main

local blockIdx = 1
local slabIdx = 5
local wallIdx = 9
local torchIdx = 13

function selectOrDie(idx)
  turtle.select(idx)
  if turtle.getItemCount() <= 0 then
    error("Out of items at idx: "..idx)
  end
end

function initial()
  turtle.up()
  selectOrDie(slabIdx)
  turtle.placeDown()
  turtle.turnRight()
  turtle.forward()
  turtle.turnLeft()
  turtle.placeDown()
end

function bridge()
  turtle.forward()
  selectOrDie(blockIdx)
  turtle.placeDown()
  turtle.turnRight()
  turtle.forward()
  selectOrDie(wallIdx)
  turtle.placeDown()
  turtle.up()
  turtle.placeDown()
  turtle.turnLeft()
  turtle.turnLeft()
  turtle.forward()
  turtle.down()
  turtle.forward()
  selectOrDie(blockIdx)
  turtle.placeDown()
  turtle.forward()
  selectOrDie(wallIdx)
  turtle.placeDown()
  turtle.up()
  turtle.placeDown()
  turtle.turnRight()
  turtle.turnRight()
  turtle.forward()
  turtle.down()
  turtle.forward()
  turtle.turnLeft()
end

function turnAround()
  turtle.turnRight()
  turtle.turnRight()
end

function torch()
  selectOrDie(torchIdx)
  turtle.up()
  turtle.turnRight()
  turtle.place()
  turnAround()
  turtle.forward()
  turtle.place()
  turnAround()
  turtle.forward()
  turtle.turnLeft()
  turtle.down()
end

--initial()
for i=1,1 do
  bridge()
end
torch()