/*
Copyright (C) 1997-2001 Id Software, Inc.

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, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "sv_local.h"

/*
=============================================================================

Encode a client frame onto the network channel

=============================================================================
*/

/*
=============
SV_EmitPacketEntities

Writes a delta update of an entity_state_t list to the message.
=============
*/
static void SV_EmitPacketEntities( client_frame_t  *from,
                                   client_frame_t  *to,
                                   int             clientEntityNum,
                                   entity_state_t  **baselines )
{
	entity_state_t	*oldent, *newent;
    const entity_state_t  *base;
	unsigned	oldindex, newindex;
	int		    oldnum, newnum;
	unsigned    from_num_entities;
	msgEsFlags_t flags;
    unsigned    i;

	if( !from )
		from_num_entities = 0;
	else
		from_num_entities = from->numEntities;

	newindex = 0;
	oldindex = 0;
	oldent = newent = NULL;
	while( newindex < to->numEntities || oldindex < from_num_entities ) {
		if( newindex >= to->numEntities ) {
			newnum = 9999;
		} else {
            i = ( to->firstEntity + newindex ) % svs.numEntityStates;
			newent = &svs.entityStates[i];
			newnum = newent->number;
		}

		if( oldindex >= from_num_entities ) {
			oldnum = 9999;
		} else {
            i = ( from->firstEntity + oldindex ) % svs.numEntityStates;
			oldent = &svs.entityStates[i];
			oldnum = oldent->number;
		}

		if( newnum == oldnum ) {
			// delta update from old position
			// because the force parm is false, this will not result
			// in any bytes being emited if the entity has not changed at all
			// note that players are always 'newentities', this updates their
            // oldorigin always and prevents warping
			flags = 0;
            //if( newent->number <= maxplayers ) {
                // flags |= MSG_ES_NEWENTITY; // FIXME: why? waste of bandwidth
            //}
            if( newent->number == clientEntityNum ) {
                flags |= MSG_ES_FIRSTPERSON;
		        VectorCopy( oldent->origin, newent->origin );
		        VectorCopy( oldent->angles, newent->angles );
            }
			MSG_WriteDeltaEntity( oldent, newent, flags );
			oldindex++;
			newindex++;
			continue;
		}

		if( newnum < oldnum ) {	
			// this is a new entity, send it from the baseline
			flags = MSG_ES_FORCE|MSG_ES_NEWENTITY;
			base = baselines[newnum >> SV_BASELINES_SHIFT];
			if( base ) {
				base += ( newnum & SV_BASELINES_MASK );
			} else {
				base = &nullEntityState;
			}
            if( newent->number == clientEntityNum ) {
                flags |= MSG_ES_FIRSTPERSON;
		        VectorCopy( base->origin, newent->origin );
		        VectorCopy( base->angles, newent->angles );
		        VectorCopy( base->old_origin, newent->old_origin );
            }
			MSG_WriteDeltaEntity( base, newent, flags );
			newindex++;
			continue;
		}

		if( newnum > oldnum ) {
			// the old entity isn't present in the new message
			MSG_WriteDeltaEntity( oldent, NULL, MSG_ES_FORCE );
			oldindex++;
			continue;
		}
	}

	MSG_WriteShort( 0 );	// end of packetentities
}

/*
==================
SV_WriteFrameToClient_Default
==================
*/
void SV_WriteFrameToClient_Default( client_t *client ) {
	client_frame_t		*frame, *oldframe;
	player_state_t		*oldstate;
	int					lastframe;

