import 'dart:convert';
import 'package:http/http.dart' as http;

/// Result of a registration API call.
class RegistrationResult {
  final bool success;
  final bool isDuplicate;
  final bool isAlreadyOffShelf;
  final bool isOffShelfSuccess;
  final String? errorMessage;
  final Map<String, dynamic>? duplicateInfo;
  final Map<String, dynamic>? conflictInfo;

  RegistrationResult({
    required this.success,
    this.isDuplicate = false,
    this.isAlreadyOffShelf = false,
    this.isOffShelfSuccess = false,
    this.errorMessage,
    this.duplicateInfo,
    this.conflictInfo,
  });

  factory RegistrationResult.ok() => RegistrationResult(success: true);

  factory RegistrationResult.offShelfSuccess() =>
      RegistrationResult(success: true, isOffShelfSuccess: true);

  factory RegistrationResult.duplicate(Map<String, dynamic> info) =>
      RegistrationResult(
        success: false,
        isDuplicate: true,
        duplicateInfo: info,
        conflictInfo: info,
      );

  factory RegistrationResult.alreadyOffShelf(Map<String, dynamic> info) =>
      RegistrationResult(
        success: false,
        isAlreadyOffShelf: true,
        errorMessage: info['message']?.toString() ?? '该总排号已下架至转运区域，不可重新上架',
        conflictInfo: info,
      );

  factory RegistrationResult.error(String message) =>
      RegistrationResult(success: false, errorMessage: message);
}

// === 装箱模块数据类 ===

/// 箱号内单个总排号明细
class BoxItemData {
  final int? boxItemId;
  final String zongpaiNo;
  final String? workOrderNo;
  final int quantity;
  final int? totalQuantity;

  BoxItemData({
    this.boxItemId,
    required this.zongpaiNo,
    this.workOrderNo,
    required this.quantity,
    this.totalQuantity,
  });

  factory BoxItemData.fromJson(Map<String, dynamic> json) {
    return BoxItemData(
      boxItemId: json['box_item_id'] as int?,
      zongpaiNo: json['zongpai_no'] as String,
      workOrderNo: json['work_order_no']?.toString(),
      quantity: json['quantity'] as int,
      totalQuantity: json['total_quantity'] as int?,
    );
  }
}

/// 箱号明细
class BoxDetailData {
  final int boxNo;
  final List<BoxItemData> items;

  BoxDetailData({required this.boxNo, required this.items});

  factory BoxDetailData.fromJson(Map<String, dynamic> json) {
    final items =
        (json['items'] as List<dynamic>?)
            ?.map((i) => BoxItemData.fromJson(i as Map<String, dynamic>))
            .toList() ??
        [];
    return BoxDetailData(boxNo: json['box_no'] as int, items: items);
  }
}

/// 当前总排号已分配的装箱明细
class CurrentZongpaiBoxData {
  final int boxItemId;
  final int boxNo;
  final int quantity;

  CurrentZongpaiBoxData({
    required this.boxItemId,
    required this.boxNo,
    required this.quantity,
  });

  factory CurrentZongpaiBoxData.fromJson(Map<String, dynamic> json) {
    return CurrentZongpaiBoxData(
      boxItemId: json['box_item_id'] as int,
      boxNo: json['box_no'] as int,
      quantity: json['quantity'] as int,
    );
  }
}

/// 装箱信息查询结果
class BoxInfoResult {
  final bool success;
  final String? errorMessage;
  final String? zongpaiNo;
  final String? paichanNo;
  final String? workOrderNo;
  final int? quantity;
  final List<CurrentZongpaiBoxData> currentZongpaiBoxes;
  final List<BoxDetailData> existingBoxes;
  final int maxBoxNo;
  final int suggestedBoxNo;

