# frozen_string_literal: true

module RBS
  class TypeName
    attr_reader :namespace
    attr_reader :name
    attr_reader :kind

    def initialize(namespace:, name:)
      @namespace = namespace
      @name = name
      @kind = case
              when name.match?(/\A[A-Z]/)
                :class
              when name.match?(/\A[a-z]/)
                :alias
              when name.start_with?("_")
                :interface
              else
                # Defaults to :class
                :class
              end
    end

    def ==(other)
      other.is_a?(self.class) && other.namespace == namespace && other.name == name
    end

    alias eql? ==

    def hash
      namespace.hash ^ name.hash
    end

    def to_s
      "#{namespace.to_s}#{name}"
    end

    def to_json(state = nil)
      to_s.to_json(state)
    end

    def to_namespace
      namespace.append(self.name)
    end

    def class?
      kind == :class
    end

    def alias?
      kind == :alias
    end

    def absolute!
      self.class.new(namespace: namespace.absolute!, name: name)
    end

    def absolute?
      namespace.absolute?
    end

    def relative!
      self.class.new(namespace: namespace.relative!, name: name)
    end

    def interface?
      kind == :interface
    end

    def with_prefix(namespace)
      self.class.new(namespace: namespace + self.namespace, name: name)
    end

    def split
      namespace.path + [name]
    end

    def +(other)
      if other.absolute?
        other
      else
        TypeName.new(
          namespace: self.to_namespace + other.namespace,
          name: other.name
        )
      end
    end
    
    def self.parse(string)
      absolute = string.start_with?("::")

      *path, name = string.delete_prefix("::").split("::").map(&:to_sym)
      raise unless name

      TypeName.new(
        name: name,
        namespace: RBS::Namespace.new(path: path, absolute: absolute)
      )
    end
  end
end
