/* tsiproxy mpeg transport stream proxy */
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <netdb.h>
#include <pthread.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>

#include <fcntl.h>
#include <errno.h>

#include "libfuncs/libfuncs.h"

#include "data.h"
#include "conf.h"
#include "proxy_common.h"

extern LIST *restreamer;
extern STATS allstats;
extern CONFIG *config;

extern char TS_NULL_FRAME[FRAME_PACKET_SIZE];
extern int keep_running;

#define MAX_ZERO_READS 3

#define CONNECT_RETRIES 2

/*         Start: 3 seconds on connect */
/* In connection: Max UDP timeout == 3 seconds (read) + 2 seconds (connect) == 5 seconds */
#define UDP_READ_RETRIES 3
#define UDP_READ_TIMEOUT 1000

/*         Start: 1/4 seconds on connect */
/* In connection: Max TCP timeout == 5 seconds (read) + 2 seconds (connect)             == 7 seconds */
/* In connection: Max TCP timeout == 5 seconds (read) + 8 seconds (connect, host unrch) == 13 seconds */
#define TCP_READ_RETRIES 5
#define TCP_READ_TIMEOUT 1000

/*
	Returns:
		0 = synced ok
		1 = not synced, reconnect
*/
int mpeg_sync(int proxysock, char *channel, channel_source source_proto) {
	time_t sync_start = time(NULL);
	unsigned int sync_packets = 0;
	unsigned int read_bytes = 0;
	char syncframe[188];

	if (!config->ts_sync)
		return 0;

	int _timeout = TCP_READ_TIMEOUT;
	int _retries = TCP_READ_RETRIES;
	if (source_proto == udp_sock) {
		_timeout = UDP_READ_TIMEOUT;
		_retries = UDP_READ_RETRIES;
	}
	do {
resync:
		if (!keep_running)
			return 1;
		if (fdread_ex(proxysock, syncframe, 1, _timeout, _retries, 1) != 1) {
			LOGf("DEBUG: mpeg_sync fdread() timeout | Channel: %s\n", channel);
			return 1; // reconnect
		}
		// LOGf("DEBUG:     Read 0x%02x Offset %u Sync: %u\n", (uint8_t)syncframe[0], read_bytes, sync_packets);
		read_bytes++;
		if (syncframe[0] == 0x47) {
			ssize_t rdsz = fdread_ex(proxysock, syncframe, 188-1, _timeout, _retries, 1);
			if (rdsz != 188-1) {
				LOGf("DEBUG: mpeg_sync fdread() timeout | Channel: %s\n", channel);
				return 1; // reconnect
			}
			read_bytes += 188-1;
			if (++sync_packets == 7) // sync 7 packets
				break;
			goto resync;
		} else {
			sync_packets = 0;
		}
		if (read_bytes > FRAME_PACKET_SIZE) { // Can't sync in 1316 bytes
			LOGf("DEBUG: Can't sync after %d bytes | Channel: %s\n", FRAME_PACKET_SIZE, channel);
			return 1; // reconnect
		}
		if (sync_start+2 <= time(NULL)) { // Do not sync in two seconds
			LOGf("DEBUG: Timeout while syncing (read %u bytes) | Channel: %s\n", read_bytes, channel);
			return 1; // reconnect
		}
	} while (1);
	LOGf("SYNC : TS synced after %u bytes | Channel: %s\n", read_bytes-FRAME_PACKET_SIZE, channel);
	return 0;
}

void * proxy_ts_stream(void *self) {
	RESTREAMER *r = self;
	int retries = CONNECT_RETRIES;
	unsigned int pos = 0;
	int first_connect = 1;

	signal(SIGPIPE, SIG_IGN);

