-- farmland plot
-- (i'm not sure how hoes work)

local mv = require("movement")
local what_to_plant = "2crops"

local function dropStuffOff(start_from)
  local prev_pos,prev_face = mv.getPosition()
  mv.goBackTo(-1,1,0)
  mv.face(0, 1)
  mv.down()
  mv.dumpInventory(start_from or 4)
  mv.up()
  mv.goBackTo(prev_pos.x, 1, prev_pos.z)
  mv.goBackTo(prev_pos.x, prev_pos.y, prev_pos.z)
  mv.face(prev_face.x, prev_face.z)
end

local function superDig()
  mv.dig()
  mv.forward()
  mv.digUp()
  mv.digDown()

  if mv.isInventoryFull() then dropStuffOff(8) end
end

local function hoe()
  turtle.digUp("right")
end

local function placeOneDirt()
  superDig()
  mv.placeItem("dirt", turtle.placeDown)
end

local function hoeOneDirt()
  mv.forward()
  hoe()
end

local function cubeLayer(action, width, depth)
  for i=1,width do
    mv.nTimes(depth-1, action)
    local turn = mv.turnLeft
    if i%2 == 0 then turn = mv.turnRight end
    if i ~= width then
      turn()
      action()
      turn()
    end
  end
end

local function placeChains()
  turtle.select(mv.findItem("chain"))
  local i = 0
  while turtle.up() do i = i + 1 end
  for j=1,i do
    turtle.down()
    turtle.placeUp()
  end
end

local function tillDirtLayer(pos)
  mv.down()
  mv.digDown()

  mv.goBackTo(pos.x, pos.y-2, pos.z)
  mv.face(1,0)
  hoe()
  cubeLayer(hoeOneDirt, 9, 9)

  mv.goBackTo(pos.x+4, pos.y-2, pos.z-4)
  mv.goBackTo(pos.x+4, pos.y, pos.z-4)
end

local function placeDirtLayer()
  mv.face(1,0)
  mv.digDown()
  mv.placeItem("dirt", turtle.placeDown)

  local pos,_ = mv.getPosition()
  cubeLayer(placeOneDirt, 9, 9)
  mv.goBackTo(pos.x+4, pos.y, pos.z-4)
  mv.down()
  mv.placeItem("dirt", turtle.placeDown)
  mv.placeItem("water", turtle.placeDown)
  tillDirtLayer(pos)

  -- no longer place the dirt there
  -- instead use a hole to stop the water flooding the basement
  mv.placeItem("slab", turtle.placeDown)
  mv.up()
  mv.placeItem("lantern", turtle.placeDown)

  mv.goBackTo(pos.x, pos.y+1, pos.z)
  placeChains()
  mv.digUp()
  mv.placeItem("lantern", turtle.placeUp)

  mv.goBackTo(-1,1,-1)
  mv.down()
  mv.placeItem("minecraft:bucket", turtle.placeDown)

  mv.goBackTo(0,0,0)
  mv.face(1,0)
end

local function placeGrid(n,m)
  local dirt_needed = m*n*9*9/64
  print(string.format("we will need %d stacks of dirt", dirt_needed))

  for i=0,n-1 do
    for j=0,m-1 do
      mv.goBackTo(1+i*9,1,-j*9)
      local success, data = turtle.inspectDown()
      if success and data.state.age ~= nil then
        print(string.format("skipping plot at position (%d, %d)", i, j))
      else
        mv.down()
        placeDirtLayer()
      end
    end
  end
end

local function growOnePlant()
  local success, data = turtle.inspectDown()
  if success and data.name:find("lantern") then
    mv.forward()
    return
  end
  if success and data.state.age == 7 then
    mv.digDown()
    if mv.isInventoryFull() then dropStuffOff() end
  elseif success and data.state.age < 7 then
    mv.forward()
    return
  end

  turtle.select(mv.findItem(what_to_plant))
  turtle.placeDown()
  mv.forward()
end

local function growInPlane(n,m)
  mv.goBackTo(1,1,0)
  mv.face(1,0)

  cubeLayer(growOnePlant, n*9, m*9)

  mv.goBackTo(0,1,0)
  mv.goBackTo(0,0,0)
  mv.face(1,0)
end

local function main(args)
  if #args == 0 then
    placeGrid(2, 2)
  elseif args[1] == "grow" then
    growInPlane(tonumber(args[2] or 2), tonumber(args[3] or 2))
  elseif #args == 2 then
    placeGrid(tonumber(args[1]), tonumber(args[2]))
  else
    print("usage: farmland [grow|dig] [depth] [width]")
    print("got the wrong number of args...")
  end
end

local args = {...}
main(args)