State Machine

local S_PREP = "PREP"
local S_MINING = "MINING"
local S_REFUEL = "REFUEL"
local S_INVENTORY = "INVENTORY"
local S_FINISH  = "FINISH"
local S_ADVANCE = "ADVANCE"

-- Chests in slot 1, fuel in slot 2
local IgnoreSlots = 3

local chestIndex = 1
local CHEST = "minecraft:chest"
local fuelIndex = 2
local bucketIndex = 3

local DepthTarget = 100
local fudgeFactor = 10

local mov = {}
local rot = {}
local dig = {}

local status = {}
local statusFileName = "mstatus"

local function loadTable(name)
        local file = fs.open(name,"r")
        if file == nil then
            return
        end
        local data = file.readAll()
        file.close()
        return textutils.unserialize(data)
end

local function saveTable(table,name)
        local file = fs.open(name,"w")
        file.write(textutils.serialize(table))
        file.close()
end

local function saveStatus()
    saveTable(status, statusFileName)
end

local function loadStatus()
    status = loadTable(statusFileName)
end

local function isChest()
   local exists, data = turtle.inspectUp()

   if not exists then return false end

   return string.find(data.name, CHEST) ~= nil
end

local DONT_NEED_FUEL = 0
local GOT_SOME_FUEL = 1
local OUT_OF_FUEL = -1

local function Refuel()
        currentFuelRequired = (40 + (DepthTarget-status.progress)*3)/20
        if turtle.getFuelLevel() < currentFuelRequired then
                turtle.select(fuelIndex)
                local r = turtle.refuel(currentFuelRequired)
                if r then
                    return GOT_SOME_FUEL
                elseif not r then
                    return OUT_OF_FUEL
                end
        else
                return DONT_NEED_FUEL
        end
end

local function CheckRefuel()
    if Refuel() == OUT_OF_FUEL then
        print("***Out of fuel***")
        status.status = S_STOP
        return
    end
    local count = 0
    while Refuel() == GOT_SOME_FUEL and count < 16 do
        count = count + 1
          print("refueling")
    end
end

mov.forward = function(times)
        local boolean v = false
        for i=1,times do
                if turtle.detect() == false then
                        while not turtle.forward() do
                                CheckRefuel()
                                sleep(1)
                        end
                        v = true
                else
                        v = false
                        return v
                end
        end
        return v
end

mov.back = function(times)
        local boolean v = false
        for i=1,times do
                while not turtle.back() do
                        CheckRefuel()
                        sleep(1)
                end
                v = true
        end
        return v
end

mov.up = function(times)
--     print("mov.up")
     -- print("-->")
    local boolean v = false
    for i=1,times do
        if turtle.detectUp() == false then
            local attempts = 0
            while turtle.up() == false and attempts < 10 do
--                 print("failed to move up")
                attempts = attempts + 1
                CheckRefuel()
                sleep(1)
                if attempts > 8 then
--                     print("LOTS of fails move up")
                    if status.status == S_FINISH then
                        status.status = S_STOP
                    else
                        status.status = S_FINISH
                    end
                    return false
                end
            end
            v = true
        else
            v = false
            -- print("<--")
            return v
        end
    end
    -- print("<--")
    return v
end

mov.down = function(times)
--     print("mov.down")
    -- print("-->")
    local boolean v = false
    for i=1,times do
        if turtle.detectDown() == false then
            local attempts = 0
            while turtle.down() == false and attempts < 10 do
--                 print("failed to move down")
                attempts = attempts + 1
                CheckRefuel()
                sleep(1)
                if attempts > 8 then
--                     print("LOTS of fails move down")
                    if status.status == S_FINISH then
                        status.status = S_STOP
                    else
                        status.status = S_FINISH
                    end
                    return false
                end
            end
            v = true
        else
            v = false
            -- print("<--")
            return v
        end
    end
    -- print("<--")
    return v
end

mov.place = function()
    while not turtle.place() do
          sleep(1)
    end
    return true
end

rot.right = function()
    while not turtle.turnRight() do
            sleep(1)
    end
    return true
end

rot.left = function()
    while not turtle.turnLeft() do
            sleep(1)
    end
    return true
end

dig.forward = function()
    print("dig.forward")
    -- print("-->")
        if turtle.detect() then
                while not turtle.dig() do
                                sleep(1)
                end
    -- print("<--")
                return true
        else
--                 print("No Block to mine forward")
    -- print("<--")
                return false
        end
end

dig.up = function()
    print("dig.up")
    -- print("-->")
        if turtle.detectUp() then
                while not turtle.digUp() do
                                sleep(1)
                end
    -- print("<--")
                return true
        else
                print("No Block to mine up")
    -- print("<--")
                return false
        end
end

dig.down = function()
    print("In dig.down")
    -- print("-->")
        if turtle.detectDown() then
                while not turtle.digDown() do
                                sleep(1)
                end
    -- print("<--")
                return true
        else
                print("No Block to mine down")
    -- print("<--")
                return false
        end
end

