/**********************************************************************
 * $Id$
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.refractions.net
 * Copyright 2008 Paul Ramsey
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU General Public Licence. See the COPYING file.
 * 
 **********************************************************************/

#include "lwalgorithm.h"


/*
** lw_segment_side()
**
** Return < 0.0 if point Q is left of segment P
** Return > 0.0 if point Q is right of segment P
** Return = 0.0 if point Q in on segment P
*/
double lw_segment_side(POINT2D *p1, POINT2D *p2, POINT2D *q)
{
	return ( (q->x - p1->x) * (p2->y - p1->y) - (p2->x - p1->x) * (q->y - p1->y) );
}

int lw_segment_envelope_intersects(POINT2D *p1, POINT2D *p2, POINT2D *q1, POINT2D *q2) 
{
	double minq=LW_MIN(q1->x,q2->x);
	double maxq=LW_MAX(q1->x,q2->x);
	double minp=LW_MIN(p1->x,p2->x);
	double maxp=LW_MAX(p1->x,p2->x);

	if(minp>maxq || maxp<minq) 
		return LW_FALSE;

	minq=LW_MIN(q1->y,q2->y);
	maxq=LW_MAX(q1->y,q2->y);
	minp=LW_MIN(p1->y,p2->y);
	maxp=LW_MAX(p1->y,p2->y);

	if(minp>maxq || maxp<minq) 
		return LW_FALSE;

	return LW_TRUE;
}

/*
** lw_segment_intersects()
** 
** Returns one of
**	SEG_ERROR = -1,
**	SEG_NO_INTERSECTION = 0, 
**	SEG_COLINEAR = 1, 
**	SEG_CROSS_LEFT = 2, 
**	SEG_CROSS_RIGHT = 3, 
**	SEG_TOUCH_LEFT = 4, 
**	SEG_TOUCH_RIGHT = 5
*/
int lw_segment_intersects(POINT2D *p1, POINT2D *p2, POINT2D *q1, POINT2D *q2) 
{
	
	double pq1, pq2, qp1, qp2;
	
	/* No envelope interaction => we are done. */
	if (!lw_segment_envelope_intersects(p1, p2, q1, p2))	
	{
		return SEG_NO_INTERSECTION;
	}

	/* Are the start and end points of q on the same side of p? */
	pq1=lw_segment_side(p1,p2,q1);
	pq2=lw_segment_side(p1,p2,q2);
	if ((pq1>0 && pq2>0) || (pq1<0 && pq2<0)) 
	{
		return SEG_NO_INTERSECTION;
	}

	/* Are the start and end points of p on the same side of q? */
	qp1=lw_segment_side(q1,q2,p1);
	qp2=lw_segment_side(q1,q2,p2);
	if ((qp1>0 && qp2>0) || (qp1<0 && qp2<0)) 
	{
		return SEG_NO_INTERSECTION;
	}

	/* Nobody is on one side or another? Must be colinear. */
	if (pq1 == 0.0 && pq2 == 0.0 && qp1 == 0.0 && qp2 == 0.0) 
	{
		return SEG_COLINEAR;
	}

	/* 
	** When one end-point touches, the sidedness is determined by the 
	** location of the other end-point.
	*/
	if ( pq2 == 0.0 ) 
	{
		if ( pq1 < 0.0 ) 
			return SEG_TOUCH_LEFT;
		else 
			return SEG_TOUCH_RIGHT;
	}
	if ( pq1 == 0.0 ) 
	{
		if ( pq2 < 0.0 ) 
			return SEG_TOUCH_LEFT;
		else 
			return SEG_TOUCH_RIGHT;
	}

	/* The segments cross, what direction is the crossing? */
	if ( pq1 < pq2 ) 
		return SEG_CROSS_RIGHT;
	else 
		return SEG_CROSS_LEFT;
	
	/* This should never happen! */
	return SEG_ERROR;
		
