/** 
 * @file linux_volume_catcher_pw.cpp
 * @brief A Linux-specific, PipeWire-specific hack to detect and volume-adjust new audio sources
 *
 * @cond
 * $LicenseInfo:firstyear=2010&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 * @endcond
 */

/*
  The high-level design is as follows:
  1) Connect to the PipeWire daemon
  2) Find all existing and new audio nodes
  3) Examine PID and parent PID's to see if it belongs to our process
  4) If so, tell PipeWire to adjust the volume of that node
  5) Keep a list of all audio nodes and adjust when we setVolume()
 */

#include "linden_common.h"

#include "volume_catcher.h"

#include <unordered_set>
#include <mutex>

extern "C" {
#include <pipewire/pipewire.h>
#include <spa/pod/builder.h>
#include <spa/param/props.h>

#include "apr_pools.h"
#include "apr_dso.h"
}

#include "media_plugin_base.h"

SymbolGrabber gSymbolGrabber;

#include "linux_volume_catcher_pw_syms.inc"

////////////////////////////////////////////////////

class VolumeCatcherImpl
{
public:
	VolumeCatcherImpl();
	~VolumeCatcherImpl();

	bool loadsyms(std::string pw_dso_name);
	void init();
	void cleanup();

	void pwLock();
	void pwUnlock();

	void setVolume(F32 volume);
	// void setPan(F32 pan);

	void handleRegistryEventGlobal(
		uint32_t id, uint32_t permissions, const char* type,
		uint32_t version, const struct spa_dict* props
	);

	class ChildNode
	{
	public:
		bool mActive = false;

		pw_proxy* mProxy = nullptr;
		spa_hook mNodeListener {};
		spa_hook mProxyListener {};
		VolumeCatcherImpl* mImpl = nullptr;

		void updateVolume();
		void destroy();
	};

	bool mGotSyms = false;

	F32 mVolume = 1.0f; // max by default
	// F32 mPan = 0.0f; // center

	pw_thread_loop* mThreadLoop;
	pw_context* mContext;
	pw_core* mCore;
	pw_registry* mRegistry;
	spa_hook mRegistryListener;

	std::unordered_set<ChildNode*> mChildNodes;
	std::mutex mChildNodesMutex;
};

VolumeCatcherImpl::VolumeCatcherImpl()
{
	init();
}

VolumeCatcherImpl::~VolumeCatcherImpl()
{
	cleanup();
}

// static void debugClear()
// {
// 	auto file = fopen("/home/maki/git/firestorm-viewer/log.txt", "w");
// 	fprintf(file, "\n");
// 	fclose(file);
// }

// static void debugPrint(const char* format, ...)
// {
//     va_list args;
//     va_start(args, format);
// 	auto file = fopen("/home/maki/git/firestorm-viewer/log.txt", "a");
//     vfprintf(file, format, args);
// 	fclose(file);
//     va_end(args);
// }

static void registryEventGlobal(
	void *data, uint32_t id, uint32_t permissions, const char *type,
	uint32_t version, const struct spa_dict *props
)
{
	static_cast<VolumeCatcherImpl*>(data)->handleRegistryEventGlobal(
		id, permissions, type, version, props
	);
}

static const struct pw_registry_events REGISTRY_EVENTS = {
	.version = PW_VERSION_REGISTRY_EVENTS,
    .global = registryEventGlobal,
};

bool VolumeCatcherImpl::loadsyms(std::string pw_dso_name)
{
	return gSymbolGrabber.grabSymbols({ pw_dso_name });
}

void VolumeCatcherImpl::init()
{
	// debugClear();
	// debugPrint("init\n");
	
	mGotSyms = loadsyms("libpipewire-0.3.so.0");
	if (!mGotSyms) return;

	llpw_init(NULL, NULL);

	mThreadLoop = llpw_thread_loop_new("SL Plugin Volume Adjuster", NULL);
	if (!mThreadLoop) return;

	pwLock();

	mContext = llpw_context_new(
		llpw_thread_loop_get_loop(mThreadLoop), NULL, 0
	);
	if (!mContext) return pwUnlock();

	mCore = llpw_context_connect(mContext, NULL, 0);
	if (!mCore) return pwUnlock();

	mRegistry = pw_core_get_registry(mCore, PW_VERSION_REGISTRY, 0);

