#define _ISOC99_SOURCE /* for llabs */
#include <lib/dvb/tstools.h>
#include <lib/base/eerror.h>
#include <unistd.h>
#include <fcntl.h>

#include <stdio.h>

eDVBTSTools::eDVBTSTools()
{
	m_pid = -1;
	m_maxrange = 256*1024;
	
	m_begin_valid = 0;
	m_end_valid = 0;
	
	m_use_streaminfo = 0;
	m_samples_taken = 0;
	
	m_last_filelength = 0;
	
	m_futile = 0;
}

eDVBTSTools::~eDVBTSTools()
{
	closeFile();
}

int eDVBTSTools::openFile(const char *filename, int nostreaminfo)
{
	closeFile();
	
	if (!nostreaminfo)
		m_streaminfo.load((std::string(filename) + ".ap").c_str());
	
	if (!m_streaminfo.empty())
		m_use_streaminfo = 1;
	else
	{
//		eDebug("no recorded stream information available");
		m_use_streaminfo = 0;
	}
	
	m_samples_taken = 0;

	if (m_file.open(filename, 1) < 0)
		return -1;
	return 0;
}

void eDVBTSTools::closeFile()
{
	m_file.close();
}

void eDVBTSTools::setSyncPID(int pid)
{
	m_pid = pid;
}

void eDVBTSTools::setSearchRange(int maxrange)
{
	m_maxrange = maxrange;
}

	/* getPTS extracts a pts value from any PID at a given offset. */
int eDVBTSTools::getPTS(off_t &offset, pts_t &pts, int fixed)
{
	if (m_use_streaminfo)
		return m_streaminfo.getPTS(offset, pts);
	
	if (!m_file.valid())
		return -1;

	offset -= offset % 188;
	
	if (m_file.lseek(offset, SEEK_SET) < 0)
	{
		eDebug("lseek failed");
		return -1;
	}
	
	int left = m_maxrange;
	
	while (left >= 188)
	{
		unsigned char packet[188];
		if (m_file.read(packet, 188) != 188)
		{
			eDebug("read error");
			break;
		}
		left -= 188;
		offset += 188;
		
		if (packet[0] != 0x47)
		{
			eDebug("resync");
			int i = 0;
			while (i < 188)
			{
				if (packet[i] == 0x47)
					break;
				++i;
			}
			offset = m_file.lseek(i - 188, SEEK_CUR);
			continue;
		}
		
		int pid = ((packet[1] << 8) | packet[2]) & 0x1FFF;
		int pusi = !!(packet[1] & 0x40);
		
//		printf("PID %04x, PUSI %d\n", pid, pusi);

		unsigned char *payload;
		
			/* check for adaption field */
		if (packet[3] & 0x20)
		{
			if (packet[4] >= 183)
				continue;
			if (packet[4])
			{
				if (packet[5] & 0x10) /* PCR present */
				{
					pts  = ((unsigned long long)(packet[ 6]&0xFF)) << 25;
					pts |= ((unsigned long long)(packet[ 7]&0xFF)) << 17;
					pts |= ((unsigned long long)(packet[ 8]&0xFE)) << 9;
					pts |= ((unsigned long long)(packet[ 9]&0xFF)) << 1;
					pts |= ((unsigned long long)(packet[10]&0x80)) >> 7;
					offset -= 188;
					eDebug("PCR  found at %llx: %16llx", offset, pts);
					if (fixed && fixupPTS(offset, pts))
						return -1;
					return 0;
				}
			}
			payload = packet + packet[4] + 4 + 1;
		} else
			payload = packet + 4;

		
		if (m_pid >= 0)
			if (pid != m_pid)
				continue;
		if (!pusi)
			continue;
		
		
			/* somehow not a startcode. (this is invalid, since pusi was set.) ignore it. */
		if (payload[0] || payload[1] || (payload[2] != 1))
			continue;
		
			/* drop non-audio, non-video packets because other streams
			   can be non-compliant.*/
		if (((payload[3] & 0xE0) != 0xC0) &&  // audio
		    ((payload[3] & 0xF0) != 0xE0))    // video
			continue;
		
		if (payload[7] & 0x80) /* PTS */
		{
			pts  = ((unsigned long long)(payload[ 9]&0xE))  << 29;
			pts |= ((unsigned long long)(payload[10]&0xFF)) << 22;
			pts |= ((unsigned long long)(payload[11]&0xFE)) << 14;
			pts |= ((unsigned long long)(payload[12]&0xFF)) << 7;
			pts |= ((unsigned long long)(payload[13]&0xFE)) >> 1;
			offset -= 188;

//			eDebug("found pts %08llx at %08llx pid %02x stream: %02x", pts, offset, pid, payload[3]);
			
