module Formtastic
  module Inputs
    module Base
      module Collections

        def label_method
          @label_method ||= (label_method_from_options || label_and_value_method.first)
        end

        def label_method_from_options
          options[:member_label]
        end

        def value_method
          @value_method ||= (value_method_from_options || label_and_value_method[-1])
        end

        def value_method_from_options
          options[:member_value]
        end

        def label_and_value_method
          @label_and_value_method ||= label_and_value_method_from_collection(raw_collection)
        end

        def label_and_value_method_from_collection(_collection)
          sample = _collection.first || _collection[-1]

          case sample
          when Array
            label, value = :first, :last
          when Integer
            label, value = :to_s, :to_i
          when Symbol, String, NilClass
            label, value = :to_s, :to_s
          end

          # Order of preference: user supplied method, class defaults, auto-detect
          label ||= builder.collection_label_methods.find { |m| sample.respond_to?(m) }
          value ||= builder.collection_value_methods.find { |m| sample.respond_to?(m) }

          [label, value]
        end

        def raw_collection
          @raw_collection ||= (collection_from_options || collection_from_enum || collection_from_association || collection_for_boolean)
        end

        def collection
          # Return if we have a plain string
          return raw_collection if raw_collection.is_a?(String)

          # Return if we have an Array of strings, integers or arrays
          return raw_collection if (raw_collection.instance_of?(Array) || raw_collection.instance_of?(Range)) &&
                               ([Array, String].include?(raw_collection.first.class) || raw_collection.first.is_a?(Integer)) &&
                               !(options.include?(:member_label) || options.include?(:member_value))

          raw_collection.map { |o| [send_or_call(label_method, o), send_or_call(value_method, o)] }
        end

        def collection_from_options
          items = options[:collection]
          case items
          when Hash
            items.to_a
          when Range
            items.to_a.collect{ |c| [c.to_s, c] }
          else
            items
          end
        end

        def collection_from_association
          if reflection
            if reflection.respond_to?(:options)
              raise PolymorphicInputWithoutCollectionError.new(
                        "A collection must be supplied for #{method} input. Collections cannot be guessed for polymorphic associations."
                    ) if reflection.options[:polymorphic] == true
            end

            conditions_from_reflection = (reflection.respond_to?(:options) && reflection.options[:conditions]) || {}
            conditions_from_reflection = conditions_from_reflection.call if conditions_from_reflection.is_a?(Proc)

            scope_conditions = conditions_from_reflection.empty? ? nil : {:conditions => conditions_from_reflection}
            where_conditions = (scope_conditions && scope_conditions[:conditions]) || {}

            reflection.klass.where(where_conditions)
          end
        end

        # Assuming the following model:
        #
        # class Post < ActiveRecord::Base
        #   enum :status => [ :active, :archived ]
        # end
        #
        # We would end up with a collection like this:
        #
        # [["Active", "active"], ["Archived", "archived"]
        #
        # The first element in each array uses String#humanize, but I18n
        # translations are available too. Set them with the following structure.
        #
        # en:
        #   activerecord:
        #     attributes:
        #       post:
        #         statuses:
        #           active: Custom Active Label Here
        #           archived: Custom Archived Label Here
        def collection_from_enum
          if collection_from_enum?
            method_name = method.to_s

            enum_options_hash = object.defined_enums[method_name]
            enum_options_hash.map do |name, value|
              key = "activerecord.attributes.#{object_name}.#{method_name.pluralize}.#{name}"
              label = ::I18n.translate(key, :default => name.humanize)
              [label, name]
            end
          end
        end

        def collection_from_enum?
          object.respond_to?(:defined_enums) && object.defined_enums.has_key?(method.to_s)
        end

        def collection_for_boolean
          true_text = options[:true] || Formtastic::I18n.t(:yes)
          false_text = options[:false] || Formtastic::I18n.t(:no)

          # TODO options[:value_as_class] = true unless options.key?(:value_as_class)

          [ [true_text, true], [false_text, false] ]
        end

        def send_or_call(duck, object)
          if duck.respond_to?(:call)
            duck.call(object)
          elsif object.respond_to? duck.to_sym
            object.send(duck)
          end
        end

        # Avoids an issue where `send_or_call` can be a String and duck can be something simple like
        # `:first`, which obviously String responds to.
        def send_or_call_or_object(duck, object)
          return object if object.is_a?(String) || object.is_a?(Integer) || object.is_a?(Symbol) # TODO what about other classes etc?
          send_or_call(duck, object)
        end

      end
    end
  end
end