slave_init.lua

local shell = require("shell")
local component = require("component")
local event = require("event")
local modem = component.modem
local robot = require("robot")
local computer = require("computer")
local serialization = require("serialization")
local sides = require("sides")
local rs = component.redstone
local ic = component.inventory_controller

local PORT = 10002
local MY_DATA = {}

local BLOCK_NAME = "minecraft:dirt"
local BLOCK_DATA = 0

local function getDependencies()
    -- First get all dependencies.
    print("Fetching the latest movescript...")
    shell.execute("pastebin get 4c2AN8Jw /lib/movescript.lua -f")
end

getDependencies()
local ms = require("movescript")

local function selectItemByName(item_name, item_data)
    for i=1,16 do
        local stack = ic.getStackInInternalSlot(i)
        if (stack ~= nil and stack.name == item_name and stack.damage == item_data) then
            robot.select(i)
            return true
        end
    end
    return false
end

local function selectEmptySlot()
    for i = 1, 16 do
        local stack = ic.getStackInInternalSlot(i)
        if (stack == nil) then
            robot.select(i)
            return true
        end
    end
    return false
end

local function fetchItemFromChest(item_name, item_damage)
    local size = ic.getInventorySize(sides.front)
    if (size == nil) then
        return false
    end
    for i = 1, size do
        local stack = ic.getStackInSlot(sides.front, i)
        if (stack ~= nil and stack.name == item_name and (item_damage == nil or stack.damage == item_damage)) then
            selectEmptySlot()
            ic.suckFromSlot(sides.front, i)
            return true
        end
    end
    return false
end

local function getDirt()
    for i = 1, 4 do
        local success = fetchItemFromChest("minecraft:dirt", 0)
        if not success then
            i = i - 1
            print("Please add some dirt to the inventory and press enter.")
            io.read()
        end
    end
end

local function returnToStart()
    local s1 = "U2R" .. MY_DATA.current_length .. "FL" .. MY_DATA.index .. "FD"
    ms.execute(s1)
end

local function returnToCurrentPosition()
    local s2 = MY_DATA.index .. "FR" .. MY_DATA.current_length .. "F"
    ms.execute(s2)
end

local function flattenSpot()
    -- Dig out top part.
    local displacement = 0
    local success, data = robot.detectUp()
    while (success) do
        ms.execute("d_U")
        success, data = robot.detectUp()
        displacement = displacement + 1
    end
    ms.execute(displacement .. "D")

    -- Fill in floor.
    displacement = 0
    success, data = robot.detectDown()
    while ((not success) or (data == "replaceable")) do
        ms.execute("d_D")
        success, data = robot.detectDown()
        displacement = displacement + 1
    end
    for i = 1, displacement do
        ms.execute("U")
        local has_dirt = selectItemByName(BLOCK_NAME, BLOCK_DATA)
        if not has_dirt then
            print("Don't have any dirt. Going back for refill.")
            -- Go back and refill.
            ms.execute((displacement - i) .. "U")
            returnToStart()
            ms.execute("L")
            -- Now facing an inventory with dirt.
            getDirt()
            ms.execute("L")
            returnToCurrentPosition()
            ms.execute((displacement - i) .. "D")
        end

        robot.placeDown()
    end
end

local function chargeUntilFull()
    local max = computer.maxEnergy()
    local current = computer.energy()
    while (current / max < 0.95) do
        print("Charging... " .. ((current / max) * 100) .. "%")
        rs.setOutput(sides.front, 15)
        os.sleep(1)
        current = computer.energy()
    end
    print("Fully charged.")
end

local function ensureEnergyLevel(ratio)
    if (computer.energy() / computer.maxEnergy() < ratio) then
        print("Energy below threshold, going to recharge.")
        returnToStart()
        ms.execute("R")
        chargeUntilFull()
        ms.execute("R")
        returnToCurrentPosition()
    end
end

modem.open(PORT)
-- Tell the master we're ready.
print("Ready to receive instructions.")
modem.broadcast(PORT, "READY")

-- Wait for a movescript to the start location.
local _, _, sender, port, dist, msg, data = event.pull("modem_message")
local master_address = sender
print("Got instructions from master: " .. msg)
MY_DATA = serialization.unserialize(data)
print("Got metadata: " .. data)
robot.select(1)
ic.equip()
ms.execute("R")
robot.suck()
ms.execute("L")

print("Moving to start...")
ms.execute(msg)

print("Beginning to dig length of " .. MY_DATA.length)
for i = 1, MY_DATA.length do
    -- Check energy level.
    ms.execute("d_F")
    MY_DATA.current_length = i
    ensureEnergyLevel(0.4)
    -- Check inventory space.
    flattenSpot()
end

print("Done! Returning to start.")
returnToStart()
modem.send(sender, PORT, "DONE")
modem.close()

computer.shutdown()