import { getDb } from '../database/database';
import { localTimestamp, formatLocalDateTime } from '../utils/time';
import { getSystemConfig } from '../admin/system-config.service';
import { QuarkDriver } from './drivers/quark.driver';
import { BaiduDriver } from './drivers/baidu.driver';
import { CloudConfig, getAndValidateCredential, getActiveCloudConfigs } from './credential.service';
import { lookupIpLocation } from './ip-lookup';

/** In-flight save dedup: prevents concurrent saves of the same URL (race condition fix) */
const inFlightSaves = new Map<string, Promise<SaveResult>>();

export interface SaveResult {
  success: boolean;
  shareUrl?: string;
  share_url?: string;
  sharePwd?: string;
  folderName?: string;
  message: string;
  file_count?: number;
  folder_count?: number;
  duration_ms?: number;
}

export interface SaveRecord {
  id: number;
  source_type: string;
  source_title: string | null;
  source_url: string;
  target_cloud: string;
  share_url: string | null;
  share_pwd: string | null;
  file_size: string | null;
  file_count: number;
  folder_count: number;
  duration_ms: number;
  status: string;
  error_message: string | null;
  folder_name: string | null;
  original_folder_name: string | null;
  ip_address: string | null;
  ip_location: string | null;
  created_at: string;
}

/** Core save logic extracted so inFlight dedup can wrap it */
async function doSaveFromShare(shareUrl: string, cloudType: string, sourceTitle?: string, ipAddress?: string): Promise<SaveResult> {
  const db = getDb();
  const ipLocation = await lookupIpLocation(ipAddress || '');

  // ── Short-term dedup: prevent duplicate saves of the same URL within 60 seconds ──
  const DEDUP_WINDOW_SEC = 60;
  let dedupCutoff = '';
  try {
    const recentCutoff = db.prepare(
      `SELECT datetime('now','localtime', '-${DEDUP_WINDOW_SEC} seconds') as cutoff`
    ).get() as { cutoff: string };
    dedupCutoff = recentCutoff.cutoff;

    const recentRecord = db.prepare(
      `SELECT share_url, share_pwd, status, error_message, folder_name, original_folder_name FROM save_records
       WHERE source_url = ? AND created_at >= ?
       ORDER BY created_at DESC LIMIT 1`
    ).get(shareUrl, dedupCutoff) as {
      share_url: string | null; share_pwd: string | null; status: string;
      error_message: string | null; folder_name: string | null; original_folder_name: string | null;
    } | undefined;

    if (recentRecord) {
      const alreadySaved = recentRecord.status === 'success' || recentRecord.status === 'reused';
      if (alreadySaved && recentRecord.share_url) {
        console.log(`[Share] 🛡️ Dedup: ${shareUrl} was saved ${DEDUP_WINDOW_SEC}s ago (status=${recentRecord.status}), returning existing share link`);
        db.prepare(
          `INSERT INTO save_records (source_type, source_title, source_url, target_cloud, share_url, share_pwd, file_size, file_count, folder_count, duration_ms, status, error_message, folder_name, original_folder_name, ip_address, ip_location, created_at)
           VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
        ).run(
          cloudType, sourceTitle || null, shareUrl, cloudType,
          recentRecord.share_url, recentRecord.share_pwd || null,
          null, 0, 0, 0, 'reused', null,
          recentRecord.folder_name || null, recentRecord.original_folder_name || null,
          ipAddress || null, ipLocation, localTimestamp(),
        );
        return {
          success: true,
          message: `🛡️ 此资源刚在 ${DEDUP_WINDOW_SEC} 秒内转存过，直接返回已有分享链接`,
          share_url: recentRecord.share_url, shareUrl: recentRecord.share_url,
          sharePwd: recentRecord.share_pwd || '', folderName: '',
          file_count: 0, folder_count: 0, duration_ms: 0,
        };
      }
    }
  } catch (err: any) {
    console.log(`[Share] Dedup check failed: ${err.message}, proceeding with normal save`);
  }

  // ── Share link reuse: if same source URL was already saved successfully, validate and reuse ──
  const reuseEnabled = getSystemConfig('save_reuse_enabled');
  if (reuseEnabled !== 'false') {
    try {
      const existing = db.prepare(
        `SELECT share_url, share_pwd, folder_name, original_folder_name FROM save_records
         WHERE source_url = ? AND status IN ('success', 'reused') AND share_url IS NOT NULL AND share_url != ''
         ORDER BY created_at DESC LIMIT 1`
      ).get(shareUrl) as { share_url: string; share_pwd: string; folder_name: string | null; original_folder_name: string | null } | undefined;

