Turtle Follower

local args = {...}
local currentPos = {
    --x, y, z, f
}

local scanner = peripheral.wrap("right")
local function getVIP(name)
    players = scanner.getPlayersInRange(120)
    for _, p in pairs(players) do
        if p == name then
            return p
        end
    end
    return players[1]
end

local function getTurtlePos()
    local handle = io.open("turtlePos", "r")
    if handle then
        line =  handle:read("l")
        currentPos.x = tonumber(line)
        line =  handle:read("l")
        currentPos.z = tonumber(line)
        line =  handle:read("l")
        currentPos.f = tonumber(line)
        handle:close()
    else
        currentPos.x = tonumber(args[1])
        currentPos.z = tonumber(args[2])
        currentPos.f = tonumber(args[3])
    end
end

local function updatePos()
    local handle = io.open("turtlePos", "w")
    handle:write(currentPos.x .. "\n")
    handle:write(currentPos.z .. "\n")
    handle:write(currentPos.f .. "\n")
    handle:close()
end

local dirTab = {
    {["x"]=0, ["z"]=-1},
    {["x"]=1, ["z"]=0},
    {["x"]=0, ["z"]=1},
    {["x"]=-1, ["z"]=0},
}
local function forward()
    turtle.forward()
    delta = dirTab[currentPos.f]
    currentPos.x = currentPos.x + delta.x
    currentPos.z = currentPos.z + delta.z
end
local function back()
    turtle.back()
    delta = dirTab[currentPos.f]
    currentPos.x = currentPos.x - delta.x
    currentPos.z = currentPos.z - delta.z
end
local function left()
    turtle.turnLeft()
    currentPos.f = currentPos.f - 1
    if currentPos.f < 1 then
        currentPos.f = currentPos.f + 4
    end
end
local function right()
    turtle.turnRight()
    currentPos.f = currentPos.f + 1
    if currentPos.f > 4 then
        currentPos.f = currentPos.f - 4
    end
end

local function step(dir)
    df = currentPos.f - dir
    if df < 0 then
        df = df + 4
    end
    if df == 0 then
        forward()
    elseif df == 1 then
        left()
    elseif df == 2 then
        back()
    elseif df == 3 then
        right()
    end
    updatePos()
end


local function moveto(pos)
    --take one step towards the goal
    dx = math.max(math.min(pos.x - currentPos.x, 1), -1)
    dz = math.max(math.min(pos.z - currentPos.z, 1), -1)

    -- get list of possible movement directions
    pDirs = {}
    if dx < 0 then
        pDirs[#pDirs+1] = 4
    elseif dx > 0 then
        pDirs[#pDirs+1] = 2
    end
    if dz < 0 then
        pDirs[#pDirs+1] = 1
    elseif dz > 0 then
        pDirs[#pDirs+1] = 3
    end

    if #pDirs == 0 then
        return
    elseif #pDirs == 1 then
        step(pDirs[1])
    else
        if currentPos.f % 2 == pDirs[1] % 2 then
            step(pDirs[1])
        else
            step(pDirs[2])
        end
    end
end

local speaker = peripheral.wrap("left")
local b_end = "betterendforge:betterendforge.ambient"
local suffixes = {
"blossoming_spires",
"chorus_forest",
--"dust_wastelands",
"foggy_mushroomland",
"glowing_grasslands",
"megalake",
"megalake_grove",
--"sulphur_springs",
"umbrella_jungle",
}

function printTime(n)
    if n > 1 then
        x, y = term.getCursorPos()
        term.setCursorPos(x, y-1)
        term.clearLine()
    end
    print(n)
end

-- radius 14 from middle
local delay = 0
local function playSound()
    local idx = math.random(1, #suffixes)
    local sound = b_end .. "." .. suffixes[idx]
    delay = math.random(65, 100)
    print("Playing " .. suffixes[idx] .. " for " .. delay .. "s")
    speaker.playSound(sound)
end

getTurtlePos()
local startTime = os.time()
local secondsMultiplier = 0.02
while true do
    player = getVIP("CaptainSpaceCat7")
    if player then
        pos = scanner.getPlayerPos(player)
        moveto(pos)
    end
    local currentTime = os.time()
    print( currentTime - startTime .. "   " .. secondsMultiplier * delay)
    if currentTime - startTime > secondsMultiplier * delay then
        playSound()
        startTime = currentTime
    end
    --printTime()
end

--[[
getTurtlePos()
local moveRoutine = coroutine.create(function ()
    while true do
        player = getVIP("CaptainSpaceCat7")
        print("found player " .. player)
        if player then
            pos = scanner.getPlayerPos(player)
            print("player at " .. pos.x .. ":" .. pos.z)
            moveto(pos)
        end
        coroutine.yield()
    end
end)

while true do
    print("routine status: " .. coroutine.status(moveRoutine))
    coroutine.resume(moveRoutine)
    sleep(0.5)
end
]]