				/* convert to zero-based */
			if (fixed && fixupPTS(offset, pts))
					return -1;
			return 0;
		}
	}
	
	return -1;
}

int eDVBTSTools::fixupPTS(const off_t &offset, pts_t &now)
{
	if (m_use_streaminfo)
	{
		return m_streaminfo.fixupPTS(offset, now);
	} else
	{
			/* for the simple case, we assume one epoch, with up to one wrap around in the middle. */
		calcBegin();
		if (!m_begin_valid)
		{	
			eDebug("begin not valid, can't fixup");
			return -1;
		}
		
		pts_t pos = m_pts_begin;
		if ((now < pos) && ((pos - now) < 90000 * 10))
		{	
			pos = 0;
			return 0;
		}
		
		if (now < pos) /* wrap around */
			now = now + 0x200000000LL - pos;
		else
			now -= pos;
		return 0;
	}
}

int eDVBTSTools::getOffset(off_t &offset, pts_t &pts)
{
	if (m_use_streaminfo)
	{
		offset = m_streaminfo.getAccessPoint(pts);
		return 0;
	} else
	{
		calcBegin(); calcEnd();
		
		if (!m_begin_valid)
			return -1;
		if (!m_end_valid)
			return -1;

		if (!m_samples_taken)
			takeSamples();
		
		if (!m_samples.empty())
		{
			int maxtries = 5;
			pts_t p = -1;
			
			while (maxtries--)
			{
					/* search entry before and after */
				std::map<pts_t, off_t>::const_iterator l = m_samples.lower_bound(pts);
				std::map<pts_t, off_t>::const_iterator u = l;

				if (l != m_samples.begin())
					--l;
				
					/* we could have seeked beyond the end */
				if (u == m_samples.end())
				{
						/* use last segment for interpolation. */
					if (l != m_samples.begin())
					{
						--u;
						--l;
					}
				}
					
					/* if we don't have enough points */
				if (u == m_samples.end())
					break;
				
				pts_t pts_diff = u->first - l->first;
				off_t offset_diff = u->second - l->second;
				
				if (offset_diff < 0)
				{
					eDebug("something went wrong when taking samples.");
					m_samples.clear();
					takeSamples();
					continue;
				}

				eDebug("using: %llx:%llx -> %llx:%llx", l->first, u->first, l->second, u->second);

				int bitrate;
				
				if (pts_diff)
					bitrate = offset_diff * 90000 * 8 / pts_diff;
				else
					bitrate = 0;

				offset = l->second;
				offset += ((pts - l->first) * (pts_t)bitrate) / 8ULL / 90000ULL;
				offset -= offset % 188;
				
				p = pts;
				
				if (!takeSample(offset, p))
				{
					int diff = (p - pts) / 90;
			
					eDebug("calculated diff %d ms", diff);
					if (abs(diff) > 300)
					{
						eDebug("diff to big, refining");
						continue;
					}
				} else
					eDebug("no sample taken, refinement not possible.");

				break;
			}
			
				/* if even the first sample couldn't be taken, fall back. */
				/* otherwise, return most refined result. */
			if (p != -1)
			{
				pts = p;
				eDebug("aborting. Taking %llx as offset for %lld", offset, pts);
				return 0;
			}
		}
		
		int bitrate = calcBitrate();
		offset = pts * (pts_t)bitrate / 8ULL / 90000ULL;
		eDebug("fallback, bitrate=%d, results in %016llx", bitrate, offset);
		offset -= offset % 188;
		
		return 0;
	}
}

int eDVBTSTools::getNextAccessPoint(pts_t &ts, const pts_t &start, int direction)
{
	if (m_use_streaminfo)
		return m_streaminfo.getNextAccessPoint(ts, start, direction);
	else
	{
		eDebug("can't get next access point without streaminfo");
		return -1;
	}
}

void eDVBTSTools::calcBegin()
{
	if (!m_file.valid())
		return;

	if (!(m_begin_valid || m_futile))
	{
		m_offset_begin = 0;
		if (!getPTS(m_offset_begin, m_pts_begin))
			m_begin_valid = 1;
		else
			m_futile = 1;
	}
}

void eDVBTSTools::calcEnd()
{
	if (!m_file.valid())
		return;
	
	off_t end = m_file.lseek(0, SEEK_END);
	
	if (llabs(end - m_last_filelength) > 1*1024*1024)
	{
		m_last_filelength = end;
		m_end_valid = 0;
		
		m_futile = 0;
//		eDebug("file size changed, recalc length");
	}
	
	int maxiter = 10;
	
	m_offset_end = m_last_filelength;
	
	while (!(m_end_valid || m_futile))
	{
		if (!--maxiter)
		{
			m_futile = 1;
			return;
		}

		m_offset_end -= m_maxrange;
		if (m_offset_end < 0)
			m_offset_end = 0;