local function DigMoveForward()
    print("In DigMoveForward")
    -- print("-->")
        if mov.forward(1) == false then
                dig.forward()
                sleep(0.5)
                DigMoveForward()
        end
    -- print("<--")
end

local function DigMoveUp()
    print("In DigMoveUp")
    -- print("-->")
    local count = 0
        while mov.up(1) == false and count < 10 do
            count = count + 1
                dig.up()
                sleep(0.5)
        end
        if count > 5 then
--             print("had a hard time moving up")
        end
    -- print("<--")
end

local function DigMoveDown()
    print("In DigMoveDown")
    -- print("-->")
    local count = 0
        while mov.down(1) == false and count < 10 do
                dig.down()
                sleep(0.5)
        end
        if count > 5 then
--             print("had a hard time moving up")
        end
        -- print("<--")
end

local function ReturnBack()
    print("In ReturnBack")
    -- print("-->")
    turtle.select(1)
    local count = 0
    while not isChest() and count < DepthTarget + fudgeFactor do
        count = count + 1
        print(count)
        mov.up(1)
    end
    -- print("<--")
end



local function DepositChest()
    print("In DepositChest")
    -- print("-->")
    if not isChest then
        print("ERROR: Should be below chest.")
        status.status = S_STOP
    -- print("<--")
        return
    end

    print("Depositing the Load...")
    for i = IgnoreSlots + 1,16 do
            turtle.select(i)
            turtle.dropUp()
    end
    print("Out DepositChest")
end

local function InventoryFull()
    print("In InventoryFull")
    -- print("-->")
    SlotsFull = 0
    for i=1,16 do
            if turtle.getItemCount(i) > 0 then
                    SlotsFull = SlotsFull + 1
            end
    end

    if SlotsFull == 16 then
       -- print("<--")
            return true;
    else
    -- print("<--")
            return false;
    end
end

local function CheckInventory()
    if InventoryFull() then
        print("***Inventory Full***")
        ReturnBack()
        DepositChest()
        for i=1,status.progress do
            DigMoveDown()
        end
    end
end

local function Harvest()
    local exist,block = turtle.inspect()
    if not exist then
        return
    end

    if string.find(block.name, "flowing_water") then
        turtle.select(1)
        turtle.place()
    elseif string.find(block.name, "flowing_lava") then
        if bucketIndex > 0 then
            turtle.select(bucketIndex)
            turtle.place()
        end
        turtle.select(1)
        turtle.place()
    end

    while turtle.suck() == true do
        CheckInventory()
    end

    dig.forward()
end

local function Progress()
    DigMoveDown()
    status.progress = status.progress + 1
    BlocksTillEnd = DepthTarget - status.progress
end

local function Finish()
    print("In Finish")
    -- print("-->")
    ReturnBack()
    DepositChest()

    status.status = S_ADVANCE
    -- print("<--")
end

local function NextColumn()
--     turtle.select(1)
--     if not turtle.compareUp() then
--         rot.right()
--         rot.right()
--         while not turtle.compareUp() do
--             DigMoveForward()
--         end
--         rot.right()
--         rot.right()
--     end
    for i=1,4 do
        DigMoveForward()
    end

    status.status = S_PREP
end


local function StartMining()
    print("In StartMining")
    -- print("-->")
    sleep(1)
    BlocksTillEnd = DepthTarget - status.progress

    while BlocksTillEnd > 0 do

        CheckRefuel()
        if status.status == S_STOP then
            return
        end
        CheckInventory()
        Harvest()

        for i=1,4 do
            Progress()
        end

        print("Depth: ")
        print(status.progress)
    end

    Harvest()

    status.status = S_FINISH

    -- print("<--")
end

local function Prepare()
    status.previous = ""
    status.progress = 0

    local data = turtle.getItemDetail(chestIndex)
    if data ~= nil and data.name ~= CHEST then
        print("need more chests")
        return
    end

    local FuelCount = turtle.getItemCount(fuelIndex)

    if FuelCount == 0 then
        print("please put fuel in the last slot of the Turtle.")
        return
    else
        if FuelCount < 10 then
            print("Please put at least 10 of the fuel you are using in the Turtle.")
            return
        end
    end

    CheckRefuel()
    if status.status == S_STOP then
        return
    end

    turtle.digUp()
    turtle.select(1)
    local result = turtle.placeUp()
    if not result then
        status.status = S_ADVANCE
        return
    end

    status.status = S_MINING
end

function Main()
    while status.status ~= S_STOP do
        saveStatus()
        sleep(1)
        if status.status == S_PREP then
            Prepare()

        elseif status.status == S_MINING then
            StartMining()

        elseif status.status == S_FINISH then
            Finish()

        elseif status.status == S_ADVANCE then
            NextColumn()

        else
            print("Unknown status: "..status.status)
            status.status = S_STOP
        end
    end
    ReturnBack()
end

-- ON LAUNCH
loadStatus()
if status == nil then
    status = { }
   status.status = S_PREP
   status.previous = ""
   status.progress = 0
end

if status.status ~= S_PREP and status.status ~= S_ADVANCE then
    turtle.select(fuelIndex)
    turtle.refuel(2)
    ReturnBack()
end

Main()