module RBS
  module Types
    # _TypeBase interface represents the operations common to all of the types.
    #
    interface _TypeBase
      # Returns names of free variables of a type.
      # You can pass a Set instance to add the free variables to the set to avoid Set object allocation.
      #
      def free_variables: (?Set[Symbol]) -> Set[Symbol]

      # Receives a substitution and returns a new type applied the substitution.
      #
      def sub: (Substitution) -> t

      # Maps type names included in the type and returns new instance of type.
      def map_type_name: () { (TypeName, Location[untyped, untyped]?, t) -> TypeName } -> t

      # Yields all direct sub types included in the type.
      # It doesn't yield the type itself.
      #
      # ```ruby
      # parse("Hash[String, Array[Symbol]]").each_type do |ty|
      #   ...       # Yields String and Array[Symbol]
      # end
      # ```
      #
      def each_type: () { (t) -> void } -> void
                   | () -> Enumerator[t, void]

      # Returns a JSON representation.
      #
      include _ToJson

      # Returns a String representation.
      # `level` is used internally.
      #
      # ```ruby
      # parse("String").to_s               # => "String"
      # parse("String | Integer").to_s()   # => "String | Integer"
      # parse("String | Integer").to_s(1)  # => "(String | Integer)"
      # ```
      #
      def to_s: (?Integer level) -> String

      # Returns `true` if it has `self` type
      #
      def has_self_type?: () -> bool

      # Returns `true` if it has `instance` or `class` types
      def has_classish_type?: () -> bool

      # Returns `true` if it has `void` types other than *return* position
      #
      # * The function return type is a return position (`() -> void`)
      # * Generic parameter is a return position (`Enumerator[Integer, void]`)
      #
      def with_nonreturn_void?: () -> bool
    end

    # t represents union of all possible types.
    #
    type t = Bases::Bool | Bases::Void | Bases::Any | Bases::Nil | Bases::Top | Bases::Bottom | Bases::Self | Bases::Instance | Bases::Class
           | Variable | ClassSingleton | Interface | ClassInstance | Alias | Tuple | Record | Optional | Union | Intersection | Proc | Literal

    module NoFreeVariables
      def free_variables: (?Set[Symbol]) -> Set[Symbol]
    end

    module NoSubst
      def sub: (Substitution) -> self
    end

    module EmptyEachType
      def each_type: () { (t) -> void } -> void
                   | () -> Enumerator[t, void]

      # `map_type` returns itself, because there is no sub type.
      #
      def map_type: () { (t) -> t } -> self
                  | () -> Enumerator[t, self]
    end

    module NoTypeName
      def map_type_name: () { (TypeName, Location[untyped, untyped]?, t) -> TypeName } -> self
    end

    module Bases
      class Base
        include _TypeBase

        attr_reader location: Location[bot, bot]?

        def initialize: (location: Location[bot, bot]?) -> void

        def ==: (untyped other) -> bool

        def hash: () -> Integer

        alias eql? ==

        include NoFreeVariables
        include NoSubst
        include EmptyEachType
        include NoTypeName
      end

      class Bool < Base
      end

      class Void < Base
      end

      class Any < Base
        @string: String?

        def todo!: () -> self
      end

      class Nil < Base
      end

      class Top < Base
      end

      class Bottom < Base
      end

      class Self < Base
      end

      class Instance < Base
        def sub: (Substitution sub) -> t
      end

      class Class < Base
      end
    end

    class Variable
      type loc = Location[bot, bot]

      attr_reader name: Symbol

      @@count: Integer

      include _TypeBase
      include NoTypeName
      include EmptyEachType

      def initialize: (name: Symbol, location: loc?) -> void

      attr_reader location: loc?

      def ==: (untyped other) -> bool

      alias eql? ==

      def hash: () -> Integer

      def self.build: (Symbol) -> Variable
                    | (Array[Symbol]) -> Array[Variable]

      # Returns fresh type variable with prefix (if given.)
      #
      #     Variable.fresh(:S)       # => S@1
      #     Variable.fresh(:S)       # => S@2
      #     Variable.fresh()         # => T@3
      #
      def self.fresh: (?Symbol prefix) -> Variable
    end

    class ClassSingleton
      # singleton(::Foo)
      #           ^^^^^  => name
      type loc = Location[:name, bot]

      def initialize: (name: TypeName, location: loc?) -> void

      attr_reader name: TypeName

      attr_reader location: loc?

