import { Injectable, Logger } from '@nestjs/common';
import * as fs from 'fs/promises';
import * as path from 'path';

/**
 * CSV Converter Service
 *
 * Détecte automatiquement le format du CSV et convertit au format attendu
 * Supporte:
 * - Format standard Xpeditis
 * - Format "Frais FOB FRET"
 */
@Injectable()
export class CsvConverterService {
  private readonly logger = new Logger(CsvConverterService.name);

  // Headers du format standard attendu
  private readonly STANDARD_HEADERS = [
    'companyName',
    'origin',
    'destination',
    'containerType',
    'minVolumeCBM',
    'maxVolumeCBM',
    'minWeightKG',
    'maxWeightKG',
    'palletCount',
    'pricePerCBM',
    'pricePerKG',
    'basePriceUSD',
    'basePriceEUR',
    'currency',
    'hasSurcharges',
    'surchargeBAF',
    'surchargeCAF',
    'surchargeDetails',
    'transitDays',
    'validFrom',
    'validUntil',
  ];

  // Headers du format "Frais FOB FRET"
  private readonly FOB_FRET_HEADERS = [
    'Origine UN code',
    'Destination UN code',
    'Devise FRET',
    'Taux de FRET (UP)',
    'Minimum FRET (LS)',
    'Transit time',
  ];

  /**
   * Parse une ligne CSV en gérant les champs entre guillemets
   */
  private parseCSVLine(line: string): string[] {
    const result: string[] = [];
    let current = '';
    let inQuotes = false;

    for (let i = 0; i < line.length; i++) {
      const char = line[i];

      if (char === '"') {
        inQuotes = !inQuotes;
      } else if (char === ',' && !inQuotes) {
        result.push(current.trim());
        current = '';
      } else {
        current += char;
      }
    }
    result.push(current.trim());

    return result;
  }

  /**
   * Détecte le format du CSV
   */
  async detectFormat(filePath: string): Promise<'STANDARD' | 'FOB_FRET' | 'UNKNOWN'> {
    try {
      const content = await fs.readFile(filePath, 'utf-8');
      const lines = content.split('\n').filter(line => line.trim());

      if (lines.length === 0) {
        return 'UNKNOWN';
      }

      // Vérifier les 2 premières lignes (parfois la vraie ligne d'en-tête est la ligne 2)
      for (let i = 0; i < Math.min(2, lines.length); i++) {
        const headers = this.parseCSVLine(lines[i]);

        // Vérifier format standard
        const hasStandardHeaders = this.STANDARD_HEADERS.some(h => headers.includes(h));
        if (hasStandardHeaders) {
          return 'STANDARD';
        }

        // Vérifier format FOB FRET
        const hasFobFretHeaders = this.FOB_FRET_HEADERS.some(h => headers.includes(h));
        if (hasFobFretHeaders) {
          return 'FOB_FRET';
        }
      }

      return 'UNKNOWN';
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : 'Unknown error';
      this.logger.error(`Error detecting CSV format: ${errorMessage}`);
      return 'UNKNOWN';
    }
  }

  /**
   * Calcule les surcharges à partir des colonnes FOB
   */
  private calculateSurcharges(row: Record<string, string>): string {
    const surcharges: string[] = [];

    const surchargeFields = [
      { key: 'Documentation (LS et Minimum)', prefix: 'DOC' },
      { key: 'ISPS (LS et Minimum)', prefix: 'ISPS' },
      { key: 'Manutention', prefix: 'HANDLING' },
      { key: 'Solas (LS et Minimum)', prefix: 'SOLAS' },
      { key: 'Douane (LS et Minimum)', prefix: 'CUSTOMS' },
      { key: 'AMS/ACI (LS et Minimum)', prefix: 'AMS_ACI' },
      { key: 'ISF5 (LS et Minimum)', prefix: 'ISF5' },
      { key: 'Frais admin de dangereux (LS et Minimum)', prefix: 'DG_FEE' },
    ];

    surchargeFields.forEach(({ key, prefix }) => {
      if (row[key]) {
        const unit = key === 'Manutention' ? row['Unité de manutention (UP;Tonne)'] || 'UP' : '';
        surcharges.push(`${prefix}:${row[key]}${unit ? ' ' + unit : ''}`);
      }
    });

    return surcharges.join(' | ');
  }

  /**
   * Convertit une ligne FOB FRET vers le format standard
   */
  private convertFobFretRow(row: Record<string, string>, companyName: string): Record<string, any> {
    const currency = row['Devise FRET'] || 'USD';
    const freightRate = parseFloat(row['Taux de FRET (UP)']) || 0;
    const minFreight = parseFloat(row['Minimum FRET (LS)']) || 0;
    const transitDays = parseInt(row['Transit time']) || 0;

    // Calcul des surcharges
    const surchargeDetails = this.calculateSurcharges(row);
    const hasSurcharges = surchargeDetails.length > 0;

    // Dates de validité (90 jours par défaut)
    const validFrom = new Date().toISOString().split('T')[0];
    const validUntil = new Date(Date.now() + 90 * 24 * 60 * 60 * 1000).toISOString().split('T')[0];