}

/*
** lwline_crossing_direction()
** 
** Returns one of
**   LINE_NO_CROSS = 0
**   LINE_CROSS_LEFT = -1
**   LINE_CROSS_RIGHT = 1
**   LINE_MULTICROSS_END_LEFT = -2
**   LINE_MULTICROSS_END_RIGHT = 2
**   LINE_MULTICROSS_END_SAME_FIRST_LEFT = -3
**   LINE_MULTICROSS_END_SAME_FIRST_RIGHT = 3
**
*/
int lwline_crossing_direction(LWLINE *l1, LWLINE *l2) 
{
	
	int i = 0, j = 0, rv = 0;
	POINT2D *p1;
	POINT2D *p2;
	POINT2D *q1;
	POINT2D *q2;
	POINTARRAY *pa1;
	POINTARRAY *pa2;
	int cross_left = 0;
	int cross_right = 0;
	int first_cross = 0;
	int final_cross = 0;
	int this_cross = 0;
	int vertex_touch = -1;
	int vertex_touch_type = 0;
	
	pa1 = (POINTARRAY*)l1->points;
	pa2 = (POINTARRAY*)l2->points;
	
	p1 = lwalloc(sizeof(POINT2D));
	p2 = lwalloc(sizeof(POINT2D));
	q1 = lwalloc(sizeof(POINT2D));
	q2 = lwalloc(sizeof(POINT2D));
	
	/* One-point lines can't intersect (and shouldn't exist). */
	if( pa1->npoints < 2 || pa2->npoints < 2 ) 
		return LINE_NO_CROSS;

	LWDEBUGF(4, "lineCrossingDirection: l1 = %s", lwgeom_to_ewkt((LWGEOM*)l1,0));
	LWDEBUGF(4, "lineCrossingDirection: l2 = %s", lwgeom_to_ewkt((LWGEOM*)l2,0));

	for ( i = 1; i < pa2->npoints; i++ ) 
	{
		
		rv = getPoint2d_p(pa2, i-1, q1);
		rv = getPoint2d_p(pa2, i, q2);
		
		for ( j = 1; j < pa1->npoints; j++ ) 
		{   
			
			rv = getPoint2d_p(pa1, j-1, p1);
			rv = getPoint2d_p(pa1, j, p2);
			
			LWDEBUGF(4, "lineCrossingDirection: i=%d, j=%d", i, j);
			
			this_cross = lw_segment_intersects(p1, p2, q1, q2);
		
			if( ! first_cross && this_cross )
				first_cross = this_cross;
			if( this_cross ) 
				final_cross = this_cross;
				
			if( this_cross == SEG_CROSS_LEFT ) 
			{
				cross_left++;
				break;
			}
				
			if( this_cross == SEG_CROSS_RIGHT ) 
			{
				cross_right++;
				break;
			}

			/*
			** Crossing at a co-linearity can be turned into crossing at
			** a vertex by pulling the original touch point forward along
			** the co-linearity.
			*/
			if( this_cross == SEG_COLINEAR && vertex_touch == (i-1) ) 
			{
				vertex_touch = i;
				break;
			}
				
			/* 
			** Crossing-at-vertex will cause four segment touch interactions, two at
			** j-1 and two at j. We avoid incrementing our cross count by ignoring the
			** second pair.
			*/
			if( this_cross == SEG_TOUCH_LEFT ) 
			{
				if ( vertex_touch == (i-1) && vertex_touch_type == SEG_TOUCH_RIGHT ) {
					cross_left++;
					vertex_touch = -1;
					vertex_touch_type = 0;
				}
				else {
					vertex_touch = i;
					vertex_touch_type = this_cross;
				}
				break;
			}
			if( this_cross == SEG_TOUCH_RIGHT ) 
			{
				if ( vertex_touch == (i-1) && vertex_touch_type == SEG_TOUCH_LEFT ) {
					cross_right++;
					vertex_touch = -1;
					vertex_touch_type = 0;
				}
				else {
					vertex_touch = i;
					vertex_touch_type = this_cross;
				}
				break;
			}

			/* 
			** TODO Handle co-linear cases. 
			*/

 			LWDEBUGF(4, "lineCrossingDirection: this_cross=%d, vertex_touch=%d, vertex_touch_type=%d", this_cross, vertex_touch, vertex_touch_type);
				
