Shaft Mine

--Shaft Mining Program
--Made by Andrew Lalis

local args = {...}

local segmentLength = 0
local sideLength = 0
local sideInterval = 0
local torchInterval = 0

--Parses command line arguments and gets input.
function parseArgs(args)
    if (args[1] ~= nil) then
        segmentLength = tonumber(args[1])
    else
        print("How long should this mine be?")
        segmentLength = tonumber(read())
    end
    if (args[2] ~= nil) then
        sideLength = tonumber(args[2])
    else
        print("How long should side shafts be?")
        sideLength = tonumber(read())
    end
    if (args[3] ~= nil) then
        sideInterval = tonumber(args[3])
    else
        print("How often should side shafts be dug?")
        sideInterval = tonumber(read())
    end
    if (args[4] ~= nil) then
        torchInterval = tonumber(args[4])
    else
        print("How often should torches be placed?")
        torchInterval = tonumber(read())
    end
end

--Rounds a number for display.
function round(num, places)
    return (string.format("%." .. (places or 0) .. "f", num))
end

--Gets the number of items in the turtle's inventory.
function getItemCount(itemName)
    local count = 0
    for i=1,16 do
        local data = turtle.getItemDetail(i)
        if (data ~= nil and data.name == itemName) then
            count = count + data.count
        end
    end
    return count
end

--Selects an item in the inventory, or the first slot if it can't be selected. Returns success.
function selectItem(itemName)
    for i=1,16 do
        local data = turtle.getItemDetail(i)
        if (data ~= nil and data.name == itemName) then
            turtle.select(i)
            return true
        end
    end
    turtle.select(0)
    return false
end

--What to do when the turtle's inventory is too full.
function onFullInventory()
    print("Inventory is full, please remove the items.")
    local clean = false
    while (not clean) do
        local event = os.pullEvent("turtle_inventory")
        for i=1,16 do
            local data = turtle.getItemDetail(i)
            if (data ~= nil and data.name ~= "minecraft:torch") then
                clean = false
                break
            end
        end
    end
    print("Inventory clean. Continuing.")
end

--Interface for loading fuel until the turtle is full.
function fuelLoader(amount)
    while (turtle.getFuelLevel() < amount) do
        print("Need "..(amount - turtle.getFuelLevel()).." more fuel units.")
        local event = os.pullEvent("turtle_inventory")
        for i=1,16 do
            turtle.select(i)
            turtle.refuel()
        end
    end
end

--Ensures the turtle will have enough fuel for a given shaft mine.
function ensureFuel(segLength, sideLength, sideInterval)
    local fuelUsage = (segLength / sideInterval) * sideLength + segLength
    if (turtle.getFuelLevel() < fuelUsage) then
        print("Not enough fuel to begin.")
        fuelLoader(fuelUsage)
        print("Fuel loaded!")
    end
end

--Ensures that the turtle will have enough torches for the shaft.
function ensureTorches(segmentLength, torchInterval)
    local torchesNeeded = (segmentLength / torchInterval)
    while (getItemCount("minecraft:torch") < torchesNeeded) do
        print("Need "..(torchesNeeded - getItemCount("minecraft:torch")).." more torches.")
        local event = os.pullEvent("turtle_inventory")
    end
    print("Torches loaded!")
end

--Moves back by some amount.
function goBack(length)
    for i=1,length do
        local success = turtle.back()
        while (not success) do
            success = turtle.back()
        end
    end
end

--Digs forward for some amount.
function digForwardSegment(length)
    for i=1,length do
        turtle.dig()
        local success = turtle.forward()
        while (not success) do
            success = turtle.forward()
        end
        turtle.digDown()
    end
end

--Digs side shafts on either side of the main shaft.
function digSideShafts(length)
    turtle.turnLeft()
    digForwardSegment(length)
    goBack(length)
    turtle.turnRight()
    turtle.turnRight()
    digForwardSegment(length)
    goBack(length)
    turtle.turnLeft()
end

--Places a torch on the ground.
function placeTorch()
    local success = selectItem("minecraft:torch")
    if (not success) then
        print("Unable to find torch to place.")
        return
    end
    turtle.placeDown()
end

--Checks if the inventory is available for more items.
function checkInventory()
    local freeSlots = 0
    for i=1,16 do
        local data = turtle.getItemDetail(i)
        if (data == nil) then
            freeSlots = freeSlots + 1
        end
    end
    if (freeSlots < 2) then
        onFullInventory()
    end
end

--Displays current statistics.
function updateStatistics(currentLength, segmentLength)
    print(round((currentLength / segmentLength) * 100, 2) .."% complete.")
end

--Main mining program.
function mineShaft(segmentLength, sideLength, sideInterval, torchInterval)
    for i=1,segmentLength do
        checkInventory()
        digForwardSegment(1)
        if ((i % sideInterval == 0) and (sideInterval > 0)) then
            digSideShafts(sideLength)
        end
        if ((i % torchInterval == 0) and (torchInterval > 0)) then
            placeTorch()
        end
        updateStatistics(i, segmentLength)
    end
end

--Main program.
parseArgs(args)
ensureFuel(segmentLength, sideLength, sideInterval)
ensureTorches(segmentLength, torchInterval)
mineShaft(segmentLength, sideLength, sideInterval, torchInterval)