module RBS
  class Environment
    type module_decl = AST::Declarations::Class | AST::Declarations::Module

    interface _ModuleOrClass
      def name: () -> TypeName

      def type_params: () -> Array[AST::TypeParam]
    end

    interface _NamedDecl
      def name: () -> TypeName
    end

    module ContextUtil
      def calculate_context: (Array[_NamedDecl]) -> Resolver::context
    end

    # Name of object, it's (multiple) declarations with the outer module declarations
    #
    class MultiEntry[M < _ModuleOrClass]
      class D[M < _ModuleOrClass]
        attr_reader decl: M
        attr_reader outer: Array[module_decl]

        def initialize: (decl: M, outer: Array[module_decl]) -> void

        include ContextUtil

        @context: Resolver::context

        def context: () -> Resolver::context
      end

      attr_reader name: TypeName
      attr_reader decls: Array[D[M]]

      @primary: D[M]?

      def initialize: (name: TypeName) -> void

      def insert: (decl: M, outer: Array[module_decl]) -> void

      def validate_type_params: () -> void

      def compatible_params?: (Array[AST::TypeParam], Array[AST::TypeParam]) -> boolish

      def type_params: () -> Array[AST::TypeParam]

      def primary: () -> D[M]
    end

    class ModuleEntry < MultiEntry[AST::Declarations::Module]
      def self_types: () -> Array[AST::Declarations::Module::Self]
    end

    class ClassEntry < MultiEntry[AST::Declarations::Class]
    end

    # Name of object, it's (single) declaration, and the outer module declarations
    #
    class SingleEntry[N, D]
      attr_reader name: N
      attr_reader decl: D
      attr_reader outer: Array[module_decl]

      def initialize: (name: N, decl: D, outer: Array[module_decl]) -> void

      include ContextUtil

      @context: Resolver::context

      def context: () -> Resolver::context
    end

    class ModuleAliasEntry < SingleEntry[TypeName, AST::Declarations::ModuleAlias]
    end

    class ClassAliasEntry < SingleEntry[TypeName, AST::Declarations::ClassAlias]
    end

    class InterfaceEntry < SingleEntry[TypeName, AST::Declarations::Interface]
    end

    class TypeAliasEntry < SingleEntry[TypeName, AST::Declarations::TypeAlias]
    end

    class ConstantEntry < SingleEntry[TypeName, AST::Declarations::Constant]
    end

    class GlobalEntry < SingleEntry[Symbol, AST::Declarations::Global]
    end

    # Top level declarations
    attr_reader declarations: Array[AST::Declarations::t]

    # Class declarations
    attr_reader class_decls: Hash[TypeName, ModuleEntry | ClassEntry]

    attr_reader class_alias_decls: Hash[TypeName, ModuleAliasEntry | ClassAliasEntry]

    # Interface declarations
    attr_reader interface_decls: Hash[TypeName, InterfaceEntry]

    # Type alias declarations
    attr_reader type_alias_decls: Hash[TypeName, TypeAliasEntry]

    # Constant declarations
    attr_reader constant_decls: Hash[TypeName, ConstantEntry]

    # Global declarations
    attr_reader global_decls: Hash[Symbol, GlobalEntry]

    # A hash from Buffer to it's contents
    #
    attr_reader signatures: Hash[Buffer, [Array[AST::Directives::t], Array[AST::Declarations::t]]]

    def initialize: () -> void

    def initialize_copy: (Environment) -> void

    # Construct an environment from EnvironmentLoader
    #
    def self.from_loader: (EnvironmentLoader) -> Environment

    def add_signature: (buffer: Buffer, directives: Array[AST::Directives::t], decls: Array[AST::Declarations::t]) -> void

    # Insert a toplevel declaration into the environment
    #
    def <<: (AST::Declarations::t decl) -> self

    # Insert a declaration into the environment
    #
    private def insert_decl: (AST::Declarations::t, outer: Array[module_decl], namespace: Namespace) -> void

    # Resolve all type names in the environment to absolute type names.
    # Relative type name will be left if absolute type name cannot be found.
    #
    # When `only` is given, it skips other _top-level_ declarations not included in the collection.
    # This helps running resolution faster in the case of _partial updates_.
    #
    def resolve_type_names: (?only: Set[AST::Declarations::t]?) -> Environment

    def inspect: () -> String

    def buffers: () -> Array[Buffer]

    # Remove declarations and directives that are loaded from `buffers`
    #
    def unload: (Set[Buffer] buffers) -> Environment