		}
		
	}

	LWDEBUGF(4, "first_cross=%d, final_cross=%d, cross_left=%d, cross_right=%d", first_cross, final_cross, cross_left, cross_right);

	lwfree(p1);
	lwfree(p2);
	lwfree(q1);
	lwfree(q2);

	if( !cross_left && !cross_right ) 
		return LINE_NO_CROSS;

	if( !cross_left && cross_right == 1 )
		return LINE_CROSS_RIGHT;
		
	if( !cross_right && cross_left == 1 )
		return LINE_CROSS_LEFT;

	if( cross_left - cross_right == 1 )
		return LINE_MULTICROSS_END_LEFT;

	if( cross_left - cross_right == -1 )
		return LINE_MULTICROSS_END_RIGHT;

	if( cross_left - cross_right == 0 && first_cross == SEG_CROSS_LEFT )
		return LINE_MULTICROSS_END_SAME_FIRST_LEFT;

	if( cross_left - cross_right == 0 && first_cross == SEG_CROSS_RIGHT )
		return LINE_MULTICROSS_END_SAME_FIRST_RIGHT;

	if( cross_left - cross_right == 0 && first_cross == SEG_TOUCH_LEFT )
		return LINE_MULTICROSS_END_SAME_FIRST_RIGHT;

	if( cross_left - cross_right == 0 && first_cross == SEG_TOUCH_RIGHT )
		return LINE_MULTICROSS_END_SAME_FIRST_LEFT;
		
	return LINE_NO_CROSS;
	
}

/*
** lwpoint_get_ordinate(point, ordinate) => double
*/
double lwpoint_get_ordinate(const POINT4D *p, int ordinate) 
{
	if( ! p ) 
	{
		lwerror("Null input geometry.");
		return 0.0;
	}
	
	if( ordinate > 3 || ordinate < 0 ) 
	{
		lwerror("Cannot extract ordinate %d.", ordinate);
		return 0.0;
	}

	if( ordinate == 3 ) 
		return p->m;
	if( ordinate == 2 ) 
		return p->z;
	if( ordinate == 1 ) 
		return p->y;

	return p->x;
	
}
void lwpoint_set_ordinate(POINT4D *p, int ordinate, double value) 
{
	if( ! p ) 
	{
		lwerror("Null input geometry.");
		return;
	}
	
	if( ordinate > 3 || ordinate < 0 ) 
	{
		lwerror("Cannot extract ordinate %d.", ordinate);
		return;
	}

	switch ( ordinate ) {
        case 3:
            p->m = value;
            return;
        case 2:
            p->z = value;
            return;
        case 1:
            p->y = value;
            return;
        case 0:
            p->x = value;
            return;
    }    	
}


int lwpoint_interpolate(const POINT4D *p1, const POINT4D *p2, POINT4D *p, int ndims, int ordinate, double interpolation_value)
{
    double p1_value = lwpoint_get_ordinate(p1, ordinate);
    double p2_value = lwpoint_get_ordinate(p2, ordinate);
    double proportion;
    int i = 0;
    
    if( ordinate < 0 || ordinate >= ndims ) 
    {
        lwerror("Ordinate (%d) is not within ndims (%d).", ordinate, ndims);
        return 0;
    }
    
    if( FP_MIN(p1_value, p2_value) > interpolation_value || 
        FP_MAX(p1_value, p2_value) < interpolation_value )
    {
        lwerror("Cannot interpolate to a value (%g) not between the input points.", interpolation_value);
        return 0;
    } 
    
    proportion = fabs((interpolation_value - p1_value) / (p2_value - p1_value));

    for( i = 0; i < ndims; i++ ) 
    {
        p1_value = lwpoint_get_ordinate(p1, i);
        p2_value = lwpoint_get_ordinate(p2, i);
        lwpoint_set_ordinate(p, i, p1_value + proportion * (p2_value - p1_value));

