module Schemable
  # The AttributeSchemaGenerator class is responsible for generating JSON schemas for model attributes.
  # It includes methods for generating the overall schema and individual attribute schemas.
  #
  # @see Schemable
  class AttributeSchemaGenerator
    attr_reader :model_definition, :configuration, :model, :schema_modifier, :response

    # Initializes a new AttributeSchemaGenerator instance.
    #
    # @param model_definition [ModelDefinition] The model definition to generate the schema for.
    # @example
    #   generator = AttributeSchemaGenerator.new(model_definition)
    def initialize(model_definition)
      @model_definition = model_definition
      @model = model_definition.model
      @configuration = Schemable.configuration
      @schema_modifier = SchemaModifier.new
      @response = nil
    end

    # Generates the JSON schema for the model attributes.
    #
    # @return [Hash] The generated schema.
    # @example
    #   schema = generator.generate
    def generate
      schema = {
        type: :object,
        properties: @model_definition.attributes.index_with do |attr|
          generate_attribute_schema(attr)
        end
      }

      # Rename enum attributes to remove the suffix or prefix if mongoid is used
      if @configuration.orm == :mongoid
        schema[:properties].transform_keys! do |key|
          key.to_s.gsub(@configuration.enum_prefix_for_simple_enum || @configuration.enum_suffix_for_simple_enum, '')
        end
      end

      # modify the schema to include additional response relations
      schema = @schema_modifier.add_properties(schema, @model_definition.additional_response_attributes, 'properties')

      # modify the schema to exclude response relations
      @model_definition.excluded_response_attributes.each do |key|
        schema = @schema_modifier.delete_properties(schema, "properties.#{key}")
      end

      schema
    end

    # Generates the JSON schema for a specific attribute.
    #
    # @param attribute [Symbol, String] The attribute to generate the schema for.
    # @return [Hash] The generated schema for the attribute.
    # @example
    #   attribute_schema = generator.generate_attribute_schema(:attribute_name)
    def generate_attribute_schema(attribute)
      if @configuration.orm == :mongoid
        # Get the column hash for the attribute
        attribute_hash = @model.fields[attribute.to_s]

        # Check if this attribute has a custom JSON Schema definition
        return @model_definition.array_types[attribute] if @model_definition.array_types.keys.include?(attribute.to_sym)
        return @model_definition.additional_response_attributes[attribute] if @model_definition.additional_response_attributes.keys.include?(attribute)

        # Check if this is an array attribute
        return @configuration.type_mapper(:array) if attribute_hash.try(:[], 'options').try(:[], 'type') == 'Array'

        # Check if this is an enum attribute
        @response = if attribute_hash.name.end_with?('_cd')
                      @configuration.type_mapper(:string)
                    else
                      # Map the column type to a JSON Schema type if none of the above conditions are met
                      @configuration.type_mapper(attribute_hash.try(:type).to_s.downcase.to_sym)
                    end

      elsif @configuration.orm == :active_record
        # Get the column hash for the attribute
        attribute_hash = @model.columns_hash[attribute.to_s]

        # Check if this attribute has a custom JSON Schema definition
        return @model_definition.array_types[attribute] if @model_definition.array_types.keys.include?(attribute.to_sym)
        return @model_definition.additional_response_attributes[attribute] if @model_definition.additional_response_attributes.keys.include?(attribute)

        # Check if this is an array attribute
        return @configuration.type_mapper(:array) if attribute_hash.as_json.try(:[], 'sql_type_metadata').try(:[], 'sql_type').include?('[]')

        # Map the column type to a JSON Schema type if none of the above conditions are met
        @response = @configuration.type_mapper(attribute_hash.try(:type))

      else
        raise 'ORM not supported'
      end

      # If the attribute is nullable, modify the schema accordingly
      return @schema_modifier.add_properties(@response, { nullable: true }, '.') if @response && @model_definition.nullable_attributes.include?(attribute)

      # If attribute is an enum, modify the schema accordingly
      if @configuration.custom_defined_enum_method && @model.respond_to?(@configuration.custom_defined_enum_method)
        defined_enums = @model.send(@configuration.custom_defined_enum_method)
        enum_attribute = attribute.to_s.gsub(@configuration.enum_prefix_for_simple_enum || @configuration.enum_suffix_for_simple_enum, '').to_s
        return @schema_modifier.add_properties(@response, { enum: defined_enums[enum_attribute].keys }, '.') if @response && defined_enums[enum_attribute].present?
      elsif @model.respond_to?(:defined_enums)
        return @schema_modifier.add_properties(@response, { enum: @model.defined_enums[attribute.to_s].keys }, '.') if @response && @model.defined_enums.key?(attribute.to_s)
      end

      return @response unless @response.nil?

      # If we haven't found a schema type yet, try to infer it from the type of the attribute's value in the instance data
      if @configuration.use_serialized_instance
        serialized_instance = @model_definition.serialized_instance

        type_from_instance = serialized_instance.as_json['data']['attributes'][attribute.to_s.camelize(:lower)]&.class&.name&.downcase

        @response = @configuration.type_mapper(type_from_instance) if type_from_instance.present?

        return @response unless @response.nil?
      end

      # If we still haven't found a schema type, default to object
      @configuration.type_mapper(:object)
    rescue NoMethodError
      # Log a warning if the attribute does not exist on the @model
      Rails.logger.warn("\e[33mWARNING: #{@model} does not have an attribute named \e[31m#{attribute}\e[0m")
      {}
    end
  end
end