# Random provides an interface to Ruby's pseudo-random number generator, or
# PRNG.  The PRNG produces a deterministic sequence of bits which approximate
# true randomness. The sequence may be represented by integers, floats, or
# binary strings.
#
# The generator may be initialized with either a system-generated or
# user-supplied seed value by using Random.srand.
#
# The class method Random.rand provides the base functionality of Kernel.rand
# along with better handling of floating point values. These are both interfaces
# to Random::DEFAULT, the Ruby system PRNG.
#
# Random.new will create a new PRNG with a state independent of Random::DEFAULT,
# allowing multiple generators with different seed values or sequence positions
# to exist simultaneously. Random objects can be marshaled, allowing sequences
# to be saved and resumed.
#
# PRNGs are currently implemented as a modified Mersenne Twister with a period
# of 2**19937-1.
#
class Random < Object
  include Random::Formatter

  # Returns true if the two generators have the same internal state, otherwise
  # false.  Equivalent generators will return the same sequence of pseudo-random
  # numbers.  Two generators will generally have the same state only if they were
  # initialized with the same seed
  #
  #     Random.new == Random.new             # => false
  #     Random.new(1234) == Random.new(1234) # => true
  #
  # and have the same invocation history.
  #
  #     prng1 = Random.new(1234)
  #     prng2 = Random.new(1234)
  #     prng1 == prng2 # => true
  #
  #     prng1.rand     # => 0.1915194503788923
  #     prng1 == prng2 # => false
  #
  #     prng2.rand     # => 0.1915194503788923
  #     prng1 == prng2 # => true
  #
  def ==: (untyped arg0) -> bool

  # Returns a random binary string containing `size` bytes.
  #
  #     random_string = Random.new.bytes(10) # => "\xD7:R\xAB?\x83\xCE\xFAkO"
  #     random_string.size                   # => 10
  #
  def bytes: (Integer size) -> String

  # Creates a new PRNG using `seed` to set the initial state. If `seed` is
  # omitted, the generator is initialized with Random.new_seed.
  #
  # See Random.srand for more information on the use of seed values.
  #
  def initialize: (?Integer seed) -> void

  # When `max` is an Integer, `rand` returns a random integer greater than or
  # equal to zero and less than `max`. Unlike Kernel.rand, when `max` is a
  # negative integer or zero, `rand` raises an ArgumentError.
  #
  #     prng = Random.new
  #     prng.rand(100)       # => 42
  #
  # When `max` is a Float, `rand` returns a random floating point number between
  # 0.0 and `max`, including 0.0 and excluding `max`.
  #
  #     prng.rand(1.5)       # => 1.4600282860034115
  #
  # When `max` is a Range, `rand` returns a random number where
  # range.member?(number) == true.
  #
  #     prng.rand(5..9)      # => one of [5, 6, 7, 8, 9]
  #     prng.rand(5...9)     # => one of [5, 6, 7, 8]
  #     prng.rand(5.0..9.0)  # => between 5.0 and 9.0, including 9.0
  #     prng.rand(5.0...9.0) # => between 5.0 and 9.0, excluding 9.0
  #
  # Both the beginning and ending values of the range must respond to subtract
  # (`-`) and add (`+`)methods, or rand will raise an ArgumentError.
  #
  def rand: () -> Float
          | (Integer | ::Range[Integer] max) -> Integer
          | (Float | ::Range[Float] max) -> Float

  # Returns the seed value used to initialize the generator. This may be used to
  # initialize another generator with the same state at a later time, causing it
  # to produce the same sequence of numbers.
  #
  #     prng1 = Random.new(1234)
  #     prng1.seed       #=> 1234
  #     prng1.rand(100)  #=> 47
  #
  #     prng2 = Random.new(prng1.seed)
  #     prng2.rand(100)  #=> 47
  #
  def seed: () -> Integer

  # Returns an arbitrary seed value. This is used by Random.new when no seed value
  # is specified as an argument.
  #
  #     Random.new_seed  #=> 115032730400174366788466674494640623225
  #
  def self.new_seed: () -> Integer

  # Alias of Random::DEFAULT.rand.
  #
  def self.rand: (?Integer max) -> Numeric

  # Seeds the system pseudo-random number generator, Random::DEFAULT, with
  # `number`.  The previous seed value is returned.
  #
  # If `number` is omitted, seeds the generator using a source of entropy provided
  # by the operating system, if available (/dev/urandom on Unix systems or the RSA
  # cryptographic provider on Windows), which is then combined with the time, the
  # process id, and a sequence number.
  #
  # srand may be used to ensure repeatable sequences of pseudo-random numbers
  # between different runs of the program. By setting the seed to a known value,
  # programs can be made deterministic during testing.
  #
  #     srand 1234               # => 268519324636777531569100071560086917274
  #     [ rand, rand ]           # => [0.1915194503788923, 0.6221087710398319]
  #     [ rand(10), rand(1000) ] # => [4, 664]
  #     srand 1234               # => 1234
  #     [ rand, rand ]           # => [0.1915194503788923, 0.6221087710398319]
  #
  def self.srand: (?Integer number) -> Numeric
end