	// this is the frame we are creating
	frame = &client->frames[sv.framenum & UPDATE_MASK];

	if( client->lastframe <= 0 ) {
		// client is asking for a retransmit
		oldframe = NULL;
        oldstate = NULL;
		lastframe = -1;
	} else if( sv.framenum - client->lastframe > UPDATE_BACKUP - 1 ) {
		// client hasn't gotten a good message through in a long time
		Com_DPrintf( "%s: delta request from out-of-date packet.\n", client->name );
		oldframe = NULL;
        oldstate = NULL;
		lastframe = -1;
	} else {
		// we have a valid message to delta from
		oldframe = &client->frames[client->lastframe & UPDATE_MASK];
		oldstate = &oldframe->ps;
		lastframe = client->lastframe;
		if( svs.nextEntityStates - oldframe->firstEntity > svs.numEntityStates ) {
			Com_DPrintf( "%s: delta request from out-of-date entities.\n", client->name );
			oldframe = NULL;
            oldstate = NULL;
			lastframe = -1;
		}
	}

	MSG_WriteByte( svc_frame );
	MSG_WriteLong( sv.framenum );
	MSG_WriteLong( lastframe );	// what we are delta'ing from
	MSG_WriteByte( client->surpressCount );	// rate dropped packets
	client->surpressCount = 0;
    client->frameflags = 0;

	// send over the areabits
	MSG_WriteByte( frame->areabytes );
	MSG_WriteData( frame->areabits, frame->areabytes );

	// delta encode the playerstate
	MSG_WriteByte( svc_playerinfo );
	MSG_WriteDeltaPlayerstate_Default( oldstate, &frame->ps );
	
	// delta encode the entities
	MSG_WriteByte( svc_packetentities );
	SV_EmitPacketEntities( oldframe, frame, 0, client->baselines );
}

/*
==================
SV_WriteFrameToClient_Enhanced
==================
*/
void SV_WriteFrameToClient_Enhanced( client_t *client ) {
	client_frame_t		*frame, *oldframe;
	player_state_t		*oldstate;
	uint32_t	extraflags;
	int			delta, surpressed;
	byte *b1, *b2;
	msgPsFlags_t	psFlags;
	int clientEntityNum;

	// this is the frame we are creating
	frame = &client->frames[sv.framenum & UPDATE_MASK];

	if( client->lastframe <= 0 ) {
		// client is asking for a retransmit
		oldframe = NULL;
        oldstate = NULL;
		delta = 31;
	} else if( sv.framenum - client->lastframe > UPDATE_BACKUP - 1 ) {
		// client hasn't gotten a good message through in a long time
		Com_DPrintf( "%s: delta request from out-of-date packet.\n", client->name );
		oldframe = NULL;
        oldstate = NULL;
		delta = 31;
	} else {
		// we have a valid message to delta from
		oldframe = &client->frames[client->lastframe & UPDATE_MASK];
		oldstate = &oldframe->ps;
		delta = sv.framenum - client->lastframe;
		if( svs.nextEntityStates - oldframe->firstEntity > svs.numEntityStates ) {
			Com_DPrintf( "%s: delta request from out-of-date entities.\n", client->name );
			oldframe = NULL;
            oldstate = NULL;
			delta = 31;
		}
	}

	// first byte to be patched
	b1 = SZ_GetSpace( &msg_write, 1 );

	MSG_WriteLong( ( sv.framenum & FRAMENUM_MASK ) | ( delta << FRAMENUM_BITS ) );

	// second byte to be patched
	b2 = SZ_GetSpace( &msg_write, 1 );

	// send over the areabits
	MSG_WriteByte( frame->areabytes );
	MSG_WriteData( frame->areabits, frame->areabytes );