	LWDEBUGF(3, "   clip ordinate(%d) p1_value(%g) p2_value(%g) proportion(%g)", i, p1_value, p2_value, proportion );
    }
    
    return 1;
}

LWCOLLECTION *lwmline_clip_to_ordinate_range(LWMLINE *mline, int ordinate, double from, double to) 
{
    LWCOLLECTION *lwgeom_out = NULL;
    
    if( ! mline ) 
    {
		lwerror("Null input geometry.");
		return NULL;
    }
    
    if( mline->ngeoms == 1) 
    {
        lwgeom_out = lwline_clip_to_ordinate_range(mline->geoms[0], ordinate, from, to);        
    }
    else 
    {
        LWCOLLECTION *col;
    	char hasz = TYPE_HASZ(mline->type);
    	char hasm = TYPE_HASM(mline->type);
    	char hassrid = TYPE_HASSRID(mline->type);
        int i, j;
        char homogeneous = 1;
        size_t geoms_size = 0;
        lwgeom_out = lwcollection_construct_empty(mline->SRID, hasz, hasm);
        lwgeom_out->type = lwgeom_makeType(hasz, hasm, hassrid, MULTILINETYPE);
        for( i = 0; i < mline->ngeoms; i ++ ) 
        {
            col = lwline_clip_to_ordinate_range(mline->geoms[i], ordinate, from, to);
            if ( col ) { /* Something was left after the clip. */
                if( lwgeom_out->ngeoms + col->ngeoms > geoms_size )
                {
                    geoms_size += 16;
                    if( lwgeom_out->geoms ) 
                    {
                        lwgeom_out->geoms = lwrealloc(lwgeom_out->geoms, geoms_size * sizeof(LWGEOM*));
                    }
                    else
                    {
                        lwgeom_out->geoms = lwalloc(geoms_size * sizeof(LWGEOM*));
                    }
                }
                for( j = 0; j < col->ngeoms; j++ ) 
                {
                    lwgeom_out->geoms[lwgeom_out->ngeoms] = col->geoms[j];
                    lwgeom_out->ngeoms++;
                }
                if( TYPE_GETTYPE(col->type) != TYPE_GETTYPE(mline->type) )
                {
                    homogeneous = 0;
                }
                /* Shallow free the struct, leaving the geoms behind. */
                if( col->bbox ) lwfree(col->bbox);
                lwfree(col); 
            }
        }
        lwgeom_dropBBOX((LWGEOM*)lwgeom_out);
		lwgeom_addBBOX((LWGEOM*)lwgeom_out);
		if ( ! homogeneous ) 
		{
		    lwgeom_out->type = lwgeom_makeType(hasz, hasm, hassrid, COLLECTIONTYPE);
	    }        
    }
    
    if( ! lwgeom_out || lwgeom_out->ngeoms == 0 ) /* Nothing left after clip. */
    {
        return NULL;
    }
    
    return lwgeom_out;    
    
}


/*
** lwline_clip_to_ordinate_range(line, ordinate, from, to) => lwmline
**
** Take in a LINESTRING and return a MULTILINESTRING of those portions of the 
** LINESTRING between the from/to range for the specified ordinate (XYZM)
*/
LWCOLLECTION *lwline_clip_to_ordinate_range(LWLINE *line, int ordinate, double from, double to) 
{
	
	POINTARRAY *pa_in = NULL;
	LWCOLLECTION *lwgeom_out = NULL;
	POINTARRAY *pa_out = NULL;
	DYNPTARRAY *dp = NULL;
	int i, rv;
	int added_last_point = 0;
	POINT4D *p = NULL, *q = NULL, *r = NULL;
	double ordinate_value_p = 0.0, ordinate_value_q = 0.0;
	char hasz = TYPE_HASZ(line->type);
	char hasm = TYPE_HASM(line->type);
	char dims = TYPE_NDIMS(line->type);
	char hassrid = TYPE_HASSRID(line->type);

	LWDEBUGF(5, "hassrid = %d", hassrid);

	/* Null input, nothing we can do. */
	if( ! line ) 
	{
		lwerror("Null input geometry.");
		return NULL;
	}
	
	/* Ensure 'from' is less than 'to'. */
	if( to < from ) 
	{
		double t = from;
		from = to;
		to = t;
	}
	
	/* Asking for an ordinate we don't have. Error. */
	if( ordinate >= dims ) 
	{
		lwerror("Cannot clip on ordinate %d in a %d-d geometry.", ordinate, dims);
		return NULL;
	}
	
	/* Prepare our working point objects. */
	p = lwalloc(sizeof(POINT4D));
	q = lwalloc(sizeof(POINT4D));
    r = lwalloc(sizeof(POINT4D));

