import { Router, Request, Response } from 'express';
import { etl } from '../config';
import { runSync, SyncResult } from '../services/etlSync';

const router = Router();

type SyncState =
  | { status: 'idle' }
  | { status: 'running'; mode: string; startedAt: string; currentMonth?: string }
  | { status: 'done'; result: SyncResult; finishedAt: string }
  | { status: 'error'; error: string; finishedAt: string };

let syncState: SyncState = { status: 'idle' };

function auth(req: Request, res: Response): boolean {
  const header = req.headers.authorization;
  if (etl.secret && header !== `Bearer ${etl.secret}`) {
    res.status(401).json({ error: 'Unauthorized' });
    return false;
  }
  return true;
}

// POST /api/etl/sync?mode=full|incremental — fires and returns immediately
router.post('/sync', (req: Request, res: Response) => {
  if (!auth(req, res)) return;

  if (syncState.status === 'running') {
    res.status(409).json({ error: 'Sync already running', state: syncState });
    return;
  }

  const mode = (req.query.mode as string) === 'full' ? 'full' : 'incremental';
  syncState = { status: 'running', mode, startedAt: new Date().toISOString() };

  res.json({ accepted: true, mode, message: 'Sync started — poll GET /api/etl/status for progress' });

  console.log(`\nETL sync started (${mode})...`);
  runSync(mode, (month) => {
    if (syncState.status === 'running') syncState = { ...syncState, currentMonth: month };
  })
    .then(result => {
      console.log(`ETL sync complete: ${result.transactionsFetched} transactions → ${result.recordsWritten} records in ${result.duration}`);
      syncState = { status: 'done', result, finishedAt: new Date().toISOString() };
    })
    .catch(err => {
      console.error('ETL sync failed:', (err as Error).message);
      syncState = { status: 'error', error: (err as Error).message, finishedAt: new Date().toISOString() };
    });
});

// GET /api/etl/status
router.get('/status', (req: Request, res: Response) => {
  if (!auth(req, res)) return;
  res.json(syncState);
});

export default router;