local VERSION = "0.1.0"
local IDLE_TIME = 2

function isMatureCrop()
  local isBlock, block = turtle.inspect()

  local blockStateAge = block and block.state and block.state.age
  return blockStateAge == 7
end

function isInventory()
  local periph = peripheral.wrap('front')

  if not periph then
    return false
  end

  return peripheral.hasType(periph, 'inventory')
end

function isSeed(item)
  local tags = item.tags or {}
  return tags['forge:seeds'] or tags['mysticalagriculture:seeds'] or false
end

function selectSeed()
  for i=1, 16,1 do
    local details = turtle.getItemDetail(i, true)

    if details and isSeed(details) then
      turtle.select(i)
      return true
    end
  end

  error("selectSeed error: seed not found")
end

function strictDrop(idx)
  if turtle.getSelectedSlot() ~= idx then
    turtle.select(idx)
  end

  local ok, err = turtle.drop()

  if not ok then
    error('strictDrop error: ' .. err)
  end

  return true
end

function dropAll()
  for i=1, 16, 1 do
    local count = turtle.getItemCount(i)

    if count > 0 then
      strictDrop(i)
    end
  end
end

function waitFor(predicate, sleepTime)
  while true do
    local result = predicate()

    if result ~= nil and result ~= false then
      return result
    end

    os.sleep(sleepTime)
  end
end

function emptyInventory()
  turtle.turnLeft()
  turtle.turnLeft()

  waitFor(isInventory, IDLE_TIME)
  dropAll()

  turtle.turnLeft()
  turtle.turnLeft()
end

function main()
  while true do
    waitFor(isMatureCrop, IDLE_TIME)
    turtle.dig()
    selectSeed()
    turtle.place()
    emptyInventory()
  end
end

print("Starting Trap's simple harvester v" .. VERSION)
print("=========================")
print()
main()