/*
Copyright 2022 The Matrix.org Foundation C.I.C

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.
*/

import { Beacon } from "matrix-js-sdk/src/matrix";

import { parseGeoUri } from "../location";

export type Bounds = {
    north: number;
    east: number;
    west: number;
    south: number;
};

/**
 * Get the geo bounds of given list of beacons
 *
 * Latitude:
 * equator: 0, North pole: 90, South pole -90
 * Longitude:
 * Prime Meridian (Greenwich): 0
 * east of Greenwich has a positive longitude, max 180
 * west of Greenwich has a negative longitude, min -180
 */
export const getBeaconBounds = (beacons: Beacon[]): Bounds | undefined => {
    const coords = beacons.filter(beacon => !!beacon.latestLocationState)
        .map(beacon => parseGeoUri(beacon.latestLocationState.uri));

    if (!coords.length) {
        return;
    }

    // sort descending
    const sortedByLat = [...coords].sort((left, right) => right.latitude - left.latitude);
    const sortedByLong = [...coords].sort((left, right) => right.longitude - left.longitude);

    return {
        north: sortedByLat[0].latitude,
        south: sortedByLat[sortedByLat.length - 1].latitude,
        east: sortedByLong[0].longitude,
        west: sortedByLong[sortedByLong.length -1].longitude,
    };
};
