CoopAllTheThings/tests/audio_hook_test.cpp

// In-process self-test for the WASAPI render-hook (hook/src/audio_hook.cpp), focused on
// audio-format detection. This process plays both "game" and "hook": it installs the
// audio hooks and renders sine tones through WASAPI at a matrix of common formats,
// exercising both code paths the hook uses to learn a stream's format:
//
//   - SEE-INIT: hooks installed before the render client is created, so the hook sees
//     IAudioClient::Initialize and records the *exact* format.
//   - GUESS:    the render client already exists when the hook installs (the real case --
//     we inject into a running game), so the hook never saw Initialize and assumes the
//     device mix format, then measures the stream's true sample rate from its cadence.
//
// For each format it asserts the hook published the right rate/channels/bits and the
// right provenance state. No game, no second Steam account. Exits 0 on pass, 1 on fail;
// SKIPs cleanly (exit 0) on a machine with no render endpoint, mirroring the other tests.

#include <cstdint>
#include <cstdio>
#include <vector>

#include <windows.h>

#include <audioclient.h>
#include <mmdeviceapi.h>
#include <mmreg.h>

#include "audio_hook.hpp"
#include "coop/audio_ring.hpp"
#include "coop/protocol.hpp"
#include "coop/shared_memory.hpp"
#include "ipc_client.hpp"
#include "tone_source.hpp"

using namespace coop;
using coop::tone::ToneFormat;
using coop::tone::ToneSource;

namespace {

int g_failures = 0;

// Returns 1 (and logs) on failure, 0 on success -- so callers can sum a tally.
int expect(bool ok, const char* what)
{
	if (!ok) {
		std::printf("  FAIL: %s\n", what);
		++g_failures;
		return 1;
	}
	return 0;
}

void reset_ring(AudioRingHeader* ring, SharedBlock* block)
{
	audio_ring_init(*ring, kAudioRingCapacity);
	ring->capture_enabled.store(1, std::memory_order_release);
	block->status.audio_streams[0] = AudioStreamInfo{}; // clear stale provenance from the last case
}

// Drain the ring and report whether any non-silent sample landed in it (capture path).
bool ring_has_nonsilent(AudioRingHeader* ring)
{
	std::vector<std::uint8_t> buf(128 * 1024, 0);
	const std::uint32_t got = audio_ring_pop(*ring, buf.data(), static_cast<std::uint32_t>(buf.size()));
	for (std::uint32_t i = 0; i < got; ++i) {
		if (buf[i] != 0) {
			return true;
		}
	}
	return false;
}

const char* fmt_desc(const ToneFormat& f, char* buf, size_t n)
{
	std::snprintf(buf, n, "%u Hz %u ch %u-bit %s", f.rate, f.channels, f.bits, f.is_float ? "float" : "pcm");
	return buf;
}

// SEE-INIT: install hooks first, then create the render client so the hook records the
// exact Initialize format. Verifies the full format and the Exact provenance.
void test_see_init(hook::IpcClient& ipc, AudioRingHeader* ring, SharedBlock* block, const ToneFormat& want)
{
	char d[64];
	reset_ring(ring, block);
	if (!hook::install_audio_hooks(ipc, ring)) {
		std::printf("  SKIP see-init (audio hooks unavailable)\n");
		return;
	}

	ToneSource tone;
	if (!tone.open(want)) {
		std::printf("  SKIP see-init %s (format unavailable here)\n", fmt_desc(want, d, sizeof(d)));
		hook::remove_audio_hooks();
		return;
	}
	const ToneFormat& f = tone.format();

	// Exact format publishes at registration; render briefly so capture fills the ring.
	const std::uint64_t silenced_before = hook::audio_frames_silenced();
	const DWORD end = GetTickCount() + 300;
	while (GetTickCount() < end) {
		tone.render_step(50);
	}

	const AudioStreamInfo& s = block->status.audio_streams[0];
	int fail = 0;
	fail += expect(audio_ring_format_ready(*ring), "see-init: format published to ring");
	fail += expect(ring->sample_rate == f.rate, "see-init: ring rate == exact rate");
	fail += expect(ring->channels == f.channels, "see-init: ring channels == exact channels");
	fail += expect(ring->bits == f.bits, "see-init: ring bits == exact bits");
	fail += expect(s.sample_rate == f.rate, "see-init: HookStatus rate == exact rate");
	fail += expect(s.format_state == AudioFormat_Exact, "see-init: provenance == Exact");
	fail += expect(ring_has_nonsilent(ring), "see-init: non-silent audio captured");
	fail += expect(hook::audio_frames_silenced() > silenced_before, "see-init: local playback muted (no echo)");
	std::printf("  %s see-init %s -> ring %uHz/%uch/%ubit state=%u\n", fail == 0 ? "PASS" : "FAIL",
	            fmt_desc(f, d, sizeof(d)), ring->sample_rate, ring->channels, ring->bits, s.format_state);

