module HTTPX
  class Headers
    include _ToS

    @headers: headers_hash

    def self.new: (?untyped headers) -> Headers

    def ==: (untyped other) -> bool

    def []: (headers_key field) -> _ToS?
    def []=: (headers_key field, headers_value value) -> void

    def add: (headers_key field, string value) -> void
    def delete: (headers_key field) -> void

    def each: () { (headers_key, String) -> void } -> void
            | () -> Enumerable[[headers_key, String], void]

    def get: (headers_key field) -> Array[String]
    def key?: (headers_key downcased_key) -> bool

    def merge: (_Each[headers_key, headers_value] other) -> Headers

    def same_headers?: (untyped headers) -> bool

    def to_a: () -> Array[[headers_key, String]]
    def to_hash: () -> Hash[headers_key, String]
    alias to_h to_hash

    def inspect: () -> String 

    private

    def initialize: (headers?) -> untyped
    def array_value: (headers_value) -> Array[String]
    def downcased: (headers_key) -> String
  end

  type headers_key = String | Symbol
  type headers_value = _ToS | Array[_ToS]
  type headers_hash = Hash[headers_key, headers_value]
  type headers_input = headers_hash | Array[[headers_key, string]]
  type headers = Headers | headers_input
end