--ThreeByThree
--Dustin Luhmann
--Version 1.0.0
--3/3/2015
--http://pastebin.com/32Y3CdgA

--[[TO RUN: pastebin get 32Y3CdgA <filename>; <filename>]]
--Example > pastebin get 32Y3CdgA test
--        > test
TUNNEL_DISTANCE = 50 --Blocks

TORCH_IDX = 2
TORCH_SPACING = 10 -- 10 --Blocks
TORCH_HEIGHT = 0 --Blocks
INVENTORY_SPACE = 16

DIRECTION_OF_CHEST_FROM_HOME = "west"


HOME_POSITION = {0,0,0} --{X,Y,Z}
HEADINGS = {"north","east","south","west"}
X_IDX = 1
Y_IDX = 2
Z_IDX = 3

currentPosition = {0,0,0}
heading = 1
isFull = false

function mine()
    turtle.dig()
end

function mineUp()
    turtle.digUp()
end

function mineDown()
    turtle.digDown()
end

function forward()
    if HEADINGS[heading] == "north" then
        currentPosition[Y_IDX] = currentPosition[Y_IDX] + 1
    elseif HEADINGS[heading] == "south" then
        currentPosition[Y_IDX] = currentPosition[Y_IDX] - 1
    elseif HEADINGS[heading] == "east" then
        currentPosition[X_IDX] = currentPosition[X_IDX] + 1
    elseif HEADINGS[heading] == "west" then
        currentPosition[X_IDX] = currentPosition[X_IDX] - 1
    end
    turtle.forward()
end

function turnLeft()
    if HEADINGS[heading] == "north" then
        heading = 4
    else
        heading = heading - 1
    end
    turtle.turnLeft()
end

function turnRight()
    if HEADINGS[heading] == "west" then
        heading = 1
    else
        heading = heading + 1
    end
    turtle.turnRight()
end

function up()
    currentPosition[Z_IDX] = currentPosition[Z_IDX] + 1
    turtle.digUp()
    turtle.up()
end

function down()
    currentPosition[Z_IDX] = currentPosition[Z_IDX] - 1
    turtle.digDown()
    turtle.down()
end

function checkSpace()
    for i = 1, INVENTORY_SPACE do
        if turtle.getItemCount(i) == 0 then
            return true
        end
    end
    isFull = true
    return false
end

function mineThreeHigh()
    up()
    up()
    mine()
    down()
    mine()
    down()
    mine()
    while turtle.detect() do
        mine()
        wait()
    end
end

function threeByThree()
    local distanceTraveled = 0
    while distanceTraveled < TUNNEL_DISTANCE and turtle.detect() and checkSpace() do
        mineThreeHigh()
        turnLeft()
        forward()
        turnRight()
        mineThreeHigh()
        turnRight()
        forward()
        forward()
        turnLeft()
        mineThreeHigh()
        turnLeft()
        forward()
        turnRight()
        if (distanceTraveled % TORCH_SPACING == 0) then
            placeTorch()
        end
        forward()
        distanceTraveled = distanceTraveled + 1
    end
    turnLeft()
    turnLeft()
    for i = 1, distanceTraveled do
        forward()
    end
    turnRight()
    turnRight()
end

function wait()
   turnLeft()
   turnRight()
end

function returnHome()
    if currentPosition[Z_IDX] > 0 then
        while turtle.detectDown() do
            mineDown()
            wait()
        end
        down()
    elseif currentPosition[Z_IDX] < 0 then
        while turtle.detectUp() do
            mineUp()
            wait()
        end
        up()
    end
    if currentPosition[Y_IDX] > 0 then
        while currentPosition[Y_IDX] > 0 do
            while HEADINGS[heading] ~= "south" do
                turnLeft()
            end
            while turtle.detect() do
                mine()
                wait()
            end
            forward()
        end
    elseif currentPosition[Y_IDX] < 0 then
        while currentPosition[Y_IDX] < 0 do
            while HEADINGS[heading] ~= "north" do
                turnLeft()
            end
            while turtle.detect() do
                mine()
                wait()
            end
            forward()
        end
    end
    if currentPosition[X_IDX] > 0 then
        while currentPosition[X_IDX] > 0 do
            while HEADINGS[heading] ~= "west" do
                turnLeft()
            end
            while turtle.detect() do
                mine()
                wait()
            end
            forward()
        end
    elseif currentPosition[X_IDX] < 0 then
        while currentPosition[X_IDX] < 0 do
            while HEADINGS[heading] ~= "east" do
                turnLeft()
            end
            while turtle.detect() do
                mine()
                wait()
            end
            forward()
        end
    end
    while HEADINGS[heading] ~= "north" do
        turnLeft()
    end
end

function go(x,y,x)
    if x >= 0 then
        while HEADINGS[heading] ~= "east" do
            turnLeft()
        end
        for i = 0, (x - 1) do
            forward()
        end
    elseif x < 0 then
        while HEADINGS[heading] ~= "west" do
            turnLeft()
        end
        for i = 0, (x - 1) * -1 do
            forward()
        end
    end
    if y >= 0 then
        while HEADINGS[heading] ~= "north" do
            turnLeft()
        end
        for i = 0, (y - 1) do
            forward()
        end
    elseif y < 0 then
        while HEADINGS[heading] ~= "south" do
            turnLeft()
        end
        for i = 0, (y - 1) * -1 do
            forward()
        end
    if z > 0 then
        for i = 0, (z - 1) do
            up()
        end
    end
    elseif z < 0 then
        for i = 0, (z - 1) * -1 do
            down()
        end
    end
end

function placeTorch()
    oldHeading = heading
    oldHeight = currentPosition[Z_IDX]
    while HEADINGS[heading] ~= "west" do
        turnLeft()
    end
    if currentPosition[Z_IDX] > TORCH_HEIGHT then
        while currentPosition[Z_IDX] > TORCH_HEIGHT do
            down()
        end
    elseif currentPosition[Z_IDX] < TORCH_HEIGHT then
        while currentPosition[Z_IDX] < TORCH_HEIGHT do
            up()
        end
    end
    -- mine()
    forward()
    turtle.select(TORCH_IDX)
    turtle.placeUp()
    turnRight()
    turnRight()
    forward()
    while heading ~= oldHeading do
        turnRight()
    end

    if oldHeight < currentPosition[Z_IDX] then
        while currentPosition[Z_IDX] > oldHeight do
            down()
        end
    elseif oldHeight > currentPosition[Z_IDX] then
        while currentPosition[Z_IDX] < oldHeight do
            up()
        end
    end
end

function emptyInventory()
    oldHeading = heading
    while HEADINGS[heading] ~= DIRECTION_OF_CHEST_FROM_HOME do
        turnLeft()
    end
    for i = 1, INVENTORY_SPACE do
        if i ~= TORCH_IDX then
            turtle.select(i)
            turtle.drop()
        end
    end
    while heading ~= oldHeading do
        turnRight()
    end
    isFull = false
    turtle.select(1)
end

function run()
    threeByThree()
    print("Program Over")
end

run()