import {
  BadRequestException,
  Body,
  Controller,
  Delete,
  Get,
  NotFoundException,
  Param,
  Post,
  Put,
  Query,
  Req,
  Res,
  UploadedFile,
  UseInterceptors,
} from '@nestjs/common';
import { FileInterceptor } from '@nestjs/platform-express';
import { ModuleManage } from '../module-registry/module.guard';
import type {
  AuthenticatedRequest,
  UploadedFileLike,
} from '../auth/types/auth-user';
import type { Response } from 'express';
import { DkvSchedulerService } from './dkv-scheduler.service';
import { DkvService } from './dkv.service';
import { DkvConfigDto } from './dto/dkv-config.dto';
import { DkvHistoryQueryDto } from './dto/dkv-history.dto';
import { CreateVehicleDto, UpdateVehicleDto } from './dto/dkv-vehicle.dto';

/**
 * DkvController — all /dkv/* routes, manager level (V4, 261002-icv).
 *
 * The whole module is Verwalten-level: `@ModuleManage('dkv-fleet')` on the
 * class replaces the former per-handler @Roles(ADMIN, SUPER_ADMIN). Access is
 * therefore limited to administrators and to users with the grant level
 * "Verwalten" (MANAGE) on the dkv-fleet module. Users with only "Benutzen"
 * (USE) keep getting 403 exactly as before — nothing was widened. The class
 * guard additionally requires the dkv-fleet module to be active for the
 * tenant (the web page already required that).
 * Global JwtAuthGuard enforces JWT authentication; ModuleGuard enforces the
 * grant level. No route is publicly accessible.
 *
 * Tenant extraction: `req.tenantId` set by TenantGuard (runs after auth guards).
 * All operations are scoped to the authenticated tenant's data.
 *
 * Routes:
 *   GET  /dkv/config                — get module config (no encrypted creds)
 *   PUT  /dkv/config                — save module config; updates scheduler
 *   POST /dkv/check-now             — manual inbox poll trigger
 *   POST /dkv/test-connection       — test inbox connection with form values
 *   GET  /dkv/history               — paginated processing history
 *   GET  /dkv/exports/:filename     — download a saved xlsx file
 *   GET  /dkv/vehicles              — list vehicle master records
 *   POST /dkv/vehicles              — create a vehicle master record
 *   PUT  /dkv/vehicles/:id          — update a vehicle master record
 *   DELETE /dkv/vehicles/:id        — delete a vehicle master record
 *   POST /dkv/vehicles/import       — bulk-import from CSV upload
 */
@Controller('dkv')
@ModuleManage('dkv-fleet')
export class DkvController {
  constructor(
    private readonly dkvService: DkvService,
    private readonly dkvScheduler: DkvSchedulerService,
  ) {}

  // ─── Config ────────────────────────────────────────────────────────────────

  /** GET /dkv/config — returns module config with username + hasPassword. 404 when not yet configured. */
  @Get('config')
  async getConfig(@Req() req: AuthenticatedRequest) {
    const tenantId = this._requireTenant(req);
    const config = await this.dkvService.getConfigForApi(tenantId);
    if (!config) {
      throw new NotFoundException('DKV module not yet configured');
    }
    return config;
  }

  /**
   * PUT /dkv/config — upsert module config.
   *
   * After saving, re-applies the cron job if isActive is true,
   * or stops the cron job if isActive is false.
   */
  @Put('config')
  async saveConfig(@Req() req: AuthenticatedRequest, @Body() dto: DkvConfigDto) {
    const tenantId = this._requireTenant(req);
    const result = await this.dkvService.saveConfig(tenantId, dto);

    // Update scheduler to reflect the new interval / active state
    if (dto.isActive && dto.pollIntervalMin) {
      this.dkvScheduler.setInterval(dto.pollIntervalMin, tenantId);
    } else if (dto.isActive === false) {
      this.dkvScheduler.stopJob(tenantId);
    }

    return result;
  }

  // ─── Manual trigger + connection test ──────────────────────────────────────

  /** POST /dkv/check-now — immediately run the inbox processing pipeline. */
  @Post('check-now')
  async checkNow(@Req() req: AuthenticatedRequest) {
    const tenantId = this._requireTenant(req);
    return this.dkvService.checkNow(tenantId);
  }

  /**
   * POST /dkv/test-connection — test inbox connection with current form values.
   * Used by the InboxConfigForm "Verbindung testen" button before saving.
   */
  @Post('test-connection')
  async testConnection(@Req() req: AuthenticatedRequest, @Body() dto: DkvConfigDto) {
    const tenantId = this._requireTenant(req);
    return this.dkvService.testConnection(tenantId, dto);
  }

