/// 引用解析器
/// 处理复杂嵌套类型和循环引用检测
library;

import 'package:logging/logging.dart';
import 'package:swagger_generator_flutter/core/models.dart';

/// 引用解析器
/// 负责处理 OpenAPI 文档中的复杂引用关系
class ReferenceResolver {
  ReferenceResolver({this.maxDepth = 50});

  static final Logger _logger = Logger('ReferenceResolver');

  /// 已解析的模型缓存
  final Map<String, ApiModel> _resolvedModels = {};

  /// 当前解析路径（用于循环引用检测）
  final Set<String> _resolutionPath = {};

  /// 原始 JSON 数据缓存
  final Map<String, Map<String, dynamic>> _rawSchemas = {};

  /// 最大解析深度（防止过深的嵌套）
  final int maxDepth;

  /// 当前解析深度
  int _currentDepth = 0;

  /// 解析所有模型，处理复杂引用关系
  Map<String, ApiModel> resolveModels(Map<String, dynamic> componentsJson) {
    final schemasJson =
        componentsJson['schemas'] as Map<String, dynamic>? ?? {};

    // 第一步：缓存所有原始 schema 数据
    _cacheRawSchemas(schemasJson);

    // 第二步：解析所有模型
    final resolvedModels = <String, ApiModel>{};
    for (final schemaName in schemasJson.keys) {
      try {
        final model = resolveModel(schemaName);
        if (model != null) {
          resolvedModels[schemaName] = model;
        }
      } on Object catch (e) {
        _logger.warning('⚠️  解析模型 $schemaName 时发生错误: $e');
        // 创建一个基本的模型作为后备
        resolvedModels[schemaName] = ApiModel(
          name: schemaName,
          description: '解析失败的模型',
          properties: {},
          required: [],
        );
      }
    }

    return resolvedModels;
  }

  /// 缓存原始 schema 数据
  void _cacheRawSchemas(Map<String, dynamic> schemasJson) {
    schemasJson.forEach((name, schemaData) {
      if (schemaData is Map<String, dynamic>) {
        _rawSchemas[name] = schemaData;
      }
    });
  }

  /// 解析单个模型
  ApiModel? resolveModel(String modelName) {
    // 检查是否已经解析过
    if (_resolvedModels.containsKey(modelName)) {
      return _resolvedModels[modelName];
    }

    // 检查循环引用
    if (_resolutionPath.contains(modelName)) {
      _logger
          .warning('🔄 检测到循环引用: ${_resolutionPath.join(' -> ')} -> $modelName');
      return _createCircularReferenceModel(modelName);
    }

    // 检查解析深度
    if (_currentDepth >= maxDepth) {
      _logger.warning('⚠️  达到最大解析深度 $maxDepth，停止解析 $modelName');
      return _createDepthLimitModel(modelName);
    }

    // 获取原始数据
    final schemaData = _rawSchemas[modelName];
    if (schemaData == null) {
      _logger.warning('⚠️  未找到模型定义: $modelName');
      return null;
    }

    // 开始解析
    _resolutionPath.add(modelName);
    _currentDepth++;

    try {
      final model = _parseModelWithContext(modelName, schemaData);
      _resolvedModels[modelName] = model;
      return model;
    } finally {
      _resolutionPath.remove(modelName);
      _currentDepth--;
    }
  }

  /// 在上下文中解析模型
  ApiModel _parseModelWithContext(String name, Map<String, dynamic> json) {
    // 检查是否是枚举类型
    final isEnum = json['enum'] != null;
    if (isEnum) {
      return _parseEnumModel(name, json);
    }

    // 检查组合模式
    if (json['allOf'] != null ||
        json['oneOf'] != null ||
        json['anyOf'] != null) {
      return _parseCompositionModel(name, json);
    }

    // 解析普通对象模型
    return _parseObjectModel(name, json);
  }

  /// 解析枚举模型
  ApiModel _parseEnumModel(String name, Map<String, dynamic> json) {
    final enumValues = List<dynamic>.from((json['enum'] as List?) ?? []);
    final enumType =
        PropertyType.fromString(json['type'] as String? ?? 'string');

    return ApiModel(
      name: name,
      description: json['description'] as String? ?? '',
      properties: {},
      required: [],
      isEnum: true,
      enumValues: enumValues,
      enumType: enumType,
    );
  }

  /// 解析组合模式模型
  ApiModel _parseCompositionModel(String name, Map<String, dynamic> json) {
    // 解析组合模式
    final allOf = _parseSchemaList(json['allOf'] as List<dynamic>? ?? []);
    final oneOf = _parseSchemaList(json['oneOf'] as List<dynamic>? ?? []);
    final anyOf = _parseSchemaList(json['anyOf'] as List<dynamic>? ?? []);

    final notJson = json['not'] as Map<String, dynamic>?;
    final not = notJson != null ? ApiSchema.fromJson(notJson) : null;

