# frozen_string_literal: true

module Grape
  module Validations
    module Validators
      class ValuesValidator < Base
        def initialize(attrs, options, required, scope, **opts)
          if options.is_a?(Hash)
            @excepts = options[:except]
            @values = options[:value]
            @proc = options[:proc]

            Grape.deprecator.warn('The values validator except option is deprecated. Use the except validator instead.') if @excepts

            raise ArgumentError, 'proc must be a Proc' if @proc && !@proc.is_a?(Proc)

            Grape.deprecator.warn('The values validator proc option is deprecated. The lambda expression can now be assigned directly to values.') if @proc
          else
            @excepts = nil
            @values = nil
            @proc = nil
            @values = options
          end
          super
        end

        def validate_param!(attr_name, params)
          return unless params.is_a?(Hash)

          val = params[attr_name]

          return if val.nil? && !required_for_root_scope?

          # don't forget that +false.blank?+ is true
          return if val != false && val.blank? && @allow_blank

          param_array = val.nil? ? [nil] : Array.wrap(val)

          raise validation_exception(attr_name, except_message) \
          unless check_excepts(param_array)

          raise validation_exception(attr_name, message(:values)) \
          unless check_values(param_array, attr_name)

          raise validation_exception(attr_name, message(:values)) \
            if @proc && !validate_proc(@proc, param_array)
        end

        private

        def check_values(param_array, attr_name)
          values = @values.is_a?(Proc) && @values.arity.zero? ? @values.call : @values
          return true if values.nil?

          begin
            return param_array.all? { |param| values.call(param) } if values.is_a? Proc
          rescue StandardError => e
            warn "Error '#{e}' raised while validating attribute '#{attr_name}'"
            return false
          end
          param_array.all? { |param| values.include?(param) }
        end

        def check_excepts(param_array)
          excepts = @excepts.is_a?(Proc) ? @excepts.call : @excepts
          return true if excepts.nil?

          param_array.none? { |param| excepts.include?(param) }
        end

        def validate_proc(proc, param_array)
          case proc.arity
          when 0
            param_array.all? { |_param| proc.call }
          when 1
            param_array.all? { |param| proc.call(param) }
          else
            raise ArgumentError, 'proc arity must be 0 or 1'
          end
        end

        def except_message
          options = instance_variable_get(:@option)
          options_key?(:except_message) ? options[:except_message] : message(:except_values)
        end

        def required_for_root_scope?
          @required && @scope.root?
        end

        def validation_exception(attr_name, message)
          Grape::Exceptions::Validation.new(params: [@scope.full_name(attr_name)], message: message)
        end
      end
    end
  end
end