#define BUFFER_SIZE (FRAME_PACKET_SIZE * BUF)

	char buff[BUFFER_SIZE];
	char *buff_end = buff + BUFFER_SIZE;

	int http_code = 0;
	while (retries--) {
		int result = connect_source(self, retries, BUFFER_SIZE, &http_code);
		if (result > 0) {
			if (!first_connect) {
				goto RECONNECT;
			} else {
				goto EXIT_THREAD;
			}
		}
		if (result < 0)
			goto EXIT_THREAD;

		switch (check_restreamer_state(r)) {
			case 1: goto RECONNECT;		// r->reconnect is on
			case 2: goto QUIT;			// r->dienow is on
		}

		channel_source sproto = get_sproto(r->channel->source);

		int mpgsync = mpeg_sync(r->sock, r->channel->name, sproto);
		if (mpgsync == 1 && first_connect) { // Timeout
			if (sproto == udp_sock) {
				goto RECONNECT;
			} else {
				goto EXIT_THREAD;
			}
		}


		char *p = buff;
		pos = 0;
		ssize_t readen = 0;
		int max_zero_reads = MAX_ZERO_READS;
		for (;;) {
			switch (check_restreamer_state(r)) {
				case 1: goto RECONNECT;		// r->reconnect is on
				case 2: goto QUIT;			// r->dienow is on
			}

			if (sproto == tcp_sock) {
				readen = fdread_ex(r->sock, p, FRAME_PACKET_SIZE, TCP_READ_TIMEOUT, TCP_READ_RETRIES, 1);
			} else {
				int read_so_far = 0;
				int buffer_left;
AGAIN:
				buffer_left = buff_end - (p + read_so_far);
				if (buffer_left >= FRAME_PACKET_SIZE) { // There is enough size for one frame in the buffer
					readen = fdread_ex(r->sock, p+read_so_far, FRAME_PACKET_SIZE, UDP_READ_TIMEOUT, UDP_READ_RETRIES, 0);
					if (readen > 0) {
						read_so_far += readen;
						if (read_so_far < FRAME_PACKET_SIZE)
							goto AGAIN;
						readen = read_so_far;
						buffer_left = buff_end - (p + read_so_far);
						if (buffer_left < FRAME_PACKET_SIZE) {
							memcpy(p+read_so_far, TS_NULL_FRAME, buffer_left);
						}
					}
				} else { // Not enough buffer space, wait a bit so the buffer can wrap around
					if (buffer_left > 0) {
						//LOGf("no read : only %d bytes left to the end of buffer, pos:%d/%d\n", buffer_left, pos, BUF);
						readen = FRAME_PACKET_SIZE; // Oh, yeah we have that many bytes already read
						if (pos+1 == BUF) { // Buffer will wrap now
							//LOGf("Reached buffer end correcting last frame\n");
							p -= FRAME_PACKET_SIZE - buffer_left; // That last packet must be sended now
						} else {
							p -= readen; // Prevent p from moving further (it will be added to bellow)
						}
					}
				}
			}
			if (readen == -1) { // timeout
				if (first_connect || sproto == udp_sock)
					goto EXIT_THREAD;
				break;
			}
			if (readen == 0) { // ho, hum, wtf is going on here?
				if (--max_zero_reads == 0) {
					LOGf("RESTR: %d zero reads on srv_fd: %i | Channel: %s Source: %s\n", MAX_ZERO_READS, r->sock, r->channel->name, r->channel->source);
					break;
				}
				continue;
			}

			max_zero_reads = MAX_ZERO_READS;
			allstats.traffic_in += readen;
			r->traffic_in += readen;

			// Fill short frame with NULL packets
			if (readen < FRAME_PACKET_SIZE) {
				LOGf("DEBUG: Short read (%d) on retreamer srv_fd: %i | Channel: %s\n", (int)readen, r->sock, r->channel->name);
				memcpy(p+readen, TS_NULL_FRAME+readen, FRAME_PACKET_SIZE - readen);
				readen = FRAME_PACKET_SIZE;
			}

			process_new_clients(r, BUFFER_SIZE, 0, 0);
			pos++;
			p += readen;
			if (pos == BUF) {
				pos = 0;
				p=buff;
			}

			int num_clients = shout(r, buff, BUF, FRAME_PACKET_SIZE, pos*FRAME_PACKET_SIZE, "Content-Type: video/mpeg\n\n", NULL, 0);
			if (!num_clients)
				goto QUIT;
			first_connect = 0;
			retries = CONNECT_RETRIES;
		}
		LOGf("DEBUG: fdread timeout restreamer srv_fd: %i | Channel: %s\n", r->sock, r->channel->name);
RECONNECT:
		if (!keep_running)
			goto QUIT;
		proxy_begin_reconnect(r);
		if (r->clients && r->clients->items)
			continue;
QUIT:
		break;
	}
EXIT_THREAD:
	proxy_close(r, http_code);
	return 0;
}