      include _TypeBase
      include NoFreeVariables
      include NoSubst
      include EmptyEachType

      def ==: (untyped other) -> bool

      alias eql? ==

      def hash: () -> Integer
    end

    module Application
      attr_reader name: TypeName
      attr_reader args: Array[t]

      def ==: (untyped) -> bool

      alias eql? ==

      def hash: () -> Integer

      def free_variables: (?Set[Symbol]) -> Set[Symbol]

      def to_s: (?Integer level) -> String

      def each_type: () { (t) -> void } -> void
                   | () -> Enumerator[t, void]

      def has_self_type?: () -> bool

      def has_classish_type?: () -> bool

      def with_nonreturn_void?: () -> bool
    end

    class Interface
      # _Foo
      # ^^^^ => name
      #
      # _Foo[Bar, Baz]
      # ^^^^           => name
      #     ^^^^^^^^^^ => args
      type loc = Location[:name, :args]

      def initialize: (name: TypeName, args: Array[t], location: loc?) -> void

      include Application
      include _TypeBase

      attr_reader location: loc?

      def map_type: () { (t) -> t } -> Interface
                  | () -> Enumerator[t, Interface]
    end

    # ClassInstance represents a type of an instance of a class.
    #
    #    String           # Type of an instance of String class.
    #    Array[String]    # Type of an instance of Array class with instances of String.
    #    Kernel           # Type of an instance of a class which includes Kernel.
    #
    class ClassInstance
      include Application

      # Foo
      # ^^^ => name
      #
      # Foo[Bar, Baz]
      # ^^^           => name
      #    ^^^^^^^^^^ => args
      #
      type loc = Location[:name, :args]

      def initialize: (name: TypeName, args: Array[t], location: loc?) -> void

      attr_reader location: loc?

      include _TypeBase

      def map_type: () { (t) -> t } -> ClassInstance
                  | () -> Enumerator[t, ClassInstance]
    end

    class Alias
      # foo
      # ^^^ => name
      #
      # foo[bar, baz]
      # ^^^           => name
      #    ^^^^^^^^^^ => args
      #
      type loc = Location[:name, :args]

      attr_reader location: loc?

      def initialize: (name: TypeName, args: Array[t], location: loc?) -> void

      include _TypeBase
      include Application

      def map_type: () { (t) -> t } -> Alias
                  | () -> Enumerator[t, Alias]
    end

    class Tuple
      attr_reader types: Array[t]

      type loc = Location[bot, bot]

      def initialize: (types: Array[t], location: loc?) -> void

      include _TypeBase

      attr_reader location: loc?

      def map_type: () { (t) -> t } -> Tuple
                  | () -> Enumerator[t, Tuple]
    end

    class Record
      attr_reader all_fields: Hash[Symbol, [t, bool]]

      attr_reader fields: Hash[Symbol, t]

      attr_reader optional_fields: Hash[Symbol, t]

      type loc = Location[bot, bot]

      def initialize: (fields: Hash[Symbol, t], location: loc?) -> void
                    | (all_fields: Hash[Symbol, [t, bool]], location: loc?) -> void

      include _TypeBase

      attr_reader location: loc?

      def map_type: () { (t) -> t } -> Record
                  | () -> Enumerator[t, Record]
    end

    class Optional
      attr_reader type: t

      type loc = Location[bot, bot]

      def initialize: (type: t, location: loc?) -> void

      include _TypeBase

      attr_reader location: loc?

      def map_type: () { (t) -> t } -> Optional
                  | () -> Enumerator[t, Optional]
    end

    class Union
      attr_reader types: Array[t]

      type loc = Location[bot, bot]

      def initialize: (types: Array[t], location: loc?) -> void

      include _TypeBase

      attr_reader location: loc?

      def map_type: () { (t) -> t } -> Union
                  | () -> Enumerator[t, Union]
    end

    class Intersection
      attr_reader types: Array[t]

      type loc = Location[bot, bot]

      def initialize: (types: Array[t], location: loc?) -> void

      include _TypeBase

      attr_reader location: loc?

      def map_type: () { (t) -> t } -> Intersection
                  | () -> Enumerator[t, Intersection]
    end

    class Function
      class Param
        type loc = Location[bot, :name]

        attr_reader type: t
        attr_reader name: Symbol?
        attr_reader location: loc?

