--Declare nescessary variables

local x, y = 0,0
local direction = "north"
local homeCoordX, homeCoordY = 0, 0

local digSize = ...

local success, idtable = turtle.inspectDown()

if success and idtable.name == "minecraft:chest" then --Make sure there is a chest at Home
    print("Success")
else
    error("Need chest below turtle to start digging!")
end

function testForAvailableFuel()
    for i = 1, 16 do
        turtle.select(i)
        if turtle.refuel(0) then --If the item in slot i is fuel, then return true but don't use it.
            return true
        end
    end
    return false
end

function testForInvSpace()
    local invTake = 0
    for i = 1, 16 do
        if turtle.getItemDetail(i) then
            invTake = invTake + 1
        end
    end
    if invTake <= 8 then
        return false
    else
        return true
    end
end

function goHomeAndBack()
    local xDig = x
    local yDig = y
    fuel()
    if xDig > 0 then moveForward("west", (0 - xDig)) elseif xDig < 0 then moveForward("east", math.abs(xDig)) end
    if yDig > 0 then moveForward("south", (0 - yDig)) elseif yDig < 0 then moveForward("north", math.abs(yDig)) end
    local success2, idtable2 = turtle.inspectDown()
    if success2 and idtable2.name == "minecraft:chest" then
        for i = 1, 16 do
            turtle.select(i)
            turtle.dropDown()
        end
    end
    if xDig > 0 then moveForward("east", xDig) elseif xDig < 0 then moveForward("west", (0 - xDig)) end
    if yDig > 0 then moveForward("north", yDig) elseif yDig < 0 then moveForward("south", (0 - yDig)) end
end

function fuel()
    local testSuccess = testForAvailableFuel()
    if turtle.getFuelLevel() <= math.floor(turtle.getFuelLimit()/2) and testSuccess == true then --If the turtle's fuel is less than half the limit AND there is fuel available
        for i = 1, 16 do
            turtle.select(i)
            if turtle.refuel(0) then
                turtle.refuel(math.floor(turtle.getItemCount(i)/2))
            end
        end
    else return "No available fuel or too much fuel"
    end
end

function basicDig()
    if turtle.detectUp() then turtle.digUp() end
    if turtle.detectDown() then turtle.digDown() end
    if turtle.detect() then turtle.dig() end
end

function moveForward(dirToGo, amount)
    if dirToGo ~= "north" or dirToGo ~= "south" or dirToGo ~= "east" or dirToGo ~= "west" or amount == 0 then return end
    for i = 1, amount do
        if dirToGo == "north" then --If needs to go north..
            y = y + 1
            if direction == "north" then --And is facing north..
                turtle.forward()
            elseif direction == "south" then --Facing south..
                turtle.turnLeft()
                turtle.turnLeft()
                turtle.forward()
            elseif direction == "west" then
                turtle.turnRight()
                turtle.forward()
            elseif direction == "east" then
                turtle.turnLeft()
                turtle.forward()
            end
            direction = "north"
        elseif dirToGo == "east" then --If needs to go east..
            x = x + 1
            if direction == "north" then
                turtle.turnRight()
                turtle.forward()
            elseif direction == "west" then
                turtle.turnLeft()
                turtle.turnLeft()
                turtle.forward()
            elseif direction == "east" then
                turtle.forward()
            elseif direction == "south" then
                turtle.turnLeft()
                turtle.forward()
            end
            direction = "east"
        elseif dirToGo == "south" then --If needs to go south..
            y = y - 1
            if direction == "south" then
                turtle.forward()
            elseif direction == "north" then
                turtle.turnLeft()
                turtle.turnLeft()
                turtle.forward()
            elseif direction == "east" then
                turtle.turnRight()
                turtle.forward()
            elseif direction == "west" then
                turtle.turnLeft()
                turtle.forward()
            end
            direction = "south"
        elseif dirToGo == "west" then --If needs to go west..
            x = x - 1
            if direction == "west" then
                turtle.forward()
            elseif direction == "east" then
                turtle.turnLeft()
                turtle.turnLeft()
                turtle.forward()
            elseif direction == "south" then
                turtle.turnRight()
                turtle.forward()
            elseif direction == "north" then
                turtle.turnLeft()
                turtle.forward()
            end
            direction = "west"
        end
        fuel()
    end
end

local compassRotation = {"north", "east", "south", "west"}

function turtleTurn(degAmt, startFace) --Use only in emergencies. Not integrated into coordinate plane
    local sNum = startFace
    if degAmt == 90 then
        turtle.turnRight()
        direction = compassRotation[startFace + 1]
    elseif degAmt == 180 then
        turtle.turnRight()
        turtle.turnRight()
        direction = compassRotation[startFace + 2]
    elseif degAmt == 270 then
        turtle.turnLeft()
    end
end

function switch(num)
    if num ~= 4 then return num + 1 end
    if num == 4 then return 1 end
end

function dig(amt) --Dig function; parameter "amt", same as digSize specified in beginning

end

dig(digSize)