	tone.close();
	hook::remove_audio_hooks();
}

// GUESS: create the render client first (its Initialize is unseen), then install hooks so
// the stream is discovered lazily and assigned the device mix format -- whose rate is then
// measured/corrected. Rendered with the device channels/bits (only the rate differs from
// the device) so the test isolates the rate-measurement logic the real bug needed.
void test_guess(hook::IpcClient& ipc, AudioRingHeader* ring, SharedBlock* block, unsigned rate)
{
	reset_ring(ring, block);

	ToneSource tone;
	ToneFormat want;
	want.rate = rate; // channels/bits resolve to the device's
	if (!tone.open(want)) {
		std::printf("  SKIP guess %u Hz (format unavailable here)\n", rate);
		return;
	}
	const ToneFormat& f = tone.format();

	// Let the stream reach steady state before attaching, like a game already running when
	// we inject (the real case) -- not a stream we caught at its first buffer.
	const DWORD warm = GetTickCount() + 300;
	while (GetTickCount() < warm) {
		tone.render_step(30);
	}

	// Hooks install *after* the client exists -> the lazy-discovery (guess) path.
	if (!hook::install_audio_hooks(ipc, ring)) {
		std::printf("  SKIP guess (audio hooks unavailable)\n");
		tone.close();
		return;
	}

	// Render while driving republish (the DLL's worker does this each tick) until the
	// measured rate is published, then render a bit more so capture fills the ring.
	const DWORD measure_deadline = GetTickCount() + 2000;
	while (GetTickCount() < measure_deadline && !audio_ring_format_ready(*ring)) {
		tone.render_step(30);
		hook::republish_audio_format();
	}
	// Format is published; from here the hook must capture AND mute (the no-echo path).
	const std::uint64_t silenced_before = hook::audio_frames_silenced();
	const DWORD cap_end = GetTickCount() + 200;
	while (GetTickCount() < cap_end) {
		tone.render_step(30);
	}

	const AudioStreamInfo& s = block->status.audio_streams[0];
	int fail = 0;
	fail += expect(audio_ring_format_ready(*ring), "guess: format published after measuring");
	fail += expect(ring->sample_rate == f.rate, "guess: measured rate == rendered rate");
	fail += expect(s.sample_rate == f.rate, "guess: HookStatus rate == rendered rate");
	fail += expect(s.format_state == AudioFormat_Measured, "guess: provenance == Measured");
	fail += expect(ring_has_nonsilent(ring), "guess: non-silent audio captured");
	// THE BROTATO BUG: a guessed (late-attach) stream is byte-compatible here (device
	// channels/bits), so the hook must mute the game's local playback too -- otherwise the
	// game plays locally AND the mirror re-renders it, slightly delayed = a metallic double.
	fail += expect(hook::audio_frames_silenced() > silenced_before,
	               "guess: local playback muted (no echo) -- the Brotato double-audio bug");
	std::printf("  %s guess %u Hz (device %uch/%ubit) -> measured %uHz state=%u\n", fail == 0 ? "PASS" : "FAIL", rate,
	            f.channels, f.bits, ring->sample_rate, s.format_state);

	tone.close();
	hook::remove_audio_hooks();
}

// GUESS-MISMATCH: the device channels/bits guess is *wrong* for this stream (its bytes/frame
// differ). We can't recover the true channels/bits, but the capture must stay safe -- the
// VirtualQuery clamp must stop the copy reading past the source buffer. We can't assert a
// "correct" format here (it's fundamentally undetectable); we assert the hook survives and
// doesn't read absurd amounts, i.e. the unit test completes without an access violation.
void test_guess_mismatch_safe(hook::IpcClient& ipc, AudioRingHeader* ring, SharedBlock* block, const ToneFormat& want,
                              const char* label)
{
	char d[64];
	reset_ring(ring, block);

	ToneSource tone;
	if (!tone.open(want)) {
		std::printf("  SKIP guess-mismatch %s (%s unavailable here)\n", label, fmt_desc(want, d, sizeof(d)));
		return;
	}
	const ToneFormat& f = tone.format();
	const DWORD warm = GetTickCount() + 300; // steady state before attaching
	while (GetTickCount() < warm) {
		tone.render_step(30);
	}
	if (!hook::install_audio_hooks(ipc, ring)) {
		std::printf("  SKIP guess-mismatch (audio hooks unavailable)\n");
		tone.close();
		return;
	}

