/*
* Copyright (C) 2012-2015 Doubango Telecom <http://www.doubango.org>
*
* This file is part of Open Source Doubango Framework.
*
* DOUBANGO 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 3 of the License, or
* (at your option) any later version.
*
* DOUBANGO 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 DOUBANGO.
*
*/

/**@file tdav_codec_ulpfec.c
 * @brief Forward Error Correction (FEC) implementation as per RFC 5109
 */
#include "tinydav/codecs/fec/tdav_codec_ulpfec.h"

#include "tinyrtp/rtp/trtp_rtp_packet.h"

#include "tsk_string.h"
#include "tsk_memory.h"
#include "tsk_debug.h"

#define TDAV_FEC_PKT_HDR_SIZE	10

typedef struct tdav_codec_ulpfec_s
{
	TMEDIA_DECLARE_CODEC_VIDEO;

	struct{
		struct tdav_fec_pkt_s* pkt;
	} encoder;
}
tdav_codec_ulpfec_t;

//
//	FEC LEVEL
//
typedef struct tdav_fec_level_s
{
	TSK_DECLARE_OBJECT;

	struct{ // 7.4. FEC Level Header for FEC Packets
		uint16_t length;
		uint64_t mask;
		tsk_size_t mask_size; // in bits
	} hdr;
	struct{
		uint8_t* ptr;
		tsk_size_t size;
	}payload;
}tdav_fec_level_t;
typedef tsk_list_t tdav_fec_levels_L_t;
static tsk_object_t* tdav_fec_level_ctor(tsk_object_t * self, va_list * app)
{
	tdav_fec_level_t *level = self;
	if (level){
		level->hdr.mask_size = 16; // L=0
	}
	return self;
}
static tsk_object_t* tdav_fec_level_dtor(tsk_object_t * self)
{
	tdav_fec_level_t *level = self;
	if (level){
		TSK_FREE(level->payload.ptr);
	}

	return self;
}
static const tsk_object_def_t tdav_fec_level_def_s =
{
	sizeof(tdav_fec_level_t),
	tdav_fec_level_ctor,
	tdav_fec_level_dtor,
	tsk_null,
};
const tsk_object_def_t *tdav_fec_level_def_t = &tdav_fec_level_def_s;


//
//	FEC PACKET
//
typedef struct tdav_fec_pkt_s
{
	TSK_DECLARE_OBJECT;

	struct{ // RFC 5109 - 7.3. FEC Header for FEC Packets
		unsigned E : 1;
		unsigned L : 1;
		unsigned P : 1;
		unsigned X : 1;
		unsigned CC : 4;
		unsigned M : 1;
		unsigned PT : 7;
		struct{
			uint16_t value;
			unsigned set : 1;
		}SN_base;
		uint32_t TS;
		uint16_t length;
	}hdr;

	tdav_fec_levels_L_t* levels;
}
tdav_fec_pkt_t;
static tsk_object_t* tdav_fec_pkt_ctor(tsk_object_t * self, va_list * app)
{
	tdav_fec_pkt_t *pkt = self;
	if (pkt){
		if (!(pkt->levels = tsk_list_create())){
			TSK_DEBUG_ERROR("Failed to create levels");
			return tsk_null;
		}
	}
	return self;
}
static tsk_object_t* tdav_fec_pkt_dtor(tsk_object_t * self)
{
	tdav_fec_pkt_t *pkt = self;
	if (pkt){
		TSK_OBJECT_SAFE_FREE(pkt->levels);
	}

	return self;
}
static int tdav_fec_pkt_cmp(const tsk_object_t *_p1, const tsk_object_t *_p2)
{
	const tdav_fec_pkt_t *p1 = _p1;
	const tdav_fec_pkt_t *p2 = _p2;

	if (p1 && p2){
		return (int)(p1->hdr.SN_base.value - p2->hdr.SN_base.value);
	}
	else if (!p1 && !p2) return 0;
	else return -1;
}
static const tsk_object_def_t tdav_fec_pkt_def_s =
{
	sizeof(tdav_fec_pkt_t),
	tdav_fec_pkt_ctor,
	tdav_fec_pkt_dtor,
	tdav_fec_pkt_cmp,
};
const tsk_object_def_t *tdav_fec_pkt_def_t = &tdav_fec_pkt_def_s;


tsk_size_t tdav_codec_ulpfec_guess_serialbuff_size(const tdav_codec_ulpfec_t* self)
{
	tsk_size_t size = TDAV_FEC_PKT_HDR_SIZE;
	tsk_list_item_t *item;
	tdav_fec_level_t* level;

	if (!self){
		TSK_DEBUG_ERROR("Invalid parameter");
		return 0;
	}

	tsk_list_foreach(item, self->encoder.pkt->levels){
		if (!(level = item->data)){
			continue;
		}
		size += 2 /* Protection length */ + (level->hdr.mask_size >> 3) + level->hdr.length;
	}

	return size;
}

int tdav_codec_ulpfec_enc_reset(tdav_codec_ulpfec_t* self)
{
	tsk_list_item_t *item;
	tdav_fec_level_t* level;

	if (!self || !self->encoder.pkt){
		TSK_DEBUG_ERROR("invalid parameter");
		return -1;
	}