      if (existing?.share_url) {
        const { LinkValidator } = await import('../validation/link-validator.service');
        const validator = new LinkValidator();
        const validation = await validator.validate(existing.share_url, 'quark');
        if (validation.status === 'valid') {
          const isFirstReuse = dedupCutoff ? !db.prepare(
            `SELECT 1 FROM save_records WHERE source_url = ? AND created_at >= ? AND status = 'reused' LIMIT 1`
          ).get(shareUrl, dedupCutoff) : true;
          const reuseStatus = isFirstReuse ? 'success' : 'reused';
          const reuseMsg = isFirstReuse
            ? `♻️ 检测到此资源之前已转存过，直接复用已存在的分享链接`
            : `♻️ 短时间内重复请求，复用已有分享链接`;

          console.log(`[Share] ♻️ Reusing existing share link for ${shareUrl}: ${existing.share_url} (firstReuse=${isFirstReuse})`);
          db.prepare(
            `INSERT INTO save_records (source_type, source_title, source_url, target_cloud, share_url, share_pwd, file_size, file_count, folder_count, duration_ms, status, error_message, folder_name, original_folder_name, ip_address, ip_location, created_at)
             VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
          ).run(
            cloudType, sourceTitle || null, shareUrl, cloudType,
            existing.share_url, existing.share_pwd || null,
            null, 0, 0, 0, reuseStatus, null,
            existing.folder_name || null, existing.original_folder_name || null,
            ipAddress || null, ipLocation, localTimestamp(),
          );
          return {
            success: true, message: reuseMsg,
            share_url: existing.share_url, shareUrl: existing.share_url,
            sharePwd: existing.share_pwd || '', folderName: '',
            file_count: 0, folder_count: 0, duration_ms: 0,
          };
        }
        console.log(`[Share] Existing share link for ${shareUrl} is invalid/expired, will re-save`);
      }
    } catch (err: any) {
      console.log(`[Share] Link reuse check failed: ${err.message}, proceeding with normal save`);
    }
  }

  // ── Unified credential validation ──
  const credential = await getAndValidateCredential(cloudType);
  if (!credential.valid || !credential.config) {
    return { success: false, message: credential.message };
  }
  const config = credential.config;
  const startTime = Date.now();

  try {
    let driverResult: { success: boolean; message: string; shareUrl?: string; sharePwd?: string; folderName?: string; fileCount?: number; folderCount?: number; originalFolderName?: string };

    switch (cloudType) {
      case 'quark': {
        const driver = new QuarkDriver({ cookie: config.cookie!, nickname: config.nickname });
        driverResult = await driver.saveFromShare(shareUrl, sourceTitle);
        break;
      }
      case 'baidu': {
        const driver = new BaiduDriver({ cookie: config.cookie!, nickname: config.nickname });
        driverResult = await driver.saveFromShare(shareUrl, sourceTitle);
        break;
      }
      case 'aliyun':
        return { success: false, message: '阿里云盘保存功能暂未实现' };
      default:
        return { success: false, message: `暂不支持 ${cloudType} 的保存功能` };
    }

    const durationMs = Date.now() - startTime;

    if (driverResult.success) {
      db.prepare(
        `UPDATE cloud_configs SET last_used_at = datetime('now','localtime'), total_saves = total_saves + 1, consecutive_failures = 0 WHERE id = ?`
      ).run(config.id);
    } else if ((driverResult as any).cookieExpired) {
      // Cookie expired — don't count as failure, user needs to re-login
    } else {
      db.prepare(
        `UPDATE cloud_configs SET consecutive_failures = consecutive_failures + 1 WHERE id = ?`
      ).run(config.id);
    }

    db.prepare(
      `INSERT INTO save_records (source_type, source_title, source_url, target_cloud, share_url, share_pwd, file_size, file_count, folder_count, duration_ms, status, error_message, folder_name, original_folder_name, ip_address, ip_location, created_at)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`
    ).run(
      cloudType, sourceTitle || driverResult.folderName || null, shareUrl, cloudType,
      driverResult.shareUrl || null, driverResult.sharePwd || null,
      null, driverResult.fileCount || 0, driverResult.folderCount || 0,
      durationMs, driverResult.success ? 'success' : 'failed',
      driverResult.success ? null : driverResult.message,
      driverResult.folderName || null, driverResult.originalFolderName || null,
      ipAddress || null, ipLocation, localTimestamp(),
    );

    return {
      success: driverResult.success,
      message: driverResult.message,
      share_url: driverResult.shareUrl || '',
      shareUrl: driverResult.shareUrl,
      sharePwd: (driverResult as any).sharePwd || '',
      folderName: driverResult.folderName || '',
      file_count: driverResult.fileCount || 0,
      folder_count: driverResult.folderCount || 0,
      duration_ms: durationMs,
    };
  } catch (err: any) {
    const durationMs = Date.now() - startTime;
    const errorMessage = err.message || 'Failed to save to cloud';

    db.prepare(
      `UPDATE cloud_configs SET consecutive_failures = consecutive_failures + 1 WHERE id = ?`
    ).run(config.id);

