const cloud = require('wx-server-sdk');

cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV });

const CONFIG_PATH = 'content/page-config.json';

const DIFFICULTY_LABELS = {
    1: '入门',
    2: '基础',
    3: '进阶',
    4: '挑战',
};

function ageBand(min, max) {
    return `${min}-${max}岁`;
}

function toHomeDisplayItem(ws) {
    return {
        id: ws._id,
        title: ws.title || '',
        subtitle: ws.subtitle || '',
        category: ws.category || '',
        ageBand: ageBand(ws.ageMin || 0, ws.ageMax || 0),
        difficulty: DIFFICULTY_LABELS[ws.difficulty] || '基础',
        icon: '',
        img: ws.previewImg || '',
        badge: ws.isNew ? 'NEW' : ws.isHot ? 'HOT' : '',
        path: ws.path || '',
        available: true,
    };
}

async function readCurrentConfig() {
    const db = cloud.database();
    try {
        const { data } = await db
            .collection('page_configs')
            .doc('current')
            .get();
        return data;
    } catch {
        return { home: null, category: null, age: null, version: 0 };
    }
}

async function saveConfig(config) {
    const db = cloud.database();
    const toSave = { ...config };
    delete toSave._id;
    try {
        await db.collection('page_configs').doc('current').get();
        await db.collection('page_configs').doc('current').update({
            data: toSave,
        });
    } catch {
        await db.collection('page_configs').doc('current').set({
            data: toSave,
        });
    }
    const buffer = Buffer.from(JSON.stringify(config), 'utf-8');
    await cloud.uploadFile({
        cloudPath: CONFIG_PATH,
        fileContent: buffer,
    });
}

async function isEnabled(db) {
    try {
        const { data } = await db
            .collection('settings')
            .doc('homeAutoRefresh')
            .get();
        return data.enabled !== false;
    } catch {
        // Document doesn't exist yet — default to enabled
        return true;
    }
}

exports.main = async () => {
    try {
        const db = cloud.database();

        // Check if timer is enabled
        if (!(await isEnabled(db))) {
            return { success: true, message: '定时任务已暂停，跳过执行' };
        }

        // Query top 5 by downloads
        const { data: topDownloads } = await db
            .collection('worksheets')
            .where({ status: 'active' })
            .orderBy('downloads', 'desc')
            .limit(5)
            .get();

        // Query top 5 by likes
        const { data: topLikes } = await db
            .collection('worksheets')
            .where({ status: 'active' })
            .orderBy('likes', 'desc')
            .limit(5)
            .get();

        const featured = topDownloads.map(toHomeDisplayItem);
        const hot = topLikes.map(toHomeDisplayItem);

        // Read current config, only update featured & hot
        const config = await readCurrentConfig();
        if (!config.home) {
            config.home = {};
        }
        config.home.featured = featured;
        config.home.hot = hot;
        config.version = (config.version || 0) + 1;
        config.updatedAt = new Date().toISOString();

        await saveConfig(config);

        return {
            success: true,
            data: {
                version: config.version,
                featured: featured.length,
                hot: hot.length,
            },
        };
    } catch (error) {
        return {
            success: false,
            message:
                error instanceof Error ? error.message : '自动刷新首页推荐失败',
        };
    }
};