module Foobara
  module Types
    # TODO: move casting interface to here?
    class Type < Value::Processor::Pipeline
      include Concerns::SupportedProcessorRegistration
      include Concerns::Reflection
      include IsManifestable

      foobara_instances_are_namespaces!

      class << self
        def requires_declaration_data?
          true
        end
      end

      # TODO: needed/useful transformers/validators to implement:
      #
      # allow_empty (validation at attribute level)
      # allow_nil (validation at attribute level)
      # one_of (validation at attribute level)

      attr_accessor :base_type,
                    :casters,
                    :transformers,
                    :validators,
                    :element_processors,
                    :structure_count,
                    :element_types,
                    :element_type,
                    :raw_declaration_data,
                    :name,
                    :target_classes,
                    :description
      attr_reader :type_symbol

      def initialize(
        *,
        target_classes:,
        base_type:,
        description: nil,
        name: "anonymous",
        casters: [],
        transformers: [],
        validators: [],
        element_processors: nil,
        element_type: nil,
        element_types: nil,
        structure_count: nil,
        **opts
      )
        self.base_type = base_type
        self.description = description
        self.casters = [*casters, *base_type&.casters]
        self.transformers = [*transformers, *base_type&.transformers]
        self.validators = [*validators, *base_type&.validators]
        self.element_processors = [*element_processors, *base_type&.element_processors]

        self.structure_count = structure_count
        # TODO: combine these maybe with the term "children_types"?
        self.element_types = element_types
        self.element_type = element_type
        self.name = name
        self.target_classes = Util.array(target_classes)

        super(*, **opts.merge(processors:, prioritize: false))

        validate_processors!
      end

      def validate_processors!
        all = [casters, transformers, validators, element_processors]

        all.each do |processor_group|
          processor_group.each.with_index do |processor, index|
            if processor.requires_parent_declaration_data?
              processor_group[index] = processor.dup_processor(parent_declaration_data: declaration_data)
            end
          end

          processor_group.group_by(&:symbol).each_pair do |symbol, members|
            if members.size > 1
              if members.map { |m| m.class.name }.uniq.size == members.size
                members[1..].each do |member|
                  processor_group.delete(member)
                end
              else
                # :nocov:
                raise "Type #{name} has multiple processors with symbol #{symbol}"
                # :nocov:
              end
            end
          end
        end
      end

      def target_class
        if target_classes.empty?
          # :nocov:
          raise "No target classes"
          # :nocov:
        elsif target_classes.size > 1
          # :nocov:
          raise "Cannot use #target_class because this type has multiple target_classes"
          # :nocov:
        end

        target_classes.first
      end

      def extends?(type)
        case type
        when Type
          extends_type?(type)
        when Symbol, String
          concrete_type = created_in_namespace.foobara_lookup_type(type)
          if concrete_type.nil?
            # :nocov:
            raise "No type found for #{type}"
            # :nocov:
          end

          extends_type?(concrete_type)
        else
          # :nocov:
          raise ArgumentError, "Expected a Type or a Symbol/String, but got #{type.inspect}"
          # :nocov:
        end
      end

      def extends_type?(type)
        return true if self == type

        unless type
          # :nocov:
          raise ArgumentError, "Expected a type but got nil"
          # :nocov:
        end

        if registered?
          if type.registered?
            if type.foobara_manifest_reference == foobara_manifest_reference
              return true
            end
          end
        end

        base_type&.extends_type?(type)
      end

      def type_symbol=(type_symbol)
        @scoped_path ||= type_symbol.to_s.split("::")
        @type_symbol = type_symbol.to_sym
      end

      def full_type_symbol
        return @full_type_symbol if defined?(@full_type_symbol)

        @full_type_symbol ||= if scoped_path_set?
                                scoped_full_name.to_sym
                              end
      end

      def processors
        [
          value_caster,
          value_transformer,
          value_validator,
          element_processor
        ].compact
      end

      def value_caster
        # TODO: how can declaration_data be blank? That seems really strange...
        Value::Processor::Casting.new({ cast_to: declaration_data }, casters:, target_classes:)
      end

      def applicable?(value)
        value_caster.can_cast?(value)
      end

      foobara_delegate :needs_cast?, to: :value_caster

      def cast(value)
        value_caster.process_value(value)
      end

      def cast!(value)
        value_caster.process_value!(value)
      end

      # TODO: an interesting thought... we have Processor and then a subclass of Processor and then an instance of
      # processor that encapsulates the declaration_data for that processor. But then we pass `value` to every
      # method in the instance of the processor as needed. This means it can't really memoize stuff. Should we create
      # an instance of something from the instance of the processor and then ask it questions?? TODO: try this
      def value_transformer
        if transformers && !transformers.empty?
          Value::Processor::Pipeline.new(processors: transformers)
        end
      end