# The default Pseudorandom number generator.  Used by class methods of Random.
#
#
Random::DEFAULT: Random

# Format raw random number as Random does
#
#
module Random::Formatter
  # SecureRandom.base64 generates a random base64 string.
  #
  # The argument *n* specifies the length, in bytes, of the random number to be
  # generated. The length of the result string is about 4/3 of *n*.
  #
  # If *n* is not specified or is nil, 16 is assumed. It may be larger in the
  # future.
  #
  # The result may contain A-Z, a-z, 0-9, "+", "/" and "=".
  #
  #     require 'securerandom'
  #
  #     SecureRandom.base64 #=> "/2BuBuLf3+WfSKyQbRcc/A=="
  #     SecureRandom.base64 #=> "6BbW0pxO0YENxn38HMUbcQ=="
  #
  # If a secure random number generator is not available, `NotImplementedError` is
  # raised.
  #
  # See RFC 3548 for the definition of base64.
  #
  def base64: (?Integer? n) -> String

  # SecureRandom.hex generates a random hexadecimal string.
  #
  # The argument *n* specifies the length, in bytes, of the random number to be
  # generated. The length of the resulting hexadecimal string is twice of *n*.
  #
  # If *n* is not specified or is nil, 16 is assumed. It may be larger in the
  # future.
  #
  # The result may contain 0-9 and a-f.
  #
  #     require 'securerandom'
  #
  #     SecureRandom.hex #=> "eb693ec8252cd630102fd0d0fb7c3485"
  #     SecureRandom.hex #=> "91dc3bfb4de5b11d029d376634589b61"
  #
  # If a secure random number generator is not available, `NotImplementedError` is
  # raised.
  #
  def hex: (?Integer? n) -> String

  # Generates formatted random number from raw random bytes. See Random#rand.
  #
  def rand: () -> Float
          | (?Float? n) -> Float
          | (?Integer? n) -> Integer
          | (?Numeric? n) -> Numeric
          | (?::Range[Float]? n) -> Float
          | (?::Range[Integer]? n) -> Integer
          | (?::Range[Numeric]? n) -> Numeric

  # SecureRandom.random_bytes generates a random binary string.
  #
  # The argument *n* specifies the length of the result string.
  #
  # If *n* is not specified or is nil, 16 is assumed. It may be larger in future.
  #
  # The result may contain any byte: "x00" - "xff".
  #
  #     require 'securerandom'
  #
  #     SecureRandom.random_bytes #=> "\xD8\\\xE0\xF4\r\xB2\xFC*WM\xFF\x83\x18\xF45\xB6"
  #     SecureRandom.random_bytes #=> "m\xDC\xFC/\a\x00Uf\xB2\xB2P\xBD\xFF6S\x97"
  #
  # If a secure random number generator is not available, `NotImplementedError` is
  # raised.
  #
  def random_bytes: (?Integer? n) -> String

  # Generates formatted random number from raw random bytes. See Random#rand.
  #
  def random_number: () -> Float
                   | (?Float? n) -> Float
                   | (?Integer? n) -> Integer
                   | (?Numeric? n) -> Numeric
                   | (?::Range[Float]? n) -> Float
                   | (?::Range[Integer]? n) -> Integer
                   | (?::Range[Numeric]? n) -> Numeric

  # SecureRandom.urlsafe_base64 generates a random URL-safe base64 string.
  #
  # The argument *n* specifies the length, in bytes, of the random number to be
  # generated. The length of the result string is about 4/3 of *n*.
  #
  # If *n* is not specified or is nil, 16 is assumed. It may be larger in the
  # future.
  #
  # The boolean argument *padding* specifies the padding. If it is false or nil,
  # padding is not generated. Otherwise padding is generated. By default, padding
  # is not generated because "=" may be used as a URL delimiter.
  #
  # The result may contain A-Z, a-z, 0-9, "-" and "_". "=" is also used if
  # *padding* is true.
  #
  #     require 'securerandom'
  #
  #     SecureRandom.urlsafe_base64 #=> "b4GOKm4pOYU_-BOXcrUGDg"
  #     SecureRandom.urlsafe_base64 #=> "UZLdOkzop70Ddx-IJR0ABg"
  #
  #     SecureRandom.urlsafe_base64(nil, true) #=> "i0XQ-7gglIsHGV2_BNPrdQ=="
  #     SecureRandom.urlsafe_base64(nil, true) #=> "-M8rLhr7JEpJlqFGUMmOxg=="
  #
  # If a secure random number generator is not available, `NotImplementedError` is
  # raised.
  #
  # See RFC 3548 for the definition of URL-safe base64.
  #
  def urlsafe_base64: (?Integer? n, ?bool padding) -> String

  # SecureRandom.uuid generates a random v4 UUID (Universally Unique IDentifier).
  #
  #     require 'securerandom'
  #
  #     SecureRandom.uuid #=> "2d931510-d99f-494a-8c67-87feb05e1594"
  #     SecureRandom.uuid #=> "bad85eb9-0713-4da7-8d36-07a8e4b00eab"
  #     SecureRandom.uuid #=> "62936e70-1815-439b-bf89-8492855a7e6b"
  #
  # The version 4 UUID is purely random (except the version). It doesn't contain
  # meaningful information such as MAC addresses, timestamps, etc.
  #
  # The result contains 122 random bits (15.25 random bytes).
  #
  # See RFC 4122 for details of UUID.
  #
  def uuid: () -> String
end