module Input
  DOWN=2
  LEFT=4
  RIGHT=6
  UP=8
  A=11
  B=12
  C=13
  X=14
  Y=15
  Z=16
  L=17
  R=18
  SHIFT=21
  CTRL=22
  ALT=23
  F5=25
  F6=26
  F7=27
  F8=28
  F9=29
  # GetAsyncKeyState or GetKeyState will work here
  @GetKeyState=Win32API.new("user32", "GetAsyncKeyState", "i", "i")
  # Returns whether a key is being pressed
  def self.getstate(key)
    return (@GetKeyState.call(key)&0x8000)>0
  end
  def self.update
    if @keystate
      for i in 0...256
        @newstate=self.getstate(i)
        @triggerstate[i]=(@newstate&&@keystate[i]==0)
        @releasestate[i]=(!@newstate&&@keystate[i]>0)
        @keystate[i]=@newstate ? @keystate[i]+1 : 0
      end    
    else
      @keystate=[]
      @triggerstate=[]
      @releasestate=[]
      for i in 0...256
        @keystate[i]=self.getstate(i) ? 1 : 0
        @triggerstate[i]=false
        @releasestate[i]=false
      end
    end
  end
  def self.buttonToKey(button)
   case button
    when Input::DOWN
     return [0x28] # Down
    when Input::LEFT
     return [0x25] # Left
    when Input::RIGHT
     return [0x27] # Right
    when Input::UP
     return [0x26] # Up
    when Input::A
     return [0x5A,0x10] # Z, Shift
    when Input::B
     return [0x58,0x1B] # X, ESC 
    when Input::C
     return [0x43,0x0d,0x20] # C, ENTER, Space
    when Input::X
     return [0x41] # A
    when Input::Y
     return [0x53] # S
    when Input::Z
     return [0x44] # D
    when Input::L
     return [0x51,0x21] # Q, Page Up
    when Input::R
     return [0x57,0x22] # W, Page Up
    when Input::SHIFT
     return [0x10] # Shift
    when Input::CTRL
     return [0x11] # Ctrl
    when Input::ALT
     return [0x12] # Alt
    when Input::F5
     return [0x74] # F5
    when Input::F6
     return [0x75] # F6
    when Input::F7
     return [0x76] # F7
    when Input::F8
     return [0x77] # F8
    when Input::F9
     return [0x78] # F9
    else
     return []
   end
  end
  def self.dir4
   button=0
   repeatcount=0
   if self.press?(Input::DOWN) && self.press?(Input::UP)
     return 0
   end
   if self.press?(Input::LEFT) && self.press?(Input::RIGHT)
     return 0
   end
   for b in [Input::DOWN,Input::LEFT,Input::RIGHT,Input::UP]
    rc=self.count(b)
    if rc>0
     if repeatcount==0 || rc<repeatcount
      button=b
      repeatcount=rc
     end
    end
   end
   return button
  end
  def self.dir8
   buttons=[]
   for b in [Input::DOWN,Input::LEFT,Input::RIGHT,Input::UP]
    rc=self.count(b)
    if rc>0
     buttons.push([b,rc])
    end
   end
   if buttons.length==0
    return 0
   elsif buttons.length==1
    return buttons[0][0]
   elsif buttons.length==2
    # since buttons sorted by button, no need to sort here
    if (buttons[0][0]==Input::DOWN && buttons[1][0]==Input::UP)
     return 0
    end
    if (buttons[0][0]==Input::LEFT && buttons[1][0]==Input::RIGHT)
     return 0
    end
   end
   buttons.sort!{|a,b| a[1]<=>b[1]}
   updown=0
   leftright=0
   for b in buttons
    if updown==0 && (b[0]==Input::UP || b[0]==Input::DOWN)
     updown=b[0]
    end
    if leftright==0 && (b[0]==Input::LEFT || b[0]==Input::RIGHT)
     leftright=b[0]
    end
   end
   if updown==Input::DOWN
    return 1 if leftright==Input::LEFT
    return 3 if leftright==Input::RIGHT
    return 2
   elsif updown==Input::UP
    return 7 if leftright==Input::LEFT
    return 9 if leftright==Input::RIGHT
    return 8
   else
    return 4 if leftright==Input::LEFT
    return 6 if leftright==Input::RIGHT
    return 0
   end
  end
  def self.count(button)
   for btn in self.buttonToKey(button)
     c=self.repeatcount(btn)
     return c if c>0
   end
   return 0
  end 
  def self.trigger?(button)
   return self.buttonToKey(button).any? {|item| self.triggerex?(item) }
  end
  def self.repeat?(button)
   return self.buttonToKey(button).any? {|item| self.repeatex?(item) }
  end
  def self.press?(button)
   return self.count(button)>0
  end
  def self.repeatex?(key)
    return false if !@keystate
    return @keystate[key]==1 || (@keystate[key]>20 && (@keystate[key]&1)==0)
  end
  def self.releaseex?(key)
    return false if !@releasestate
    return @releasestate[key]
  end
  def self.triggerex?(key)
    return false if !@triggerstate
    return @triggerstate[key]
  end
  def self.repeatcount(key)
    return 0 if !@keystate
    return @keystate[key]
  end
  def self.pressex?(key)
    return self.repeatcount(key)>0
  end
end