module Watir
  module Generator
    class Base
      class Visitor < WebIDL::RubySexpVisitor
        STRING_TYPES = ['WindowProxy', 'ValidityState', 'TimeRanges', 'Location',
                        'Any', 'TimedTrackArray', 'TimedTrack', 'TextTrackArray', 'TextTrack',
                        /Media.+/, 'TextTrackKind', 'Function', /.*EventHandler$/,
                        'Document', 'DocumentFragment', 'DOMTokenList', 'DOMSettableTokenList',
                        'DOMStringMap', 'HTMLPropertiesCollection', /HTML.*Element/, /HTML.*Collection/,
                        'CSSStyleDeclaration', /.+List$/, 'Date', 'Element', /DOM.+ReadOnly/,
                        /SVGAnimated.+/, /SVG.*Element/, /SVG.*Collection/, 'SVGViewSpec',
                        'Object', 'USVString'].freeze
        def initialize
          super

          # When an interface has multiple IDL definitions in the spec, the inheritance is sometimes
          # not repeated. So we'll keep track ourselves.
          @inheritance_map = {}

          @already_defined = []
        end

        #
        # WebIDL visitor interface
        #

        def visit_interface(interface)
          name   = interface.name
          parent = interface.inherits.first

          warn name
          return if name !~ interface_regexp || name =~ /(Collection|Document)$/

          parent = if force_inheritance.key?(name)
                     force_inheritance[name]
                   else
                     @inheritance_map[name] ||= parent&.name
                     return unless @inheritance_map[name]

                     @inheritance_map[name]
                   end

          [:scope,
           [:block,
            element_class(interface.name, extract_attributes(interface), parent),
            collection_class(interface.name)]]
        end

        def visit_module(mod)
          # ignored
        end

        def visit_implements_statement(stmt)
          # ignored
        end

        private

        def element_class(name, attributes, parent)
          [:class, Util.classify(classify_regexp, name), [:const, Util.classify(classify_regexp, parent)],
           *attribute_calls(attributes)]
        end

        def extract_attributes(interface)
          members = interface.members
          members += interface.implements.flat_map(&:members)
          members += interface.includes.flat_map(&:members)

          members.select { |e| e.is_a?(WebIDL::Ast::Attribute) }.uniq(&:name)
        end

        def collection_class(name)
          return if @already_defined.include?(name)

          @already_defined << name
          name = Util.classify(classify_regexp, name)

          [:class, "#{name}Collection", %i[const ElementCollection]]
        end

        def attribute_calls(attributes)
          attributes.map do |attribute|
            call(:attribute, [
                   [:lit, ruby_type_for(attribute.type)],
                   [:lit, ruby_method_name_for(attribute)],
                   [:lit, attribute.name.to_sym]
                 ])
          end
        end

        def call(name, args)
          [:call, nil, name.to_sym, [:arglist] + args]
        end

        def ruby_method_name_for(attribute)
          str = if %w[httpEquiv contentEditable acceptCharset isContentEditable].include? attribute.name
                  attribute.name.snake_case
                else
                  attribute.name.downcase
                end

          if attribute.type.name == :Boolean
            str = Regexp.last_match(1) if str =~ /^is_(.+)/
            str << '?'
          end

          str = 'for' if str == 'htmlfor'

          str.to_sym
        end

        def ruby_type_for(type)
          case type.name.to_s
          when 'DOMString', 'any'
            String
          when 'UnsignedLong', 'Long', 'Integer', 'Short', 'UnsignedShort',
              'SVGAnimatedLength'
            Integer
          when 'Float', /.*Double$/
            Float
          when 'Boolean'
            'Boolean'
          when *STRING_TYPES
            # probably completely wrong.
            String
          else
            raise "unknown type: #{type.name}"
          end
        end
      end # Visitor
    end # Base
  end # Generator
end # Watir