/**
 * INTEGRATION GUIDE: RECIPE IMPORT SERVICE
 * 
 * This file shows how to integrate recipe-document-converter with recipe-app backend.
 * Copy and adapt this code to your recipe-app/backend directory.
 * 
 * Path: backend/src/modules/import/import.service.ts
 */

import { Injectable, HttpException, HttpStatus } from '@nestjs/common';
import axios from 'axios';
import FormData from 'form-data';
import * as fs from 'fs';
import { PrismaService } from '../../prisma/prisma.service'; // Adjust path based on your project

interface RecipeImportDTO {
  name: string;
  ingredients: Array<{
    name: string;
    quantity?: number;
    unit?: string;
  }>;
  instructions: string[];
  metadata?: {
    prepTime?: string;
    servings?: number;
    author?: string;
  };
}

@Injectable()
export class ImportService {
  private readonly IMPORT_SERVICE_URL = process.env.IMPORT_SERVICE_URL || 'http://import-service:3000';

  constructor(private prisma: PrismaService) {}

  /**
   * Upload a PDF file to the import service and extract recipe data
   * 
   * Usage in your recipe controller:
   * @Post('import/pdf')
   * @UseInterceptors(FileInterceptor('file'))
   * async importRecipeFromPDF(@UploadedFile() file: Express.Multer.File) {
   *   return this.importService.importRecipeFromPDF(file);
   * }
   */
  async importRecipeFromPDF(file: Express.Multer.File) {
    try {
      // Validate file
      if (!file) {
        throw new HttpException('Ingen fil angiven', HttpStatus.BAD_REQUEST);
      }

      if (file.mimetype !== 'application/pdf') {
        throw new HttpException('Endast PDF-filer tillåtna', HttpStatus.BAD_REQUEST);
      }

      // Call import-service
      const form = new FormData();
      form.append('file', fs.createReadStream(file.path));

      const response = await axios.post(`${this.IMPORT_SERVICE_URL}/import/pdf`, form, {
        headers: form.getHeaders(),
        timeout: 30000,
      });

      if (!response.data.success) {
        throw new HttpException(response.data.error || 'Receptextrahering misslyckades', HttpStatus.BAD_REQUEST);
      }

      // Extract and validate recipe data
      const recipeData = this.mapImportDataToRecipe(response.data.structuredData);

      return {
        success: true,
        data: recipeData,
        metadata: response.data.pdfMetadata,
      };
    } catch (error) {
      // Clean up uploaded file
      if (file && file.path && fs.existsSync(file.path)) {
        fs.unlinkSync(file.path);
      }

      if (error instanceof axios.AxiosError) {
        throw new HttpException(
          `Receptextrahering misslyckades: ${error.message}`,
          HttpStatus.SERVICE_UNAVAILABLE,
        );
      }

      throw error;
    }
  }

  /**
   * Save imported recipe to database
   * 
   * Usage in your recipe controller:
   * @Post('import/pdf/save')
   * @UseInterceptors(FileInterceptor('file'))
   * async importAndSaveRecipe(@UploadedFile() file: Express.Multer.File) {
   *   const imported = await this.importService.importRecipeFromPDF(file);
   *   return this.importService.saveImportedRecipe(imported.data);
   * }
   */
  async saveImportedRecipe(recipeData: RecipeImportDTO) {
    try {
      // Create recipe with ingredients
      const recipe = await this.prisma.recipe.create({
        data: {
          name: recipeData.name,
          instructions: recipeData.instructions.join('\n'),
          prepTime: recipeData.metadata?.prepTime,
          servings: recipeData.metadata?.servings,
          author: recipeData.metadata?.author,
          ingredients: {
            create: recipeData.ingredients.map((ing) => ({
              name: ing.name,
              quantity: ing.quantity,
              unit: ing.unit,
            })),
          },
        },
        include: {
          ingredients: true,
        },
      });

      return {
        success: true,
        message: 'Recept sparat',
        recipe,
      };
    } catch (error) {
      throw new HttpException(
        `Kunde inte spara recept: ${error instanceof Error ? error.message : 'Okänt fel'}`,
        HttpStatus.INTERNAL_SERVER_ERROR,
      );
    }
  }

  /**
   * Map import service data to recipe format
   */
  private mapImportDataToRecipe(importedData: any): RecipeImportDTO {
    return {
      name: importedData.name || 'Importerat recept',
      ingredients: importedData.ingredients || [],
      instructions: importedData.instructions || [],
      metadata: importedData.metadata || {},
    };
  }

  /**
   * Health check for import service (useful for monitoring)
   */
  async checkImportServiceHealth() {
    try {
      const response = await axios.get(`${this.IMPORT_SERVICE_URL}/health`, {
        timeout: 5000,
      });
      return response.data;
    } catch {
      throw new HttpException('Import-service är ej tillgänglig', HttpStatus.SERVICE_UNAVAILABLE);
    }
  }
}