import {
  BadRequestException,
  Controller,
  Get,
  Post,
  Res,
  UploadedFile,
  UseInterceptors,
} from '@nestjs/common';
import { FileInterceptor } from '@nestjs/platform-express';
import { ApiBearerAuth, ApiConsumes, ApiTags } from '@nestjs/swagger';
import type { Response } from 'express';
import { RequirePermission } from '../auth/decorators/require-permission.decorator';
import { CurrentUser } from '../auth/decorators/current-user.decorator';
import type { AuthenticatedUser } from '../auth/types/authenticated-user';
import { BackupBundle, BackupService } from './backup.service';
import {
  BackupScheduleStatus,
  BackupSchedulerService,
} from './backup-scheduler.service';

// A full backup bundle can be much larger than the 5mb CSV import cap
// elsewhere (dozens of tables, potentially years of records, plus embedded
// label-template images) - 50mb comfortably covers a real dataset without
// raising the app-wide JSON body limit for every other route.
const MAX_BACKUP_FILE_SIZE_BYTES = 50 * 1024 * 1024;

@ApiTags('backup')
@ApiBearerAuth()
@Controller('backup')
export class BackupController {
  constructor(
    private readonly backupService: BackupService,
    private readonly backupSchedulerService: BackupSchedulerService,
  ) {}

  @RequirePermission('backup:export')
  @Get('schedule')
  getSchedule(): Promise<BackupScheduleStatus> {
    return this.backupSchedulerService.getStatus();
  }

  @RequirePermission('backup:export')
  @Post('schedule/run-now')
  runScheduleNow(): Promise<{ filePath: string }> {
    return this.backupSchedulerService.runNow();
  }

  @RequirePermission('backup:export')
  @Get('export')
  async export(@Res() res: Response): Promise<void> {
    const bundle = await this.backupService.exportAll();
    const filename = `apicore-backup-${new Date().toISOString().slice(0, 10)}.json`;
    res.setHeader('Content-Type', 'application/json; charset=utf-8');
    res.setHeader('Content-Disposition', `attachment; filename="${filename}"`);
    res.send(JSON.stringify(bundle, null, 2));
  }

  @RequirePermission('backup:import')
  @Post('import')
  @ApiConsumes('multipart/form-data')
  @UseInterceptors(
    FileInterceptor('file', {
      limits: { fileSize: MAX_BACKUP_FILE_SIZE_BYTES },
      fileFilter: (_req, file, callback) => {
        if (!file.originalname.toLowerCase().endsWith('.json')) {
          callback(
            new BadRequestException('Nur JSON-Dateien werden unterstützt'),
            false,
          );
          return;
        }
        callback(null, true);
      },
    }),
  )
  async import(
    @UploadedFile() file: Express.Multer.File | undefined,
    @CurrentUser() actor: AuthenticatedUser,
  ) {
    if (!file) {
      throw new BadRequestException('No file uploaded');
    }
    let bundle: BackupBundle;
    try {
      bundle = JSON.parse(file.buffer.toString('utf-8')) as BackupBundle;
    } catch {
      throw new BadRequestException('Datei ist kein gültiges JSON');
    }
    return this.backupService.importAll(bundle, actor.id);
  }
}