funtun_v3

local tpos = require("TurtlePosition")
local tctl = require("TurtleControl")

function scanInventoryForTorches()
    local torchesPresent = false
    local previousSlot = turtle.getSelectedSlot()
    local torchesIndex = tctl.searchInventoryForItem("minecraft:torch")
    if torchesIndex > -1 then
        torchesPresent = true
        turtle.select(torchesIndex)
        turtle.transferTo(16)
        turtle.select(previousSlot)
    end
    return torchesPresent
end

function placeTorch()
    if turtle.getItemDetail(16) ~= nil then
        if turtle.getItemDetail(16).name == "minecraft:torch" then
            tctl.turnLeft()
            local previousSlot = turtle.getSelectedSlot()
            turtle.select(16)
            local placeTorchSuccess = turtle.place()
            if placeTorchSuccess == false then
                tctl.forward()
                local cobblestoneIndex = searchInventoryForItem("minecraft:cobblestone")
                if cobblestoneIndex>-1 then
                    turtle.select(cobblestoneIndex)
                    turtle.place()
                end
                tctl.turnRight()
                tctl.turnRight()
                tctl.forward()
                tctl.turnLeft()
                tctl.turnLeft()
                turtle.select(16)
                turtle.place()
            end
            turtle.select(previousSlot)
            tctl.turnRight()
        end
    end
end

function level()
    tctl.turnRight()
    while turtle.detect() do
        turtle.dig()
        sleep(.5)
    end
    tctl.turnLeft()
    tctl.turnLeft()
    while turtle.detect() do
        turtle.dig()
        sleep(.5)
    end
    tctl.turnRight()
end

function slice( withTorch )
    tctl.forward()
    tctl.up()
    level()
    if withTorch==true then
        placeTorch()
    end
    tctl.down()
    level()
    tctl.down()
    level()
    tctl.up()
end

function inventoryFull( howFar, torches )
    local lastSlot = 16
    local excludeSlots = {}
    if torches then
        lastSlot = 15
        excludeSlots = {16}
    end

    if turtle.getItemCount(lastSlot) > 0 then
        tctl.print("Inventory full. Returning home to dump items.")
        tctl.turnRight()
        tctl.turnRight()
        for i=1,howFar do
            tctl.forward()
        end
        tctl.down()
        tctl.emptyInventory(excludeSlots)
        tctl.up()
        tctl.turnRight()
        tctl.turnRight()
        for i=1,howFar do
            tctl.forward()
        end
        tctl.print("Inventory dump complete. Resuming tunnel.")
    end
end

local arg = { ... }
distance = arg[1]
local tunnelDepth = 0
local torches = scanInventoryForTorches()
tctl.up()
for i=1,distance do
    if (i%5)==0 or i==1 then
        slice(torches)
    else
        slice(false)
    end
    tunnelDepth = tunnelDepth + 1
    tctl.print("Depth "..i.." of "..distance)
    inventoryFull(tunnelDepth, torches)
end
-- End of tunnel. Turn around.
tctl.turnRight()
tctl.turnRight()
-- Go back to start of tunnel
for i=1,distance do
    tctl.forward()
end
-- drop remaining inventory [in chest?]
tctl.down()
for i=1,15 do
    turtle.select(i)
    turtle.drop()
end
turtle.select(1)
-- Home position. Ideally in the exact same position the user started the program
tctl.turnRight()
tctl.turnRight()
tctl.print("Tunnel Complete!")