/******************************************************************************
    Copyright (C) 2014 by Hugh Bailey <obs.jim@gmail.com>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 2 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
******************************************************************************/

#include <obs-module.h>
#include <obs-avc.h>
#include <util/platform.h>
#include <util/circlebuf.h>
#include <util/dstr.h>
#include <util/threading.h>
#include <inttypes.h>
#include "librtmp/rtmp.h"
#include "librtmp/log.h"
#include "flv-mux.h"

#define do_log(level, format, ...) \
	blog(level, "[rtmp stream: '%s'] " format, \
			obs_output_get_name(stream->output), ##__VA_ARGS__)

#define warn(format, ...)  do_log(LOG_WARNING, format, ##__VA_ARGS__)
#define info(format, ...)  do_log(LOG_INFO,    format, ##__VA_ARGS__)
#define debug(format, ...) do_log(LOG_DEBUG,   format, ##__VA_ARGS__)

#define OPT_DROP_THRESHOLD "drop_threshold_ms"

//#define TEST_FRAMEDROPS

struct rtmp_stream {
	obs_output_t     output;

	pthread_mutex_t  packets_mutex;
	struct circlebuf packets;

	bool             connecting;
	pthread_t        connect_thread;

	bool             active;
	pthread_t        send_thread;

	os_sem_t         send_sem;
	os_event_t       stop_event;

	struct dstr      path, key;
	struct dstr      username, password;

	/* frame drop variables */
	int64_t          drop_threshold_usec;
	int64_t          min_drop_dts_usec;
	int              min_priority;

	int64_t          last_dts_usec;

	uint64_t         total_bytes_sent;
	int              dropped_frames;

	RTMP             rtmp;
};

static const char *rtmp_stream_getname(void)
{
	return obs_module_text("RTMPStream");
}

static void log_rtmp(int level, const char *format, va_list args)
{
	if (level > RTMP_LOGWARNING)
		return;

	blogva(LOG_INFO, format, args);
}

static inline void free_packets(struct rtmp_stream *stream)
{
	while (stream->packets.size) {
		struct encoder_packet packet;
		circlebuf_pop_front(&stream->packets, &packet, sizeof(packet));
		obs_free_encoder_packet(&packet);
	}
}

static void rtmp_stream_stop(void *data);

static void rtmp_stream_destroy(void *data)
{
	struct rtmp_stream *stream = data;

	if (stream->active)
		rtmp_stream_stop(data);

	if (stream) {
		free_packets(stream);
		dstr_free(&stream->path);
		dstr_free(&stream->key);
		dstr_free(&stream->username);
		dstr_free(&stream->password);
		os_event_destroy(stream->stop_event);
		os_sem_destroy(stream->send_sem);
		pthread_mutex_destroy(&stream->packets_mutex);
		circlebuf_free(&stream->packets);
		bfree(stream);
	}
}

static void *rtmp_stream_create(obs_data_t settings, obs_output_t output)
{
	struct rtmp_stream *stream = bzalloc(sizeof(struct rtmp_stream));
	stream->output = output;
	pthread_mutex_init_value(&stream->packets_mutex);

	RTMP_Init(&stream->rtmp);
	RTMP_LogSetCallback(log_rtmp);
	RTMP_LogSetLevel(RTMP_LOGWARNING);

	if (pthread_mutex_init(&stream->packets_mutex, NULL) != 0)
		goto fail;
	if (os_event_init(&stream->stop_event, OS_EVENT_TYPE_MANUAL) != 0)
		goto fail;

	UNUSED_PARAMETER(settings);
	return stream;

fail:
	rtmp_stream_destroy(stream);
	return NULL;
}

static void rtmp_stream_stop(void *data)
{
	struct rtmp_stream *stream = data;
	void *ret;

	os_event_signal(stream->stop_event);

	if (stream->connecting)
		pthread_join(stream->connect_thread, &ret);

	if (stream->active) {
		obs_output_end_data_capture(stream->output);
		os_sem_post(stream->send_sem);
		pthread_join(stream->send_thread, &ret);
		RTMP_Close(&stream->rtmp);
	}

	os_event_reset(stream->stop_event);
}

static inline void set_rtmp_str(AVal *val, const char *str)
{
	bool valid  = (str && *str);
	val->av_val = valid ? (char*)str       : NULL;
	val->av_len = valid ? (int)strlen(str) : 0;
}

static inline void set_rtmp_dstr(AVal *val, struct dstr *str)
{
	bool valid  = !dstr_isempty(str);
	val->av_val = valid ? str->array    : NULL;
	val->av_len = valid ? (int)str->len : 0;
}