	/* Construct a collection to hold our outputs. */
	lwgeom_out = lwalloc(sizeof(LWCOLLECTION));
	lwgeom_out->type = lwgeom_makeType(hasz, hasm, hassrid, MULTILINETYPE);
	if(hassrid) 
		lwgeom_out->SRID = line->SRID;
	else
		lwgeom_out->SRID = -1;
	lwgeom_out->bbox = NULL;
	lwgeom_out->ngeoms = 0;
	lwgeom_out->geoms = NULL;

	pa_in = (POINTARRAY*)line->points;

	for ( i = 0; i < pa_in->npoints; i++ ) 
	{
		LWDEBUGF(4, "Point #%d", i);
		if( i > 0 ) {
			q->x = p->x;
			q->y = p->y;
			q->z = p->z;
			q->m = p->m;
			ordinate_value_q = ordinate_value_p;
		}
		rv = getPoint4d_p(pa_in, i, p);
		ordinate_value_p = lwpoint_get_ordinate(p, ordinate);
		LWDEBUGF(4, " ordinate_value_p %g (current)", ordinate_value_p);
		LWDEBUGF(4, " ordinate_value_q %g (previous)", ordinate_value_q);

		/* Is this point inside the ordinate range? Yes. */
		if ( ordinate_value_p >= from && ordinate_value_p <= to )
		{
			LWDEBUGF(4, " inside ordinate range (%g, %g)", from, to);

			if ( ! added_last_point ) 
			{
				/* We didn't add the previous point, so this is a new segment.
				*  Make a new point array. */
				if( dp ) lwfree(dp);
				dp = dynptarray_create(64, line->type);

