CC: Locked Turtle + backtrack to start

--DETTA SKRIPT ÄR SKRIVET
--PÅ HELLO WORLD!
--
--DU FÅR GÄRNA LÄSA DET
--MEN BLI INTE FÖR DISTRAHERAD
--DET ÄR ETT GANSKA AVANCERAT SKRIPT

--(( SETTINGS ))--

local turtle_path_file = ".path"

local turtle_goal = "minecraft:lit_redstone_lamp"
local turtle_disabled = {
--  "turnLeft",
--  "turnRight",
    "up",
    "down",
}

local turtle_goal_success = "Du klarade pusslet! Tjohoo!"
local turtle_goal_fail = "Ajaj, du klarade det inte. Tryck valfri knapp för att återvända till början..."

local hiddenFiles = {
    "startup.lua",
    turtle_path_file
}

-- Colours
local promptColour, textColour, bgColour, errColour
if term.isColour() then
    promptColour = colours.yellow
    textColour = colours.white
    bgColour = colours.black
    errColour = colours.red
else
    promptColour = colours.white
    textColour = colours.white
    bgColour = colours.black
    errColour = colours.white
end

--(( VARIABLES ))--

local turtle_path = nil
local turtle_reverse = {
    forward = turtle.back,
    back = turtle.forward,
    up = turtle.down,
    down = turtle.up,
    turnRight = turtle.turnLeft,
    turnLeft = turtle.turnRight,
}
local turtle_track = {
    "forward",
    "back",
    "up",
    "down",
    "turnLeft",
    "turnRight",
}

--(( FUNCTIONS ))--

local function tryRefuel()
    local oldSlot = turtle.getSelectedSlot()
    for slot=1,16 do
        if turtle.getItemCount(slot) > 0 then
            turtle.select(slot)
            if turtle.refuel(1) then
                turtle.select(oldSlot)
                return true
            end
        end
    end
    turtle.select(oldSlot)
    return false
end

local function forceRefuel()
    if turtle.getFuelLevel() == 0 and not tryRefuel() then
        print("Slut på bränsle! Mata mig kol så jag kan åka hem.")
        repeat
            os.pullEvent("turtle_inventory")
            tryRefuel()
        until turtle.getFuelLevel() ~= 0
        print("Tack så mycket :)")
    end
end

local function savePath()
    local file = fs.open(turtle_path_file, "w")
    file.write(textutils.serialize(turtle_path))
    file.close()
end

local function resetPath()
    turtle_path = {}
    savePath()
end

local function removeFromPath(index)
    table.remove(turtle_path, index)
    savePath()
end

local function addToPath(name)
    table.insert(turtle_path, name)
    savePath()
end

local function loadPath()
    if fs.exists(turtle_path_file) then
        local file = fs.open(turtle_path_file, "r")
        local data = file.readAll()
        file.close()
        turtle_path = textutils.unserialize(data)
    else
        resetPath()
    end
end

-- Reverse
local function reversePath()
    for i=#turtle_path,1,-1 do
        local func = turtle_path[i]
        local reverse = turtle_reverse[func]
        forceRefuel()
        repeat until reverse()
        removeFromPath(i)
    end
end

local function hasReachedGoal()
    rs.setOutput("front", true)
    local succ, data = turtle.inspect()
    if succ and data and data.name == turtle_goal then
        return true
    end
    rs.setOutput("bottom", true)
    succ, data = turtle.inspectDown()
    if succ and data and data.name == turtle_goal then
        return true
    end
    return false
end

-- keep tracks
local function trackTurtleFunc(func, name)
    return function(...)
        local res = {func(...)}
        if res[1] then
            addToPath(name)
        elseif res[2] == "Out of fuel" then
            error("Fanns inget bränsle kvar vid turtle."..name.."()", 2)
        elseif res[2] == "Movement obstructed" then
            error("Något var ivägen för turtle."..name.."()", 2)
        end
        return unpack(res)
    end
end

local function pause()
    term.setCursorBlink(true)
    repeat until os.pullEvent() == "key"
    term.setCursorBlink(false)
    print()
end

local function tableRemoveFirst(tbl, elem)
    for k,v in pairs(tbl) do
        if v == elem then
            return table.remove(tbl, k)
        end
    end
end

local function setupTurtleFuncs()
    -- lock functions
    for i,v in ipairs(turtle_disabled) do
        turtle[v] = function()
            error("turtle."..v.."() är avstängd för denna turtle!", 0)
            return false
        end
        tableRemoveFirst(turtle_track, v)
    end

    -- Track the functions
    for i,v in ipairs(turtle_track) do
        turtle[v] = trackTurtleFunc(turtle[v], v)
    end
end

local function setupHideFiles()
    -- Hide startup.lua from listing
    local _fsList = fs.list
    function fs.list(...)
        local args = {...}
        local res = {_fsList(...)}

        -- filter out /startup.lua
        if res[1] and args[1] == "" then
            for _, file in ipairs(hiddenFiles) do
                tableRemoveFirst(res[1], file)
            end
        end

        return unpack(res)
    end
end

local function setupDisableEditRun()
    -- Pretty haxy, but the edit.lua program checks
    -- if shell.openTab then //add run button
    shell.openTab = nil
end

local function checkGoal()
    if #turtle_path > 0 then
        term.setBackgroundColor(bgColour)
        term.setTextColour(promptColour)
        if hasReachedGoal() then
            print(turtle_goal_success)
            resetPath()
        else
            write(turtle_goal_fail)
            term.setTextColour(textColour)
            pause()
            reversePath()
        end
    end
end

local function main()
    loadPath()
    checkGoal()

    -- Read commands and execute them
    local tCommandHistory = {}
    while true do
        term.setBackgroundColor(bgColour)
        term.setTextColour(promptColour)
        write(shell.dir() .. "> ")
        term.setTextColour(textColour)

        local sLine
        if settings.get("shell.autocomplete") then
            sLine = read(nil, tCommandHistory, shell.complete)
        else
            sLine = read(nil, tCommandHistory)
        end
        if sLine:match("%S") and tCommandHistory[#tCommandHistory] ~= sLine then
            table.insert(tCommandHistory, sLine)
        end
        shell.run(sLine)

        checkGoal()
    end
end

--(( SETUP ))--

setupHideFiles()
setupTurtleFuncs()
setupDisableEditRun()

--(( MAIN PROGRAM ))--

local succ,err = pcall(main)

-- Print error if any
term.setTextColour(errColour)
term.setCursorBlink(false)
print(err)
shell.run("shutdown")

--(( EOF ))--