// ============================================================
// 闲言APP — 云端暂存API路由
// 创建时间: 2026-05-12
// 更新时间: 2026-05-12
// 作用: 云端暂存文件上传/下载/列表/删除/定时清理
// 上次更新: v11.3.0 初始版本 — Express+multer+node-cron
// ============================================================

const express = require('express');
const multer = require('multer');
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');

const router = express.Router();

// ============================================================
// 配置
// ============================================================

const DATA_DIR = path.join(__dirname, 'data', 'cloud_cache');
const META_FILE = path.join(DATA_DIR, 'meta.json');
const MAX_FILE_SIZE = 500 * 1024 * 1024; // 500MB
const DEFAULT_EXPIRE_HOURS = 24;
const CLEANUP_INTERVAL_MS = 60 * 60 * 1000; // 1小时

// ============================================================
// 初始化
// ============================================================

function ensureDataDir() {
    if (!fs.existsSync(DATA_DIR)) {
        fs.mkdirSync(DATA_DIR, { recursive: true });
    }
}

function loadMeta() {
    ensureDataDir();
    try {
        if (fs.existsSync(META_FILE)) {
            return JSON.parse(fs.readFileSync(META_FILE, 'utf8'));
        }
    } catch (e) {
        console.error('CloudCache: Failed to load meta:', e.message);
    }
    return {};
}

function saveMeta(meta) {
    ensureDataDir();
    try {
        fs.writeFileSync(META_FILE, JSON.stringify(meta, null, 2));
    } catch (e) {
        console.error('CloudCache: Failed to save meta:', e.message);
    }
}

// ============================================================
// Multer配置
// ============================================================

const storage = multer.diskStorage({
    destination: function (req, file, cb) {
        ensureDataDir();
        cb(null, DATA_DIR);
    },
    filename: function (req, file, cb) {
        const cacheId = req.body.cacheId || crypto.randomUUID();
        const ext = path.extname(file.originalname) || '.enc';
        cb(null, cacheId + ext);
    }
});

const upload = multer({
    storage: storage,
    limits: { fileSize: MAX_FILE_SIZE }
});

// ============================================================
// 中间件: 请求日志
// ============================================================

router.use((req, res, next) => {
    const start = Date.now();
    res.on('finish', () => {
        const duration = Date.now() - start;
        console.log(`CloudCache: ${req.method} ${req.path} ${res.statusCode} ${duration}ms`);
    });
    next();
});

// ============================================================
// POST /upload — 上传暂存文件
// ============================================================

router.post('/upload', upload.single('file'), (req, res) => {
    try {
        if (!req.file) {
            return res.json({ code: 0, msg: 'No file provided', data: null });
        }

        const fromId = req.body.fromId || '';
        const toId = req.body.toId || '';
        const encryptKeyHash = req.body.encryptKeyHash || '';
        const expireHours = parseInt(req.body.expireHours) || DEFAULT_EXPIRE_HOURS;
        const fileName = req.body.fileName || req.file.originalname;
        const fileSize = parseInt(req.body.fileSize) || req.file.size;
        const mimeType = req.body.mimeType || 'application/octet-stream';

        if (!fromId || !toId) {
            fs.unlinkSync(req.file.path);
            return res.json({ code: 0, msg: 'fromId and toId required', data: null });
        }

        const cacheId = path.basename(req.file.filename, path.extname(req.file.filename));
        const now = Date.now();
        const expiresAt = now + expireHours * 3600 * 1000;

        const meta = loadMeta();
        meta[cacheId] = {
            id: cacheId,
            fileName: fileName,
            fileSize: fileSize,
            mimeType: mimeType,
            fromId: fromId,
            toId: toId,
            encryptKeyHash: encryptKeyHash,
            storedFile: req.file.filename,
            uploadedAt: now,
            expiresAt: expiresAt,
            downloadedBy: [],
            status: 'active'
        };
        saveMeta(meta);

        console.log(`CloudCache: Uploaded cacheId=${cacheId} fileName=${fileName} fromId=${fromId} toId=${toId} expiresAt=${expiresAt}`);

        res.json({
            code: 1,
            msg: 'ok',
            data: {
                cacheId: cacheId,
                expiresAt: expiresAt,
                uploadedAt: now
            }
        });
    } catch (e) {
        console.error('CloudCache: Upload error:', e.message);
        res.json({ code: 0, msg: 'Upload failed: ' + e.message, data: null });
    }
});

