import 'dart:typed_data';
import 'package:flutter/services.dart';
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart' as pw;
import 'package:em2rp/services/qr_code_service.dart';

/// Formats d'étiquettes QR disponibles
enum QRLabelFormat { small, medium, large }

/// Configuration pour la génération de PDF
class PDFGeneratorConfig {
  final double qrCodeSize;
  final int itemsPerPage;
  final bool withProgress;

  const PDFGeneratorConfig({
    required this.qrCodeSize,
    required this.itemsPerPage,
    this.withProgress = false,
  });

  static const small = PDFGeneratorConfig(
    qrCodeSize: 150,
    itemsPerPage: 20,
  );

  static const medium = PDFGeneratorConfig(
    qrCodeSize: 250,
    itemsPerPage: 6,
  );

  static const large = PDFGeneratorConfig(
    qrCodeSize: 300,
    itemsPerPage: 10,
  );

  static PDFGeneratorConfig fromFormat(QRLabelFormat format) {
    switch (format) {
      case QRLabelFormat.small:
        return small;
      case QRLabelFormat.medium:
        return medium;
      case QRLabelFormat.large:
        return large;
    }
  }
}

/// Service UNIQUE et optimisé pour la génération de PDFs avec QR codes
/// Remplace PDFGeneratorService, ContainerPDFGeneratorService et UnifiedPDFGeneratorService
class PDFService {
  static Uint8List? _cachedLogoBytes;
  static bool _logoLoadAttempted = false;

  /// Charge le logo en cache une seule fois
  static Future<void> _ensureLogoLoaded() async {
    if (_logoLoadAttempted) return;
    _logoLoadAttempted = true;

    try {
      final logoData = await rootBundle.load('assets/logos/LowQRectangleLogoBlack.png');
      _cachedLogoBytes = logoData.buffer.asUint8List();
    } catch (e) {
      _cachedLogoBytes = Uint8List(0);
    }
  }

  /// Tronque un texte
  static String _truncate(String text, int max) {
    return text.length <= max ? text : '${text.substring(0, max - 3)}...';
  }

  /// Génère un PDF avec QR codes pour n'importe quel type d'objet
  /// 
  /// [items] : Liste des objets à générer
  /// [format] : Format des étiquettes (small, medium, large)
  /// [getId] : Fonction pour obtenir l'ID unique
  /// [getTitle] : Fonction pour obtenir le titre (optionnel)
  /// [getDetails] : Fonction pour obtenir les détails (optionnel, seulement pour large)
  /// [onProgress] : Callback de progression (optionnel)
  static Future<Uint8List> generatePDF<T>({
    required List<T> items,
    required QRLabelFormat format,
    required String Function(T) getId,
    String Function(T)? getTitle,
    List<String> Function(T)? getDetails,
    Function(int current, int total)? onProgress,
  }) async {
    if (items.isEmpty) {
      throw Exception('La liste d\'items est vide');
    }

    final config = PDFGeneratorConfig.fromFormat(format);
    final pdf = pw.Document();

    // Pré-charger le logo pour format large
    if (format == QRLabelFormat.large) {
      await _ensureLogoLoaded();
    }

    // Générer tous les QR codes en bulk avec progression
    final allQRImages = await QRCodeService.generateBulkQRCodes(
      items.map((item) => getId(item)).toList(),
      size: config.qrCodeSize,
      withLogo: false,
      useCache: true,
      onProgress: onProgress,
    );

    // Générer les pages
    switch (format) {
      case QRLabelFormat.small:
        _addSmallLabels(pdf, items, getId, allQRImages, config);
        break;
      case QRLabelFormat.medium:
        _addMediumLabels(pdf, items, getId, getTitle, allQRImages, config);
        break;
      case QRLabelFormat.large:
        _addLargeLabels(pdf, items, getId, getTitle, getDetails, allQRImages, config);
        break;
    }

    return pdf.save();
  }

  // ========================================================================
  // PETITS LABELS (2x2 cm, 20 par page)
  // ========================================================================
  static void _addSmallLabels<T>(
    pw.Document pdf,
    List<T> items,
    String Function(T) getId,
    List<Uint8List> qrImages,
    PDFGeneratorConfig config,
  ) {
    const qrSize = 56.69; // 2cm

    for (int pageStart = 0; pageStart < items.length; pageStart += config.itemsPerPage) {
      final pageItems = items.skip(pageStart).take(config.itemsPerPage).toList();
      final pageQRs = qrImages.skip(pageStart).take(config.itemsPerPage).toList();

      pdf.addPage(
        pw.Page(
          pageFormat: PdfPageFormat.a4,
          margin: const pw.EdgeInsets.all(20),
          build: (_) => pw.Wrap(
            spacing: 10,
            runSpacing: 10,
            children: List.generate(pageItems.length, (i) {
              return pw.Container(
                width: qrSize,
                height: qrSize + 20,
                child: pw.Column(
                  mainAxisAlignment: pw.MainAxisAlignment.center,
                  children: [
                    pw.Image(pw.MemoryImage(pageQRs[i])),
                    pw.SizedBox(height: 2),
                    pw.Text(
                      getId(pageItems[i]),
                      style: pw.TextStyle(fontSize: 6, fontWeight: pw.FontWeight.bold),
                      textAlign: pw.TextAlign.center,
                    ),
                  ],
                ),
              );
            }),
          ),
        ),
      );
    }
  }