	// debugPrint("got registry\n");

	spa_zero(mRegistryListener);

	pw_registry_add_listener(
		mRegistry, &mRegistryListener, &REGISTRY_EVENTS, this
	);

	llpw_thread_loop_start(mThreadLoop);

	pwUnlock();

	// debugPrint("started thread loop\n");
}

void VolumeCatcherImpl::cleanup()
{
	mChildNodesMutex.lock();
	for (auto* childNode : mChildNodes) {
		childNode->destroy();
	}
	mChildNodes.clear();
	mChildNodesMutex.unlock();

	pwLock();
	if (mRegistry) llpw_proxy_destroy((struct pw_proxy*)mRegistry);
	spa_zero(mRegistryListener);
	if (mCore) llpw_core_disconnect(mCore);
	if (mContext) llpw_context_destroy(mContext);
	pwUnlock();

	if (!mThreadLoop) return;

	llpw_thread_loop_stop(mThreadLoop);
	llpw_thread_loop_destroy(mThreadLoop);

	// debugPrint("cleanup done\n");
}

void VolumeCatcherImpl::pwLock() {
	if (!mThreadLoop) return;
	llpw_thread_loop_lock(mThreadLoop);
}

void VolumeCatcherImpl::pwUnlock() {
	if (!mThreadLoop) return;
	llpw_thread_loop_unlock(mThreadLoop);
}

// #define INV_LERP(a, b, v) (v - a) / (b - a)

// #include <sys/time.h>

void VolumeCatcherImpl::ChildNode::updateVolume()
{
	if (!mActive) return;

	F32 volume = std::clamp(mImpl->mVolume, 0.0f, 1.0f);
	// F32 pan = std::clamp(mImpl->mPan, -1.0f, 1.0f);

	// debugClear();
	// struct timeval time;
	// gettimeofday(&time, NULL);
	// double t = (double)time.tv_sec + (double)(time.tv_usec / 1000) / 1000;
	// debugPrint("time is %f\n", t);
	// F32 pan = std::sin(t * 2.0d);
	// debugPrint("pan is %f\n", pan);

	// uint32_t channels = 2;
	// float volumes[channels];
	// volumes[1] = INV_LERP(-1.0f, 0.0f, pan) * volume; // left
	// volumes[0] = INV_LERP(1.0f, 0.0f, pan) * volume; // right

	uint32_t channels = 1;
	float volumes[channels];
	volumes[0] = volume;

	uint8_t buffer[512];

	spa_pod_builder builder;
	spa_pod_builder_init(&builder, buffer, sizeof(buffer));

	spa_pod_frame frame;
	spa_pod_builder_push_object(&builder, &frame, SPA_TYPE_OBJECT_Props, SPA_PARAM_Props);
	spa_pod_builder_prop(&builder, SPA_PROP_channelVolumes, 0);
	spa_pod_builder_array(&builder, sizeof(float), SPA_TYPE_Float, channels, volumes);
	spa_pod* pod = static_cast<spa_pod*>(spa_pod_builder_pop(&builder, &frame));

	mImpl->pwLock();
	pw_node_set_param(mProxy, SPA_PARAM_Props, 0, pod);
	mImpl->pwUnlock();
}

void VolumeCatcherImpl::ChildNode::destroy()
{
	if (!mActive) return;
	mActive = false;

	mImpl->mChildNodesMutex.lock();
	mImpl->mChildNodes.erase(this);
	mImpl->mChildNodesMutex.unlock();
	
	spa_hook_remove(&mNodeListener);
	spa_hook_remove(&mProxyListener);

	mImpl->pwLock();	
	llpw_proxy_destroy(mProxy);
	mImpl->pwUnlock();	
}

static pid_t getParentPid(pid_t aPid)
{
	std::stringstream strm;
	strm << "/proc/" << aPid << "/status";
	std::ifstream in{ strm.str() };

	if (!in.is_open()) return 0;

	pid_t res {0};
	while (!in.eof() && res == 0)
	{
		std::string line;
		line.resize( 1024, 0 );
		in.getline( &line[0], line.length() );	

		auto i = line.find("PPid:");
		
		if (i == std::string::npos) continue;
		
		char const *pIn = line.c_str() + 5; // Skip over pid;
		while (*pIn != 0 && isspace( *pIn )) ++pIn;