  // ─── History ───────────────────────────────────────────────────────────────

  /**
   * GET /dkv/history?page=1&limit=20 — paginated processing history.
   * T-07-06: pagination parameters validated by DkvHistoryQueryDto.
   */
  @Get('history')
  async getHistory(@Req() req: AuthenticatedRequest, @Query() query: DkvHistoryQueryDto) {
    const tenantId = this._requireTenant(req);
    const page = query.page ?? 1;
    const limit = query.limit ?? 20;
    return this.dkvService.getHistory(tenantId, page, limit);
  }

  // ─── Export file download ──────────────────────────────────────────────────

  /**
   * GET /dkv/exports/:filename — stream a DKV xlsx export file as an attachment.
   *
   * T-07-09: DkvService.getExportFile() validates the filename against the
   * `DKV_*.xlsx` whitelist pattern before reading from user-files/. Any filename
   * containing path separators or non-whitelisted characters is rejected.
   */
  @Get('exports/:filename')
  async downloadExport(
    @Req() req: AuthenticatedRequest,
    @Param('filename') filename: string,
    @Res() res: Response,
  ) {
    const tenantId = this._requireTenant(req);

    try {
      const buffer = await this.dkvService.getExportFile(tenantId, filename);
      res.setHeader('Content-Disposition', `attachment; filename="${filename}"`);
      res.setHeader(
        'Content-Type',
        'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
      );
      res.send(buffer);
    } catch (error) {
      if (error instanceof NotFoundException || error instanceof BadRequestException) {
        throw error;
      }
      throw error;
    }
  }

  // ─── Vehicle Master CRUD ───────────────────────────────────────────────────

  /** GET /dkv/vehicles — list all vehicle master records for this tenant. */
  @Get('vehicles')
  async listVehicles(@Req() req: AuthenticatedRequest) {
    const tenantId = this._requireTenant(req);
    return this.dkvService.listVehicles(tenantId);
  }

  /** POST /dkv/vehicles — create a new vehicle master record. */
  @Post('vehicles')
  async createVehicle(@Req() req: AuthenticatedRequest, @Body() dto: CreateVehicleDto) {
    const tenantId = this._requireTenant(req);
    return this.dkvService.createVehicle(tenantId, dto);
  }

  /** PUT /dkv/vehicles/:id — update an existing vehicle master record. */
  @Put('vehicles/:id')
  async updateVehicle(
    @Req() req: AuthenticatedRequest,
    @Param('id') id: string,
    @Body() dto: UpdateVehicleDto,
  ) {
    const tenantId = this._requireTenant(req);
    return this.dkvService.updateVehicle(tenantId, id, dto);
  }

  /** DELETE /dkv/vehicles/:id — delete a vehicle master record. */
  @Delete('vehicles/:id')
  async deleteVehicle(@Req() req: AuthenticatedRequest, @Param('id') id: string) {
    const tenantId = this._requireTenant(req);
    return this.dkvService.deleteVehicle(tenantId, id);
  }

  /**
   * POST /dkv/vehicles/import — bulk import from a CSV file upload.
   *
   * Accepts a multipart form with:
   * - `file`: the CSV file (field name must be "file")
   * - `mode`: 'merge' (default) or 'replace'
   *
   * FileInterceptor buffers the upload in memory (no disk write).
   * The controller reads `file.buffer.toString('utf-8')` and passes to DkvService.
   */
  @Post('vehicles/import')
  @UseInterceptors(FileInterceptor('file', {
    limits: { fileSize: 5 * 1024 * 1024 }, // 5 MB — generous for any realistic vehicle list (WR-05)
  }))
  async importVehicles(
    @Req() req: AuthenticatedRequest,
    @UploadedFile() file: UploadedFileLike | undefined,
    @Body('mode') mode: string,
  ) {
    const tenantId = this._requireTenant(req);

    if (!file?.buffer) {
      throw new BadRequestException('No CSV file uploaded (field name must be "file")');
    }

    const csvText = file.buffer.toString('utf-8');
    const importMode = mode === 'replace' ? 'replace' : 'merge';

    return this.dkvService.importVehiclesCsv(tenantId, csvText, importMode);
  }

  // ─── Private helpers ───────────────────────────────────────────────────────

  /** Extract and validate tenantId from request; throw BadRequestException when absent. */
  private _requireTenant(req: AuthenticatedRequest): string {
    const tenantId = req.tenantId;
    if (!tenantId) {
      throw new BadRequestException('No tenant context');
    }
    return tenantId;
  }
}