    // Volumes et poids standards pour LCL
    const minVolumeCBM = 1;
    const maxVolumeCBM = 20;
    const minWeightKG = 100;
    const maxWeightKG = 20000;

    // Prix par CBM
    const pricePerCBM = freightRate > 0 ? freightRate : minFreight;

    // Prix par KG (estimation: prix CBM / 200 kg/m³)
    const pricePerKG = pricePerCBM > 0 ? (pricePerCBM / 200).toFixed(2) : '0';

    return {
      companyName,
      origin: row['Origine UN code'] || '',
      destination: row['Destination UN code'] || '',
      containerType: 'LCL',
      minVolumeCBM,
      maxVolumeCBM,
      minWeightKG,
      maxWeightKG,
      palletCount: 0,
      pricePerCBM,
      pricePerKG,
      basePriceUSD: currency === 'USD' ? pricePerCBM : 0,
      basePriceEUR: currency === 'EUR' ? pricePerCBM : 0,
      currency,
      hasSurcharges,
      surchargeBAF: '',
      surchargeCAF: '',
      surchargeDetails,
      transitDays,
      validFrom,
      validUntil,
    };
  }

  /**
   * Convertit un CSV FOB FRET vers le format standard
   */
  async convertFobFretToStandard(
    inputPath: string,
    companyName: string
  ): Promise<{ outputPath: string; rowsConverted: number }> {
    this.logger.log(`Converting FOB FRET CSV: ${inputPath}`);

    try {
      // Lire le fichier
      const content = await fs.readFile(inputPath, 'utf-8');
      const lines = content.split('\n').filter(line => line.trim());

      if (lines.length < 2) {
        throw new Error('CSV file is empty or has no data rows');
      }

      // Trouver la ligne d'en-tête réelle (chercher celle avec "Devise FRET")
      let headerLineIndex = 0;
      for (let i = 0; i < Math.min(2, lines.length); i++) {
        const headers = this.parseCSVLine(lines[i]);
        if (this.FOB_FRET_HEADERS.some(h => headers.includes(h))) {
          headerLineIndex = i;
          break;
        }
      }

      // Parse headers
      const headers = this.parseCSVLine(lines[headerLineIndex]);
      this.logger.log(`Found FOB FRET headers at line ${headerLineIndex + 1}`);

      // Parse data rows (commencer après la ligne d'en-tête)
      const dataRows: Record<string, string>[] = [];
      for (let i = headerLineIndex + 1; i < lines.length; i++) {
        const values = this.parseCSVLine(lines[i]);
        const row: Record<string, string> = {};

        headers.forEach((header, index) => {
          row[header] = values[index] || '';
        });

        // Vérifier que la ligne a des données valides
        if (row['Origine UN code'] && row['Destination UN code']) {
          dataRows.push(row);
        }
      }

      this.logger.log(`Found ${dataRows.length} valid data rows`);

      // Convertir les lignes
      const convertedRows = dataRows.map(row => this.convertFobFretRow(row, companyName));

      // Générer le CSV de sortie
      const outputLines: string[] = [this.STANDARD_HEADERS.join(',')];

      convertedRows.forEach(row => {
        const values = this.STANDARD_HEADERS.map(header => {
          const value = row[header];

          // Échapper les virgules et quotes
          if (
            typeof value === 'string' &&
            (value.includes(',') || value.includes('"') || value.includes('\n'))
          ) {
            return `"${value.replace(/"/g, '""')}"`;
          }
          return value;
        });
        outputLines.push(values.join(','));
      });

      // Écrire le fichier converti (garder le chemin absolu)
      const outputPath = inputPath.replace('.csv', '-converted.csv');
      const absoluteOutputPath = path.isAbsolute(outputPath)
        ? outputPath
        : path.resolve(process.cwd(), outputPath);

      await fs.writeFile(absoluteOutputPath, outputLines.join('\n'), 'utf-8');

      this.logger.log(`Conversion completed: ${absoluteOutputPath} (${convertedRows.length} rows)`);

      return {
        outputPath: absoluteOutputPath,
        rowsConverted: convertedRows.length,
      };
    } catch (error) {
      const errorMessage = error instanceof Error ? error.message : 'Unknown error';
      const errorStack = error instanceof Error ? error.stack : undefined;
      this.logger.error(`Error converting CSV: ${errorMessage}`, errorStack);
      throw new Error(`CSV conversion failed: ${errorMessage}`);
    }
  }

  /**
   * Convertit automatiquement un CSV si nécessaire
   */
  async autoConvert(
    inputPath: string,
    companyName: string
  ): Promise<{ convertedPath: string; wasConverted: boolean; rowsConverted?: number }> {
    const format = await this.detectFormat(inputPath);

    this.logger.log(`Detected CSV format: ${format}`);

    if (format === 'STANDARD') {
      return {
        convertedPath: inputPath,
        wasConverted: false,
      };
    }

    if (format === 'FOB_FRET') {
      const result = await this.convertFobFretToStandard(inputPath, companyName);
      return {
        convertedPath: result.outputPath,
        wasConverted: true,
        rowsConverted: result.rowsConverted,
      };
    }

    throw new Error(`Unknown CSV format. Please provide a valid CSV file.`);
  }
}