feat: add user download traffic reports and restore OSS direct downloads

backend/database.js

@@ -365,6 +365,21 @@ function initDatabase() {
     )
   `);
 
+  // 下载流量日统计表（用于用户侧报表）
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS user_download_traffic_daily (
+      id INTEGER PRIMARY KEY AUTOINCREMENT,
+      user_id INTEGER NOT NULL,
+      date_key TEXT NOT NULL, -- YYYY-MM-DD（本地时区）
+      bytes_used INTEGER NOT NULL DEFAULT 0,
+      download_count INTEGER NOT NULL DEFAULT 0,
+      created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+      updated_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+      UNIQUE(user_id, date_key),
+      FOREIGN KEY (user_id) REFERENCES users (id) ON DELETE CASCADE
+    )
+  `);
+
   // 日志表索引
   db.exec(`
     CREATE INDEX IF NOT EXISTS idx_logs_created_at ON system_logs(created_at);
@@ -377,6 +392,9 @@ function initDatabase() {
     -- 优势：快速查询用户最近的活动记录，支持时间范围过滤
     -- 使用场景：用户活动历史、审计日志查询
     CREATE INDEX IF NOT EXISTS idx_logs_user_created ON system_logs(user_id, created_at);
+
+    -- 下载流量报表索引（按用户+日期查询）
+    CREATE INDEX IF NOT EXISTS idx_download_traffic_user_date ON user_download_traffic_daily(user_id, date_key);
   `);
 
   console.log('[数据库性能优化] ✓ 日志表复合索引已创建');
@@ -1421,6 +1439,104 @@ function migrateDownloadTrafficFields() {
   }
 }
 
+// 下载流量报表（按天聚合）
+const DownloadTrafficReportDB = {
+  normalizeDays(days, defaultDays = 30, maxDays = 365) {
+    const parsed = Number(days);
+    if (!Number.isFinite(parsed) || parsed <= 0) {
+      return defaultDays;
+    }
+    return Math.min(maxDays, Math.max(1, Math.floor(parsed)));
+  },
+
+  formatDateKey(date = new Date()) {
+    const target = date instanceof Date ? date : new Date(date);
+    if (Number.isNaN(target.getTime())) {
+      return null;
+    }
+    const year = target.getFullYear();
+    const month = String(target.getMonth() + 1).padStart(2, '0');
+    const day = String(target.getDate()).padStart(2, '0');
+    return `${year}-${month}-${day}`;
+  },
+
+  addUsage(userId, bytesUsed, downloadCount = 1, date = new Date()) {
+    const uid = Number(userId);
+    const bytes = Math.floor(Number(bytesUsed));
+    const count = Math.floor(Number(downloadCount));
+    const dateKey = this.formatDateKey(date);
+
+    if (!Number.isFinite(uid) || uid <= 0 || !Number.isFinite(bytes) || bytes <= 0 || !dateKey) {
+      return null;
+    }
+
+    const normalizedCount = Number.isFinite(count) && count > 0 ? count : 1;
+
+    return db.prepare(`
+      INSERT INTO user_download_traffic_daily (user_id, date_key, bytes_used, download_count, created_at, updated_at)
+      VALUES (?, ?, ?, ?, datetime('now', 'localtime'), datetime('now', 'localtime'))
+      ON CONFLICT(user_id, date_key)
+      DO UPDATE SET
+        bytes_used = user_download_traffic_daily.bytes_used + excluded.bytes_used,
+        download_count = user_download_traffic_daily.download_count + excluded.download_count,
+        updated_at = datetime('now', 'localtime')
+    `).run(uid, dateKey, bytes, normalizedCount);
+  },
+
+  getDailyUsage(userId, days = 30) {
+    const uid = Number(userId);
+    if (!Number.isFinite(uid) || uid <= 0) {
+      return [];
+    }
+
+    const safeDays = this.normalizeDays(days);
+    const offset = `-${safeDays - 1} days`;
+
+    return db.prepare(`
+      SELECT
+        date_key,
+        bytes_used,
+        download_count
+      FROM user_download_traffic_daily
+      WHERE user_id = ?
+        AND date_key >= date('now', 'localtime', ?)
+      ORDER BY date_key ASC
+    `).all(uid, offset);
+  },
+
+  getPeriodSummary(userId, days = null) {
+    const uid = Number(userId);
+    if (!Number.isFinite(uid) || uid <= 0) {
+      return { bytes_used: 0, download_count: 0 };
+    }
+
+    if (days === null || days === undefined) {
+      const row = db.prepare(`
+        SELECT
+          COALESCE(SUM(bytes_used), 0) AS bytes_used,
+          COALESCE(SUM(download_count), 0) AS download_count
+        FROM user_download_traffic_daily
+        WHERE user_id = ?
+      `).get(uid);
+      return row || { bytes_used: 0, download_count: 0 };
+    }
+
+    const safeDays = this.normalizeDays(days);
+    const offset = `-${safeDays - 1} days`;
+
+    const row = db.prepare(`
+      SELECT
+        COALESCE(SUM(bytes_used), 0) AS bytes_used,
+        COALESCE(SUM(download_count), 0) AS download_count
+      FROM user_download_traffic_daily
+      WHERE user_id = ?
+        AND date_key >= date('now', 'localtime', ?)
+    `).get(uid, offset);
+
+    return row || { bytes_used: 0, download_count: 0 };
+  }
+};
+
 // 系统日志操作
 const SystemLogDB = {
   // 日志级别常量
@@ -1616,6 +1732,7 @@ module.exports = {
   SettingsDB,
   VerificationDB,
   PasswordResetTokenDB,
+  DownloadTrafficReportDB,
   SystemLogDB,
   TransactionDB,
   WalManager