#include <postgres.h>		// Datum, etc.
#include <fmgr.h>			// PG_FUNCTION_ARGS, etc.
#include <utils/array.h>	// using arrays

#include <h3api.h> // Main H3 include
#include "extension.h"

#include "wkb_linked_geo.h"
#include "wkb_split.h"
#include "wkb.h"

PG_FUNCTION_INFO_V1(h3_cells_to_multi_polygon_wkb);

/* Converts LinkedGeoPolygon vertex coordinates to degrees in place */
static void
linked_geo_polygon_to_degs(LinkedGeoPolygon * multiPolygon);

Datum
h3_cells_to_multi_polygon_wkb(PG_FUNCTION_ARGS)
{
	ArrayType	*array = PG_GETARG_ARRAYTYPE_P(0);
	LinkedGeoPolygon *linkedPolygon;
	H3Error	error;
	int 		numHexes;
	ArrayIterator iterator;
	Datum		value;
	bool		isnull;
	H3Index	*h3set;
	bytea		*wkb;

	numHexes = ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array));
	h3set = palloc(numHexes * sizeof(H3Index));

	/* Extract data from array into h3set */

	iterator = array_create_iterator(array, 0, NULL);
	numHexes = 0;
	while (array_iterate(iterator, &value, &isnull))
	{
		h3set[numHexes++] = DatumGetH3Index(value);
	}

	/* produce hexagons into allocated memory */
	linkedPolygon = palloc(sizeof(LinkedGeoPolygon));
	error = cellsToLinkedMultiPolygon(h3set, numHexes, linkedPolygon);
	H3_ERROR(error, "cellsToLinkedMultiPolygon");

	if (is_linked_polygon_crossed_by_180(linkedPolygon))
	{
		/* Split by 180th meridian */
		LinkedGeoPolygon *splitPolygon = split_linked_polygon_by_180(linkedPolygon);
		linked_geo_polygon_to_degs(splitPolygon);
		wkb = linked_geo_polygon_to_wkb(splitPolygon);
		free_linked_geo_polygon(splitPolygon);
	}
	else
	{
		linked_geo_polygon_to_degs(linkedPolygon);
		wkb = linked_geo_polygon_to_wkb(linkedPolygon);
	}

	destroyLinkedMultiPolygon(linkedPolygon);
	pfree(linkedPolygon);

	PG_RETURN_BYTEA_P(wkb);
}

void
linked_geo_polygon_to_degs(LinkedGeoPolygon * multiPolygon)
{
	FOREACH_LINKED_POLYGON_NOCONST(multiPolygon, polygon)
	{
		FOREACH_LINKED_LOOP_NOCONST(polygon, loop)
		{
			FOREACH_LINKED_LAT_LNG_NOCONST(loop, latlng)
			{
				LatLng *vertex = &latlng->vertex;
				vertex->lat = radsToDegs(vertex->lat);
				vertex->lng = radsToDegs(vertex->lng);
			}
		}
	}
}