static inline bool get_next_packet(struct rtmp_stream *stream,
		struct encoder_packet *packet)
{
	bool new_packet = false;

	pthread_mutex_lock(&stream->packets_mutex);
	if (stream->packets.size) {
		circlebuf_pop_front(&stream->packets, packet,
				sizeof(struct encoder_packet));
		new_packet = true;
	}
	pthread_mutex_unlock(&stream->packets_mutex);

	return new_packet;
}

static int send_packet(struct rtmp_stream *stream,
		struct encoder_packet *packet, bool is_header)
{
	uint8_t *data;
	size_t  size;
	int     ret = 0;

	flv_packet_mux(packet, &data, &size, is_header);
#ifdef TEST_FRAMEDROPS
	os_sleep_ms(rand() % 40);
#endif
	ret = RTMP_Write(&stream->rtmp, (char*)data, (int)size);
	bfree(data);

	obs_free_encoder_packet(packet);

	stream->total_bytes_sent += size;
	return ret;
}

static bool send_remaining_packets(struct rtmp_stream *stream)
{
	struct encoder_packet packet;

	while (get_next_packet(stream, &packet))
		if (send_packet(stream, &packet, false) < 0)
			return false;

	return true;
}

static void *send_thread(void *data)
{
	struct rtmp_stream *stream = data;
	bool disconnected = false;

	while (os_sem_wait(stream->send_sem) == 0) {
		struct encoder_packet packet;

		if (os_event_try(stream->stop_event) != EAGAIN)
			break;
		if (!get_next_packet(stream, &packet))
			continue;
		if (send_packet(stream, &packet, false) < 0) {
			disconnected = true;
			break;
		}
	}

	if (!disconnected && !send_remaining_packets(stream))
		disconnected = true;

	if (disconnected) {
		info("Disconnected from %s", stream->path.array);
		free_packets(stream);
	} else {
		info("User stopped the stream");
	}

	if (os_event_try(stream->stop_event) == EAGAIN) {
		pthread_detach(stream->send_thread);
		obs_output_signal_stop(stream->output, OBS_OUTPUT_DISCONNECTED);
	}

	stream->active = false;
	return NULL;
}

static void send_meta_data(struct rtmp_stream *stream)
{
	uint8_t *meta_data;
	size_t  meta_data_size;

	flv_meta_data(stream->output, &meta_data, &meta_data_size, false);
	RTMP_Write(&stream->rtmp, (char*)meta_data, (int)meta_data_size);
	bfree(meta_data);
}

static void send_audio_header(struct rtmp_stream *stream)
{
	obs_output_t  context  = stream->output;
	obs_encoder_t aencoder = obs_output_get_audio_encoder(context);
	uint8_t       *header;

	struct encoder_packet packet   = {
		.type         = OBS_ENCODER_AUDIO,
		.timebase_den = 1
	};

	obs_encoder_get_extra_data(aencoder, &header, &packet.size);
	packet.data = bmemdup(header, packet.size);
	send_packet(stream, &packet, true);
}

static void send_video_header(struct rtmp_stream *stream)
{
	obs_output_t  context  = stream->output;
	obs_encoder_t vencoder = obs_output_get_video_encoder(context);
	uint8_t       *header;
	size_t        size;

	struct encoder_packet packet   = {
		.type         = OBS_ENCODER_VIDEO,
		.timebase_den = 1,
		.keyframe     = true
	};

	obs_encoder_get_extra_data(vencoder, &header, &size);
	packet.size = obs_parse_avc_header(&packet.data, header, size);
	send_packet(stream, &packet, true);
}

static void send_headers(struct rtmp_stream *stream)
{
	send_meta_data(stream);
	send_audio_header(stream);
	send_video_header(stream);
}

static inline bool reset_semaphore(struct rtmp_stream *stream)
{
	os_sem_destroy(stream->send_sem);
	return os_sem_init(&stream->send_sem, 0) == 0;
}

#ifdef _WIN32
#define socklen_t int
#endif

#define MIN_SENDBUF_SIZE 65535

static void adjust_sndbuf_size(struct rtmp_stream *stream, int new_size)
{
	int cur_sendbuf_size = new_size;
	socklen_t int_size = sizeof(int);

	getsockopt(stream->rtmp.m_sb.sb_socket, SOL_SOCKET, SO_SNDBUF,
			(char*)&cur_sendbuf_size, &int_size);

	if (cur_sendbuf_size < new_size) {
		cur_sendbuf_size = new_size;
		setsockopt(stream->rtmp.m_sb.sb_socket, SOL_SOCKET, SO_SNDBUF,
				(const char*)&cur_sendbuf_size, int_size);
	}
}

static int init_send(struct rtmp_stream *stream)
{
	int ret;

