brancher turtle script

-- Branch Mining Turtle (with Recursion!)
-- Mines and follows ores (and returns!)
-- Variables
turtle.select(1)

term.clear()
term.setCursorPos(1,1)
print(os.getComputerLabel() .. " at your service!")
print()
print("Please place blocks as follows:")
print("Slot 1 - Enderchest")
print("Slot 2 - Stone (Smooth)")
print("Slot 3 - Dirt")
print("Slot 4 - Gravel")
print("Slot 5 - Fuel (coal or lava)")
print()
print("Press [ENTER] when ready.")
read(input)

-- Starting Out
for s = 1,5 do
    if turtle.getItemCount(s) < 1 then
        print("Fill your slots!")
        quit()
    end
end

continue = false
continueStepCount = 0
continueYCount = 0
facing = 0
currentY = 0
currentX = 0
currentZ = 0
maxChase = 100
currentChase = 0

-- Functions
function trackUp()
    if turtle.up() then
        currentZ = currentZ + 1
        return true;
    else
        return false;
    end
end

function trackDown()
    if turtle.down() then
        currentZ = currentZ - 1
        return true;
    else
        return false;
    end
end

function trackForward()
    if turtle.forward() then
        if facing == 0 then
            currentY = currentY + 1
        elseif facing == 1 then
            currentX = currentX + 1
        elseif facing == 2 then
            currentY = currentY - 1
        elseif facing == 3 then
            currentX = currentX - 1
        end
        return true;
    else
        return false;
    end
end

function trackBackward()
    if turtle.back() then
        if facing == 0 then
            currentY = currentY - 1
        elseif facing == 1 then
            currentX = currentX - 1
        elseif facing == 2 then
            currentY = currentY + 1
        elseif facing == 3 then
            currentX = currentX + 1
        end
        return true;
    else
        return false;
    end
end

function trackRight()
    turtle.turnRight()
    facing = facing + 1;
    if facing == 4 then
        facing = 0
    end
end

function trackLeft()
    turtle.turnLeft()
    facing = facing - 1;
    if facing == -1 then
        facing = 3
    end
end

function tfuel()
    if turtle.getItemCount(16) > 0 then emptyOres() end
    if turtle.getFuelLevel() < 16 then
        turtle.select(5)
        turtle.refuel(1)
    end
end

local function turnAround()
    trackRight()
    trackRight()
end

local function attemptForward()
    while trackForward() == false do
        turtle.dig()
        os.sleep(.5)
    end
end

function emptyOres()
    while turtle.detect() == true do
        turtle.dig()
        os.sleep(.5)
    end
    turtle.select(1)
    turtle.place()
    local i
    for i = 6, 16 do
        turtle.select(i)
        turtle.drop()
    end
    turtle.select(1)
    turtle.dig()
    os.sleep(.5)
end

local function checkUp()
    if turtle.detectUp() == false then
        return false;
    end
    local i
    for i = 2, 5 do
        turtle.select(i)
        if turtle.compareUp() == true then
            return false;
        end
    end
    return true;
end

local function checkDown()
    if turtle.detectDown() == false then
        return false;
    end
    local i
    for i = 2, 5 do
        turtle.select(i)
        if turtle.compareDown() == true then
            return false;
        end
    end
    return true;
end

local function checkForward()
    if turtle.detect() == false then
        return false;
    end
    local i
    for i = 2, 5 do
        turtle.select(i)
        if turtle.compare() == true then
            return false;
        end
    end
    return true;
end

