local scene = {}
local love = assert( love )

local callbacks = {
  draw = true,
  mousepressed = true,
  mousemoved = true,
  keypressed = true,
  update = true,
  resize = true,
}

local mt = {}

print( 'scene', scene )

function scene.loadScene( scen, params )
  print( "Loading Scene:", scen.name )
  for k, v in pairs( callbacks ) do
    if not scen[k] then print( "Warning: scene missing callback.", scen.name, k ) end
    love[k] = scen[k] or love[k]
  end
  scen:onLoad( params )
end

local function newScene( scenes, name, t )
  t.name = t.name or name
  print( "Adding Scene:", t.name )
  setmetatable( t, { __call = function() return scene.loadScene( t ) end } )
  rawset( scenes, name, t )
end

function scene.overlayScene( scen, params )
  print( "Adding Scene:", scen.name )
  for k, v in pairs( callbacks ) do
    local old = love[k]
    local new = scen[k]
    if new then
      love[k] = function( ... ) return new( ... ) and old( ... ) end
    end
  end
  scen:onLoad( params )
end

return setmetatable( scene,
  {__call = scene.loadScene,
    __newindex = newScene
    } )