	// ignore some parts of playerstate if not recording demo
	psFlags = 0;
	if( !client->settings[CLS_RECORDING] ) {
		if( client->settings[CLS_NOGUN] ) {
			psFlags |= MSG_PS_IGNORE_GUNFRAMES;
			if( client->settings[CLS_NOGUN] != 2 ) {
				psFlags |= MSG_PS_IGNORE_GUNINDEX;
			}
		}
		if( client->settings[CLS_NOBLEND] ) {
			psFlags |= MSG_PS_IGNORE_BLEND;
		}
		if( frame->ps.pmove.pm_type < PM_DEAD ) {
			if( !( frame->ps.pmove.pm_flags & PMF_NO_PREDICTION ) ) {
				psFlags |= MSG_PS_IGNORE_VIEWANGLES;
			}
		} else {
			// lying dead on a rotating platform?
			psFlags |= MSG_PS_IGNORE_DELTAANGLES;
		}
	}

	clientEntityNum = 0;
	if( client->protocol == PROTOCOL_VERSION_Q2PRO ) {
        if( frame->ps.pmove.pm_type < PM_DEAD ) {
            clientEntityNum = frame->clientNum + 1;
        }
		if( client->settings[CLS_NOPREDICT] ) {
			psFlags |= MSG_PS_IGNORE_PREDICTION;
		}
        surpressed = client->frameflags;
	} else {
        surpressed = client->surpressCount;
    }

	// delta encode the playerstate
	extraflags = MSG_WriteDeltaPlayerstate_Enhanced( oldstate, &frame->ps, psFlags );

	if( client->protocol == PROTOCOL_VERSION_Q2PRO ) {
        // delta encode the clientNum
        if( client->version < PROTOCOL_VERSION_Q2PRO_CLIENTFIX ) {
            if( !oldframe || frame->clientNum != oldframe->clientNum ) {
                extraflags |= EPS_CLIENTNUM;
                MSG_WriteByte( frame->clientNum );
            }
        } else {
            int clientNum = oldframe ? oldframe->clientNum : 0;
            if( clientNum != frame->clientNum ) {
                extraflags |= EPS_CLIENTNUM;
                MSG_WriteByte( frame->clientNum );
            }
        }
    }

	// save 3 high bits of extraflags
	*b1 = svc_frame | ( ( ( extraflags & 0x70 ) << 1 ) );

	// save 4 low bits of extraflags
	*b2 = ( surpressed & SURPRESSCOUNT_MASK ) |
        ( ( extraflags & 0x0F ) << SURPRESSCOUNT_BITS );

	client->surpressCount = 0;
    client->frameflags = 0;

	// delta encode the entities
    SV_EmitPacketEntities( oldframe, frame, clientEntityNum, client->baselines );
}

/*
=============================================================================

Build a client frame structure

=============================================================================
*/

qboolean SV_EdictPV( cm_t *cm, edict_t *ent, byte *mask ) {
    cnode_t *node;
    int i, l;

    if( ent->num_clusters == -1 ) {	
        // too many leafs for individual check, go by headnode
        node = CM_NodeNum( cm, ent->headnode );
        return CM_HeadnodeVisible( node, mask );
    }

    // check individual leafs
    for( i = 0; i < ent->num_clusters; i++ ) {
        l = ent->clusternums[i];
        if( Q_IsBitSet( mask, l ) ) {
            return qtrue;
        }
    }
    return qfalse;		// not visible
}

/*
=============
SV_BuildClientFrame

Decides which entities are going to be visible to the client, and
copies off the playerstat and areabits.
=============
*/
void SV_BuildClientFrame( client_t *client ) {
	int		e;
	vec3_t	org;
	edict_t	*ent;
	edict_t	*clent;
	client_frame_t	*frame;
	entity_state_t	*state;
    player_state_t  *ps;
	int		l;
	int		clientarea, clientcluster;
	cleaf_t	*leaf;
	byte	*clientphs;
	byte	*clientpvs;

	clent = client->edict;
	if( !clent->client )
		return;		// not in game yet

	// this is the frame we are creating
	frame = &client->frames[sv.framenum & UPDATE_MASK];
	client->frame_latency[sv.framenum & LATENCY_MASK] = -1;

	frame->sentTime = com_eventTime; // save it for ping calc later

	// find the client's PVS
    ps = &clent->client->ps;
	VectorMA( ps->viewoffset, 0.125f, ps->pmove.origin, org );

	leaf = CM_PointLeaf( client->cm, org );
	clientarea = CM_LeafArea( leaf );
	clientcluster = CM_LeafCluster( leaf );