	// Render and capture through the guessed (too-large) block. The clamp must keep this
	// from over-reading; reaching the end of the loop is the pass (no AV).
	const DWORD end = GetTickCount() + 600;
	while (GetTickCount() < end) {
		tone.render_step(30);
		hook::republish_audio_format();
	}
	std::printf("  PASS guess-mismatch %s (%s) survived capture with a too-large guessed block (no over-read)\n",
	            fmt_desc(f, d, sizeof(d)), label);

	tone.close();
	hook::remove_audio_hooks();
}

} // namespace

int main()
{
	if (FAILED(CoInitializeEx(nullptr, COINIT_MULTITHREADED))) {
		std::printf("FAIL: CoInitializeEx\n");
		return 1;
	}

	// Host side: the IPC SharedBlock (named by our pid) the hook's IpcClient connects to,
	// plus one producer ring with capture enabled.
	SharedMemory shm;
	if (!shm.create(shared_memory_name(GetCurrentProcessId()), sizeof(SharedBlock))) {
		std::printf("FAIL: create shared memory\n");
		return 1;
	}
	auto* block = shm.as<SharedBlock>(); // OS zero-inits the mapping
	block->version = kProtocolVersion;
	block->sequence.store(0, std::memory_order_relaxed);
	block->magic = kProtocolMagic;

	std::vector<std::uint8_t> ring_storage(audio_ring_total_size(kAudioRingCapacity), 0);
	auto* ring = new (ring_storage.data()) AudioRingHeader();
	audio_ring_init(*ring, kAudioRingCapacity);

	hook::IpcClient ipc;
	expect(ipc.connect(10, 5), "IPC client connect");

	// Probe the endpoint once; SKIP cleanly on a headless machine (no render device).
	// Capture the device mix format so the guess-mismatch cases can pick formats whose
	// bytes/frame are guaranteed to differ from the device's.
	ToneFormat dev;
	{
		ToneSource probe;
		if (!probe.open(ToneFormat{})) {
			std::printf("SKIP: no default render endpoint (no audio device?)\n");
			CoUninitialize();
			return 0;
		}
		dev = probe.format();
		probe.close();
	}
	std::printf("Device mix format: %u Hz %u ch %u-bit %s\n", dev.rate, dev.channels, dev.bits,
	            dev.is_float ? "float" : "pcm");

	// SEE-INIT: exact full-format detection across common rate/channel/bit-depth combos.
	std::printf("== SEE-INIT (hook sees Initialize -> exact format) ==\n");
	const ToneFormat see_init[] = {
	    {44100, 2, 16, false}, // CD-quality stereo PCM
	    {48000, 2, 32, true},  // common float stereo
	    {96000, 2, 32, true},  // hi-res stereo float
	    {44100, 1, 16, false}, // mono PCM
	    {48000, 6, 32, true},  // 5.1 float
	};
	for (const ToneFormat& f : see_init) {
		test_see_init(ipc, ring, block, f);
	}

	// GUESS (match): the lazy-discovery path with the device channels/bits, so only the
	// rate differs -- the hook measures + corrects it to the true rate (the Brotato/Godot
	// case). Rendered at the device's channel/bit layout, so the bytes/frame match.
	std::printf("== GUESS, byte-compatible (pre-existing client -> measure the true rate) ==\n");
	for (unsigned rate : {44100u, 48000u, 96000u}) {
		test_guess(ipc, ring, block, rate);
	}

	// GUESS (byte-incompatible): a pre-existing client whose channels/bits differ from the
	// device. The hook can't recover them (so it can't be pitch/format-correct here -- that's
	// a documented limitation), but the VirtualQuery clamp must keep the capture safe rather
	// than over-reading the source buffer.
	std::printf("== GUESS, byte-incompatible (channels/bits differ -> capture must stay safe) ==\n");
	if (dev.channels >= 2) {
		test_guess_mismatch_safe(ipc, ring, block, {dev.rate, 1, dev.bits, dev.is_float}, "mono");
	}
	{
		const unsigned alt_bits = (dev.bits == 32) ? 16u : 32u;
		const bool alt_float = (alt_bits == 32);
		test_guess_mismatch_safe(ipc, ring, block, {dev.rate, dev.channels, alt_bits, alt_float}, "alt bit depth");
	}

	CoUninitialize();
	std::printf(g_failures == 0 ? "AUDIO HOOK TEST PASS\n" : "AUDIO HOOK TEST FAILED (%d)\n", g_failures);
	return g_failures == 0 ? 0 : 1;
}