// macOS CoreAudio device model for SDL's coreaudio backend (macOS build).
// FX_LIB_COREAUDIO: one virtual output device (the iPhone route), answering the AudioObject
// properties SDL 2.24 queries. Playback itself uses the real iOS AudioQueue.
// FX_LIB_AUDIOTOOLBOX: AudioQueueSetProperty passes through, except macOS-only CurrentDevice.
#include <AudioToolbox/AudioToolbox.h>
#include <CoreFoundation/CoreFoundation.h>
#include <dlfcn.h>
#include <string.h>
#include "fx.h"

#define FOURCC(a, b, c, d) ((uint32_t)(a) << 24 | (uint32_t)(b) << 16 | (uint32_t)(c) << 8 | (uint32_t)(d))

#ifdef FX_LIB_COREAUDIO
typedef uint32_t AudioObjectID;
typedef struct { uint32_t mSelector, mScope, mElement; } FXPropertyAddress;
typedef OSStatus (*FXPropertyListener)(AudioObjectID, uint32_t, const FXPropertyAddress *, void *);

enum {
    kSystemObject = 1, kSpeaker = 0x100,
    kDevices = FOURCC('d', 'e', 'v', '#'), kDefaultOutput = FOURCC('d', 'O', 'u', 't'),
    kDefaultInput = FOURCC('d', 'I', 'n', ' '), kStreamConfiguration = FOURCC('s', 'l', 'a', 'y'),
    kName = FOURCC('l', 'n', 'a', 'm'), kNominalSampleRate = FOURCC('n', 's', 'r', 't'),
    kIsAlive = FOURCC('l', 'i', 'v', 'n'), kHogMode = FOURCC('o', 'i', 'n', 'k'),
    kUID = FOURCC('u', 'i', 'd', ' '), kScopeInput = FOURCC('i', 'n', 'p', 't'),
    kUnknownProperty = FOURCC('w', 'h', 'o', '?'), kBadObject = FOURCC('!', 'o', 'b', 'j'),
};

// Writes the property into `out` (when non-NULL) and returns its size, or 0 if unsupported.
static uint32_t fx_property(AudioObjectID object, const FXPropertyAddress *a, void *out, OSStatus *status) {
    *status = 0;
    if (object == kSystemObject) {
        switch (a->mSelector) {
            case kDevices: case kDefaultOutput: if (out) *(AudioObjectID *)out = kSpeaker; return 4;
            case kDefaultInput: if (out) *(AudioObjectID *)out = 0; return 4;  // no capture device
        }
    } else if (object == kSpeaker) {
        int input = a->mScope == kScopeInput;
        switch (a->mSelector) {
            case kStreamConfiguration:
                if (out) {
                    AudioBufferList *list = out;
                    list->mNumberBuffers = input ? 0 : 1;
                    list->mBuffers[0] = (AudioBuffer){2, 0, NULL};
                }
                return sizeof(AudioBufferList);
            case kName: if (out) *(CFStringRef *)out = CFStringCreateCopy(NULL, CFSTR("iPhone")); return sizeof(CFStringRef);
            case kUID: if (out) *(CFStringRef *)out = CFStringCreateCopy(NULL, CFSTR("fx-ios-output")); return sizeof(CFStringRef);
            case kNominalSampleRate: if (out) *(Float64 *)out = 48000.0; return sizeof(Float64);
            case kIsAlive: if (out) *(uint32_t *)out = !input; return 4;
            case kHogMode: if (out) *(pid_t *)out = -1; return sizeof(pid_t);
        }
    } else {
        *status = kBadObject;
        return 0;
    }
    *status = kUnknownProperty;
    fx_log("[fx] CoreAudio: unsupported property '%c%c%c%c' on object %u", a->mSelector >> 24, a->mSelector >> 16,
           a->mSelector >> 8, a->mSelector, object);
    return 0;
}

FX_EXPORT Boolean AudioObjectHasProperty(AudioObjectID object, const FXPropertyAddress *a) {
    OSStatus status;
    return fx_property(object, a, NULL, &status) && !status;
}
FX_EXPORT OSStatus AudioObjectGetPropertyDataSize(AudioObjectID object, const FXPropertyAddress *a, uint32_t qsize,
                                                  const void *q, uint32_t *size) {
    OSStatus status;
    uint32_t n = fx_property(object, a, NULL, &status);
    if (!status && size) *size = n;
    return status;
}
FX_EXPORT OSStatus AudioObjectGetPropertyData(AudioObjectID object, const FXPropertyAddress *a, uint32_t qsize,
                                              const void *q, uint32_t *size, void *data) {
    OSStatus status;
    uint32_t n = fx_property(object, a, NULL, &status);
    if (status) return status;
    if (!size || *size < n) return FOURCC('!', 's', 'i', 'z');
    fx_property(object, a, data, &status);
    *size = n;
    return status;
}
FX_EXPORT OSStatus AudioObjectAddPropertyListener(AudioObjectID o, const FXPropertyAddress *a, FXPropertyListener l, void *c) { return 0; }
FX_EXPORT OSStatus AudioObjectRemovePropertyListener(AudioObjectID o, const FXPropertyAddress *a, FXPropertyListener l, void *c) { return 0; }
#endif

#ifdef FX_LIB_AUDIOTOOLBOX
FX_EXPORT OSStatus AudioQueueSetProperty(AudioQueueRef queue, AudioQueuePropertyID id, const void *data, UInt32 size) {
    static OSStatus (*real)(AudioQueueRef, AudioQueuePropertyID, const void *, UInt32);
    if (!real) {
        void *toolbox = dlopen("/System/Library/Frameworks/AudioToolbox.framework/AudioToolbox", RTLD_LAZY | RTLD_NOLOAD);
        real = toolbox ? dlsym(toolbox, "AudioQueueSetProperty") : NULL;
    }
    if (id == FOURCC('a', 'q', 'c', 'd')) return 0;  // kAudioQueueProperty_CurrentDevice: iOS routes itself
    return real ? real(queue, id, data, size) : -1;
}
#endif