#include <lib/dvb/pvrparse.h>
#include <lib/base/eerror.h>
#include <byteswap.h>

#ifndef BYTE_ORDER
#error no byte order defined!
#endif

int eMPEGStreamInformation::save(const char *filename)
{
	FILE *f = fopen(filename, "wb");
	if (!f)
		return -1;
	
	for (std::map<off_t, pts_t>::const_iterator i(m_access_points.begin()); i != m_access_points.end(); ++i)
	{
		unsigned long long d[2];
#if BYTE_ORDER == BIG_ENDIAN
		d[0] = i->first;
		d[1] = i->second;
#else
		d[0] = bswap_64(i->first);
		d[1] = bswap_64(i->second);
#endif
		fwrite(d, sizeof(d), 1, f);
	}
	fclose(f);
	
	return 0;
}

int eMPEGStreamInformation::load(const char *filename)
{
	FILE *f = fopen(filename, "rb");
	if (!f)
		return -1;
	m_access_points.clear();
	while (1)
	{
		unsigned long long d[2];
		if (fread(d, sizeof(d), 1, f) < 1)
			break;
		
#if BYTE_ORDER == LITTLE_ENDIAN
		d[0] = bswap_64(d[0]);
		d[1] = bswap_64(d[1]);
#endif
		m_access_points[d[0]] = d[1];
	}
	fclose(f);
	fixupDiscontinuties();
	return 0;
}

bool eMPEGStreamInformation::empty()
{
	return m_access_points.empty();
}

void eMPEGStreamInformation::fixupDiscontinuties()
{
	m_timestamp_deltas.clear();
	if (!m_access_points.size())
		return;
		
	eDebug("Fixing discontinuities ...");

			/* if we have no delta at the beginning, extrapolate it */
	if ((m_access_points.find(0) == m_access_points.end()) && (m_access_points.size() > 1))
	{
		std::map<off_t,pts_t>::const_iterator second = m_access_points.begin();
		std::map<off_t,pts_t>::const_iterator first  = second++;
		if (first->first < second->first) /* i.e., not equal or broken */
		{
			off_t diff = second->first - first->first;
			pts_t tdiff = second->second - first->second;
			tdiff *= first->first;
			tdiff /= diff;
			m_timestamp_deltas[0] = first->second - tdiff;
			eDebug("first delta is %08llx", first->second - tdiff);
		}
	}

	if (m_timestamp_deltas.empty())
		m_timestamp_deltas[m_access_points.begin()->first] = m_access_points.begin()->second;

	pts_t currentDelta = m_timestamp_deltas.begin()->second, lastpts_t = 0;
	for (std::map<off_t,pts_t>::const_iterator i(m_access_points.begin()); i != m_access_points.end(); ++i)
	{
		pts_t current = i->second - currentDelta;
		pts_t diff = current - lastpts_t;
		
		if (llabs(diff) > (90000*5)) // 5sec diff
		{
			eDebug("%llx < %llx, have discont. new timestamp is %llx (diff is %llx)!", current, lastpts_t, i->second, diff);
			currentDelta = i->second - lastpts_t; /* FIXME: should be the extrapolated new timestamp, based on the current rate */
			eDebug("current delta now %llx, making current to %llx", currentDelta, i->second - currentDelta);
			m_timestamp_deltas[i->first] = currentDelta;
		}
		lastpts_t = i->second - currentDelta;
	}
	
	
	eDebug("ok, found %d disconts.", m_timestamp_deltas.size());

#if 0	
	for (off_t x=0x25807E34ULL; x < 0x25B3CF70; x+= 100000)
	{
		off_t o = x;
		pts_t p;
		int r = getPTS(o, p);
		eDebug("%08llx -> %08llx | %08llx, %d, %08llx %08llx", x, getDelta(x), getInterpolated(x), r, o, p);
	}
#endif
}

pts_t eMPEGStreamInformation::getDelta(off_t offset)
{
	if (!m_timestamp_deltas.size())
		return 0;
	std::map<off_t,pts_t>::iterator i = m_timestamp_deltas.upper_bound(offset);

		/* i can be the first when you query for something before the first PTS */
	if (i != m_timestamp_deltas.begin())
		--i;
	
	return i->second;
}

int eMPEGStreamInformation::fixupPTS(const off_t &offset, pts_t &ts)
{
	if (!m_timestamp_deltas.size())
		return -1;

	std::map<off_t, pts_t>::const_iterator i = m_access_points.upper_bound(offset - 4 * 1024 * 1024), nearest = m_access_points.end();
	
	while (i != m_access_points.end())
	{
		if ((nearest == m_access_points.end()) || (llabs(i->second - ts) < llabs(nearest->second - ts)))
			nearest = i;
		++i;
	}
	if (nearest == m_access_points.end())
		return -1;
	ts -= getDelta(nearest->first);
	return 0;
}

int eMPEGStreamInformation::getPTS(off_t &offset, pts_t &pts)
{
	std::map<off_t,pts_t>::iterator before = m_access_points.lower_bound(offset);
	