// ============================================================
// GET /download — 下载暂存文件
// ============================================================

router.get('/download', (req, res) => {
    try {
        const cacheId = req.query.cacheId;
        const deviceId = req.query.deviceId || req.headers['x-device-id'] || '';

        if (!cacheId) {
            return res.json({ code: 0, msg: 'cacheId required', data: null });
        }

        const meta = loadMeta();
        const record = meta[cacheId];

        if (!record || record.status !== 'active') {
            return res.json({ code: 0, msg: 'Cache not found or expired', data: null });
        }

        if (Date.now() > record.expiresAt) {
            _deleteCache(cacheId, meta);
            return res.json({ code: 0, msg: 'Cache expired', data: null });
        }

        const filePath = path.join(DATA_DIR, record.storedFile);
        if (!fs.existsSync(filePath)) {
            delete meta[cacheId];
            saveMeta(meta);
            return res.json({ code: 0, msg: 'File not found on disk', data: null });
        }

        if (deviceId && !record.downloadedBy.includes(deviceId)) {
            record.downloadedBy.push(deviceId);
            saveMeta(meta);
        }

        const downloadName = record.fileName || cacheId + '.enc';
        res.setHeader('Content-Type', 'application/octet-stream');
        res.setHeader('Content-Disposition', `attachment; filename="${encodeURIComponent(downloadName)}"`);
        res.setHeader('X-Cache-Id', cacheId);
        res.setHeader('X-From-Id', record.fromId);

        const fileStream = fs.createReadStream(filePath);
        fileStream.pipe(res);

        console.log(`CloudCache: Downloaded cacheId=${cacheId} deviceId=${deviceId}`);
    } catch (e) {
        console.error('CloudCache: Download error:', e.message);
        res.json({ code: 0, msg: 'Download failed: ' + e.message, data: null });
    }
});

// ============================================================
// GET /list — 查询暂存列表
// ============================================================

router.get('/list', (req, res) => {
    try {
        const userId = req.query.userId || req.headers['x-device-id'] || '';

        if (!userId) {
            return res.json({ code: 0, msg: 'userId required', data: null });
        }

        const meta = loadMeta();
        const now = Date.now();
        const items = [];

        for (const [cacheId, record] of Object.entries(meta)) {
            if (record.status !== 'active') continue;
            if (now > record.expiresAt) continue;

            if (record.toId === userId || record.fromId === userId) {
                items.push({
                    cacheId: record.id,
                    fileName: record.fileName,
                    fileSize: record.fileSize,
                    mimeType: record.mimeType,
                    fromId: record.fromId,
                    toId: record.toId,
                    encryptKeyHash: record.encryptKeyHash,
                    uploadedAt: record.uploadedAt,
                    expiresAt: record.expiresAt,
                    isDownloaded: record.downloadedBy.includes(userId),
                    direction: record.toId === userId ? 'incoming' : 'outgoing'
                });
            }
        }

        items.sort((a, b) => b.uploadedAt - a.uploadedAt);

        res.json({
            code: 1,
            msg: 'ok',
            data: items
        });
    } catch (e) {
        console.error('CloudCache: List error:', e.message);
        res.json({ code: 0, msg: 'List failed: ' + e.message, data: null });
    }
});

// ============================================================
// DELETE /delete — 删除暂存
// ============================================================

router.delete('/delete', (req, res) => {
    try {
        const { cacheId, deviceId } = req.body;

        if (!cacheId) {
            return res.json({ code: 0, msg: 'cacheId required', data: null });
        }

        const meta = loadMeta();
        const record = meta[cacheId];

        if (!record) {
            return res.json({ code: 0, msg: 'Cache not found', data: null });
        }

        if (deviceId && record.fromId !== deviceId && record.toId !== deviceId) {
            return res.json({ code: 0, msg: 'Not authorized', data: null });
        }

        _deleteCache(cacheId, meta);

        res.json({
            code: 1,
            msg: 'ok',
            data: { cacheId: cacheId }
        });
    } catch (e) {
        console.error('CloudCache: Delete error:', e.message);
        res.json({ code: 0, msg: 'Delete failed: ' + e.message, data: null });
    }
});

