# Extend Numeric with simple angle conversion methods,
# for easier integration with Chipmunk.
class ::Numeric
  def degrees_to_radians
    self * Math::PI / 180.0
  end

  def radians_to_degrees
    self * 180.0 / Math::PI
  end

  def gosu_to_radians
    (self - 90) * Math::PI / 180.0
  end

  def radians_to_gosu
    self * 180.0 / Math::PI + 90
  end
end

# Backwards compatibility:
# Support for KbLeft instead of KB_LEFT and Gp3Button2 instead of GP_3_BUTTON_2.
# Also import old-style constants into Gosu::Button.
module Gosu::Button; end
Gosu.constants.grep(/^KB_|MS_|GP_/).each do |c|
  old_name = case c
  when :KB_ISO then "KbISO"
  when :KB_NUMPAD_PLUS then "KbNumpadAdd"
  when :KB_NUMPAD_MINUS then "KbNumpadSubtract"
  when :KB_EQUALS then "KbEqual"
  when :KB_LEFT_BRACKET then "KbBracketLeft"
  when :KB_RIGHT_BRACKET then "KbBracketRight"
  else c.to_s.capitalize.gsub(/_(.)/) { $1.upcase }
  end
  Gosu.const_set old_name, Gosu.const_get(c)
  Gosu::Button.const_set old_name, Gosu.const_get(c)
end

# Backwards compatibility:
# Passing a Window to initialize and from_text has been deprecated in Gosu 0.9.
class Gosu::Image
  alias initialize_without_window initialize

  def initialize(*args)
    if args[0].is_a? Gosu::Window
      if args.size == 7
        initialize_without_window args[1], :tileable => args[2], :rect => args[3..-1]
      else
        initialize_without_window args[1], :tileable => args[2]
      end
    else
      initialize_without_window(*args)
    end
  end

  class << self
    alias from_text_without_window from_text
  end

  def self.from_text(*args)
    if args.size == 4
      from_text_without_window(args[1], args[3], :font => args[2])
    elsif args.size == 7
      from_text_without_window(args[1], args[3], :font => args[2],
        :spacing => args[4], :width => args[5], :align => args[6])
    else
      from_text_without_window(*args)
    end
  end
end

# Backwards compatibility:
# Passing a Window to Sample#initialize has been deprecated in Gosu 0.7.17.
class Gosu::Sample
  alias initialize_without_window initialize

  def initialize(*args)
    args.shift if args.first.is_a? Gosu::Window
    initialize_without_window(*args)
  end
end

# Backwards compatibility:
# Passing a Window to Song#initialize has been deprecated in Gosu 0.7.17.
class Gosu::Song
  alias initialize_without_window initialize

  def initialize(*args)
    args.shift if args.first.is_a? Gosu::Window
    initialize_without_window(*args)
  end
end

# Color constants.
# This is cleaner than having SWIG define them.
module Gosu
  class ImmutableColor < Color
    private :alpha=, :red=, :green=, :blue=, :hue=, :saturation=, :value=
  end

  class Color
    NONE    = Gosu::ImmutableColor.new(0x00_000000)
    BLACK   = Gosu::ImmutableColor.new(0xff_000000)
    GRAY    = Gosu::ImmutableColor.new(0xff_808080)
    WHITE   = Gosu::ImmutableColor.new(0xff_ffffff)
    AQUA    = Gosu::ImmutableColor.new(0xff_00ffff)
    RED     = Gosu::ImmutableColor.new(0xff_ff0000)
    GREEN   = Gosu::ImmutableColor.new(0xff_00ff00)
    BLUE    = Gosu::ImmutableColor.new(0xff_0000ff)
    YELLOW  = Gosu::ImmutableColor.new(0xff_ffff00)
    FUCHSIA = Gosu::ImmutableColor.new(0xff_ff00ff)
    CYAN    = Gosu::ImmutableColor.new(0xff_00ffff)

    alias hash gl
    def eql?(other)
      gl == other.gl
    end
  end
end

class Gosu::Window
  # Backwards compatibility:
  # Class methods that have been turned into module methods.

  def self.button_id_to_char(id)
    Gosu.button_id_to_char(id)
  end

  def self.char_to_button_id(ch)
    Gosu.char_to_button_id(ch)
  end

  # Backwards compatibility:
  # Instance methods that have been turned into module methods.

  %w(draw_line draw_triangle draw_quad
     flush gl clip_to record
     transform translate rotate scale
     button_id_to_char char_to_button_id button_down?).each do |method|
    define_method method.to_sym do |*args, &block|
      Gosu.send method, *args, &block
    end
  end

  # Call Thread.pass every tick, which may or may not be necessary for friendly co-existence with
  # Ruby's Thread class.

  alias _tick tick

  def tick
    Thread.pass
    _tick
  end
end

# Backwards compatibility:
# This was renamed, because it's not actually a "copyright notice" (Wikipedia: https://en.wikipedia.org/wiki/Copyright_notice).
Gosu::GOSU_COPYRIGHT_NOTICE = Gosu::LICENSES

# Release OpenAL resources during Ruby's shutdown, not Gosu's.
at_exit do
  begin
    Gosu::Song.current_song.stop if Gosu::Song.current_song
    Gosu._release_all_openal_resources
  rescue
  end
end