_version: minUniVersion } = stablePublishDb;
			const appUpdate = compare(version, appVersion) === 1;
			const wgtUpdate = compare(version, wgtVersion) === 1;

			if (appUpdate && wgtUpdate) {
				if (isValidVersion(minUniVersion) && compare(minUniVersion, appVersion) < 1) {
					return {
						code: 101,
						message: 'wgt更新',
						...stablePublishDb
					};
				}
				if (hasAppPackage && compare(appVersionInDb.version, appVersion) === 1) {
					return {
						code: 102,
						message: '整包更新',
						...appVersionInDb
					};
				}
			}
		}

		return { code: 0, message: '当前版本已经是最新的，不需要更新' };
	} catch (e) {
		console.error('[checkVersion]', e);
		return errorResult(-500, '检查版本失败');
	}
};

/**
 * 对比版本号。v1 > v2 返回 1，v1 < v2 返回 -1，版本相同返回 0。
 */
function compare(v1 = '0', v2 = '0') {
	const left = String(v1).split('.').map(Number);
	const right = String(v2).split('.').map(Number);
	const length = Math.max(left.length, right.length);
	for (let i = 0; i < length; i++) {
		const leftPart = Number.isFinite(left[i]) ? left[i] : 0;
		const rightPart = Number.isFinite(right[i]) ? right[i] : 0;
		if (leftPart > rightPart) return 1;
		if (leftPart < rightPart) return -1;
	}
	return 0;
}

module.exports.compare = compare;