tree

local TARGET_WOOD = arg[1] or "minecraft:spruce"

local MAX_HEIGHT = 50
local FUEL_THRESHOLD = MAX_HEIGHT * 2 + 20

local LOG = TARGET_WOOD .. "_log"
local SAPLING = TARGET_WOOD .. "_sapling"

local function forward()
    while not turtle.forward() do
        turtle.dig()
    end
end

local function hasItem(name)
    for slot = 1, 16 do
        local info = turtle.getItemDetail(slot)

        if info and info.name == name then
            return true, info.count, slot
        end
    end

    return false, 0, 1
end

local function checkEnvironment()
    turtle.turnLeft()

    if not turtle.suck(4) then
        turtle.turnRight()

        return false, "Missing sapling storage, or no saplings in storage!"
    end

    if not hasItem(SAPLING) then
        turtle.turnRight()

        return false, "Non-sapling items in sapling storage!"
    end

    turtle.drop(4)

    turtle.turnRight()

    local exists, info = turtle.inspect()

    if not exists or not info.name:match(TARGET_WOOD) then
        return false, "Missing tree!"
    end

    return true
end

-- cycle functions

local function waitForTree()
    while true do
        local exists, block = turtle.inspect()

        if exists and block.name == LOG then
            break
        end

        if not exists or block.name ~= SAPLING then -- we're not looking at a sapling? look around, maybe we're out of alignment
            turtle.turnRight()
        end

        sleep(1)
    end
end

local function chopTree()
    forward()

    local y = 0

    while turtle.detectUp() do
        turtle.dig()
        turtle.turnRight()
        turtle.dig()
        turtle.turnLeft()

        turtle.digUp()
        turtle.up()

        if y > MAX_HEIGHT then
            break
        end

        y = y + 1
    end

    turtle.dig()

    turtle.turnRight()
    forward()
    turtle.turnLeft()
    forward()

    for _ = 1, y do
        turtle.digDown()
        turtle.down()
    end

    turtle.back()
    turtle.turnRight()
    turtle.back()
    turtle.turnLeft()
    turtle.back()
end

local function checkFuel()
    if turtle.getFuelLevel() > FUEL_THRESHOLD then
        return
    end

    for slot = 1, 16 do
        local info = turtle.getItemDetail(slot)

        if info then
            turtle.select(slot)

            local isCombustable = turtle.refuel(0)

            if isCombustable then
                turtle.refuel(16)
            end
        end
    end

    checkFuel()
end

local function dropoffItems()
    turtle.turnLeft()
    turtle.turnLeft()

    for slot = 1, 16 do
        local info = turtle.getItemDetail(slot)

        if info then
            turtle.select(slot)

            if info.name == LOG then
                turtle.drop(info.count)
            elseif info.name == SAPLING then
                turtle.turnRight()
                turtle.drop(info.count)
                turtle.turnLeft()
            else
                turtle.turnLeft()
                turtle.drop(info.count)
                turtle.turnRight()
            end
        end
    end

    turtle.select(1)

    turtle.turnRight()
    turtle.turnRight()
end

local function replantTree()
    local exists, count, slot = hasItem(SAPLING)

    if not exists or count < 4 then
        turtle.turnLeft()

        if slot then
            turtle.select(slot)
            turtle.transferTo(1)
            turtle.select(1)
        end

        turtle.suck(4 - count)
        turtle.turnRight()
    end

    local _, newCount = hasItem(SAPLING)

    if newCount < 4 then
        printError("Not enough saplings in storage!")

        sleep(30)

        return replantTree()
    end

    turtle.forward()
    turtle.forward()

    for _ = 1, 2 do
        turtle.turnRight()
        turtle.place()
        turtle.turnLeft()
        turtle.back()
        turtle.place()
    end
end

term.clear()
term.setCursorPos(1, 1)

print("checking environment")

local good, reason = checkEnvironment()

if not good then
    printError(reason)

    return
end

print("env good")

local cycles = 0

while true do
    print("waiting for tree...")
    waitForTree()

    print("chop cycle " .. cycles)
    chopTree()

    print("checking fuel...")
    checkFuel()

    dropoffItems()

    print("replanting...")
    replantTree()

    cycles = cycles + 1
end