#include "postgres.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "fmgr.h"

#include "lwgeom_pg.h"
#include "liblwgeom.h"

Datum postgis_geos_version(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(postgis_geos_version);
Datum postgis_geos_version(PG_FUNCTION_ARGS)
{
	//elog(ERROR,"JTSversion:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL();
}

Datum postgis_jts_version(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(postgis_jts_version);
Datum postgis_jts_version(PG_FUNCTION_ARGS)
{
	PG_RETURN_NULL();
}

Datum intersection(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(intersection);
Datum intersection(PG_FUNCTION_ARGS)
{
	elog(ERROR,"intersection:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum convexhull(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(convexhull);
Datum convexhull(PG_FUNCTION_ARGS)
{
	elog(ERROR,"convexhull:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum difference(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(difference);
Datum difference(PG_FUNCTION_ARGS)
{
	elog(ERROR,"difference:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum boundary(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(boundary);
Datum boundary(PG_FUNCTION_ARGS)
{
	elog(ERROR,"boundary:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum symdifference(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(symdifference);
Datum symdifference(PG_FUNCTION_ARGS)
{
	elog(ERROR,"symdifference:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum geomunion(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(geomunion);
Datum geomunion(PG_FUNCTION_ARGS)
{
	elog(ERROR,"geomunion:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum buffer(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(buffer);
Datum buffer(PG_FUNCTION_ARGS)
{
	elog(ERROR,"buffer:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum relate_full(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(relate_full);
Datum relate_full(PG_FUNCTION_ARGS)
{
	elog(ERROR,"relate_full:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum relate_pattern(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(relate_pattern);
Datum relate_pattern(PG_FUNCTION_ARGS)
{
	elog(ERROR,"relate_pattern:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum disjoint(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(disjoint);
Datum disjoint(PG_FUNCTION_ARGS)
{
	elog(ERROR,"disjoint:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum intersects(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(intersects);
Datum intersects(PG_FUNCTION_ARGS)
{
	elog(ERROR,"intersects:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum touches(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(touches);
Datum touches(PG_FUNCTION_ARGS)
{
	elog(ERROR,"touches:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum crosses(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(crosses);
Datum crosses(PG_FUNCTION_ARGS)
{
	elog(ERROR,"crosses:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum within(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(within);
Datum within(PG_FUNCTION_ARGS)
{
	elog(ERROR,"within:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum contains(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(contains);
Datum contains(PG_FUNCTION_ARGS)
{
	elog(ERROR,"contains:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum overlaps(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(overlaps);
Datum overlaps(PG_FUNCTION_ARGS)
{
	elog(ERROR,"overlaps:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum isvalid(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(isvalid);
Datum isvalid(PG_FUNCTION_ARGS)
{
	elog(ERROR,"isvalid:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum issimple(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(issimple);
Datum issimple(PG_FUNCTION_ARGS)
{
	elog(ERROR,"issimple:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum geomequals(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(geomequals);
Datum geomequals(PG_FUNCTION_ARGS)
{
	elog(ERROR,"geomequals:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum isring(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(isring);
Datum isring(PG_FUNCTION_ARGS)
{
	elog(ERROR,"isring:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum pointonsurface(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(pointonsurface);
Datum pointonsurface(PG_FUNCTION_ARGS)
{
	elog(ERROR,"pointonsurface:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum unite_garray(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(unite_garray);
Datum unite_garray(PG_FUNCTION_ARGS)
{
	elog(ERROR,"unite_garray:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum polygonize_garray(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(polygonize_garray);
Datum polygonize_garray(PG_FUNCTION_ARGS)
{
	elog(ERROR,"polygonize_garray:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum linemerge(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(linemerge);
Datum linemerge(PG_FUNCTION_ARGS)
{
	elog(ERROR,"linemerge:: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum JTSnoop(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(JTSnoop);
Datum JTSnoop(PG_FUNCTION_ARGS)
{
	elog(ERROR,"JTSnoop:: operation not implemented - compile PostGIS with JTS support");
	PG_RETURN_NULL(); // never get here
}

Datum GEOSnoop(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(GEOSnoop);
Datum GEOSnoop(PG_FUNCTION_ARGS)
{
	elog(ERROR,"GEOSnoop:: operation not implemented - compile PostGIS with GEOS support");
	PG_RETURN_NULL(); // never get here
}

Datum LWGEOM_buildarea(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(LWGEOM_buildarea);
Datum LWGEOM_buildarea(PG_FUNCTION_ARGS)
{
	elog(ERROR,"BuildArea: operation not implemented - compile PostGIS with JTS or GEOS support");
	PG_RETURN_NULL(); // never get here
}

LWGEOM *lwgeom_centroid(LWGEOM *in);

LWGEOM *
lwgeom_centroid(LWGEOM *in)
{
	int type = lwgeom_getType(in->type);
	LWPOLY *poly;
	LWPOINT *point;
	LWMPOLY *mpoly;
	POINTARRAY *ring, *pa;
	POINT3DZ p, *cent;
	int i,j,k;
	uint32 num_points_tot = 0;
	double tot_x=0, tot_y=0, tot_z=0;

	if (type == POLYGONTYPE)
	{
		poly = (LWPOLY*)in;
		for (j=0; j<poly->nrings; j++)
		{
			ring = poly->rings[j];
			for (k=0; k<ring->npoints-1; k++)
			{
				getPoint3dz_p(ring, k, &p);
				tot_x += p.x;
				tot_y += p.y;
				if ( TYPE_HASZ(ring->dims) ) tot_z += p.z;
			}
			num_points_tot += ring->npoints-1;
		}
	}
	else if ( type == MULTIPOLYGONTYPE )
	{
		mpoly = (LWMPOLY*)in;
		for (i=0; i<mpoly->ngeoms; i++)
		{
			poly = mpoly->geoms[i];
			for (j=0; j<poly->nrings; j++)
			{
				ring = poly->rings[j];
				for (k=0; k<ring->npoints-1; k++)
				{
					getPoint3dz_p(ring, k, &p);
					tot_x += p.x;
					tot_y += p.y;
					if ( TYPE_HASZ(ring->dims) ) tot_z += p.z;
				}
				num_points_tot += ring->npoints-1;
			}
		}
	}
	else
	{
		return NULL;
	}

	// Setup point
	cent = lwalloc(sizeof(POINT3DZ));
	cent->x = tot_x/num_points_tot;
	cent->y = tot_y/num_points_tot;
	cent->z = tot_z/num_points_tot;

	// Construct POINTARRAY (paranoia?)
	pa = pointArray_construct((uchar *)cent, 1, 0, 1);

	// Construct LWPOINT
	point = lwpoint_construct(in->SRID, NULL, pa);

	return (LWGEOM *)point;
}

Datum centroid(PG_FUNCTION_ARGS);
PG_FUNCTION_INFO_V1(centroid);
Datum centroid(PG_FUNCTION_ARGS)
{
	PG_LWGEOM *geom = (PG_LWGEOM *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
	LWGEOM *lwgeom = lwgeom_deserialize(SERIALIZED_FORM(geom));
	LWGEOM *centroid = lwgeom_centroid(lwgeom);
	PG_LWGEOM *ret;

	lwgeom_release(lwgeom);
	if ( ! centroid ) PG_RETURN_NULL();
	ret = pglwgeom_serialize(centroid);
	lwgeom_release((LWGEOM *)centroid);
	PG_FREE_IF_COPY(geom, 0);
	PG_RETURN_POINTER(ret);
}