		if (*pIn) res = atoll(pIn);
	}
 	return res;
}

static bool isPluginPid(pid_t aPid)
{
	auto myPid = getpid();

	do
	{
		if(aPid == myPid) return true;
		aPid = getParentPid( aPid );
	} while(aPid > 1);

	return false;
}

static void nodeEventInfo(void* data, const struct pw_node_info* info)
{
	const char* processId = spa_dict_lookup(info->props, PW_KEY_APP_PROCESS_ID);
	if (processId == nullptr) return;
	
	pid_t pid = atoll(processId);
	if (!isPluginPid(pid)) return;

	// const char* appName = spa_dict_lookup(info->props, PW_KEY_APP_NAME);
	// debugPrint("got app: %s\n", appName);
	
	auto* const childNode = static_cast<VolumeCatcherImpl::ChildNode*>(data);
	// debugPrint("init volume to: %f\n", childNode->mImpl->mDesiredVolume);

	childNode->updateVolume();

	childNode->mImpl->mChildNodesMutex.lock();
	childNode->mImpl->mChildNodes.insert(childNode);
	childNode->mImpl->mChildNodesMutex.unlock();
}

static const struct pw_node_events NODE_EVENTS = {
	.version = PW_VERSION_CLIENT_EVENTS,
	.info = nodeEventInfo,
};

static void proxyEventDestroy(void* data)
{
	auto* const childNode = static_cast<VolumeCatcherImpl::ChildNode*>(data);
	childNode->destroy();
}

static void proxyEventRemoved(void* data)
{
	auto* const childNode = static_cast<VolumeCatcherImpl::ChildNode*>(data);
	childNode->destroy();
}

static const struct pw_proxy_events PROXY_EVENTS = {
	.version = PW_VERSION_PROXY_EVENTS,
    .destroy = proxyEventDestroy,
	.removed = proxyEventRemoved,
};

void VolumeCatcherImpl::handleRegistryEventGlobal(
	uint32_t id, uint32_t permissions, const char *type, uint32_t version,
	const struct spa_dict *props
) {
	if (props == nullptr || strcmp(type, PW_TYPE_INTERFACE_Node) != 0) return;

	const char* mediaClass = spa_dict_lookup(props, PW_KEY_MEDIA_CLASS);
	if (mediaClass == nullptr || strcmp(mediaClass, "Stream/Output/Audio") != 0) return;
	
	pw_proxy* proxy = static_cast<pw_proxy*>(
		pw_registry_bind(mRegistry, id, type, PW_VERSION_CLIENT, sizeof(ChildNode))
	);

	auto* const childNode = static_cast<ChildNode*>(llpw_proxy_get_user_data(proxy));

	childNode->mActive = true;
	childNode->mProxy = proxy;
	childNode->mImpl = this;

	pw_node_add_listener(proxy, &childNode->mNodeListener, &NODE_EVENTS, childNode);
	llpw_proxy_add_listener(proxy, &childNode->mProxyListener, &PROXY_EVENTS, childNode);
}

void VolumeCatcherImpl::setVolume(F32 volume)
{
	// debugPrint("setting all volume to: %f\n", volume);

	mVolume = volume;

	mChildNodesMutex.lock();
	std::unordered_set<ChildNode*> copyOfChildNodes(mChildNodes);
	mChildNodesMutex.unlock();

	// debugPrint("for %d nodes\n", copyOfChildNodes.size());

	for (auto* childNode : copyOfChildNodes) {
		childNode->updateVolume();
	}
}

// void VolumeCatcherImpl::setPan(F32 pan)
// {
// 	mPan = pan;
// 	setVolume(mVolume);
// }

/////////////////////////////////////////////////////

VolumeCatcher::VolumeCatcher()
{
	pimpl = new VolumeCatcherImpl();
}

VolumeCatcher::~VolumeCatcher()
{
	delete pimpl;
	pimpl = nullptr;
}

void VolumeCatcher::setVolume(F32 volume)
{
	llassert(pimpl);
	pimpl->setVolume(volume);
}

void VolumeCatcher::setPan(F32 pan)
{
	// llassert(pimpl);
	// pimpl->setPan(pan);
}

void VolumeCatcher::pump()
{
}