#if defined(_WIN32)
	adjust_sndbuf_size(stream, MIN_SENDBUF_SIZE);
#endif

	reset_semaphore(stream);

	ret = pthread_create(&stream->send_thread, NULL, send_thread, stream);
	if (ret != 0) {
		RTMP_Close(&stream->rtmp);
		warn("Failed to create send thread");
		return OBS_OUTPUT_ERROR;
	}

	stream->active = true;
	send_headers(stream);
	obs_output_begin_data_capture(stream->output, 0);

	return OBS_OUTPUT_SUCCESS;
}

static int try_connect(struct rtmp_stream *stream)
{
	if (dstr_isempty(&stream->path)) {
		warn("URL is empty");
		return OBS_OUTPUT_BAD_PATH;
	}

	if (dstr_isempty(&stream->key)) {
		warn("Stream key is empty");
		return OBS_OUTPUT_BAD_PATH;
	}

	info("Connecting to RTMP URL %s...", stream->path.array);

	if (!RTMP_SetupURL2(&stream->rtmp, stream->path.array,
				stream->key.array))
		return OBS_OUTPUT_BAD_PATH;

	RTMP_EnableWrite(&stream->rtmp);

	set_rtmp_dstr(&stream->rtmp.Link.pubUser,   &stream->username);
	set_rtmp_dstr(&stream->rtmp.Link.pubPasswd, &stream->password);
	stream->rtmp.Link.swfUrl = stream->rtmp.Link.tcUrl;
	set_rtmp_str(&stream->rtmp.Link.flashVer,
			"FMLE/3.0 (compatible; FMSc/1.0)");

	stream->rtmp.m_outChunkSize       = 4096;
	stream->rtmp.m_bSendChunkSizeInfo = true;
	stream->rtmp.m_bUseNagle          = true;

	if (!RTMP_Connect(&stream->rtmp, NULL))
		return OBS_OUTPUT_CONNECT_FAILED;
	if (!RTMP_ConnectStream(&stream->rtmp, 0))
		return OBS_OUTPUT_INVALID_STREAM;

	info("Connection to %s successful", stream->path.array);

	return init_send(stream);
}

static void *connect_thread(void *data)
{
	struct rtmp_stream *stream = data;
	int ret = try_connect(stream);

	if (ret != OBS_OUTPUT_SUCCESS) {
		obs_output_signal_stop(stream->output, ret);
		info("Connection to %s failed: %d", stream->path.array, ret);
	}

	if (os_event_try(stream->stop_event) == EAGAIN)
		pthread_detach(stream->connect_thread);

	stream->connecting = false;
	return NULL;
}

static bool rtmp_stream_start(void *data)
{
	struct rtmp_stream *stream = data;
	obs_service_t service = obs_output_get_service(stream->output);
	obs_data_t settings;

	if (!obs_output_can_begin_data_capture(stream->output, 0))
		return false;
	if (!obs_output_initialize_encoders(stream->output, 0))
		return false;

	stream->total_bytes_sent = 0;
	stream->dropped_frames   = 0;

	settings = obs_output_get_settings(stream->output);
	dstr_copy(&stream->path,     obs_service_get_url(service));
	dstr_copy(&stream->key,      obs_service_get_key(service));
	dstr_copy(&stream->username, obs_service_get_username(service));
	dstr_copy(&stream->password, obs_service_get_password(service));
	stream->drop_threshold_usec =
		(int64_t)obs_data_getint(settings, OPT_DROP_THRESHOLD) * 1000;
	obs_data_release(settings);

	return pthread_create(&stream->connect_thread, NULL, connect_thread,
			stream) == 0;
}

static inline bool add_packet(struct rtmp_stream *stream,
		struct encoder_packet *packet)
{
	circlebuf_push_back(&stream->packets, packet,
			sizeof(struct encoder_packet));
	stream->last_dts_usec = packet->dts_usec;
	return true;
}

static inline size_t num_buffered_packets(struct rtmp_stream *stream)
{
	return stream->packets.size / sizeof(struct encoder_packet);
}

static void drop_frames(struct rtmp_stream *stream)
{
	struct circlebuf new_buf            = {0};
	int              drop_priority      = 0;
	uint64_t         last_drop_dts_usec = 0;
	int              num_frames_dropped = 0;

	debug("Previous packet count: %d", (int)num_buffered_packets(stream));

	circlebuf_reserve(&new_buf, sizeof(struct encoder_packet) * 8);

	while (stream->packets.size) {
		struct encoder_packet packet;
		circlebuf_pop_front(&stream->packets, &packet, sizeof(packet));

		last_drop_dts_usec = packet.dts_usec;

		if (packet.type == OBS_ENCODER_AUDIO) {
			circlebuf_push_back(&new_buf, &packet, sizeof(packet));