	// calculate the visible areas
	frame->areabytes = CM_WriteAreaBits( client->cm, frame->areabits, clientarea );
    if( !frame->areabytes && client->protocol != PROTOCOL_VERSION_Q2PRO ) {
        frame->areabits[0] = 255;
        frame->areabytes = 1;
    }

	// grab the current player_state_t
	frame->ps = *ps;

    // grab the current clientNum
    if( g_features->integer & GMF_CLIENTNUM ) {
    	frame->clientNum = clent->client->clientNum;
    } else {
	    frame->clientNum = client->number;
    }

	clientpvs = CM_FatPVS( client->cm, org );
	clientphs = CM_ClusterPHS( client->cm, clientcluster );

	// build up the list of visible entities
	frame->numEntities = 0;
	frame->firstEntity = svs.nextEntityStates;

	for( e = 1; e < client->pool->num_edicts; e++ ) {
		ent = EDICT_POOL( client, e );

        // ignore entities not in use
        if( ( g_features->integer & GMF_PROPERINUSE ) && !ent->inuse ) {
            continue;
        }

		// ignore ents without visible models
		if( ent->svflags & SVF_NOCLIENT )
			continue;

		// ignore ents without visible models unless they have an effect
		if( !ent->s.modelindex && !ent->s.effects && !ent->s.sound ) {
			if( !ent->s.event ) {
				continue;
			}
			if( ent->s.event == EV_FOOTSTEP && client->settings[CLS_NOFOOTSTEPS] ) {
				continue;
			}
		}

		if( ( ent->s.effects & EF_GIB ) && client->settings[CLS_NOGIBS] ) {
			continue;
		}

		// ignore if not touching a PV leaf
		if( ent != clent ) {
			// check area
			if( !CM_AreasConnected( client->cm, clientarea, ent->areanum ) ) {	
				// doors can legally straddle two areas, so
				// we may need to check another one
				if( !ent->areanum2 ||
                    !CM_AreasConnected( client->cm, clientarea, ent->areanum2 ) )
                {
					continue;		// blocked by a door
                }
			}

			// beams just check one point for PHS
			if( ent->s.renderfx & RF_BEAM ) {
				l = ent->clusternums[0];
				if( !Q_IsBitSet( clientphs, l ) )
					continue;
			} else {
                if( !SV_EdictPV( client->cm, ent, clientpvs ) ) {
                    continue;
                }

				if( !ent->s.modelindex ) {	
					// don't send sounds if they will be attenuated away
					vec3_t	delta;
					float	len;

					VectorSubtract( org, ent->s.origin, delta );
					len = VectorLength( delta );
					if( len > 400 )
						continue;
				}
			}
		}

		if( ent->s.number != e ) {
			Com_DPrintf( "FIXING ENT->S.NUMBER!!!\n" );
			ent->s.number = e;
		}

		// add it to the circular client_entities array
        state = &svs.entityStates[svs.nextEntityStates % svs.numEntityStates];
		*state = ent->s;

        // clear footsteps
		if( ent->s.event == EV_FOOTSTEP && client->settings[CLS_NOFOOTSTEPS] ) {
			state->event = 0;
		}

        // XXX: hide this enitity from renderer
		if( ( client->protocol != PROTOCOL_VERSION_Q2PRO ||
              client->settings[CLS_RECORDING] ) &&
            ( g_features->integer & GMF_CLIENTNUM ) &&
			e == frame->clientNum + 1 && ent != clent )
		{
			state->modelindex = 0;
		}

		// don't mark players missiles as solid
		if( ent->owner == client->edict )
			state->solid = 0;

        svs.nextEntityStates++;

		if( ++frame->numEntities == MAX_PACKET_ENTITIES ) {
			break;
		}
	}
}