module HTTPX
  module Transcoder
    module Multipart
      interface _MultipartInput
        def filename: () -> String
        def content_type: () -> String
        def read: (?int? length, ?string? output) -> String?
      end

      MULTIPART_VALUE_COND: ^(_Reader | record_multipart_value value) -> bool

      type multipart_value = string | Pathname | File | _Reader

      type record_multipart_value = { content_type: String, filename: String, body: multipart_value } |
                                    { content_type: String, body: multipart_value }

      type multipart_nested_value = multipart_value | _ToAry[multipart_value] | _ToHash[string, multipart_value]

      class Encoder
        @boundary: String
        @part_index: Integer
        @buffer: String

        @form: Enumerable[[Symbol | string, Object & multipart_nested_value]]
        @parts: Array[Object & _Reader]

        def bytesize: () -> Integer

        def content_type: () -> String

        def to_s: () -> String

        def read: (?int? length, ?string? buffer) -> String?

        def rewind: () -> void

        private

        def to_parts: (Enumerable[[Symbol | string, multipart_nested_value]] multipart_data) -> Array[_Reader]

        def initialize: (Enumerable[[Symbol | string, multipart_nested_value]] multipart_data) -> untyped

        def header_part: (string key, String content_type, String? filename) -> StringIO

        def read_chunks: (String buffer, ?int? length) -> void

        def read_from_part: (?int? max_length) -> String?
      end

      class Decoder
        CRLF: String
        BOUNDARY_RE: Regexp
        MULTIPART_CONTENT_TYPE: Regexp
        MULTIPART_CONTENT_DISPOSITION: Regexp
        MULTIPART_CONTENT_ID: Regexp
        WINDOW_SIZE: Integer

        @state: :idle | :part_header | :part_body | :parse_boundary | :done
        @buffer: String
        @parts: Hash[String, untyped]
        @boundary: String
        @intermediate_boundary: String

        def call: (Response response, *untyped) -> Hash[String, untyped]

        private

        def initialize: (Response response) -> void

        def parse: () -> void
      end

      class FilePart #  < SimpleDelegator
        attr_reader original_filename: String
        attr_reader content_type: String

        # @file: Tempfile

        # private

        def initialize: (String filename, String content_type) -> void
      end

      module Part
        def self?.call: [U] (Object & _MultipartInput multipart_input) -> [U, String, String]
                      | (Object & multipart_nested_value input) -> ([StringIO, String, String?] | [File, String, String])
      end

      module MimeTypeDetector
        DEFAULT_MIMETYPE: String

        def self?.call: (::IO file, String filename) -> String?
      end
    end
  end
end