local screen_w, screen_h

local kill_messages = { "", "DOUBLE KILL", "TRIPLE KILL", "QUADRA KILL", "PENTA KILL" }
local kill_manager = { }
local kill_count = 0
local kill_message_font = draw.CreateFont( "Tahoma", 20, 700 )

local function clean_objects( )
   for i = #kill_manager, 1, -1 do
      table.remove( kill_manager, i )
   end
   kill_count = 0
end

local function kill_count_clamp( value )
   if ( value > #kill_messages ) then
      return #kill_messages
   else
      return value
   end
end

local function game_event_listener( event )
   if ( event:GetName() == "round_start" or event:GetName() == "game_start" ) then
      clean_objects( )
   end

   if ( event:GetName() == "player_death" ) then
      local local_player_index = client.GetLocalPlayerIndex( )

      local attacker_uid = event:GetInt( 'attacker' )
      local attacker_index = client.GetPlayerIndexByUserID( attacker_uid )

      if ( local_player_index == attacker_index ) then
         kill_count = kill_count + 1

         kill_manager[#kill_manager + 1] = {
            x = screen_w / 2,
            y = screen_h / 2,
            angle = math.rad( math.random( 0, 360 ) ),
            string = kill_messages[kill_count_clamp( kill_count )],
            adjusted = false
         }
      end
   end
end

client.AllowListener( "player_death" )
callbacks.Register( "FireGameEvent", game_event_listener )

local function draw_text( x, y, font, string, r, g, b, a )
  draw.SetFont( font )
  draw.Color( r, g, b, a )
  draw.Text( x, y, string )
end

local function check_screen_bound( x, y, size_x, size_y )
   if ( x > 0 and x + size_x < screen_w and y > 0 and y + size_y < screen_h ) then
      return true
   else
      return false
   end
end

local function center_string( object, size_x, size_y )
   object.x = object.x - size_x
   object.y = object.y - size_y
   object.adjusted = true
end

local function draw_messages( )
   if ( not engine.GetServerIP( ) ) then
      clean_objects( )
      return
   end

   screen_w, screen_h = draw.GetScreenSize( )

   for i = #kill_manager, 1, -1 do
      local string_size_x, string_size_y = draw.GetTextSize( kill_manager[i].string )

      if ( not kill_manager[i].adjusted ) then
         center_string( kill_manager[i], string_size_x, string_size_y )
      end

      local x = math.sin( kill_manager[i].angle ) * 1.5
      local y = math.cos( kill_manager[i].angle ) * 1.5
      kill_manager[i].x = kill_manager[i].x + x
      kill_manager[i].y = kill_manager[i].y + y

      local in_screen_bounds = check_screen_bound( kill_manager[i].x, kill_manager[i].y, string_size_x, string_size_y )

      if ( in_screen_bounds ) then
         draw_text( kill_manager[i].x, kill_manager[i].y, kill_message_font, kill_manager[i].string, 255, 255, 255, 255 )
      elseif ( not in_screen_bounds ) then
         table.remove( kill_manager, i )
      end
   end
end

callbacks.Register( "Draw", draw_messages )