badapple.lua

local component = require("component")
local event = require("event")
local filesystem = require("filesystem")
local bit32 = require("bit32")
local os = require("os")
local modem = component.modem

local CONTROLLER_PORT = 1
local WORKER_PORT = 2
local PING_TIMEOUT = 20
local AUDIO_FILE_PATH = "/home/badapple.audio"  -- Path to the encoded audio file

local function tickTime()
    return os.time() * (1000/60/60)
end

-- Function to convert MIDI pitch to frequency in Hz
local function midiToFrequency(midiNote)
    return 440 * 2 ^ ((midiNote - 69) / 12)
end

-- Function to read a variable-length integer from the file
local function readVarInt(file)
    local value = 0
    local shift = 0
    while true do
        local byte = file:read(1)
        if not byte then return nil end
        byte = string.byte(byte)
        value = value + bit32.lshift(bit32.band(byte, 0x7F), shift)
        if bit32.band(byte, 0x80) == 0 then break end
        shift = shift + 7
    end
    return value
end

-- Step 1: Broadcast a ping to discover worker addresses
modem.open(WORKER_PORT)

local function discoverWorkers()
    local addresses = {}

    modem.broadcast(CONTROLLER_PORT, "ping")

    local deadline = tickTime() + PING_TIMEOUT
    while tickTime() < deadline do
        local _, _, from, port = event.pull((deadline - tickTime()) / 20, "modem_message")
        if port == WORKER_PORT then
            table.insert(addresses, from)
        end
    end

    return addresses
end

local workerAddresses = discoverWorkers()

if #workerAddresses == 0 then
    print("No workers found. Exiting...")
    return
end

-- Initialize worker availability tracking
local workerAvailability = {}
for _, address in ipairs(workerAddresses) do
    workerAvailability[address] = 0  -- All workers are initially free
end

-- Step 2: Read the encoded audio file and play notes
if not filesystem.exists(AUDIO_FILE_PATH) then
    print("Audio file not found: " .. AUDIO_FILE_PATH)
    return
end

local file, err = io.open(AUDIO_FILE_PATH, "rb")
if not file then
    print("Failed to open audio file: " .. err)
    return
end

local referenceTick = tickTime()

while true do
    -- Read deltaTick
    local deltaTick = readVarInt(file)
    if not deltaTick then break end

    -- Read duration
    local durationTicks = readVarInt(file)
    if not durationTicks then break end

    -- Read pitch
    local pitchByte = file:read(1)
    if not pitchByte then break end
    local pitch = string.byte(pitchByte)

    -- Wait until desired time
    referenceTick = referenceTick + deltaTick
    while tickTime() < referenceTick do
        os.sleep(0.01)  -- Sleep to avoid busy waiting
    end

    -- Convert pitch to frequency and duration to seconds
    local frequency = midiToFrequency(pitch)
    local durationSeconds = durationTicks * 0.05

    -- Find the earliest available worker
    local currentTick = tickTime()
    local earliestFreeTime = math.huge
    local selectedWorker = nil
    for address, freeTime in pairs(workerAvailability) do
        if freeTime < earliestFreeTime then
            earliestFreeTime = freeTime
            selectedWorker = address
        end
    end

    if selectedWorker and workerAvailability[selectedWorker] <= currentTick then
        -- Send the note to the selected worker
        modem.send(selectedWorker, CONTROLLER_PORT, "note", frequency, durationSeconds - 0.1)
        -- Update the worker's next free time
        workerAvailability[selectedWorker] = currentTick + math.max(durationTicks, 3)
    else
        -- No workers are currently free; note cannot be played
        print(string.format("Note at tick %.2f (frequency: %.2f Hz, duration: %.2f s) could not be played; all workers are busy.", currentTick, frequency, durationSeconds))
    end
end

file:close()
print("Playback finished.")