import { Request, Response } from 'express';
import multer from 'multer';
import { bulkUploadMeters, generateMeterTemplate } from '../services/bulk-upload.service';

// Configure multer for memory storage
const storage = multer.memoryStorage();

export const upload = multer({
  storage,
  limits: {
    fileSize: 10 * 1024 * 1024, // 10MB max
  },
  fileFilter: (_req, file, cb) => {
    // Accept Excel files only
    const allowedMimes = [
      'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', // .xlsx
      'application/vnd.ms-excel', // .xls
    ];

    if (allowedMimes.includes(file.mimetype)) {
      cb(null, true);
    } else {
      cb(new Error('Solo se permiten archivos Excel (.xlsx, .xls)'));
    }
  },
});

/**
 * POST /api/bulk-upload/meters
 * Upload Excel file with meters data
 */
export async function uploadMeters(req: Request, res: Response): Promise<void> {
  try {
    if (!req.file) {
      res.status(400).json({
        success: false,
        error: 'No se proporcionó ningún archivo',
      });
      return;
    }

    const result = await bulkUploadMeters(req.file.buffer);

    res.status(result.success ? 200 : 207).json({
      success: result.success,
      data: {
        totalRows: result.totalRows,
        inserted: result.inserted,
        failed: result.errors.length,
        errors: result.errors.slice(0, 50), // Limit errors in response
      },
    });
  } catch (err) {
    const error = err as Error;
    console.error('Error in bulk upload:', error);
    res.status(500).json({
      success: false,
      error: error.message || 'Error procesando la carga masiva',
    });
  }
}

/**
 * GET /api/bulk-upload/meters/template
 * Download Excel template for meters
 */
export async function downloadMeterTemplate(_req: Request, res: Response): Promise<void> {
  try {
    const buffer = generateMeterTemplate();

    res.setHeader('Content-Type', 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
    res.setHeader('Content-Disposition', 'attachment; filename=plantilla_medidores.xlsx');
    res.send(buffer);
  } catch (err) {
    const error = err as Error;
    console.error('Error generating template:', error);
    res.status(500).json({
      success: false,
      error: 'Error generando la plantilla',
    });
  }
}