function world_init()
  worldtiles = {}
  --test start
  bob = build(3,2,buildings.jam_workshop)
  bob = replace(bob, buildings.city)
  destroy(bob)
  --test end
end

function world_update()
  if (btnp(5)) compute_effect_array(worldtiles)
end

function world_draw()
  draw_array(worldtiles)
end


buildings = {
  jam_workshop = 
  {
    sprite = 1,
    inputs = {
      {fruit = 2}
    },
    outputs = {jam = 3}
  },
  city = 
  {
    sprite = 5,
    inputs = {jam = 1},
    outputs = {money = 1}
  },
}


function draw_ressource_bar()
  rectfill(0, 0, 127, 7, 1)
  for _,res in pairs(ressources) do
    spr(res.sprite, res.x, 0)
    print(res.quantity, res.x + 8, 1, 6)
  end
end

          
function updatecycle()

end

function compute_effect_array(array)
  for obj in all(array) do
    obj.compute_effet(obj)
  end
end

function draw_array(array)
  for obj in all(array) do
    obj.draw(obj)
  end
end



function new_worldtile(x, y, building)
    local worldtile = {}
    worldtile.x = x
    worldtile.y = y
    worldtile.building = building
    worldtile.draw = function(this)
      spr(worldtile.building.sprite,worldtile.x*2*8,8+worldtile.y*2*8, 2, 2)
    end
    worldtile.compute_effet = function(this)
        for _,input in pairs(worldtile.building.inputs) do
          --input.
        end
    end
    return worldtile
end

function build(x, y, building)
    newtile = new_worldtile(x,y,building)
    add(worldtiles, newtile)
    return newtile
end

function destroy(worldtile)
    del(worldtiles, worldtile)
end

function replace(worldtile, building)
    destroy(worldtile)
    return build(worldtile.x, worldtile.y, building)
end