ClearOut

local xPos, yPos, zPos = 0, 0, 0 --location zPos (bigger then zero is below startpoint and smaller then zero is above startpoint)
local xSave, ySave, zSave, dirSave = 0, 0, 0, 0
local direction = 0 --direction in for ways 0 is start position
local al = true --alternate
local al2 = true --alternate2

local firsttime = true
local length, width, height = 0, 0, 0

local args={...}

function main()
    if #args ~= 3 then
        print("ClearOut<height><width><length>")
    else
        length = tonumber(args[1])
        width = tonumber(args[2])
        height = tonumber(args[3])

        for z = 0, height - 1 do
            for x = 0, width - 1 do
                for y = 0, length - 2 do
                    if firsttime then
                        y = y + 1
                        firsttime = false
                    end
                    Forward()
                end
                if x < length - 1 then
                    if al then
                        RightUTurn(true)
                        al = false
                    else
                        LeftUTurn(true)
                        al = true
                    end
                end
            end
            if height > 0 then
                Down()
            else
                Up()
            end
            RightUTurn(false)

            if al2 then
                if direction == 0 then
                    al = false
                else
                    al = true
                end
                al2 = false
            else
                if direction == 0 then
                    al = true
                else
                    al = false
                end
                al2 = true
            end
        end
    end
end

function CheckFuel()
    local fuel = turtle.getFuelLevel()
    local level = xPos + yPos + math.abs(zPos) + 2

    if fuel > level then
        return true;
    else
        print("Taking new fuel from slot 1")
        if turtle.getItemCount(1) > 0 then
            turtle.select(1)
            if turtle.refuel(5) == false then
                print("No fuel in slot")
                SaveLocation()
                print("Going back to chest")
                Goto(0,0,0)
                if CheckChestFuel() == false then
                    RightUTurn(false)
                    error("No fuel in chest")
                end
                CheckFuel()
                RestoreLocation()
            end
        end
    end
end

function Forward()
    CheckFuel()
    while turtle.forward() == false do
        CheckInventory(0)
        turtle.select(2)
        turtle.dig()
    end

    if direction == 0 then
        yPos = yPos + 1
    elseif direction == 2 then
        yPos = yPos - 1
    elseif direction == 1 then
        xPos = xPos + 1
    else
        xPos = xPos - 1
    end
end

function Down()
    CheckFuel()
    while turtle.down() == false do
        CheckInventory(2)
        turtle.select(2)
        turtle.digDown()
    end
    zPos = zPos + 1
end

function Up()
    CheckFuel()
    while turtle.up() == false do
        CheckInventory(1)
        turtle.select(2)
        turtle.digUp()
    end
    zPos = zPos - 1
end

function Left(forward)
    turtle.turnLeft()

    SubstractDirection()

    if forward then
        Forward()
    end
end

function Right(forward)
    turtle.turnRight()

    AddDirection()

    if forward then
        Forward()
    end
end

function AddDirection()
    direction = direction + 1

    if direction > 3 then
        direction = 0
    end
end

function SubstractDirection()
    direction = direction - 1

    if direction < 0 then
        direction = 3
    end
end

function RightUTurn(forward)
    Right(forward)
    Right(false)
end

function LeftUTurn(forward)
    Left(forward)
    Left(false)
end

function Goto(xLoc, yLoc, zLoc)
    while zPos ~= zLoc do
        if zLoc > zPos then
            Up()
        else
            Down()
        end
    end

    while direction ~= 3 do
        if direction == 0 then
            Left(false)
        else
            Right(false)
        end
    end

    while xPos > xLoc do
        Forward()
    end

    Left()

    while yPos > yLoc do
        Forward()
    end
end

function ChangeDirection(dir)
    while direction ~= dir do
        Right(false)
    end
end

function SaveLocation()
    xSave, ySave, zSave, dirSave = xPos, yPos, zPos, direction
end

function RestoreLocation()
    Goto(xSave, ySave, zSave)
    ChangeDirection(dirSave)
end

function CheckInventory(check)
    if turtle.getItemCount(16) > 0 then
        if BlockFit(check) == false then
            print("Inventory is full")
            SaveLocation()
            print("Returning to chest...")
            Goto(0, 0, 0)

            print("Empty inventory")
            EmptyInventory()

            print("Restore location")
            RestoreLocation()
        end
    end
end

function BlockFit(check)
    for i = 1, 16 do
        if turtle.getItemSpace(i) > 0 then
            turtle.select(i)
            if check == 0 then
                if turtle.compare() then
                    return true
                end
            elseif check == 1 then
                if turtle.compareUp() then
                    return true
                end
            else
                if turtle.compareDown() then
                    return true
                end
            end
        end
    end
    return false
end

function EmptyInventory()
    for i = 2, 16 do
        print("Emptying slot " .. i)
        if turtle.getItemCount(i) ~= 0 then
            turtle.select(i)

            if turtle.drop() == false then
                RightUTurn(false)
                error("Chest is full")
            end
        end
    end
end

function GetEmptySlot()
    for i = 2, 16 do
        if turtle.getItemCount(i) == 0 then
            return i
        end
    end
    return 0
end

function CheckChestFuel()
    local slot = GetEmptySlot()
    if slot == 0 then
        EmptyInventory()
    else
        turtle.select(slot)
        for i = 0, 10 do
            if turtle.suck() == false then
                RightUTurn(false)
                error("No fuel found")
            end
            if turtle.drop() == false then
                RightUTurn(false)
                error("Chest is full")
            end
        end
        CheckFuel()
    end
end

main()