        def initialize: (type: t, name: Symbol?, ?location: loc?) -> void

        def map_type: { (t) -> t } -> Param
                    | -> Enumerator[t, Param]
      end

      attr_reader required_positionals: Array[Param]
      attr_reader optional_positionals: Array[Param]
      attr_reader rest_positionals: Param?
      attr_reader trailing_positionals: Array[Param]
      attr_reader required_keywords: Hash[Symbol, Param]
      attr_reader optional_keywords: Hash[Symbol, Param]
      attr_reader rest_keywords: Param?
      attr_reader return_type: t

      def initialize: (required_positionals: Array[Param],
                       optional_positionals: Array[Param],
                       rest_positionals: Param?,
                       trailing_positionals: Array[Param],
                       required_keywords: Hash[Symbol, Param],
                       optional_keywords: Hash[Symbol, Param],
                       rest_keywords: Param?,
                       return_type: t) -> void

      def free_variables: (?Set[Symbol]) -> Set[Symbol]

      def map_type: { (t) -> t } -> Function
                  | -> Enumerator[t, Function]

      def map_type_name: () { (TypeName, Location[untyped, untyped]?, t) -> TypeName } -> Function

      def each_type: () { (t) -> void } -> void
                   | -> Enumerator[t, void]

      def each_param: () { (Param) -> void } -> void
                    | -> Enumerator[Param, void]

      include _ToJson

      def sub: (Substitution) -> Function

      def self.empty: (t) -> instance

      def with_return_type: (t) -> Function

      def update: (?required_positionals: Array[Param],
                   ?optional_positionals: Array[Param],
                   ?rest_positionals: Param?,
                   ?trailing_positionals: Array[Param],
                   ?required_keywords: Hash[Symbol, Param],
                   ?optional_keywords: Hash[Symbol, Param],
                   ?rest_keywords: Param?,
                   ?return_type: t) -> Function

      def empty?: () -> bool

      def param_to_s: () -> String
      def return_to_s: () -> String

      def drop_head: () -> [Param, Function]
      def drop_tail: () -> [Param, Function]

      def has_keyword?: () -> bool

      def amap: [A, B] (Array[A]) { (A) -> B } -> Array[B]

      def hmapv: [X, Y, Z] (Hash[X, Y]) { (Y) -> Z } -> Hash[X, Z]

      def has_self_type?: () -> bool

      def has_classish_type?: () -> bool

      def with_nonreturn_void?: () -> bool

      def ==: (untyped) -> bool

      alias eql? ==

      def hash: () -> Integer
    end

    # Function type without type checking arguments
    #
    class UntypedFunction
      attr_reader return_type: t

      def initialize: (return_type: t) -> void

      def free_variables: (?Set[Symbol]) -> Set[Symbol]

      def map_type: { (t) -> t } -> UntypedFunction
                  | -> Enumerator[t, UntypedFunction]

      def map_type_name: () { (TypeName, Location[untyped, untyped]?, t) -> TypeName } -> UntypedFunction

      def each_type: () { (t) -> void } -> void
                   | -> Enumerator[t, void]

      def each_param: () { (Function::Param) -> void } -> void
                    | -> Enumerator[Function::Param, void]

      include _ToJson

      def sub: (Substitution) -> UntypedFunction

      def with_return_type: (t) -> UntypedFunction

      def update: (?return_type: t) -> UntypedFunction

      def empty?: () -> bool

      def has_self_type?: () -> bool

      def has_classish_type?: () -> bool

      def with_nonreturn_void?: () -> bool

      # Returns `?`
      def param_to_s: () -> String

      # Returns `return_type.to_s(1)`
      def return_to_s: () -> String

      def ==: (untyped) -> bool

      alias eql? ==

      def hash: () -> Integer
    end

    type function = Types::Function | Types::UntypedFunction

    class Block
      attr_reader type: function
      attr_reader required: bool

      attr_reader self_type: t?

      def initialize: (type: function, ?self_type: t?, required: boolish) -> void

      def ==: (untyped other) -> bool

      include _ToJson

      def sub: (Substitution) -> Block

      def map_type: () { (t) -> t } -> Block
    end

    module SelfTypeBindingHelper
      def self?.self_type_binding_to_s: (t?) -> String
    end

    class Proc
      attr_reader type: function
      attr_reader block: Block?

      attr_reader self_type: t?

      type loc = Location[bot, bot]

      def initialize: (location: loc?, type: function, ?self_type: t?, block: Block?) -> void

      include _TypeBase

      attr_reader location: loc?

      def map_type: () { (t) -> t } -> Proc
                  | () -> Enumerator[t, Proc]
    end

    class Literal
      type literal = String | Integer | Symbol | TrueClass | FalseClass
      type loc = Location[bot, bot]

      attr_reader literal: literal

      def initialize: (literal: literal, location: loc?) -> void

      include _TypeBase
      include NoFreeVariables
      include NoSubst
      include EmptyEachType
      include NoTypeName

      attr_reader location: loc?

      TABLE: Hash[String, String]

      # Unescape string type body
      def self.unescape_string: (String, bool is_double_quote) -> String
    end
  end
end