-- Recursive ore detection and "chase".
-- 0 is none, 1 is below, 2 is above, 3 is behind
local function detectAndChaseOre(arrivalFrom)
    local retries = 10
    tfuel()
    if arrivalFrom == 0 then
        currentChase = 0
    end
    if checkUp() == true then
        retries = 10
        while currentChase < maxChase and trackUp() == false and retries > 0 do
            turtle.digUp()
            os.sleep(.5)
            retries = retries - 1
        end
        if retries ~= 0 and currentChase < maxChase then
            currentChase = currentChase + 1
            detectAndChaseOre(1)
        end
    end
    if checkDown() == true then
        retries = 10
        while currentChase < maxChase and trackDown() == false and retries > 0 do
            turtle.digDown()
            os.sleep(.5)
            retries = retries - 1
        end
        if retries ~= 0 and currentChase < maxChase then
            currentChase = currentChase + 1
            detectAndChaseOre(2)
        end
    end
    -- check all 4 directions
    local rotation
    for rotation = 0, 3 do
        if checkForward() == true then
            retries = 10
            while currentChase < maxChase and trackForward() == false and retries > 0 do
                turtle.dig()
                os.sleep(.5)
                retries = retries - 1
            end
            if retries ~= 0 and currentChase < maxChase then
                currentChase = currentChase + 1
                detectAndChaseOre(3)
            end
        end
        trackRight()
    end

    if arrivalFrom == 1 then
        trackDown()
    elseif arrivalFrom == 2 then
        trackUp()
    elseif arrivalFrom == 3 then
        trackBackward()
    end
end

local function digBranch()
    local branchLength
    for branchLength = 0, 20 do
        while attemptForward() == false do
            turtle.dig()
        end
        writeStatusDisplay()
        detectAndChaseOre(0)
    end
    turnAround()
    for branchLength = 0, 20 do
        while attemptForward() == false do
            turtle.dig()
        end
        tfuel()
    end
end

function writeContinueFile(theStepCount, theYCount)
    h = fs.open("r86brancont", "w")
    h.writeLine(currentY)
    h.writeLine(currentZ)
    h.writeLine(theStepCount)
    h.writeLine(theYCount)
    h.close()
end

function writeStatusDisplay()
    term.clear()
    term.setCursorPos(1,1)
    print("Current Fuel: " .. turtle.getFuelLevel())
    print("Current Length: " .. (currentY + 1) .. "/52")
    print("Current Height: " .. (math.abs(currentZ) + 1) .. "/9")
end

function digMainChamber()
    local stepCount = 0
    local YCount = 0
    if math.abs(currentZ) % 2 == 1 then
        stepCount = -2
    end
    if continue == true then
        stepCount = continueStepCount
        YCount = continueYCount
        continue = false
    end
    local chamberLength
    for chamberLength = YCount, 51 do
        if stepCount % 4 == 0 then
            writeContinueFile(stepCount, chamberLength)
            trackLeft()
            digBranch()
            digBranch()
            trackRight()
        end
        while attemptForward() == false do
            turtle.dig()
        end
        stepCount = stepCount + 1
        writeStatusDisplay()
        detectAndChaseOre(0)
    end
end

if fs.exists("r86brancont") then
    continue = nil
    while continue ~= "y" and continue ~= "Y" and continue ~= "n" and continue ~= "N" do
        print("Detected previous mining operation")
        print("Continue previous operation? (Y/N)")
    continue = read(input)
    end
    if continue == "Y" or continue == "y" then
        h = fs.open("r86brancont", "r")
        contY = tonumber(h.readLine())
        contZ = tonumber(h.readLine())
        continueStepCount = tonumber(h.readLine())
        continueYCount = tonumber(h.readLine())
        h.close()
        if contY ~= nil and contZ ~= nil and continueStepCount ~= nil and continueYCount ~= nil then
            while currentY ~= contY do
                while trackForward() == false do
                    turtle.dig()
                    os.sleep(.5)
                end
            end
            while currentZ ~= contZ do
                while trackDown() == false do
                    turtle.digDown()
                    os.sleep(.5)
                end
            end
            if contZ % 2 == 1 then
                turnAround()
            end
        continue = true
        else
            print("Unable to continue, file malformation detected")
        fs.delete("r86brancont")
        end
    elseif continue == "N" or continue == "n" then
        print("Starting new mining operation")
    fs.delete("r86brancont")
    end
end

local totalHeight
for totalHeight = math.abs(currentZ),8 do
    digMainChamber()
    turnAround()
    turtle.digDown()
    trackDown()
end
for totalHeight = 0,8 do
    trackUp()
end
turnAround()

fs.delete("r86brancont")
emptyOres()