		/* usually, we prefer the AP before the given offset. however if there is none, we take any. */
	if (before != m_access_points.begin())
		--before;
	
	if (before == m_access_points.end())
	{
		pts = 0;
		return -1;
	}
	
	offset = before->first;
	pts = before->second - getDelta(offset);
	
	return 0;
}

pts_t eMPEGStreamInformation::getInterpolated(off_t offset)
{
		/* get the PTS values before and after the offset. */
	std::map<off_t,pts_t>::iterator before, after;
	
	after = m_access_points.upper_bound(offset);
	before = after;

	if (before != m_access_points.begin())
		--before;
	else	/* we query before the first known timestamp ... FIXME */
		return 0;

		/* empty... */
	if (before == m_access_points.end())
		return 0;

		/* if after == end, then we need to extrapolate ... FIXME */
	if ((before->first == offset) || (after == m_access_points.end()))
		return before->second - getDelta(offset);
	
	pts_t before_ts = before->second - getDelta(before->first);
	pts_t after_ts = after->second - getDelta(after->first);
	
//	eDebug("%08llx .. ? .. %08llx", before_ts, after_ts);
//	eDebug("%08llx .. %08llx .. %08llx", before->first, offset, after->first);
	
	pts_t diff = after_ts - before_ts;
	off_t diff_off = after->first - before->first;
	
	diff = (offset - before->first) * diff / diff_off;
//	eDebug("%08llx .. %08llx .. %08llx", before_ts, before_ts + diff, after_ts);
	return before_ts + diff;
}
 
off_t eMPEGStreamInformation::getAccessPoint(pts_t ts)
{
		/* FIXME: more efficient implementation */
	pts_t delta = 0;
	off_t last = 0;
	for (std::map<off_t, pts_t>::const_iterator i(m_access_points.begin()); i != m_access_points.end(); ++i)
	{
		pts_t delta = getDelta(i->first);
		pts_t c = i->second - delta;
		if (c > ts)
			break;
		last = i->first;
	}
	return last;
}

int eMPEGStreamInformation::getNextAccessPoint(pts_t &ts, const pts_t &start, int direction)
{
	off_t offset = getAccessPoint(start);
	std::map<off_t, pts_t>::const_iterator i = m_access_points.find(offset);
	if (i == m_access_points.end())
	{
		eDebug("getNextAccessPoint: initial AP not found");
		return -1;
	}
	while (direction)
	{
		if (direction > 0)
		{
			if (i == m_access_points.end())
				return -1;
			++i;
			direction--;
		}
		if (direction < 0)
		{
			if (i == m_access_points.begin())
			{
				eDebug("at start");
				return -1;
			}
			--i;
			direction++;
		}
	}
	ts = i->second - getDelta(i->first);
	eDebug("fine, at %llx - %llx = %llx", ts, i->second, getDelta(i->first));
	eDebug("fine, at %lld - %lld = %lld", ts, i->second, getDelta(i->first));
	return 0;
}

eMPEGStreamParserTS::eMPEGStreamParserTS(eMPEGStreamInformation &streaminfo): m_streaminfo(streaminfo), m_pktptr(0), m_pid(-1), m_need_next_packet(0), m_skip(0)
{
}

int eMPEGStreamParserTS::processPacket(const unsigned char *pkt, off_t offset)
{
	if (!wantPacket(pkt))
		eWarning("something's wrong.");

	const unsigned char *end = pkt + 188;
	
	if (!(pkt[3] & 0x10))
	{
		eWarning("[TSPARSE] PUSI set but no payload.");
		return 0;
	}
	
	if (pkt[3] & 0x20) // adaption field present?
		pkt += pkt[4] + 4 + 1;  /* skip adaption field and header */
	else
		pkt += 4; /* skip header */

	if (pkt > end)
	{
		eWarning("[TSPARSE] dropping huge adaption field");
		return 0;
	}
	
		// ok, we now have the start of the payload, aligned with the PES packet start.
	if (pkt[0] || pkt[1] || (pkt[2] != 1))
	{
		eWarning("broken startcode");
		return 0;
	}
	
	
	pts_t pts = 0;
	int ptsvalid = 0;
	
	if (pkt[7] & 0x80) // PTS present?
	{
		pts  = ((unsigned long long)(pkt[ 9]&0xE))  << 29;
		pts |= ((unsigned long long)(pkt[10]&0xFF)) << 22;
		pts |= ((unsigned long long)(pkt[11]&0xFE)) << 14;
		pts |= ((unsigned long long)(pkt[12]&0xFF)) << 7;
		pts |= ((unsigned long long)(pkt[13]&0xFE)) >> 1;
		ptsvalid = 1;

