CC - Advanced Miner

print("------------")
print("digDown v1.0")
print("------------")

-- Constants
local params = {...}
local enderChestItem = "kibe:entangled_chest"

-- Variables
local posX = 0 -- rot 0 = forward
local posY = 0 -- rot 1 = right
local posZ = 0 -- rot 2 = back
local rot = 0 -- rot 3 = left
local lengthX
local lengthY
local lengthZ

local hasEnderChest = false
local isNewSession = true

-- Prototypes
local ParseParams
local ReadLengthParams
local CheckFuel
local ResumeSession

local SaveSessionStatic
local SaveSession
local LoadSessionStatic
local LoadSession
local RemoveSession

local CheckEnderChest
local CheckForFullInventory
local StoreItems

local Forward
local Up
local Down
local ForceForward
local ForceUp
local ForceDown
local Right
local Left
local Dig
local DigUp
local DigDown
local Face
local MoveX
local MoveY
local MoveZ

local GoDig
local GetLevel
local GetTargetX
local GetTargetY
local GetTargetZ

local DigZ

-- Parse params

ParseParams = function()
    if (#params == 1 and params[1] == "resume") then
        local hasValidLastSession = ResumeSession()
        isNewSession = false
        return hasValidLastSession
    elseif (#params == 3) then
        local hasValidParams = ReadLengthParams()
        if (not hasValidParams) then
            return false
        end
        local hasEnoughtFuel = CheckFuel()
        if (not hasEnoughtFuel) then
            return false
        end
        isNewSession = true
        return true
    else
        print("Usage:")
        print("  digDown [lengthX] [lengthY] [lenghtZ]")
        print("    The turle will dig down to the left from the turtle's position")
        print("  digDown resume")
        print("    Resumes the last saved digDown session")
        return false
    end
end

ReadLengthParams = function()
    -- Validade Params
    if (tonumber(params[1]) < 1) then
        term.write("Param [" .. params[1] .. "] is invalid")
        return false
    elseif (tonumber(params[2]) < 1) then
        term.write("Param [" .. params[2] .. "] is invalid")
        return false
    elseif (tonumber(params[3]) < 1) then
        term.write("Param [" .. params[3] .. "] is invalid")
        return false
    end
    lengthX = tonumber(params[1])
    lengthY = tonumber(params[2])
    lengthZ = tonumber(params[3])
    return true
end

CheckFuel = function()
    local fuelRequired = lengthX * lengthZ * math.ceil(lengthY / 3)
    fuelRequired = fuelRequired + lengthX + lengthY + lengthZ
    if (lengthY > 1) then
        fuelRequired = fuelRequired + math.floor(lengthY / 3) * 3
    end

    if (turtle.getFuelLevel() < fuelRequired) then
        term.write("Fuel required: " .. fuelRequired .. ", turtle fuel: " .. turtle.getFuelLevel())
        return false
    end
    return true
end

ResumeSession = function()
    local loadedSessionStatic = LoadSessionStatic()
    if (not loadedSessionStatic) then
        return false
    end
    local loadedSession = LoadSession()
    if (not loadedSession) then
        return false
    end
    return true
end

-- File

SaveSessionStatic = function()
    if (not fs.exists(".digDown/")) then
        fs.makeDir(".digDown/")
    end
    local file = fs.open(".digDown/lastSessionStatic.txt", "w")
    file.write(tostring(lengthX) .. "\n")
    file.write(tostring(lengthY) .. "\n")
    file.write(tostring(lengthZ) .. "\n")
    file.close()
end

SaveSession = function()
    if (not fs.exists(".digDown/")) then
        fs.makeDir(".digDown/")
    end
    local file = fs.open(".digDown/lastSession.txt", "w")
    file.write(tostring(posX) .. "\n")
    file.write(tostring(posY) .. "\n")
    file.write(tostring(posZ) .. "\n")
    file.write(tostring(rot) .. "\n")
    file.close()
end

LoadSessionStatic = function()
    if (not fs.exists(".digDown/lastSessionStatic.txt")) then
        return false
    end
    local file = fs.open(".digDown/lastSessionStatic.txt", "r")
    lengthX = tonumber(file.readLine())
    lengthY = tonumber(file.readLine())
    lengthZ = tonumber(file.readLine())
    file.close()
    return true
end

LoadSession = function()
    if (not fs.exists(".digDown/lastSession.txt")) then
        return false
    end
    local file = fs.open(".digDown/lastSession.txt", "r")
    posX = tonumber(file.readLine())
    posY = tonumber(file.readLine())
    posZ = tonumber(file.readLine())
    rot = tonumber(file.readLine())
    file.close()
    return true
end

RemoveSession = function()
    if (fs.exists(".digDown/lastSessionStatic.txt")) then
        fs.delete(".digDown/lastSessionStatic.txt")
    end
    if (fs.exists(".digDown/lastSession.txt")) then
        fs.delete(".digDown/lastSession.txt")
    end
end

-- Chest
CheckEnderChest = function()
    turtle.select(1)
    local info = turtle.getItemDetail()
    if (info ~= nil and info.name == enderChestItem) then
        hasEnderChest = true
    end
end

