Navigation API

local facingTable = {
    [0] = "south",
    [1]= "west",
    [2] = "north",
    [3] = "east",
    ["south"] = 0,
    ["west"] = 1,
    ["north"] = 2,
    ["east"] = 3,
}

local fuelTable = {
    ["Biofuel Can"] = 624,
    ["Scrap"] = 18,
    ["Coalfuel Can"] = 1824,
    ["Wooden Scaffolding"] = 18,
    ["Peat"] = 96,
    ["Wooden Tools"] = 12,
    ["Lava"] = 1200,
    ["Blaze Rod"] = 144,
    ["Wood Blocks"] = 18,
    ["Sticks"] = 6,
    ["Coal/Charcoal"] = 96,
    ["Mushroom Blocks"] = 18,
    ["Coal Coke"] = 192,
}

local vars = {
    currentFacing = 0
}

function saveVars()
    local handle = fs.open("Guidance.vars", "w")
    handle.write(textutils.serialize(vars))
    handle.close()
end

function loadVars()
    if fs.exists("guidance.vars") then
        local handle = fs.open("Guidance.vars", "r")
        vars = textutils.unserialize(handle.readAll())
        handle.close()
    end
end

function getPos()
    local currentX, currentY, currentZ = 0
    if vars.useGPS then
        rednet.open("right")
        currentX, currentY, currentZ = gps.locate(5)
    end
    if vars.deadReckon ~= nil and (currentX == nil or currentX == 0) then
        currentX = vars.deadReckon.x
        currentY = vars.deadReckon.y
        currentZ = vars.deadReckon.z
    end
    if currentX ~= nil then
        vars.deadReckon = {}
        vars.deadReckon.x = currentX
        vars.deadReckon.y = currentY
        vars.deadReckon.z = currentZ
    end
    return currentX, currentY, currentZ
end

function turnToFacing(f)
    while true do
        if facingTable[f] == facingTable[vars.currentFacing] then
            break
        end
        turtle.turnRight()
        vars.currentFacing = vars.currentFacing + 1
        if vars.currentFacing > 3 then
            vars.currentFacing = 0
        end
    end
    saveVars()
end

function setFacing(f)
    vars.currentFacing = f
    saveVars()
end

function useGPS(b)
    vars.useGPS = b
    saveVars()
end

function getVar(key, value)
    return vars[key]
end

function editVar(key, value)
    vars[key] = value
end

function calculateFuelUsage(distance, fuelType)
    return math.ceil(distance / fuelTable[fuelType]), math.ceil(distance % fuelTable[fuelType])
end

