chop.lua

local xPos,zPos = 0,-1
local xDir,zDir = 0,1
local depth = 0
local trees = 0  -- trees or saplings detected
local choppedTrees = 0

local tArgs = { ... }
if #tArgs < 2 then
    print( "Usage: chop <front_size> <right_size>" )
    print( "Pattern: ")
    print( "###" )
    print( "###" )
    print( "###" )
    print( "^    <-turtle, chest" )
    return
end
zSize = tonumber( tArgs[1] ) -- front_size
xSize = tonumber( tArgs[2] ) -- right_size
cycleDelay = 10
if #tArgs > 2 then
    cycleDelay = tonumber( tArgs[3] )
end




local function checkFuel(needed)
    local fuelLevel = turtle.getFuelLevel()
    if fuelLevel == "unlimited" then
        return true
    end
    return fuelLevel >= needed
end

-- position: in front of a tree
local function chopForward()
    turtle.dig()
    while not turtle.forward() do
        turtle.attack()
        sleep(1)
    end

    local height = 0
    while true do
        local r, item = turtle.inspectUp()
        if r then
            if item.name == "minecraft:log" then
                turtle.digUp()
                while not turtle.up() do
                    turtle.digUp()
                    sleep(1)
                end
                height = height + 1
            else
                break
            end
        else
            break
        end
    end
    while height > 0 do
        while not turtle.down() do
            turtle.digDown()
            sleep(1)
        end
        height = height - 1
    end

    while not turtle.digDown() do
        sleep(1)
    end

    choppedTrees = choppedTrees + 1

    for slot=1,16 do
        local t = turtle.getItemDetail(slot)
        if t then
            if t.name == "minecraft:sapling" then
                turtle.select(slot)
                while not turtle.placeDown() do
                    sleep(1)
                end
                turtle.select(1)
                return
            end
        end
    end
end

local function countSaplings()
    local count = 0
    for slot=1,16 do
        local t = turtle.getItemDetail(slot)
        if t then
            if t.name == "minecraft:sapling" then
                count = count + t.count
            end
        end
    end
    return count
end

-- position: above the chest
local function unload()
    local r, block = turtle.inspectDown()
    if not r then
        return false
    end
    if block.name ~= "minecraft:chest" then
        return false
    end

    for slot=1,16 do
        local t = turtle.getItemDetail(slot)
        if t then
            if t.name ~= "minecraft:sapling" then
                turtle.select(slot)
                if not turtle.dropDown() then
                    -- no space
                    return false
                end
            end
        end
    end

    -- optimize saplings
    for slot=2,16 do
        for i=1,slot-1 do
            if turtle.getItemCount(slot) == 0 then
                break
            end
            turtle.select(slot)
            turtle.transferTo(i)
        end
    end

    turtle.select(1)
    return true
end

-- position: above the chest
local function unloadSaplings()
    local toUnload = 0
    if trees > 0 then
        -- unload saplings
        local saplings = countSaplings()
        if saplings > trees then
            toUnload = saplings - trees
        end
    end

    if toUnload == 0 then
        return true
    end

    for slot=1,16 do
        local t = turtle.getItemDetail(slot)
        if t and toUnload > 0 then
            if t.name == "minecraft:sapling" then
                local slotUnload = t.count
                if toUnload < t.count then
                    slotUnload = toUnload
                end
                turtle.select(slot)
                if not turtle.dropDown(slotUnload) then
                    -- no space
                    return false
                end
                toUnload = toUnload - slotUnload
            end
        end
    end

    turtle.select(1)
    return true
end

local function forceForward()
    while true do
        if turtle.forward() then
            xPos = xPos + xDir
            zPos = zPos + zDir
            if not turtle.inspectDown() then
                -- suck only if there is no chest below
                turtle.suckDown()
            end
            return
        end

        local r, block = turtle.inspect()
        if r then
            if block.name == "minecraft:log" then
                chopForward()
                xPos = xPos + xDir
                zPos = zPos + zDir
                return
            end
        else
            turtle.attack()
            sleep(0.5)
        end
    end
end

local function turnLeft()
    turtle.turnLeft()
    xDir, zDir = -zDir, xDir
end

local function turnRight()
    turtle.turnRight()
    xDir, zDir = zDir, -xDir
end

local function gotoDir(xd, zd)
    while (xDir ~= xd) or (zDir ~= zd) do
        turnLeft()
    end
end

local function goto(x, z, xd0, zd0)
    if (xPos ~= x) or (zPos ~= y) then
        local xd = 0
        if (xPos-x) < 0 then
            xd = 1
        else
            xd = -1
        end

        local zd = 0
        if (zPos-z) < 0 then
            zd = 1
        else
            zd = -1
        end

        gotoDir(xd, 0)
        while xPos ~= x do
            forceForward()
        end

        gotoDir(0, zd)
        while zPos ~= z do
            forceForward()
        end
    end

    gotoDir(xd0, zd0)
end

local function goNext()
    local z = zPos + zDir
    if (z>=0) and (z<zSize) then
        forceForward()
        return true
    end
    -- can't move forward, try to shift

    if (xPos+1) >= xSize then
        -- can't shift
        return false
    end
    local zd = zDir
    if zd==1 then
        turnRight()
    else
        turnLeft()
    end
    forceForward()
    if zd==1 then
        turnRight()
    else
        turnLeft()
    end
    return true
end

-- position: above the chest
local function chopCycle()
    if not checkFuel((zSize + 1) * (xSize + 1) * 2) then
        print("Not enough fuel")
        return false
    end

    if not unload() then
        print("Unload failed")
        return false
    end

    -- reset tree counter
    trees = 0

    while goNext() do
        turtle.suckDown()

        local r, block = turtle.inspectDown()
        if r then
            if block.name == "minecraft:sapling" then
                trees = trees + 1
            end
        end
    end
    -- save a copy to ignore trees on a way back
    local trees2 = trees

    goto(0, -1, 0, 1)

    trees = trees2
    print("Trees: "..trees)

    return true
end


while true do
    -- initial position: above the chest

    local saplingsBefore = countSaplings()
    local fuelBefore = turtle.getFuelLevel()

    choppedTrees = 0
    if not chopCycle() then
        return
    end
    local saplingsAfter = countSaplings()
    local fuelAfter = turtle.getFuelLevel()

    local deltaSaplings = saplingsAfter - saplingsBefore
    local saplingsBudget = saplingsAfter - trees
    local deltaFuel = 0
    if fuelAfter ~= "unlimited" then
        deltaFuel = fuelAfter - fuelBefore
    end

    print("chopped: "..choppedTrees..", saplings: "..deltaSaplings..", fuel: "..deltaFuel)

    if not unload() then
        print("Unload failed")
        return
    end
    if not unloadSaplings() then
        print("Unload failed")
        return
    end

    if choppedTrees == 0 or saplingsBudget >= 0 then
        sleep(cycleDelay)
    end
end

-- turtle.inspectDown()
-- true, {name="minecraft:sapling", metadata=2}
-- true, {name="minecraft:log", metadata=2}

-- turtle.getItemDetail(slot)
-- {count=1, name="minecraft:sapling", damage=2}