// ============================================================
// POST /notify — 通知接收方有暂存文件
// ============================================================

router.post('/notify', (req, res) => {
    try {
        const { cacheId, toId, fromId, fileName } = req.body;

        if (!cacheId || !toId) {
            return res.json({ code: 0, msg: 'cacheId and toId required', data: null });
        }

        if (typeof notifyCallback === 'function') {
            notifyCallback({
                type: 'cloud-cache-notify',
                from: fromId || 'server',
                to: toId,
                payload: {
                    cacheId: cacheId,
                    fileName: fileName || '',
                    fromId: fromId || ''
                }
            });
        }

        res.json({
            code: 1,
            msg: 'ok',
            data: { notified: true, toId: toId }
        });
    } catch (e) {
        console.error('CloudCache: Notify error:', e.message);
        res.json({ code: 0, msg: 'Notify failed: ' + e.message, data: null });
    }
});

// ============================================================
// GET /info — 查询单个暂存信息
// ============================================================

router.get('/info', (req, res) => {
    try {
        const cacheId = req.query.cacheId;

        if (!cacheId) {
            return res.json({ code: 0, msg: 'cacheId required', data: null });
        }

        const meta = loadMeta();
        const record = meta[cacheId];

        if (!record || record.status !== 'active') {
            return res.json({ code: 0, msg: 'Cache not found', data: null });
        }

        res.json({
            code: 1,
            msg: 'ok',
            data: {
                cacheId: record.id,
                fileName: record.fileName,
                fileSize: record.fileSize,
                mimeType: record.mimeType,
                fromId: record.fromId,
                toId: record.toId,
                uploadedAt: record.uploadedAt,
                expiresAt: record.expiresAt,
                downloadedBy: record.downloadedBy,
                isExpired: Date.now() > record.expiresAt
            }
        });
    } catch (e) {
        console.error('CloudCache: Info error:', e.message);
        res.json({ code: 0, msg: 'Info failed: ' + e.message, data: null });
    }
});

// ============================================================
// 内部方法
// ============================================================

function _deleteCache(cacheId, meta) {
    const record = meta[cacheId];
    if (record && record.storedFile) {
        const filePath = path.join(DATA_DIR, record.storedFile);
        try {
            if (fs.existsSync(filePath)) {
                fs.unlinkSync(filePath);
            }
        } catch (e) {
            console.error('CloudCache: Failed to delete file:', e.message);
        }
    }
    delete meta[cacheId];
    saveMeta(meta);
    console.log(`CloudCache: Deleted cacheId=${cacheId}`);
}

function _cleanupExpired() {
    const meta = loadMeta();
    const now = Date.now();
    let cleaned = 0;

    for (const [cacheId, record] of Object.entries(meta)) {
        if (now > record.expiresAt || record.status === 'deleted') {
            _deleteCache(cacheId, meta);
            cleaned++;
        }
    }

    if (cleaned > 0) {
        console.log(`CloudCache: Cleaned ${cleaned} expired caches`);
    }

    return cleaned;
}

// ============================================================
// 定时清理
// ============================================================

let _cleanupTimer = null;

function startCleanupSchedule() {
    if (_cleanupTimer) return;
    _cleanupTimer = setInterval(_cleanupExpired, CLEANUP_INTERVAL_MS);
    console.log('CloudCache: Cleanup schedule started (every 1 hour)');
}

function stopCleanupSchedule() {
    if (_cleanupTimer) {
        clearInterval(_cleanupTimer);
        _cleanupTimer = null;
        console.log('CloudCache: Cleanup schedule stopped');
    }
}

// ============================================================
// 通知回调(由外部设置)
// ============================================================

let notifyCallback = null;

function setNotifyCallback(callback) {
    notifyCallback = callback;
}

// ============================================================
// 统计
// ============================================================

function getStats() {
    const meta = loadMeta();
    const now = Date.now();
    let total = 0, active = 0, expired = 0, totalSize = 0;

    for (const [cacheId, record] of Object.entries(meta)) {
        total++;
        if (now > record.expiresAt) {
            expired++;
        } else if (record.status === 'active') {
            active++;
            totalSize += record.fileSize || 0;
        }
    }

    return { total, active, expired, totalSize };
}

// ============================================================
// 导出
// ============================================================

module.exports = {
    router,
    startCleanupSchedule,
    stopCleanupSchedule,
    setNotifyCallback,
    getStats,
    _cleanupExpired
};