      # TODO: figure out how to safely memoize stuff so like this for performance reasons
      # A good way, but potentially a decent amount of work, is to have a class that takes value to its initialize
      # method.
      def value_validator
        if validators && !validators.empty?
          Value::Processor::Pipeline.new(processors: validators)
        end
      end

      def element_processor
        if element_processors && !element_processors.empty?
          Value::Processor::Pipeline.new(processors: element_processors)
        end
      end

      # TODO: some way of memoizing these values? Would need to introduce a new class that takes the value to its
      # constructor
      def validation_errors(value)
        value = cast!(value)
        if value_transformer
          value = value_transformer.process_value!(value)
        end

        if value_validator
          value_validator.process_value(value).errors
        else
          []
        end
      end

      def full_type_name
        scoped_full_name
      end

      def reference_or_declaration_data(declaration_data = self.declaration_data)
        if registered?
          # TODO: we should just use the symbol and nothing else in this context instead of a hash with 1 element.
          { type: foobara_manifest_reference.to_sym }
        else
          declaration_data
        end
      end

      # TODO: put this somewhere else
      def foobara_manifest_reference
        scoped_full_name
      end

      def foobara_manifest(to_include: Set.new)
        types = []

        types_depended_on.each do |dependent_type|
          if dependent_type.registered?
            types << dependent_type.foobara_manifest_reference
            to_include << dependent_type
          end
        end

        possible_errors_manifests = possible_errors.map do |possible_error|
          [possible_error.key.to_s, possible_error.foobara_manifest(to_include:)]
        end.sort.to_h

        h = Util.remove_blank(
          name:,
          target_classes: target_classes.map(&:name).sort,
          declaration_data:,
          types_depended_on: types.sort,
          possible_errors: possible_errors_manifests
        ).merge(description:, base_type: base_type&.full_type_name&.to_sym)

        h.merge!(
          supported_processor_manifest(to_include).merge(
            Util.remove_blank(processors: processor_manifest(to_include))
          )
        )

        target_classes.sort_by(&:name).each do |target_class|
          if target_class.respond_to?(:foobara_manifest)
            h.merge!(target_class.foobara_manifest(to_include:))
          end
        end

        super.merge(h)
      end

      def supported_processor_manifest(to_include)
        supported_casters = []
        supported_transformers = []
        supported_validators = []
        supported_processors = []

        all_supported_processor_classes.each do |processor_class|
          to_include << processor_class

          target = if processor_class < Value::Caster
                     supported_casters
                   elsif processor_class < Value::Validator
                     supported_validators
                   elsif processor_class < Value::Transformer
                     supported_transformers
                   else
                     supported_processors
                   end

          target << processor_class.foobara_manifest_reference
        end

        Util.remove_blank(
          supported_casters: supported_casters.sort,
          supported_transformers: supported_transformers.sort,
          supported_validators: supported_validators.sort,
          supported_processors: supported_processors.sort
        )
      end

      def processor_manifest(to_include)
        casters_manifest = []
        transformers_manifest = []
        validators_manifest = []
        caster_classes_manifest = []
        transformer_classes_manifest = []
        validator_classes_manifest = []

        casters.each do |caster|
          klass = caster.class
          to_include << klass
          caster_classes_manifest << klass.foobara_manifest_reference

          if caster.scoped_path_set?
            to_include << caster
            casters_manifest << caster.foobara_manifest_reference
          end
        end

        transformers.each do |transformer|
          klass = transformer.class
          to_include << klass
          transformer_classes_manifest << klass.foobara_manifest_reference

          if transformer.scoped_path_set?
            to_include << transformer
            transformers_manifest << transformer.foobara_manifest_reference
          end
        end

        validators.each do |validator|
          klass = validator.class
          to_include << klass
          validator_classes_manifest << klass.foobara_manifest_reference

          if validator.scoped_path_set?
            to_include << validator
            validators_manifest << validator.foobara_manifest_reference
          end
        end

        Util.remove_blank(
          casters: casters_manifest.sort,
          caster_classes: caster_classes_manifest.sort,
          transformers: transformers_manifest.sort,
          transformer_classes: transformer_classes_manifest.sort,
          validators: validators_manifest.sort,
          validator_classes: validator_classes_manifest.sort
        )
      end

      def registered?
        !!type_symbol
      end
    end
  end

  Type = Foobara::Types::Type
end