		} else {
			if (drop_priority < packet.drop_priority)
				drop_priority = packet.drop_priority;

			num_frames_dropped++;
			obs_free_encoder_packet(&packet);
		}
	}

	circlebuf_free(&stream->packets);
	stream->packets           = new_buf;
	stream->min_priority      = drop_priority;
	stream->min_drop_dts_usec = last_drop_dts_usec;

	stream->dropped_frames += num_frames_dropped;
	debug("New packet count: %d", (int)num_buffered_packets(stream));
}

static void check_to_drop_frames(struct rtmp_stream *stream)
{
	struct encoder_packet first;
	int64_t buffer_duration_usec;

	if (num_buffered_packets(stream) < 5)
		return;

	circlebuf_peek_front(&stream->packets, &first, sizeof(first));

	/* do not drop frames if frames were just dropped within this time */
	if (first.dts_usec < stream->min_drop_dts_usec)
		return;

	/* if the amount of time stored in the buffered packets waiting to be
	 * sent is higher than threshold, drop frames */
	buffer_duration_usec = stream->last_dts_usec - first.dts_usec;

	if (buffer_duration_usec > stream->drop_threshold_usec) {
		drop_frames(stream);
		debug("dropping %" PRId64 " worth of frames",
				buffer_duration_usec);
	}
}

static bool add_video_packet(struct rtmp_stream *stream,
		struct encoder_packet *packet)
{
	check_to_drop_frames(stream);

	/* if currently dropping frames, drop packets until it reaches the
	 * desired priority */
	if (packet->priority < stream->min_priority) {
		stream->dropped_frames++;
		return false;
	} else {
		stream->min_priority = 0;
	}

	return add_packet(stream, packet);
}

static void rtmp_stream_data(void *data, struct encoder_packet *packet)
{
	struct rtmp_stream    *stream = data;
	struct encoder_packet new_packet;
	bool                  added_packet;

	if (packet->type == OBS_ENCODER_VIDEO)
		obs_parse_avc_packet(&new_packet, packet);
	else
		obs_duplicate_encoder_packet(&new_packet, packet);

	pthread_mutex_lock(&stream->packets_mutex);

	added_packet = (packet->type == OBS_ENCODER_VIDEO) ?
		add_video_packet(stream, &new_packet) :
		add_packet(stream, &new_packet);

	pthread_mutex_unlock(&stream->packets_mutex);

	if (added_packet)
		os_sem_post(stream->send_sem);
	else
		obs_free_encoder_packet(&new_packet);
}

static void rtmp_stream_defaults(obs_data_t defaults)
{
	obs_data_set_default_int(defaults, OPT_DROP_THRESHOLD, 600);
}

static obs_properties_t rtmp_stream_properties(void)
{
	obs_properties_t props = obs_properties_create();

	obs_properties_add_int(props, OPT_DROP_THRESHOLD,
			obs_module_text("RTMPStream.DropThreshold"),
			200, 10000, 100);
	return props;
}

static uint64_t rtmp_stream_total_bytes_sent(void *data)
{
	struct rtmp_stream *stream = data;
	return stream->total_bytes_sent;
}

static int rtmp_stream_dropped_frames(void *data)
{
	struct rtmp_stream *stream = data;
	return stream->dropped_frames;
}

struct obs_output_info rtmp_output_info = {
	.id             = "rtmp_output",
	.flags          = OBS_OUTPUT_AV |
	                  OBS_OUTPUT_ENCODED |
	                  OBS_OUTPUT_SERVICE,
	.get_name       = rtmp_stream_getname,
	.create         = rtmp_stream_create,
	.destroy        = rtmp_stream_destroy,
	.start          = rtmp_stream_start,
	.stop           = rtmp_stream_stop,
	.encoded_packet = rtmp_stream_data,
	.defaults       = rtmp_stream_defaults,
	.properties     = rtmp_stream_properties,
	.total_bytes    = rtmp_stream_total_bytes_sent,
	.dropped_frames = rtmp_stream_dropped_frames
};