  // ========================================================================
  // LABELS MOYENS (4x4 cm, 6 par page)
  // ========================================================================
  static void _addMediumLabels<T>(
    pw.Document pdf,
    List<T> items,
    String Function(T) getId,
    String Function(T)? getTitle,
    List<Uint8List> qrImages,
    PDFGeneratorConfig config,
  ) {
    const qrSize = 113.39; // 4cm

    for (int pageStart = 0; pageStart < items.length; pageStart += config.itemsPerPage) {
      final pageItems = items.skip(pageStart).take(config.itemsPerPage).toList();
      final pageQRs = qrImages.skip(pageStart).take(config.itemsPerPage).toList();

      pdf.addPage(
        pw.Page(
          pageFormat: PdfPageFormat.a4,
          margin: const pw.EdgeInsets.all(20),
          build: (_) => pw.Wrap(
            spacing: 20,
            runSpacing: 20,
            children: List.generate(pageItems.length, (i) {
              return pw.Container(
                width: qrSize,
                height: qrSize + 30,
                child: pw.Column(
                  mainAxisAlignment: pw.MainAxisAlignment.center,
                  children: [
                    pw.Image(pw.MemoryImage(pageQRs[i])),
                    pw.SizedBox(height: 4),
                    pw.Text(
                      getId(pageItems[i]),
                      style: pw.TextStyle(fontSize: 10, fontWeight: pw.FontWeight.bold),
                      textAlign: pw.TextAlign.center,
                    ),
                    if (getTitle != null) ...[
                      pw.SizedBox(height: 2),
                      pw.Text(
                        _truncate(getTitle(pageItems[i]), 25),
                        style: const pw.TextStyle(fontSize: 8, color: PdfColors.grey700),
                        textAlign: pw.TextAlign.center,
                      ),
                    ],
                  ],
                ),
              );
            }),
          ),
        ),
      );
    }
  }

  // ========================================================================
  // GRANDS LABELS (avec détails, 10 par page)
  // ========================================================================
  static void _addLargeLabels<T>(
    pw.Document pdf,
    List<T> items,
    String Function(T) getId,
    String Function(T)? getTitle,
    List<String> Function(T)? getDetails,
    List<Uint8List> qrImages,
    PDFGeneratorConfig config,
  ) {
    const qrSize = 100.0;

    for (int pageStart = 0; pageStart < items.length; pageStart += config.itemsPerPage) {
      final pageItems = items.skip(pageStart).take(config.itemsPerPage).toList();
      final pageQRs = qrImages.skip(pageStart).take(config.itemsPerPage).toList();

      pdf.addPage(
        pw.Page(
          pageFormat: PdfPageFormat.a4,
          margin: const pw.EdgeInsets.all(20),
          build: (_) => pw.Wrap(
            spacing: 10,
            runSpacing: 10,
            children: List.generate(pageItems.length, (i) {
              final item = pageItems[i];
              return pw.Container(
                width: 260,
                height: 120,
                decoration: pw.BoxDecoration(
                  border: pw.Border.all(color: PdfColors.grey400),
                  borderRadius: pw.BorderRadius.circular(4),
                ),
                padding: const pw.EdgeInsets.all(8),
                child: pw.Row(
                  crossAxisAlignment: pw.CrossAxisAlignment.start,
                  children: [
                    // QR Code
                    pw.Container(
                      width: qrSize,
                      height: qrSize,
                      child: pw.Image(pw.MemoryImage(pageQRs[i])),
                    ),
                    pw.SizedBox(width: 8),
                    // Détails
                    pw.Expanded(
                      child: pw.Column(
                        crossAxisAlignment: pw.CrossAxisAlignment.start,
                        children: [
                          // Logo
                          if (_cachedLogoBytes != null && _cachedLogoBytes!.isNotEmpty)
                            pw.Center(
                              child: pw.Container(
                                height: 25,
                                margin: const pw.EdgeInsets.only(bottom: 6),
                                child: pw.Image(pw.MemoryImage(_cachedLogoBytes!)),
                              ),
                            ),
                          // Titre
                          if (getTitle != null) ...[
                            pw.SizedBox(height: 2),
                            pw.Text(
                              _truncate(getTitle(item), 20),
                              style: pw.TextStyle(fontSize: 10, fontWeight: pw.FontWeight.bold),
                              maxLines: 2,
                            ),
                          ],
                          // ID
                          pw.SizedBox(height: 2),
                          pw.Text(
                            getId(item),
                            style: const pw.TextStyle(fontSize: 8, color: PdfColors.grey700),
                            maxLines: 1,
                          ),
                          // Détails supplémentaires
                          if (getDetails != null) ...[
                            pw.SizedBox(height: 4),
                            ...getDetails(item).take(5).map((line) {
                              return pw.Padding(
                                padding: const pw.EdgeInsets.only(bottom: 1),
                                child: pw.Text(
                                  _truncate(line, 25),
                                  style: const pw.TextStyle(fontSize: 6, color: PdfColors.grey800),
                                ),
                              );
                            }),
                          ],
                        ],
                      ),
                    ),
                  ],
                ),
              );
            }),
          ),
        ),
      );
    }
  }

  /// Nettoie le cache (logo)
  static void clearCache() {
    _cachedLogoBytes = null;
    _logoLoadAttempted = false;
  }
}