    // 解析 discriminator
    final discriminatorJson = json['discriminator'] as Map<String, dynamic>?;
    final discriminator = discriminatorJson != null
        ? ApiDiscriminator.fromJson(discriminatorJson)
        : null;

    // 对于组合模式，我们需要合并属性
    final mergedProperties = <String, ApiProperty>{};
    final mergedRequired = <String>[];

    // 从 allOf 中合并属性
    for (final schema in allOf) {
      _mergeSchemaProperties(schema, mergedProperties, mergedRequired);
    }

    // 如果有直接的 properties，也要合并
    if (json['properties'] != null) {
      final directProperties = _parseProperties(
        json['properties'] as Map<String, dynamic>,
        List<String>.from((json['required'] as List?) ?? []),
      );
      mergedProperties.addAll(directProperties);
      mergedRequired
          .addAll(List<String>.from((json['required'] as List?) ?? []));
    }

    return ApiModel(
      name: name,
      description: json['description'] as String? ?? '',
      properties: mergedProperties,
      required: mergedRequired.toSet().toList(),
      allOf: allOf,
      oneOf: oneOf,
      anyOf: anyOf,
      not: not,
      discriminator: discriminator,
    );
  }

  /// 解析对象模型
  ApiModel _parseObjectModel(String name, Map<String, dynamic> json) {
    final properties = _parseProperties(
      json['properties'] as Map<String, dynamic>? ?? {},
      List<String>.from((json['required'] as List?) ?? []),
    );

    final required = List<String>.from((json['required'] as List?) ?? []);

    return ApiModel(
      name: name,
      description: json['description'] as String? ?? '',
      properties: properties,
      required: required,
    );
  }

  /// 解析 schema 列表
  List<ApiSchema> _parseSchemaList(List<dynamic> schemaList) {
    return schemaList
        .map((schema) => ApiSchema.fromJson(schema as Map<String, dynamic>))
        .toList();
  }

  /// 合并 schema 的属性
  void _mergeSchemaProperties(
    ApiSchema schema,
    Map<String, ApiProperty> targetProperties,
    List<String> targetRequired,
  ) {
    // 如果是引用，解析引用的模型
    if (schema.isReference && schema.reference != null) {
      final referencedModel = resolveModel(schema.reference!);
      if (referencedModel != null) {
        targetProperties.addAll(referencedModel.properties);
        targetRequired.addAll(referencedModel.required);
      }
    } else {
      // 直接合并属性
      targetProperties.addAll(schema.properties);
      targetRequired.addAll(schema.required);
    }
  }

  /// 解析属性
  Map<String, ApiProperty> _parseProperties(
    Map<String, dynamic> propertiesJson,
    List<String> requiredFields,
  ) {
    final properties = <String, ApiProperty>{};

    propertiesJson.forEach((propName, propData) {
      if (propData is Map<String, dynamic>) {
        try {
          final property =
              _parsePropertyWithContext(propName, propData, requiredFields);
          properties[propName] = property;
        } on Object catch (e) {
          _logger.warning('⚠️  解析属性 $propName 时发生错误: $e');
          // 创建一个基本属性作为后备
          properties[propName] = ApiProperty(
            name: propName,
            type: PropertyType.string,
            description: '解析失败的属性',
            required: requiredFields.contains(propName),
          );
        }
      }
    });

    return properties;
  }

  /// 在上下文中解析属性
  ApiProperty _parsePropertyWithContext(
    String name,
    Map<String, dynamic> json,
    List<String> requiredFields,
  ) {
    // 使用现有的 ApiProperty.fromJson，但在循环引用检测的上下文中
    return ApiProperty.fromJson(name, json, requiredFields);
  }

  /// 创建循环引用模型
  ApiModel _createCircularReferenceModel(String modelName) {
    return ApiModel(
      name: modelName,
      description: '循环引用模型 - 为避免无限递归而创建的占位符',
      properties: {},
      required: [],
    );
  }

  /// 创建深度限制模型
  ApiModel _createDepthLimitModel(String modelName) {
    return ApiModel(
      name: modelName,
      description: '深度限制模型 - 达到最大解析深度而创建的占位符',
      properties: {},
      required: [],
    );
  }

  /// 清理缓存
  void clearCache() {
    _resolvedModels.clear();
    _resolutionPath.clear();
    _rawSchemas.clear();
    _currentDepth = 0;
  }
}