	// reset packet
	memset(&self->encoder.pkt->hdr, 0, sizeof(self->encoder.pkt->hdr));

	// reset levels
	tsk_list_foreach(item, self->encoder.pkt->levels){
		if ((level = item->data)){
			memset(&level->hdr, 0, sizeof(level->hdr));
			if (level->payload.ptr){
				memset(level->payload.ptr, 0, level->payload.size);
			}
		}
	}
	return 0;
}

int tdav_codec_ulpfec_enc_protect(tdav_codec_ulpfec_t* self, const trtp_rtp_packet_t* rtp_packet)
{
	if (!self || !self->encoder.pkt || !rtp_packet || !rtp_packet->header){
		TSK_DEBUG_ERROR("invalid parameter");
		return -1;
	}

	// Packet
	self->encoder.pkt->hdr.P ^= rtp_packet->header->padding;
	self->encoder.pkt->hdr.X ^= rtp_packet->header->extension;
	self->encoder.pkt->hdr.CC ^= rtp_packet->header->csrc_count;
	self->encoder.pkt->hdr.M ^= rtp_packet->header->marker;
	self->encoder.pkt->hdr.PT ^= rtp_packet->header->payload_type;
	if (!self->encoder.pkt->hdr.SN_base.set){
		self->encoder.pkt->hdr.SN_base.value = rtp_packet->header->seq_num;
		self->encoder.pkt->hdr.SN_base.set = 1;
	}
	else{
		self->encoder.pkt->hdr.SN_base.value = TSK_MIN(self->encoder.pkt->hdr.SN_base.value, rtp_packet->header->seq_num);
	}
	self->encoder.pkt->hdr.TS ^= rtp_packet->header->timestamp;
	self->encoder.pkt->hdr.length ^= (trtp_rtp_packet_guess_serialbuff_size(rtp_packet) - TRTP_RTP_HEADER_MIN_SIZE);

	// Level
	// For now, always single-level protection
	{
		tdav_fec_level_t* level0 = TSK_LIST_FIRST_DATA(self->encoder.pkt->levels);
		const uint8_t* rtp_payload = (const uint8_t*)(rtp_packet->payload.data_const ? rtp_packet->payload.data_const : rtp_packet->payload.data);
		tsk_size_t i;
		if (!level0){
			tdav_fec_level_t* _level0;
			if (!(_level0 = tsk_object_new(tdav_fec_level_def_t))){
				TSK_DEBUG_ERROR("Failed to create level");
				return -2;
			}
			level0 = _level0;
			tsk_list_push_back_data(self->encoder.pkt->levels, (void**)&_level0);
		}
		if (level0->payload.size < rtp_packet->payload.size){
			if (!(level0->payload.ptr = tsk_realloc(level0->payload.ptr, rtp_packet->payload.size))){
				TSK_DEBUG_ERROR("Failed to realloc size %d", rtp_packet->payload.size);
				level0->payload.size = 0;
				return -3;
			}
			level0->payload.size = rtp_packet->payload.size;
		}
		for (i = 0; i < rtp_packet->payload.size; ++i){
			level0->payload.ptr[i] ^= rtp_payload[i];
		}
		level0->hdr.mask_size = self->encoder.pkt->hdr.L ? 48 : 16;
		level0->hdr.mask |= (uint64_t)((uint64_t)1 << (level0->hdr.mask_size - (rtp_packet->header->seq_num - self->encoder.pkt->hdr.SN_base.value)));
		level0->hdr.length = (uint16_t)(TSK_MAX(level0->hdr.length, rtp_packet->payload.size));
	}

	return 0;
}

tsk_size_t tdav_codec_ulpfec_enc_serialize(const tdav_codec_ulpfec_t* self, void** out_data, tsk_size_t* out_max_size)
{
	uint8_t* pdata;
	tsk_size_t xsize;
	int32_t i;
	tsk_list_item_t* item;
	tdav_fec_level_t* level;

	if (!self || !self->encoder.pkt || !out_data){
		TSK_DEBUG_ERROR("Invalid parameter");
		return 0;
	}
	xsize = tdav_codec_ulpfec_guess_serialbuff_size(self);

	if (*out_max_size < xsize){
		if (!(*out_data = tsk_realloc(*out_data, xsize))){
			TSK_DEBUG_ERROR("Failed to reallocate buffer with size =%d", xsize);
			*out_max_size = 0;
			return 0;
		}
		*out_max_size = xsize;
	}
	pdata = (uint8_t*)*out_data;

