import { fetchPageConfig } from './services/site-api';
import { normalizePreviewImages } from './config/assets';
import { defaultPrintConfig } from './config/config';
import { getUser } from './utils/auth';
import { generateUUID, getAppUUID, setAppUUID } from './utils/uuid';

let _refreshGeneration = 0;

const STORAGE_KEY_PAGE_CONFIG = 'pageConfig';

// Pending resolvers for getPageConfig() callers waiting on config
let _configResolvers: Array<(config: PageConfigData | null) => void> = [];

// app.ts
App<IAppOption>({
    globalData: {
        env: 'release',
        uuid: '',
        user: null,
        printConfig: defaultPrintConfig,
        pageConfig: undefined,
        pageConfigReady: false,
    },
    onLaunch() {
        try {
            wx.removeStorageSync('user_info');
            wx.removeStorageSync('user_info_expire');
        } catch {
            /* 旧云登录缓存清理失败不影响新凭证命名空间。 */
        }
        const accountInfo = wx.getAccountInfoSync();
        const env = accountInfo.miniProgram.envVersion || 'release';
        this.globalData.env = env;

        let uuid = getAppUUID();
        if (!uuid) {
            uuid = generateUUID();
            setAppUUID(uuid);
            console.log('生成并存储 UUID', uuid);
        }
        this.globalData.uuid = uuid;

        if (env !== 'release') {
            const printConfig =
                wx.getStorageSync('printConfig') || defaultPrintConfig;
            this.globalData.printConfig = printConfig;
        }

        // 启动与回到前台共用登录 Promise，不阻塞公开页面渲染。
        this.warmAuthentication();

        void this.loadPageConfig();
    },

    onShow() {
        this.warmAuthentication();
        if (this.globalData.pageConfigReady) void this.refreshPageConfig();
    },

    warmAuthentication() {
        void getUser().catch(() => {
            console.warn('静默登录暂未完成，公开浏览仍可使用');
        });
    },

    onHide() {},

    getPrintConfig(): PrintConfig {
        return this.globalData.printConfig || defaultPrintConfig;
    },

    setPrintConfig(config: PrintConfig) {
        this.globalData.printConfig = config;
        wx.setStorageSync('printConfig', config);
    },

    async loadPageConfig() {
        let config: PageConfigData | null = null;

        // L1: 数据预拉取
        try {
            const res = await new Promise<{ fetchedData: string }>(
                (resolve, reject) => {
                    wx.getBackgroundFetchData({
                        fetchType: 'pre',
                        success: resolve as any,
                        fail: reject,
                    });
                },
            );
            if (res.fetchedData) {
                const parsed = JSON.parse(res.fetchedData);
                config = parsed?.data || parsed;
            }
        } catch {
            // 预拉取失败，继续降级
        }

        // L2: storage 缓存
        if (!config) {
            try {
                const cached = wx.getStorageSync(STORAGE_KEY_PAGE_CONFIG);
                if (cached && typeof cached === 'object') {
                    config = cached;
                }
            } catch {
                // storage 读取失败，继续降级
            }
        }

        // L3: 新后端动态兜底；微信预拉取机制和地址保持不变。
        const hadCachedConfig = !!config;
        if (!config) {
            try {
                config = await fetchPageConfig();
            } catch {
                /* 新后端不可用时继续展示空状态，本地生成仍可使用。 */
            }
        }

        // 三种数据入口都先转换预览图，旧缓存会随成功加载写回新地址。
        config = normalizePreviewImages(config);

        // 写入 globalData
        if (config) {
            this.globalData.pageConfig = config;
            // 成功获取后写入 storage 缓存
            try {
                wx.setStorageSync(STORAGE_KEY_PAGE_CONFIG, config);
            } catch {
                // storage 写入失败不影响主流程
            }
        }

        // 标记就绪，通知等待中的页面
        this.globalData.pageConfigReady = true;
        for (const resolve of _configResolvers) {
            resolve(config);
        }
        _configResolvers = [];
        // 预拉取/缓存先渲染，再用新后端刷新，避免旧静态配置长期覆盖管理修改。
        if (hadCachedConfig) void this.refreshPageConfig();
    },

    async refreshPageConfig() {
        const generation = ++_refreshGeneration;
        try {
            const config = normalizePreviewImages(await fetchPageConfig());
            if (generation !== _refreshGeneration) return;
            this.globalData.pageConfig = config;
            try {
                wx.setStorageSync(STORAGE_KEY_PAGE_CONFIG, config);
            } catch {
                /* 缓存失败不影响当前数据。 */
            }
            for (const page of getCurrentPages()) {
                if (
                    page.route === 'pages/home/home' &&
                    typeof page.initData === 'function'
                )
                    void page.initData(config);
            }
        } catch {
            /* 保留已显示的数据，网络错误不清空预拉取首屏。 */
        }
    },

    getPageConfig(): Promise<PageConfigData | null> {
        if (this.globalData.pageConfigReady) {
            return Promise.resolve(this.globalData.pageConfig || null);
        }
        return new Promise((resolve) => {
            _configResolvers.push(resolve);
        });
    },
});