function goTo(x,y,z)
    rednet.open("right")
    if vars.useGPS then
        local currentX, currentY, currentZ = gps.locate(5)
    end
    if vars.deadReckon ~= nil and currentX == nil then
        currentX = vars.deadReckon.x
        currentY = vars.deadReckon.y
        currentZ = vars.deadReckon.z
    end
    if currentX ~= nil then
        vars.deadReckon = {}
        vars.deadReckon.x = currentX
        vars.deadReckon.y = currentY
        vars.deadReckon.z = currentZ
        saveVars()
        local offsetX = currentX - x
        local offsetY = currentY - y
        local offsetZ = currentZ - z
        print("Location is: "..currentX.." "..currentY.." "..currentZ)
        local distance = math.abs(offsetX)+math.abs(offsetY)+math.abs(offsetZ)
        print("Calculated distance to travel: "..distance.." blocks.")
        local coalUsed = calculateFuelUsage(distance, "Coal/Charcoal")
        if turtle.getFuelLevel() ~= "unlimited" then
            if turtle.getFuelLevel() < distance then
                print("Fuel will be required.")
                print("Please put coal in the lower left slot.")
                if coalUsed ~= 1 then
                    print("You will need "..coalUsed.." units of coal.")
                else
                    print("You will need 1 unit of coal.")
                end
                while true do
                    if turtle.getItemCount(16) > 0 then
                        turtle.select(16)
                        turtle.refuel()
                        if turtle.getFuelLevel() > distance then
                            print("Fueling complete.")
                            break
                        end
                    end
                    os.sleep(0)
                end
            end
        end
        if offsetZ < 0 then
            turnToFacing(facingTable["south"])
        elseif offsetZ > 0 then
            turnToFacing(facingTable["north"])
        end
        for i=1, math.abs(offsetZ) do
            while true do
                if turtle.detect() then
                    if not ((peripheral.getType("front") == "turtle") or (peripheral.getType("front") == "computer")) then
                        turtle.dig()
                    end
                else
                    break
                end
                os.sleep(0)
            end
            turtle.forward()
            if offsetZ < 0 then
                vars.deadReckon.z = vars.deadReckon.z+1
            else
                vars.deadReckon.z = vars.deadReckon.z-1
            end
        end
        if offsetX < 0 then
            turnToFacing(facingTable["east"])
        elseif offsetX > 0 then
            turnToFacing(facingTable["west"])
        end
        for i=1, math.abs(offsetX) do
            while true do
                if turtle.detect() then
                    if not ((peripheral.getType("front") == "turtle") or (peripheral.getType("front") == "computer")) then
                        turtle.dig()
                    end
                else
                    break
                end
                os.sleep(0)
            end
            turtle.forward()
            if offsetX < 0 then
                vars.deadReckon.x = vars.deadReckon.x+1
            else
                vars.deadReckon.x = vars.deadReckon.x-1
            end
        end
        for i=1, math.abs(offsetY) do
            if offsetY < 0 then
                while true do
                    if turtle.detectUp() then
                        if not ((peripheral.getType("top") == "turtle") or (peripheral.getType("top") == "computer")) then
                            turtle.digUp()
                        end
                    else
                        break
                    end
                    os.sleep(0)
                end
                turtle.up()
                vars.deadReckon.y = vars.deadReckon.y+1
            elseif offsetY > 0 then
                while true do
                    if turtle.detectDown() then
                        if not ((peripheral.getType("bottom") == "turtle") or (peripheral.getType("bottom") == "computer")) then
                            turtle.digDown()
                        end
                    else
                        break
                    end
                    os.sleep(0)
                end
                turtle.down()
                vars.deadReckon.y = vars.deadReckon.y-1
            end
        end
    end
    saveVars()
end

function printDeadReckon()
    if vars.deadReckon ~= nil then
        print("X: "..vars.deadReckon["x"])
        print("Y: "..vars.deadReckon["y"])
        print("Z: "..vars.deadReckon["z"])
    end
end

function primeDeadReckon(x,y,z)
    if x == nil then
        rednet.open("right")
        local currentX, currentY, currentZ = gps.locate(5)
        vars.deadReckon = {}
        vars.deadReckon.x = currentX
        vars.deadReckon.y = currentY
        vars.deadReckon.z = currentZ
    else
        vars.deadReckon = {}
        vars.deadReckon.x = x
        vars.deadReckon.y = y
        vars.deadReckon.z = z
    end
    saveVars()
    printDeadReckon()
end

function setup(x,y,z,f,gps)
    if (x ~= nil) and (y ~= nil) and (z ~= nil) and (f ~= nil) then
        primeDeadReckon(x,y,z)
        setFacing(f)
        useGPS(gps)
    else
        print("Setup Utility:")
        print("Please enter the coordinates for this turtle's location:")
        write("X: ")
        local XLoc = ""
        while true do
            XLoc = tonumber(read())
            if XLoc then
                break
            end
        end

        write("Y: ")
        local YLoc = ""
        while true do
            YLoc = tonumber(read())
            if YLoc then
                break
            end
        end

        write("Z: ")
        local ZLoc = ""
        while true do
            ZLoc = tonumber(read())
            if ZLoc then
                break
            end
        end

        write("Facing: ")
        local Facing = ""
        while true do
            Facing = tonumber(read())
            if Facing then
                break
            end
        end
        primeDeadReckon(XLoc, YLoc, ZLoc)
        setFacing(Facing)
        while true do
            print("Should this turtle use GPS?")
            write(">")
            term.setCursorBlink(true)
            answer = string.lower(string.sub(read(),1,1))
            if answer == "n" then
                gps = false
                break
            elseif answer == "y" then
                gps = true
                break
            else
                local x,y = term.getCursorPos()
                print("Please provide a valid answer.")
                term.setCursorPos(1, y-1)
            end
        end
        useGPS(gps)
        print("Setup complete.")
        saveVars()
    end
end

loadVars()