-- wget https://mc.cortan122.de/cc/flatten.lua

local mv = require("movement")

local function placeTorch()
  mv.turnAround()
  mv.placeItem("torch", turtle.place)
  mv.turnAround()
end

local function placeFloor()
  local success, data = turtle.inspectDown()
  if not success then
    mv.placeItem("minecraft:cobblestone", turtle.placeDown)
  elseif data.name:find("torch") then
    turtle.digDown()
    mv.placeItem("minecraft:cobblestone", turtle.placeDown)
  end
end

local function digWithFloor()
  turtle.dig()
  mv.forward()
  turtle.digUp()
  placeFloor()
end

local function clearOneRow(n, torches, rotate)
  for i=1,n do
    digWithFloor()
    if torches and i % 7 == 1 then
      placeTorch()
    end
  end
  rotate()
  digWithFloor()
  if torches and (n+1) % 7 == 1 then
    placeTorch()
  end
  rotate()
end

local function clearSquare(n, m)
  if not (n % 7 == 1) then n = math.ceil(n/7)*7+1 end
  if not (m % 7 == 1) then m = math.ceil(m/7)*7+1 end

  local area = n*m
  local perimeter = n+m
  local torches = area/7/7 + perimeter/7 + 1

  print(string.format("flattening %dx%d area", n, m))
  print(string.format("we need %d torches", torches))
  for i=1,m do
    if i % 2 == 1 then
      clearOneRow(n-1, i % 7 == 1, turtle.turnRight)
    else
      clearOneRow(n-1, i % 7 == 1, turtle.turnLeft)
    end
  end
end

local args = {...}

print("program called with", table.concat(args, ", "))
print("note: n and m will be rounded up")
clearSquare(args[1], args[2])