// Spike C — Core Audio Process Taps auf M5 Pro / macOS 26
//
// Fragen:
//   1. Liefert kAudioHardwarePropertyProcessObjectList die Audio-Prozesse?
//   2. Lässt sich pro Prozess ein Tap erzeugen (AudioHardwareCreateProcessTap)?
//   3. Lässt sich ein privates Aggregate-Device mit diesem Tap bauen?
//   4. Liefert ein IOProc darauf tatsächlich Samples?
//
// Der Tap wird mit muteBehavior = .unmuted angelegt — dieser Spike hört nur zu und
// verändert NICHTS an der Wiedergabe. Der stummschaltende Modus, den der spätere
// Mixer braucht, wird hier bewusst nicht benutzt.
//
// Bauen: Spikes/build-audiotap-probe.sh

import Foundation
import AppKit
import AVFoundation
import CoreAudio
import AudioToolbox

// MARK: - Property-Hilfen

func address(_ selector: AudioObjectPropertySelector,
             _ scope: AudioObjectPropertyScope = kAudioObjectPropertyScopeGlobal)
-> AudioObjectPropertyAddress {
    AudioObjectPropertyAddress(mSelector: selector, mScope: scope,
                               mElement: kAudioObjectPropertyElementMain)
}

func readArray<T>(_ object: AudioObjectID, _ addr: AudioObjectPropertyAddress, _ type: T.Type) -> [T] {
    var addr = addr
    var size: UInt32 = 0
    guard AudioObjectGetPropertyDataSize(object, &addr, 0, nil, &size) == noErr, size > 0 else { return [] }

    let count = Int(size) / MemoryLayout<T>.stride
    let raw = UnsafeMutableRawPointer.allocate(byteCount: Int(size),
                                               alignment: MemoryLayout<T>.alignment)
    defer { raw.deallocate() }

    guard AudioObjectGetPropertyData(object, &addr, 0, nil, &size, raw) == noErr else { return [] }
    return Array(UnsafeBufferPointer(start: raw.assumingMemoryBound(to: T.self), count: count))
}

func readValue<T>(_ object: AudioObjectID, _ addr: AudioObjectPropertyAddress, _ initial: T) -> T? {
    var addr = addr
    var value = initial
    var size = UInt32(MemoryLayout<T>.size)
    guard AudioObjectGetPropertyData(object, &addr, 0, nil, &size, &value) == noErr else { return nil }
    return value
}

func readString(_ object: AudioObjectID, _ addr: AudioObjectPropertyAddress) -> String? {
    var addr = addr
    var cf: CFString? = nil
    var size = UInt32(MemoryLayout<CFString?>.size)
    let status = withUnsafeMutablePointer(to: &cf) {
        AudioObjectGetPropertyData(object, &addr, 0, nil, &size, $0)
    }
    guard status == noErr, let cf else { return nil }
    return cf as String
}

let system = AudioObjectID(kAudioObjectSystemObject)

print("Core-Audio-Process-Tap-Probe")
print("macOS \(ProcessInfo.processInfo.operatingSystemVersionString)")
print(String(repeating: "─", count: 68))

// MARK: - 1. Audio-Prozesse auflisten

let processes = readArray(system, address(kAudioHardwarePropertyProcessObjectList), AudioObjectID.self)
print("\n1. Audio-Prozesse: \(processes.count)")

struct AudioProc {
    let objectID: AudioObjectID
    let pid: pid_t
    let bundleID: String
    let running: Bool
    var name: String {
        guard let app = NSRunningApplication(processIdentifier: pid) else { return bundleID }
        return app.localizedName ?? bundleID
    }
}

var procs: [AudioProc] = []
for obj in processes {
    let pid = readValue(obj, address(kAudioProcessPropertyPID), pid_t(0)) ?? -1
    let bundle = readString(obj, address(kAudioProcessPropertyBundleID)) ?? "—"
    let running = (readValue(obj, address(kAudioProcessPropertyIsRunningOutput), UInt32(0)) ?? 0) != 0
    procs.append(AudioProc(objectID: obj, pid: pid, bundleID: bundle, running: running))
}

for p in procs.sorted(by: { $0.running && !$1.running }) {
    let mark = p.running ? "▶ SPIELT AB" : "  still"
    print("   \(mark)  pid \(String(p.pid).padding(toLength: 6, withPad: " ", startingAt: 0)) \(p.bundleID)")
}

guard let target = procs.first(where: { $0.running }) else {
    print("\nKein Prozess gibt gerade Audio aus — bitte etwas abspielen und erneut starten.")
    exit(2)
}
print("\n   Ziel: \(target.bundleID) (pid \(target.pid))")