  BoxInfoResult({
    required this.success,
    this.errorMessage,
    this.zongpaiNo,
    this.paichanNo,
    this.workOrderNo,
    this.quantity,
    this.currentZongpaiBoxes = const [],
    this.existingBoxes = const [],
    this.maxBoxNo = 0,
    this.suggestedBoxNo = 1,
  });

  factory BoxInfoResult.ok(Map<String, dynamic> json) {
    final boxes =
        (json['existing_boxes'] as List<dynamic>?)
            ?.map((b) => BoxDetailData.fromJson(b as Map<String, dynamic>))
            .toList() ??
        [];
    final currentBoxes =
        (json['current_zongpai_boxes'] as List<dynamic>?)
            ?.map(
              (b) => CurrentZongpaiBoxData.fromJson(b as Map<String, dynamic>),
            )
            .toList() ??
        [];
    return BoxInfoResult(
      success: true,
      zongpaiNo: json['zongpai_no'] as String?,
      paichanNo: json['paichan_no'] as String?,
      workOrderNo: json['work_order_no']?.toString(),
      quantity: json['quantity'] as int?,
      currentZongpaiBoxes: currentBoxes,
      existingBoxes: boxes,
      maxBoxNo: json['max_box_no'] as int? ?? 0,
      suggestedBoxNo: json['suggested_box_no'] as int? ?? 1,
    );
  }

  factory BoxInfoResult.error(String message) {
    return BoxInfoResult(success: false, errorMessage: message);
  }
}

/// 装箱保存结果
class BoxSaveResult {
  final bool success;
  final bool isDuplicate;
  final String? errorMessage;
  final String? errorCode;
  final int? boxItemId;
  final String? paichanNo;
  final String? zongpaiNo;
  final int? boxNo;
  final int? quantity;

  BoxSaveResult({
    required this.success,
    this.isDuplicate = false,
    this.errorMessage,
    this.errorCode,
    this.boxItemId,
    this.paichanNo,
    this.zongpaiNo,
    this.boxNo,
    this.quantity,
  });

  factory BoxSaveResult.ok(Map<String, dynamic> json) {
    return BoxSaveResult(
      success: true,
      boxItemId: json['box_item_id'] as int?,
      paichanNo: json['paichan_no'] as String?,
      zongpaiNo: json['zongpai_no'] as String?,
      boxNo: json['box_no'] as int?,
      quantity: json['quantity'] as int?,
    );
  }

  factory BoxSaveResult.duplicate(Map<String, dynamic> json) {
    return BoxSaveResult(
      success: false,
      isDuplicate: true,
      errorCode: json['error_code']?.toString(),
      errorMessage: json['message']?.toString(),
      paichanNo: json['paichan_no'] as String?,
      zongpaiNo: json['zongpai_no'] as String?,
      boxNo: json['box_no'] as int?,
    );
  }

  factory BoxSaveResult.error(String message) {
    return BoxSaveResult(success: false, errorMessage: message);
  }
}

class BoxDeleteResult {
  final bool success;
  final String? errorMessage;

  BoxDeleteResult({required this.success, this.errorMessage});
}

class ApiService {
  final http.Client _client;
  final Duration timeout;

  ApiService({http.Client? client, this.timeout = const Duration(seconds: 5)})
    : _client = client ?? http.Client();

  /// Submit a shelf registration (上架登记).
  Future<RegistrationResult> registerLocation({
    required String baseUrl,
    required String zongpaiNo,
    required String locationCode,
  }) async {
    final uri = Uri.parse('$baseUrl/CargoTrace/location');
    try {
      final response = await _client
          .post(
            uri,
            headers: {'Content-Type': 'application/json'},
            body: jsonEncode({
              'zongpai_no': zongpaiNo,
              'location_code': locationCode,
            }),
          )
          .timeout(timeout);

      switch (response.statusCode) {
        case 200:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          if (body['previous_location'] != null) {
            return RegistrationResult.offShelfSuccess();
          }
          return RegistrationResult.ok();
        case 400:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          final msg = body['message']?.toString() ?? '请求参数错误';
          return RegistrationResult.error(msg);
        case 409:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          final errorCode = body['error_code']?.toString();
          if (errorCode == 'DUPLICATE_LOCATION') {
            return RegistrationResult.duplicate(body);
          }
          if (errorCode == 'ALREADY_OFF_SHELF') {
            return RegistrationResult.alreadyOffShelf(body);
          }
          final msg = body['message']?.toString() ?? '提交失败';
          return RegistrationResult.error(msg);
        default:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          final msg =
              body['message'] ??
              body['error'] ??
              'Unknown error (${response.statusCode})';
          return RegistrationResult.error(msg.toString());
      }
    } catch (e) {
      return RegistrationResult.error('网络异常，请检查网络连接');
    }
  }