			/* restore offset if getpts fails */
		off_t off = m_offset_end;

		if (!getPTS(m_offset_end, m_pts_end))
			m_end_valid = 1;
		else
			m_offset_end = off;

		if (!m_offset_end)
		{
			m_futile = 1;
			break;
		}
	}
}

int eDVBTSTools::calcLen(pts_t &len)
{
	calcBegin(); calcEnd();
	if (!(m_begin_valid && m_end_valid))
		return -1;
	len = m_pts_end - m_pts_begin;
		/* wrap around? */
	if (len < 0)
		len += 0x200000000LL;
	return 0;
}

int eDVBTSTools::calcBitrate()
{
	calcBegin(); calcEnd();
	if (!(m_begin_valid && m_end_valid))
		return -1;

	pts_t len_in_pts = m_pts_end - m_pts_begin;

		/* wrap around? */
	if (len_in_pts < 0)
		len_in_pts += 0x200000000LL;
	off_t len_in_bytes = m_offset_end - m_offset_begin;
	
	if (!len_in_pts)
		return -1;
	
	unsigned long long bitrate = len_in_bytes * 90000 * 8 / len_in_pts;
	if ((bitrate < 10000) || (bitrate > 100000000))
		return -1;
	
	return bitrate;
}

	/* pts, off */
void eDVBTSTools::takeSamples()
{
	m_samples_taken = 1;
	m_samples.clear();
	pts_t dummy;
	if (calcLen(dummy) == -1)
		return;
	
	int nr_samples = 30;
	off_t bytes_per_sample = (m_offset_end - m_offset_begin) / (long long)nr_samples;
	if (bytes_per_sample < 40*1024*1024)
		bytes_per_sample = 40*1024*1024;

	bytes_per_sample -= bytes_per_sample % 188;
	
	for (off_t offset = m_offset_begin; offset < m_offset_end; offset += bytes_per_sample)
	{
		pts_t p;
		takeSample(offset, p);
	}
	m_samples[0] = m_offset_begin;
	m_samples[m_pts_end - m_pts_begin] = m_offset_end;
	
//	eDebug("begin, end: %llx %llx", m_offset_begin, m_offset_end); 
}

	/* returns 0 when a sample was taken. */
int eDVBTSTools::takeSample(off_t off, pts_t &p)
{
	if (!eDVBTSTools::getPTS(off, p, 1))
	{
			/* as we are happily mixing PTS and PCR values (no comment, please), we might
			   end up with some "negative" segments. 
			   
			   so check if this new sample is between the previous and the next field*/

		std::map<pts_t, off_t>::const_iterator l = m_samples.lower_bound(p);
		std::map<pts_t, off_t>::const_iterator u = l;

		if (l != m_samples.begin())
		{
			--l;
			if (u != m_samples.end())
			{
				if ((l->second > off) || (u->second < off))
				{
					eDebug("ignoring sample %llx %llx %llx (%lld %lld %lld)",
						l->second, off, u->second, l->first, p, u->first);
					return 1;
				}
			}
		}

		
		m_samples[p] = off;
		return 0;
	}
	return 1;
}

int eDVBTSTools::findPMT(int &pmt_pid, int &service_id)
{
		/* FIXME: this will be factored out soon! */
	if (!m_file.valid())
	{
		eDebug(" file not valid");
		return -1;
	}

	if (m_file.lseek(0, SEEK_SET) < 0)
	{
		eDebug("seek failed");
		return -1;
	}

	int left = 5*1024*1024;
	
	while (left >= 188)
	{
		unsigned char packet[188];
		if (m_file.read(packet, 188) != 188)
		{
			eDebug("read error");
			break;
		}
		left -= 188;
		
		if (packet[0] != 0x47)
		{
			int i = 0;
			while (i < 188)
			{
				if (packet[i] == 0x47)
					break;
				++i;
			}
			m_file.lseek(i - 188, SEEK_CUR);
			continue;
		}
		
		int pid = ((packet[1] << 8) | packet[2]) & 0x1FFF;
		
		int pusi = !!(packet[1] & 0x40);
		
		if (!pusi)
			continue;
		
			/* ok, now we have a PES header or section header*/
		unsigned char *sec;
		
			/* check for adaption field */
		if (packet[3] & 0x20)
		{
			if (packet[4] >= 183)
				continue;
			sec = packet + packet[4] + 4 + 1;
		} else
			sec = packet + 4;
		
		if (sec[0])	/* table pointer, assumed to be 0 */
			continue;

		if (sec[1] == 0x02) /* program map section */
		{
			pmt_pid = pid;
			service_id = (sec[4] << 8) | sec[5];
			return 0;
		}
	}
	
	return -1;
}