// MARK: - 2. Tap erzeugen

print("\n2. Process Tap")
let tapDescription = CATapDescription(stereoMixdownOfProcesses: [target.objectID])
tapDescription.uuid = UUID()
tapDescription.name = "Onyx Spike Tap"
tapDescription.isPrivate = true
// Bewusst NICHT .mutedWhenTapped — dieser Spike verändert die Wiedergabe nicht.
tapDescription.muteBehavior = .unmuted

var tapID = AudioObjectID(kAudioObjectUnknown)
let tapStatus = AudioHardwareCreateProcessTap(tapDescription, &tapID)
guard tapStatus == noErr else {
    print("   FEHLGESCHLAGEN: OSStatus \(tapStatus)")
    if tapStatus == 1751737219 { // 'nope' — kAudioHardwareIllegalOperationError
        print("   → Vermutlich fehlt die TCC-Berechtigung für Systemaudioaufnahme.")
        print("     Systemeinstellungen → Datenschutz & Sicherheit → Audioaufnahme")
    }
    exit(1)
}
print("   erzeugt, Tap-Objekt \(tapID)")

defer { AudioHardwareDestroyProcessTap(tapID) }

let tapFormat = readValue(tapID, address(kAudioTapPropertyFormat), AudioStreamBasicDescription())
if let f = tapFormat {
    print("   Format: \(Int(f.mSampleRate)) Hz, \(f.mChannelsPerFrame) Kanäle, \(f.mBitsPerChannel) bit")
}

// MARK: - 3. Privates Aggregate-Device

print("\n3. Privates Aggregate-Device")
guard let outputDevice = readValue(system, address(kAudioHardwarePropertyDefaultOutputDevice),
                                   AudioObjectID(kAudioObjectUnknown)),
      let outputUID = readString(outputDevice, address(kAudioDevicePropertyDeviceUID)) else {
    print("   Standard-Ausgabegerät nicht ermittelbar")
    exit(1)
}
print("   Ausgabegerät: \(readString(outputDevice, address(kAudioObjectPropertyName)) ?? outputUID)")

let aggregateUID = UUID().uuidString
let description: [String: Any] = [
    kAudioAggregateDeviceNameKey: "Onyx Spike Aggregate",
    kAudioAggregateDeviceUIDKey: aggregateUID,
    kAudioAggregateDeviceIsPrivateKey: true,
    kAudioAggregateDeviceIsStackedKey: false,
    kAudioAggregateDeviceMainSubDeviceKey: outputUID,
    kAudioAggregateDeviceSubDeviceListKey: [[kAudioSubDeviceUIDKey: outputUID]],
    kAudioAggregateDeviceTapListKey: [[
        kAudioSubTapUIDKey: tapDescription.uuid.uuidString,
        kAudioSubTapDriftCompensationKey: true,
    ]],
]

var aggregateID = AudioObjectID(kAudioObjectUnknown)
let aggStatus = AudioHardwareCreateAggregateDevice(description as CFDictionary, &aggregateID)
guard aggStatus == noErr else {
    print("   FEHLGESCHLAGEN: OSStatus \(aggStatus)")
    exit(1)
}
print("   erzeugt, Device \(aggregateID), UID \(aggregateUID)")
defer { AudioHardwareDestroyAggregateDevice(aggregateID) }

// MARK: - 4. IOProc — kommen Samples an?

print("\n4. IOProc (5 s messen)")

final class Meter: @unchecked Sendable {
    var callbacks = 0
    var frames = 0
    var peak: Float = 0
    var silentBuffers = 0
    let lock = NSLock()
}
let meter = Meter()

var procID: AudioDeviceIOProcID?
let ioStatus = AudioDeviceCreateIOProcIDWithBlock(&procID, aggregateID, nil) {
    _, inputData, _, _, _ in
    let buffers = UnsafeMutableAudioBufferListPointer(UnsafeMutablePointer(mutating: inputData))
    var localPeak: Float = 0
    var frameCount = 0
    for buffer in buffers {
        guard let data = buffer.mData else { continue }
        let count = Int(buffer.mDataByteSize) / MemoryLayout<Float>.size
        frameCount += count
        let samples = data.assumingMemoryBound(to: Float.self)
        for i in 0..<count { localPeak = max(localPeak, abs(samples[i])) }
    }
    meter.lock.lock()
    meter.callbacks += 1
    meter.frames += frameCount
    meter.peak = max(meter.peak, localPeak)
    if localPeak == 0 { meter.silentBuffers += 1 }
    meter.lock.unlock()
}

guard ioStatus == noErr, let procID else {
    print("   IOProc-Erzeugung fehlgeschlagen: \(ioStatus)")
    exit(1)
}
defer { AudioDeviceDestroyIOProcID(aggregateID, procID) }

guard AudioDeviceStart(aggregateID, procID) == noErr else {
    print("   AudioDeviceStart fehlgeschlagen")
    exit(1)
}
Thread.sleep(forTimeInterval: 5)
AudioDeviceStop(aggregateID, procID)

meter.lock.lock()
let (cb, fr, pk, silent) = (meter.callbacks, meter.frames, meter.peak, meter.silentBuffers)
meter.lock.unlock()

print("   Callbacks:      \(cb)  (\(cb / 5)/s)")
print("   Frames:         \(fr)")
print("   Spitzenpegel:   \(String(format: "%.4f", pk))")
print("   Stille Puffer:  \(silent) von \(cb)")

print("\n" + String(repeating: "─", count: 68))
if cb > 0 && pk > 0 {
    print("ERGEBNIS: Tap liefert echte Samples. Per-App-Mixer ist umsetzbar.")
} else if cb > 0 {
    print("ERGEBNIS: Callbacks kommen, aber nur Stille — spielte das Ziel wirklich ab?")
} else {
    print("ERGEBNIS: keine Callbacks. Aggregate-Device liefert nichts.")
}