           		/* We're transiting into the range so add an interpolated 
				*  point at the range boundary. 
				*  If we're on a boundary and crossing from the far side, 
				*  we also need an interpolated point. */
    			if ( i > 0 && ( /* Don't try to interpolate if this is the first point */
				     ( ordinate_value_p > from && ordinate_value_p < to ) || /* Inside */
				     ( ordinate_value_p == from && ordinate_value_q > to ) || /* Hopping from above */
				     ( ordinate_value_p == to && ordinate_value_q < from ) ) ) /* Hopping from below */
    		    {
                    double interpolation_value;
                    (ordinate_value_q > to) ? (interpolation_value = to) : (interpolation_value = from);
                    rv = lwpoint_interpolate(q, p, r, dims, ordinate, interpolation_value);
                    rv = dynptarray_addPoint4d(dp, r, 0);
  			LWDEBUGF(4, " interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
    		    }
			}
		    /* Add the current vertex to the point array. */
    		rv = dynptarray_addPoint4d(dp, p, 0);
			if ( ordinate_value_p == from || ordinate_value_p == to ) 
			{
            	added_last_point = 2; /* Added on boundary. */
			}
			else
			{
            	added_last_point = 1; /* Added inside range. */
			}
		} 
		/* Is this point inside the ordinate range? No. */
		else 
		{
			LWDEBUGF(4, "  added_last_point (%d)", added_last_point);
		    if( added_last_point == 1 ) 
		    {
		        /* We're transiting out of the range, so add an interpolated point 
				*  to the point array at the range boundary. */
                double interpolation_value;
                (ordinate_value_p > to) ? (interpolation_value = to) : (interpolation_value = from);
                rv = lwpoint_interpolate(q, p, r, dims, ordinate, interpolation_value);
                rv = dynptarray_addPoint4d(dp, r, 0);
				LWDEBUGF(4, " interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
	        }
			else if ( added_last_point == 2 ) 
			{
				/* We're out and the last point was on the boundary.
				*  If the last point was the near boundary, nothing to do.
				*  If it was the far boundary, we need an interpolated point. */
				if( (ordinate_value_q == from && ordinate_value_p > from) || 
				    (ordinate_value_q == to && ordinate_value_p < to) ) 
				{
	                double interpolation_value;
                	(ordinate_value_p > to) ? (interpolation_value = to) : (interpolation_value = from);
                	rv = lwpoint_interpolate(q, p, r, dims, ordinate, interpolation_value);
                	rv = dynptarray_addPoint4d(dp, r, 0);
					LWDEBUGF(4, " interpolating between (%g, %g) with interpolation point (%g)", ordinate_value_q, ordinate_value_p, interpolation_value);
				}
			}
			else if ( ordinate_value_q < from && ordinate_value_p > to ) {
				/* We just hopped over the whole range, from bottom to top, 
				*  so we need to add *two* interpolated points! */
				pa_out = ptarray_construct(hasz, hasm, 2);
				/* Interpolate lower point. */
				rv = lwpoint_interpolate(p, q, r, dims, ordinate, from);
				setPoint4d(pa_out, 0, r);
				/* Interpolate upper point. */
				rv = lwpoint_interpolate(p, q, r, dims, ordinate, to);
				setPoint4d(pa_out, 1, r);
			}
			else if ( ordinate_value_q > to && ordinate_value_p < from ) {
				/* We just hopped over the whole range, from top to bottom, 
				*  so we need to add *two* interpolated points! */
				pa_out = ptarray_construct(hasz, hasm, 2);
				/* Interpolate upper point. */
				rv = lwpoint_interpolate(p, q, r, dims, ordinate, to);
				setPoint4d(pa_out, 0, r);
				/* Interpolate lower point. */
				rv = lwpoint_interpolate(p, q, r, dims, ordinate, from);
				setPoint4d(pa_out, 1, r);
			}
			/* We have an extant point-array, save it out to a multi-line. */
			if ( dp || pa_out ) {
				LWGEOM *oline;
				if( dp ) 
				{
					/* Only one point, so we have to make an lwpoint to hold this
					*  and set the overall output type to a generic collection. */
					if( dp->pa->npoints == 1 ) 
					{
						oline = (LWGEOM*)lwpoint_construct(line->SRID, NULL, dp->pa);
						oline->type = lwgeom_makeType(hasz, hasm, hassrid, POINTTYPE);
						lwgeom_out->type = lwgeom_makeType(hasz, hasm, hassrid, COLLECTIONTYPE);
					}
					else
					{
						oline = (LWGEOM*)lwline_construct(line->SRID, NULL, dp->pa);
						oline->type = lwgeom_makeType(hasz, hasm, hassrid, LINETYPE);
					}
				}
				else 
				{
					oline = (LWGEOM*)lwline_construct(line->SRID, NULL, pa_out);
				}
				lwgeom_out->ngeoms++;
				if( lwgeom_out->geoms ) /* We can't just realloc, since repalloc chokes on a starting null ptr. */
				{
					lwgeom_out->geoms = lwrealloc(lwgeom_out->geoms, sizeof(LWGEOM*) * lwgeom_out->ngeoms);
				}
				else
				{
					lwgeom_out->geoms = lwalloc(sizeof(LWGEOM*) * lwgeom_out->ngeoms);
				}
				lwgeom_out->geoms[lwgeom_out->ngeoms - 1] = oline;				
				lwgeom_dropBBOX((LWGEOM*)lwgeom_out);
				lwgeom_addBBOX((LWGEOM*)lwgeom_out);
				if( dp ) lwfree(dp);
				dp = NULL;
				if( pa_out ) pa_out = NULL;
			}
            added_last_point = 0;

	    }
	}

	/* Still some points left to be saved out. */
	if( dp && dp->pa->npoints > 0 ) {
		LWGEOM *oline;
		oline = (LWGEOM*)lwline_construct(line->SRID, NULL, dp->pa);
		oline->type = lwgeom_makeType(hasz, hasm, hassrid, LINETYPE);
		lwgeom_out->ngeoms++;
		if( lwgeom_out->geoms ) /* We can't just realloc, since repalloc chokes on a starting null ptr. */
		{
			lwgeom_out->geoms = lwrealloc(lwgeom_out->geoms, sizeof(LWGEOM*) * lwgeom_out->ngeoms);
		}
		else
		{
			lwgeom_out->geoms = lwalloc(sizeof(LWGEOM*) * lwgeom_out->ngeoms);
		}
		lwgeom_out->geoms[lwgeom_out->ngeoms - 1] = oline;				
		lwgeom_dropBBOX((LWGEOM*)lwgeom_out);
		lwgeom_addBBOX((LWGEOM*)lwgeom_out);
		lwfree(dp);
	}
    lwfree(p);
    lwfree(q);
    lwfree(r);

	if( lwgeom_out->ngeoms > 0 ) 
		return lwgeom_out;
		
	return NULL;

}