  /// 查询装箱信息 — GET /CargoTrace/box/info
  Future<BoxInfoResult> fetchBoxInfo({
    required String baseUrl,
    required String zongpaiNo,
  }) async {
    final uri = Uri.parse(
      '$baseUrl/CargoTrace/box/info',
    ).replace(queryParameters: {'zongpai_no': zongpaiNo});
    try {
      final response = await _client
          .get(uri, headers: {'Content-Type': 'application/json'})
          .timeout(timeout);

      switch (response.statusCode) {
        case 200:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          return BoxInfoResult.ok(body);
        case 400:
          return BoxInfoResult.error('无效的总排号格式');
        case 404:
          return BoxInfoResult.error('未找到该总排号对应的排产号信息');
        default:
          return BoxInfoResult.error('查询失败 (${response.statusCode})');
      }
    } catch (e) {
      return BoxInfoResult.error('网络异常，请检查网络连接');
    }
  }

  /// 保存装箱记录 — POST /CargoTrace/box
  Future<BoxSaveResult> saveBoxRecord({
    required String baseUrl,
    required String zongpaiNo,
    required int boxNo,
    required int quantity,
    required String boxMode,
  }) async {
    final uri = Uri.parse('$baseUrl/CargoTrace/box');
    try {
      final response = await _client
          .post(
            uri,
            headers: {'Content-Type': 'application/json'},
            body: jsonEncode({
              'zongpai_no': zongpaiNo,
              'box_no': boxNo,
              'quantity': quantity,
              'box_mode': boxMode,
            }),
          )
          .timeout(timeout);

      switch (response.statusCode) {
        case 200:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          return BoxSaveResult.ok(body);
        case 400:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          final msg = body['message']?.toString() ?? '请求参数错误';
          return BoxSaveResult.error(msg);
        case 409:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          return BoxSaveResult.duplicate(body);
        case 404:
          return BoxSaveResult.error('未找到该总排号对应的排产号信息');
        default:
          return BoxSaveResult.error('提交失败 (${response.statusCode})');
      }
    } catch (e) {
      return BoxSaveResult.error('网络异常，请检查网络连接');
    }
  }

  /// 更新装箱明细 — PATCH /CargoTrace/box/{boxItemId}
  Future<BoxSaveResult> updateBoxRecord({
    required String baseUrl,
    required int boxItemId,
    required int boxNo,
    required int quantity,
    String boxMode = 'one-to-many',
  }) async {
    final uri = Uri.parse('$baseUrl/CargoTrace/box/$boxItemId');
    try {
      final response = await _client
          .patch(
            uri,
            headers: {'Content-Type': 'application/json'},
            body: jsonEncode({
              'box_no': boxNo,
              'quantity': quantity,
              'box_mode': boxMode,
            }),
          )
          .timeout(timeout);

      switch (response.statusCode) {
        case 200:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          return BoxSaveResult.ok(body);
        case 400:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          final msg = body['message']?.toString() ?? '请求参数错误';
          return BoxSaveResult.error(msg);
        case 409:
          final body = jsonDecode(response.body) as Map<String, dynamic>;
          return BoxSaveResult.duplicate(body);
        case 404:
          return BoxSaveResult.error('指定装箱明细不存在');
        default:
          return BoxSaveResult.error('修改失败 (${response.statusCode})');
      }
    } catch (e) {
      return BoxSaveResult.error('网络异常，请检查网络连接');
    }
  }

  /// 删除装箱明细 — DELETE /CargoTrace/box/{boxItemId}
  Future<BoxDeleteResult> deleteBoxRecord({
    required String baseUrl,
    required int boxItemId,
  }) async {
    final uri = Uri.parse('$baseUrl/CargoTrace/box/$boxItemId');
    try {
      final response = await _client
          .delete(uri, headers: {'Content-Type': 'application/json'})
          .timeout(timeout);

      switch (response.statusCode) {
        case 200:
          return BoxDeleteResult(success: true);
        case 404:
          return BoxDeleteResult(success: false, errorMessage: '指定装箱明细不存在');
        default:
          return BoxDeleteResult(
            success: false,
            errorMessage: '删除失败 (${response.statusCode})',
          );
      }
    } catch (e) {
      return BoxDeleteResult(success: false, errorMessage: '网络异常，请检查网络连接');
    }
  }

  /// Test connectivity by making a HEAD request to the base URL.
  Future<bool> testConnection(String baseUrl) async {
    try {
      final uri = Uri.parse(baseUrl);
      final response = await _client.head(uri).timeout(timeout);
      return response.statusCode < 500;
    } catch (_) {
      return false;
    }
  }
}