StoreItems = function(side)
    if (hasEnderChest) then
        turtle.select(1)
        if (side == 1) then
            turtle.place()
            for i = 2, 16 do
                turtle.select(i)
                turtle.drop()
            end
            turtle.select(1)
            turtle.dig()
        elseif (side == 2) then
            turtle.placeUp()
            for i = 2, 16 do
                turtle.select(i)
                turtle.dropUp()
            end
            turtle.select(1)
            turtle.digUp()
        elseif (side == 3) then
            turtle.placeDown()
            for i = 2, 16 do
                turtle.select(i)
                turtle.dropDown()
            end
            turtle.select(1)
            turtle.digDown()
        end
    end
end

CheckForFullInventory = function(side)
    if (turtle.getItemCount(16) ~= 0) then
        CheckEnderChest()
        StoreItems(side)
    end
end

-- Moviment
Forward = function()
    if (turtle.forward()) then
        if (rot == 0) then
            posZ = posZ + 1
        elseif (rot == 1) then
            posX = posX - 1
        elseif (rot == 2) then
            posZ = posZ - 1
        elseif (rot == 3) then
            posX = posX + 1
        end
        SaveSession()
        return true
    end
    return false
end

Up = function()
    if (turtle.up()) then
        posY = posY + 1
        SaveSession()
        return true
    end
    return false
end

Down = function()
    if (turtle.down()) then
        posY = posY - 1
        SaveSession()
        return true
    end
    return false
end

ForceForward = function()
    while Forward() == false do
    end
end

ForceUp = function()
    while Up() == false do
    end
end

ForceDown = function()
    while Down() == false do
    end
end

Right = function()
    turtle.turnRight()
    rot = (rot + 1) % 4
    SaveSession()
end

Left = function()
    turtle.turnLeft()
    rot = (rot - 1) % 4
    SaveSession()
end

Dig = function()
    while (turtle.detect()) do
        turtle.dig()
    end
    CheckForFullInventory(1)
end

DigUp = function()
    while (turtle.detectUp()) do
        turtle.digUp()
    end
    CheckForFullInventory(2)
end

DigDown = function()
    while (turtle.detectDown()) do
        turtle.digDown()
    end
    CheckForFullInventory(3)
end

Face = function(direction)
    if (rot == direction) then
        return
    end
    local map = {function()
        Right()
    end, function()
        Right()
        Right()
    end, function()
        Left()
    end};
    local mapIndex = (4 + direction - rot) % 4
    map[mapIndex]()
end

MoveX = function(x, preWork, postWork)
    local face
    if (posX == x) then
        return
    elseif (posX > x) then
        face = 1
    else
        face = 3
    end
    while (posX ~= x) do
        if (preWork) then
            preWork()
        end
        Face(face)
        Dig()
        ForceForward()
        if (postWork) then
            postWork()
        end
    end
end

MoveY = function(y, preWork, postWork)
    local dig
    local move
    if (posY == y) then
        return
    elseif (posY > y) then
        dig = DigDown
        move = ForceDown
    else
        dig = DigUp
        move = ForceUp
    end
    while (posY ~= y) do
        if (preWork) then
            preWork()
        end
        dig()
        move()
        if (postWork) then
            postWork()
        end
    end
end

MoveZ = function(z, preWork, postWork)
    local face
    if (posZ == z) then
        return
    elseif (posZ < z) then
        face = 0
    else
        face = 2
    end
    while (posZ ~= z) do
        if (preWork) then
            preWork()
        end
        Face(face)
        Dig()
        ForceForward()
        if (postWork) then
            postWork()
        end
    end
end

-- Functions
GoDig = function()
    if (posY + 1 <= 0) then
        DigUp()
    end
    if (posY - 1 > -lengthY) then
        DigDown()
    end
    if (rot == 0) then
        if (posZ + 1 <= lengthZ) then
            Dig()
        end
    elseif (rot == 2) then
        if (posZ - 1 > 0) then
            Dig()
        end
    end
end

GetLevel = function()
    return math.floor(math.abs(posY) / 3)
end

GetTargetX = function()
    local level = GetLevel()
    local levelMod = level % 2
    if (levelMod == 0) then
        return lengthX - 1
    else
        return 0
    end
end

GetTargetY = function(level)
    local mod = lengthY % 3
    if (mod == 1) then
        return level * -3
    else
        return (level * -3) - 1
    end
end

GetTargetZ = function()
    local level = GetLevel()
    local levelMod = level % 2
    local posMod = posX % 2
    if (levelMod == posMod) then
        return lengthZ
    else
        return 1
    end
end

DigZ = function()
    local targetZ = GetTargetZ()
    MoveZ(targetZ, GoDig, GoDig)
end

-- Dig Loop
-- ::dig::

ParseParams()

print("Now digging...")
print("  " .. lengthX * lengthY * lengthZ .. " blocks")

local levels = math.ceil(lengthY / 3)
if (isNewSession) then
    SaveSessionStatic()
    SaveSession()

    Dig()
    ForceForward()
    if (lengthY > 1) then
        DigDown()
        ForceDown()
    end
end

local level = GetLevel()
repeat
    -- Navigate X
    local targetX = GetTargetX()
    MoveX(targetX, DigZ, DigZ)
    level = level + 1
    if (level < levels) then
        local targetY = GetTargetY(level)
        MoveY(targetY)
    end
until level == levels

CheckEnderChest()
if (hasEnderChest) then
    Face((rot + 2) % 4)
    StoreItems(1)
end

MoveY(0)
MoveX(0)
MoveZ(0)

RemoveSession()