	// E(1), L(1), P(1), X(1), CC(4)
	pdata[0] =
		(self->encoder.pkt->hdr.E << 7) |
		(self->encoder.pkt->hdr.L << 6) |
		(self->encoder.pkt->hdr.P << 5) |
		(self->encoder.pkt->hdr.X << 4) |
		(self->encoder.pkt->hdr.CC & 0x0F);
	// M(1), PT(7)
	pdata[1] = (self->encoder.pkt->hdr.M << 7) | (self->encoder.pkt->hdr.PT & 0x7F);
	// SN base (16)
	pdata[2] = (self->encoder.pkt->hdr.SN_base.value >> 8);
	pdata[3] = (self->encoder.pkt->hdr.SN_base.value & 0xFF);
	// TS (32)
	pdata[4] = self->encoder.pkt->hdr.TS >> 24;
	pdata[5] = (self->encoder.pkt->hdr.TS >> 16) & 0xFF;
	pdata[6] = (self->encoder.pkt->hdr.TS >> 8) & 0xFF;
	pdata[7] = (self->encoder.pkt->hdr.TS & 0xFF);
	// Length (16)
	pdata[8] = (self->encoder.pkt->hdr.length >> 8);
	pdata[9] = (self->encoder.pkt->hdr.length & 0xFF);

	pdata += 10;

	tsk_list_foreach(item, self->encoder.pkt->levels){
		if (!(level = item->data)){
			continue;
		}
		// Protection length (16)
		pdata[0] = (level->hdr.length >> 8);
		pdata[1] = (level->hdr.length & 0xFF);
		pdata += 2;
		// mask (16 or 48)
		for (i = (int32_t)(level->hdr.mask_size - 8); i >= 0; i -= 8){
			*pdata = ((level->hdr.mask >> i) & 0xFF); ++pdata;
		}
		// payload
		memcpy(pdata, level->payload.ptr, level->hdr.length);
	}

	return xsize;
}



static int tdav_codec_ulpfec_open(tmedia_codec_t* self)
{
	return 0;
}

static int tdav_codec_ulpfec_close(tmedia_codec_t* self)
{
	return 0;
}

static tsk_size_t tdav_codec_ulpfec_encode(tmedia_codec_t* self, const void* in_data, tsk_size_t in_size, void** out_data, tsk_size_t* out_max_size)
{
	TSK_DEBUG_ERROR("Not expected to be called");
	return 0;
}

static tsk_size_t tdav_codec_ulpfec_decode(tmedia_codec_t* self, const void* in_data, tsk_size_t in_size, void** out_data, tsk_size_t* out_max_size, const tsk_object_t* proto_hdr)
{
	TSK_DEBUG_ERROR("Not expected to be called");
	return 0;
}

static tsk_bool_t tdav_codec_ulpfec_sdp_att_match(const tmedia_codec_t* codec, const char* att_name, const char* att_value)
{
	return tsk_true;
}

static char* tdav_codec_ulpfec_sdp_att_get(const tmedia_codec_t* self, const char* att_name)
{
	return tsk_null;
}


/* ============ ULPFEC object definition ================= */

/* constructor */
static tsk_object_t* tdav_codec_ulpfec_ctor(tsk_object_t * self, va_list * app)
{
	tdav_codec_ulpfec_t *ulpfec = self;
	if (ulpfec){
		/* init base: called by tmedia_codec_create() */
		/* init self */
		if (!(ulpfec->encoder.pkt = tsk_object_new(tdav_fec_pkt_def_t))){
			TSK_DEBUG_ERROR("Failed to create FEC packet");
			return tsk_null;
		}
	}
	return self;
}
/* destructor */
static tsk_object_t* tdav_codec_ulpfec_dtor(tsk_object_t * self)
{
	tdav_codec_ulpfec_t *ulpfec = self;
	if (ulpfec){
		/* deinit base */
		tmedia_codec_video_deinit(ulpfec);
		/* deinit self */
		TSK_OBJECT_SAFE_FREE(ulpfec->encoder.pkt);
	}

	return self;
}
/* object definition */
static const tsk_object_def_t tdav_codec_ulpfec_def_s =
{
	sizeof(tdav_codec_ulpfec_t),
	tdav_codec_ulpfec_ctor,
	tdav_codec_ulpfec_dtor,
	tmedia_codec_cmp,
};
/* plugin definition*/
static const tmedia_codec_plugin_def_t tdav_codec_ulpfec_plugin_def_s =
{
	&tdav_codec_ulpfec_def_s,

	tmedia_video,
	tmedia_codec_id_none, // fake codec
	"ulpfec",
	"ulpfec codec",
	TMEDIA_CODEC_FORMAT_ULPFEC,
	tsk_true,
	90000, // rate

	/* audio */
	{ 0 },

	/* video (defaul width,height,fps) */
	{ 176, 144, 15 },

	tsk_null, // set()
	tdav_codec_ulpfec_open,
	tdav_codec_ulpfec_close,
	tdav_codec_ulpfec_encode,
	tdav_codec_ulpfec_decode,
	tdav_codec_ulpfec_sdp_att_match,
	tdav_codec_ulpfec_sdp_att_get
};
const tmedia_codec_plugin_def_t *tdav_codec_ulpfec_plugin_def_t = &tdav_codec_ulpfec_plugin_def_s;