require 'active_model/type/registry'

module ActiveRecord
  # :stopdoc:
  module Type
    class AdapterSpecificRegistry < ActiveModel::Type::Registry
      def add_modifier(options, klass, **args)
        registrations << DecorationRegistration.new(options, klass, **args)
      end

      private

      def registration_klass
        Registration
      end

      def find_registration(symbol, *args)
        registrations
          .select { |registration| registration.matches?(symbol, *args) }
          .max
      end
    end

    class Registration
      def initialize(name, block, adapter: nil, override: nil)
        @name = name
        @block = block
        @adapter = adapter
        @override = override
      end

      def call(_registry, *args, adapter: nil, **kwargs)
        if kwargs.any? # https://bugs.ruby-lang.org/issues/10856
          block.call(*args, **kwargs)
        else
          block.call(*args)
        end
      end

      def matches?(type_name, *args, **kwargs)
        type_name == name && matches_adapter?(**kwargs)
      end

      def <=>(other)
        if conflicts_with?(other)
          raise TypeConflictError.new("Type #{name} was registered for all
                                      adapters, but shadows a native type with
                                      the same name for #{other.adapter}".squish)
        end
        priority <=> other.priority
      end

      protected

      attr_reader :name, :block, :adapter, :override

      def priority
        result = 0
        if adapter
          result |= 1
        end
        if override
          result |= 2
        end
        result
      end

      def priority_except_adapter
        priority & 0b111111100
      end

      private

      def matches_adapter?(adapter: nil, **)
        (self.adapter.nil? || adapter == self.adapter)
      end

      def conflicts_with?(other)
        same_priority_except_adapter?(other) &&
          has_adapter_conflict?(other)
      end

      def same_priority_except_adapter?(other)
        priority_except_adapter == other.priority_except_adapter
      end

      def has_adapter_conflict?(other)
        (override.nil? && other.adapter) ||
          (adapter && other.override.nil?)
      end
    end

    class DecorationRegistration < Registration
      def initialize(options, klass, adapter: nil)
        @options = options
        @klass = klass
        @adapter = adapter
      end

      def call(registry, *args, **kwargs)
        subtype = registry.lookup(*args, **kwargs.except(*options.keys))
        klass.new(subtype)
      end

      def matches?(*args, **kwargs)
        matches_adapter?(**kwargs) && matches_options?(**kwargs)
      end

      def priority
        super | 4
      end

      protected

      attr_reader :options, :klass

      private

      def matches_options?(**kwargs)
        options.all? do |key, value|
          kwargs[key] == value
        end
      end
    end
  end

  class TypeConflictError < StandardError
  end
  # :startdoc:
end
