/*
 * Copyright 2018-2022 Bytes & Brains
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *	   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <postgres.h>		 // Datum, etc.
#include <fmgr.h>			 // PG_FUNCTION_ARGS, etc.
#include <utils/geo_decls.h> // making native points

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

PG_FUNCTION_INFO_V1(h3_lat_lng_to_cell);
PG_FUNCTION_INFO_V1(h3_cell_to_lat_lng);
PG_FUNCTION_INFO_V1(h3_cell_to_boundary);

/* Indexes the location at the specified resolution */
Datum
h3_lat_lng_to_cell(PG_FUNCTION_ARGS)
{
	H3Index		cell;
	H3Error		error;
	LatLng		location;
	Point	   *point = PG_GETARG_POINT_P(0);
	int			resolution = PG_GETARG_INT32(1);

	if (h3_guc_strict)
	{
		ASSERT(
			   point->x >= -180 && point->x <= 180,
			   ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE,
			   "Longitude must be between -180 and 180 degrees inclusive, but got %f.",
			   point->x
			);
		ASSERT(
			   point->y >= -90 && point->y <= 90,
			   ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE,
		"Latitude must be between -90 and 90 degrees inclusive, but got %f.",
			   point->y
			);
	}

	location.lng = degsToRads(point->x);
	location.lat = degsToRads(point->y);

	error = latLngToCell(&location, resolution, &cell);
	H3_ERROR(error, "latLngToCell");

	PG_FREE_IF_COPY(point, 0);
	PG_RETURN_H3INDEX(cell);
}

/* Finds the centroid of the index */
Datum
h3_cell_to_lat_lng(PG_FUNCTION_ARGS)
{
	LatLng		center;
	H3Error		error;
	Point	   *point = palloc(sizeof(Point));
	H3Index		cell = PG_GETARG_H3INDEX(0);

	error = cellToLatLng(cell, &center);
	H3_ERROR(error, "cellToLatLng");

	point->x = radsToDegs(center.lng);
	point->y = radsToDegs(center.lat);

	PG_RETURN_POINT_P(point);
}

/* Finds the boundary of the index */
Datum
h3_cell_to_boundary(PG_FUNCTION_ARGS)
{
	H3Index		cell = PG_GETARG_H3INDEX(0);

	double		delta,
				firstLon,
				lon,
				lat;
	H3Error		error;
	int			size;
	POLYGON    *polygon;
	CellBoundary boundary;

	// DEPRECATION BEGIN: Remove next major
	bool		extend;
	if (PG_NARGS() == 1) {
		extend = h3_guc_extend_antimeridian;
	} else {
		extend = PG_GETARG_BOOL(1);
		H3_DEPRECATION("Please use `SET h3.extend_antimeridian TO true` instead of extend flag");
	}
	// DEPRECATION END

	error = cellToBoundary(cell, &boundary);
	H3_ERROR(error, "cellToBoundary");

	size = offsetof(POLYGON, p) +sizeof(polygon->p[0]) * boundary.numVerts;
	polygon = (POLYGON *) palloc(size);
	SET_VARSIZE(polygon, size);
	polygon->npts = boundary.numVerts;

	firstLon = boundary.verts[0].lng;
	if (firstLon < 0)
	{
		delta = -2 * M_PI;
	}
	else
	{
		delta = +2 * M_PI;
	}

	for (int v = 0; v < boundary.numVerts; v++)
	{
		lon = boundary.verts[v].lng;
		lat = boundary.verts[v].lat;

		/* check if different sign */
		if (extend && fabs(lon - firstLon) > M_PI)
			lon = lon + delta;

		polygon->p[v].x = radsToDegs(lon);
		polygon->p[v].y = radsToDegs(lat);
	}

	PG_RETURN_POLYGON_P(polygon);
}