    db.prepare(
      `INSERT INTO save_records (source_type, source_url, target_cloud, duration_ms, status, error_message, ip_address, ip_location, created_at)
       VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)`
    ).run(cloudType, shareUrl, cloudType, durationMs, 'failed', errorMessage, ipAddress || null, ipLocation, localTimestamp());

    return { success: false, message: errorMessage };
  }
}

export async function saveFromShare(shareUrl: string, cloudType: string, sourceTitle?: string, ipAddress?: string): Promise<SaveResult> {
  const key = `${cloudType}:${shareUrl}`;

  const inflight = inFlightSaves.get(key);
  if (inflight) {
    console.log(`[Share] ⏳ In-flight: ${shareUrl} — another save is already running, awaiting result`);
    return inflight;
  }

  const promise = doSaveFromShare(shareUrl, cloudType, sourceTitle, ipAddress);
  inFlightSaves.set(key, promise);
  try {
    return await promise;
  } finally {
    inFlightSaves.delete(key);
  }
}

// ── Save Records ──────────────────────────────────────────────────

export function getSaveRecords(page: number = 1, pageSize: number = 20, startDate?: string, endDate?: string, status?: string, sourceType?: string, keyword?: string): { total: number; records: SaveRecord[]; summary?: { total: number; success: number; failed: number; reused: number } } {
  const db = getDb();
  const offset = (page - 1) * pageSize;
  const conditions: string[] = [];
  const params: any[] = [];
  const summaryConditions: string[] = [];
  const summaryParams: any[] = [];
  if (startDate) {
    conditions.push('created_at >= ?'); params.push(startDate);
    summaryConditions.push('created_at >= ?'); summaryParams.push(startDate);
  }
  if (endDate) {
    conditions.push('created_at < ?'); params.push(endDate);
    summaryConditions.push('created_at < ?'); summaryParams.push(endDate);
  }
  if (status) { conditions.push('status = ?'); params.push(status); }
  if (sourceType) {
    conditions.push('source_type = ?'); params.push(sourceType);
    summaryConditions.push('source_type = ?'); summaryParams.push(sourceType);
  }
  if (keyword) { conditions.push('source_title LIKE ?'); params.push(`%${keyword}%`); }
  const where = conditions.length > 0 ? 'WHERE ' + conditions.join(' AND ') : '';
  const total = (db.prepare(`SELECT COUNT(*) as count FROM save_records ${where}`).get(...params) as any).count;
  const records = db.prepare(
    `SELECT * FROM save_records ${where} ORDER BY created_at DESC LIMIT ? OFFSET ?`
  ).all(...params, pageSize, offset) as SaveRecord[];

  const summaryWhere = summaryConditions.length > 0 ? 'WHERE ' + summaryConditions.join(' AND ') : '';
  const summaryRows = db.prepare(
    `SELECT status, COUNT(*) as cnt FROM save_records ${summaryWhere} GROUP BY status`
  ).all(...summaryParams) as { status: string; cnt: number }[];
  let sumTotal = 0, sumSuccess = 0, sumFailed = 0, sumReused = 0;
  for (const r of summaryRows) {
    sumTotal += r.cnt;
    if (r.status === 'success') sumSuccess = r.cnt;
    else if (r.status === 'failed') sumFailed = r.cnt;
    else if (r.status === 'reused') sumReused = r.cnt;
  }
  const summary = { total: sumTotal, success: sumSuccess, failed: sumFailed, reused: sumReused };

  return { total, records, summary };
}

export function cleanupOldSaveRecords(): void {
  const db = getDb();
  const cutoff = formatLocalDateTime(new Date(Date.now() - 60 * 24 * 60 * 60 * 1000));
  const deleted = db.prepare('DELETE FROM save_records WHERE created_at < ?').run(cutoff);
  console.log(`[Cleanup] Deleted ${deleted.changes} save records older than 60 days (before ${cutoff})`);
}

// ── Storage Refresh ───────────────────────────────────────────────

export async function refreshAllStorageInfo(): Promise<void> {
  const configs = getActiveCloudConfigs().filter(c => c.cloud_type === 'quark' && c.cookie);
  if (configs.length === 0) return;

  for (const cfg of configs) {
    try {
      const { QuarkDriver } = require('./drivers/quark.driver');
      const driver = new QuarkDriver({ cookie: cfg.cookie, nickname: cfg.nickname });
      const storage = await driver.getStorageInfo();
      if (storage.totalBytes > 0 || storage.usedBytes > 0) {
        const db = getDb();
        db.prepare(
          `UPDATE cloud_configs SET storage_used = ?, storage_total = ? WHERE id = ?`
        ).run(storage.used, storage.total, cfg.id);
      }
    } catch (err: any) {
      console.error(`[Storage] Failed to refresh quark#${cfg.id}:`, err.message);
    }
  }
}