#if 0		
		int sec = pts / 90000;
		int frm = pts % 90000;
		int min = sec / 60;
		sec %= 60;
		int hr = min / 60;
		min %= 60;
		int d = hr / 24;
		hr %= 24;
		
		eDebug("pts: %016llx %d:%02d:%02d:%02d:%05d", pts, d, hr, min, sec, frm);
#endif
	}
	
		/* advance to payload */
	pkt += pkt[8] + 9;
	
		/* if startcode found */
	if (!(pkt[0] || pkt[1] || (pkt[2] != 1)))
	{
		if (pkt[3] == 0xb3) /* sequence header */
		{
			if (ptsvalid)
			{
				m_streaminfo.m_access_points[offset] = pts;
				eDebug("Sequence header at %llx, pts %llx", offset, pts);
			} else
				eDebug("Sequence header but no valid PTS value.");
		}
	}
	return 0;
}

inline int eMPEGStreamParserTS::wantPacket(const unsigned char *hdr) const
{
	if (hdr[0] != 0x47)
	{
		eDebug("missing sync!");
		return 0;
	}
	int ppid = ((hdr[1]&0x1F) << 8) | hdr[2];

	if (ppid != m_pid)
		return 0;
		
	if (m_need_next_packet)  /* next packet (on this pid) was required? */
		return 1;
	
	if (hdr[1] & 0x40)	 /* pusi set: yes. */
		return 1;

	return 0;
}

void eMPEGStreamParserTS::parseData(off_t offset, const void *data, unsigned int len)
{
	const unsigned char *packet = (const unsigned char*)data;
	const unsigned char *packet_start = packet;
	
			/* sorry for the redundant code here, but there are too many special cases... */
	while (len)
	{
			/* emergency resync. usually, this should not happen, because the data should 
			   be sync-aligned.
			   
			   to make this code work for non-strictly-sync-aligned data, (for example, bad 
			   files) we fix a possible resync here by skipping data until the next 0x47.
			   
			   if this is a false 0x47, the packet will be dropped by wantPacket, and the
			   next time, sync will be re-established. */
		int skipped = 0;
		while (!m_pktptr && len)
		{
			if (packet[0] == 0x47)
				break;
			len--;
			packet++;
			skipped++;
		}
		
		if (skipped)
			eDebug("SYNC LOST: skipped %d bytes.", skipped);
		
		if (!len)
			break;
		
		if (m_pktptr)
		{
				/* skip last packet */
			if (m_pktptr < 0)
			{
				unsigned int skiplen = -m_pktptr;
				if (skiplen > len)
					skiplen = len;
				packet += skiplen;
				len -= skiplen;
				m_pktptr += skiplen;
				continue;
			} else if (m_pktptr < 4) /* header not complete, thus we don't know if we want this packet */
			{
				unsigned int storelen = 4 - m_pktptr;
				if (storelen > len)
					storelen = len;
				memcpy(m_pkt + m_pktptr, packet,  storelen);
				
				m_pktptr += storelen;
				len -= storelen;
				packet += storelen;
				
				if (m_pktptr == 4)
					if (!wantPacket(m_pkt))
					{
							/* skip packet */
						packet += 184;
						len -= 184;
						m_pktptr = 0;
						continue;
					}
			}
				/* otherwise we complete up to the full packet */
			unsigned int storelen = 188 - m_pktptr;
			if (storelen > len)
				storelen = len;
			memcpy(m_pkt + m_pktptr, packet,  storelen);
			m_pktptr += storelen;
			len -= storelen;
			packet += storelen;
			
			if (m_pktptr == 188)
			{
				m_need_next_packet = processPacket(m_pkt, offset + (packet - packet_start));
				m_pktptr = 0;
			}
		} else if (len >= 4)  /* if we have a full header... */
		{
			if (wantPacket(packet))  /* decide wheter we need it ... */
			{
				if (len >= 188)          /* packet complete? */
				{
					m_need_next_packet = processPacket(packet, offset + (packet - packet_start)); /* process it now. */
				} else
				{
					memcpy(m_pkt, packet, len);  /* otherwise queue it up */
					m_pktptr = len;
				}
			}

				/* skip packet */
			int sk = len;
			if (sk >= 188)
				sk = 188;
			else if (!m_pktptr) /* we dont want this packet, otherwise m_pktptr = sk (=len) > 4 */
				m_pktptr = sk - 188;

			len -= sk;
			packet += sk;
		} else             /* if we don't have a complete header */
		{
			memcpy(m_pkt, packet, len);   /* complete header next time */
			m_pktptr = len;
			packet += len;
			len = 0;
		}
	}
}

void eMPEGStreamParserTS::setPid(int _pid)
{
	m_pktptr = 0;
	m_pid = _pid;
}