    # Returns true if an interface with the type name is defined
    #
    def interface_name?: (TypeName) -> bool

    # Returns true if a type alias with the type name is defined
    #
    def type_alias_name?: (TypeName) -> bool

    # Returns true if a module or class with the type name is defined
    #
    def module_name?: (TypeName) -> bool

    # Returns true if the type name is defined
    #
    def type_name?: (TypeName) -> bool

    # Returns if a constant of the name is defined
    #
    def constant_name?: (TypeName) -> bool

    # Returns true if the type name is defined by constant declaration
    #
    def constant_decl?: (TypeName) -> bool

    # Returns true if the type name is defined by class declaration
    #
    def class_decl?: (TypeName) -> bool

    # Returns true if the type name is defined by module declaration
    #
    def module_decl?: (TypeName) -> bool

    # Returns true if the type name is a module alias
    #
    def module_alias?: (TypeName) -> bool

    # Returns true if the type name is a class alias
    def class_alias?: (TypeName) -> bool

    def class_entry: (TypeName) -> (ClassEntry | ClassAliasEntry | nil)

    # Returns ClassEntry if the class definition is found, normalized in case of alias
    #
    def normalized_class_entry: (TypeName) -> ClassEntry?

    def module_entry: (TypeName) -> (ModuleEntry | ModuleAliasEntry | nil)

    # Returns ModuleEntry if the module definition is found, normalized in case of alias
    #
    def normalized_module_entry: (TypeName) -> ModuleEntry?

    def constant_entry: (TypeName) -> (ClassEntry | ClassAliasEntry | ModuleEntry | ModuleAliasEntry | ConstantEntry | nil)

    def module_class_entry: (TypeName) -> (ClassEntry | ClassAliasEntry | ModuleEntry | ModuleAliasEntry | nil)

    def normalized_module_class_entry: (TypeName) -> (ClassEntry | ModuleEntry | nil)

    @normalize_module_name_cache: Hash[TypeName, TypeName | false | nil]

    # Returns the original module name that is defined with `module` declaration
    #
    # * Calls `#absolute!` for relative module names
    # * Returns `nil` if the rhs name cannot be found
    # * Returns `false` if the name is cyclic
    #
    def normalize_module_name?: (TypeName) -> (TypeName | nil | false)

    # Returns the original module name that is defined with `module` declaration
    #
    # * Raises an error if given type name is not module
    # * Calls `#absolute!` for relative module names
    # * Returns the name itself if the name cannot be normalized to a class/module
    #
    def normalize_module_name: (TypeName) -> TypeName

    # Returns a normalized module/class name or a type name with a normalized namespace
    #
    # * Calls `#absolute!` for relative module names
    # * Returns `nil` if the typename cannot be found
    # * Returns `false` if the name is cyclic
    #
    def normalize_type_name?: (TypeName) -> (TypeName | nil | false)

    # Normalize the type name or raises an error
    # 
    def normalize_type_name!: (TypeName) -> TypeName

    # Returns a normalized module/class name or a type name with a normalized namespace
    #
    # * Calls `#absolute!` for relative module names
    # * Returns the typename itself if the name cannot be normalized
    #
    def normalize_type_name: (TypeName) -> TypeName

    # Returns `true` if given type name is normalized
    #
    def normalized_type_name?: (TypeName) -> bool

    # Returns the given type name if it's normalized, or raises
    #
    def normalized_type_name!: (TypeName) -> TypeName

    # Runs generics type params validation over each class definitions
    def validate_type_params: () -> void

    private

    # Returns a context for inside given decls
    #
    def resolver_context: (*module_decl) -> Resolver::context

    def append_context: (Resolver::context, module_decl) -> Resolver::context

    def resolve_declaration: (Resolver::TypeNameResolver resolver, UseMap map, AST::Declarations::t decl, outer: Array[module_decl], prefix: Namespace) -> AST::Declarations::t

    def resolve_member: (Resolver::TypeNameResolver, UseMap map, AST::Members::t, context: Resolver::context) -> AST::Members::t

    def resolve_method_type: (Resolver::TypeNameResolver, UseMap map, RBS::MethodType, context: Resolver::context) -> RBS::MethodType

    def resolve_type_params: (Resolver::TypeNameResolver resolver, UseMap map, Array[AST::TypeParam], context: Resolver::context) ->  Array[AST::TypeParam]

    def absolute_type: (Resolver::TypeNameResolver, UseMap map, Types::t, context: Resolver::context) -> Types::t

    def absolute_type_name: (Resolver::TypeNameResolver, UseMap map, TypeName, context: Resolver::context) -> TypeName
  end
end