import { Router } from 'express';
import multer from 'multer';
import { asyncHandler } from '../utils';
import { importStatement, isValidationError } from '../services/import';
import {
  convertPdfToStatement,
  isPdfConversionError,
} from '../services/pdfToStatement';

const upload = multer({
  storage: multer.memoryStorage(),
  limits: { fileSize: 15 * 1024 * 1024 },
});

function isPdfFile(file: { mimetype: string; originalname: string }): boolean {
  const name = file.originalname.toLowerCase();
  return (
    file.mimetype === 'application/pdf' ||
    name.endsWith('.pdf')
  );
}

function isJsonFile(file: { mimetype: string; originalname: string }): boolean {
  const name = file.originalname.toLowerCase();
  return (
    file.mimetype === 'application/json' ||
    name.endsWith('.json')
  );
}

const router = Router();

router.post(
  '/statement',
  upload.single('file'),
  asyncHandler(async (req, res) => {
    const file = req.file;
    if (!file) {
      res.status(400).json({
        error: 'BAD_REQUEST',
        message: 'Файл не загружен',
      });
      return;
    }

    if (!isPdfFile(file) && !isJsonFile(file)) {
      res.status(400).json({
        error: 'BAD_REQUEST',
        message: 'Допустимы только файлы PDF или JSON',
      });
      return;
    }

    let body: unknown;

    if (isPdfFile(file)) {
      const converted = await convertPdfToStatement(file.buffer);
      if (isPdfConversionError(converted)) {
        res.status(converted.status).json({
          error: converted.error,
          message: converted.message,
        });
        return;
      }
      body = converted;
    } else {
      try {
        body = JSON.parse(file.buffer.toString('utf-8'));
      } catch {
        res.status(400).json({
          error: 'BAD_REQUEST',
          message: 'Некорректный JSON-файл',
        });
        return;
      }
    }

    const result = await importStatement(body);
    if (isValidationError(result)) {
      res.status((result as { status: number }).status).json({
        error: (result as { error: string }).error,
        message: (result as { message: string }).message,
      });
      return;
    }
    res.json(result);
  }),
);

export default router;