import * as turf from "@turf/turf";

/**
 * Converts an array of canvas-compatible points into a Turf.js Polygon.
 *
 * @param {{x: number, y: number}[]} points - Array of points with x and y properties.
 *
 * @returns {import('@turf/turf').Feature<import('@turf/turf').Polygon> | null} A Turf.js Polygon feature, or null if input is invalid.
 */
export function toTurfPolygon(points) {
    if (!points || points.length < 3) {
        console.error("Invalid input for polygon:", points);
        return null;
    }

    const coords = points.map(p => [p.y, p.x]);
    coords.push(coords[0]);
    return turf.polygon([coords]);
}

/**
 * Merges two polygons (in canvas format) into a single Turf.js polygon using turf.union.
 *
 * @param {{x: number, y: number}[]} polygonA - First polygon (array of points).
 * @param {{x: number, y: number}[]} polygonB - Second polygon (array of points).
 *
 * @returns {import('@turf/turf').Feature<import('@turf/turf').Polygon> | null} A merged Turf.js polygon, or null on failure.
 */
export function mergeTurfPolygons(polygonA, polygonB) {
    const turfPolygonA = toTurfPolygon(polygonA);
    const turfPolygonB = toTurfPolygon(polygonB);

    return turf.union(turf.featureCollection([turfPolygonA, turfPolygonB]));
}

/**
 * Adds a new polygon to an existing merged Turf.js polygon.
 *
 * @param {import('@turf/turf').Feature<import('@turf/turf').Polygon>} polygonA - Existing merged Turf.js polygon.
 * @param {{x: number, y: number}[]} polygonB - New polygon in canvas point format to add to the merge.
 *
 * @returns {import('@turf/turf').Feature<import('@turf/turf').Polygon>} Updated merged Turf.js polygon.
 */
export function addTurfPolygonToMerge(polygonA, polygonB) {
    const testB = toTurfPolygon(polygonB);
    return turf.union(turf.featureCollection([polygonA, testB]));
}

/**
 * @param {{x: number, y: number}[][]} polygons
 * @returns {Feature<Polygon | MultiPolygon, GeoJsonProperties>}
 */

export function mergePolygons(polygons) {

    if (!polygons || polygons.length === 0)
        return undefined;

    if (polygons.length === 1)
        return toTurfPolygon(polygons[0]);

    return turf.union(turf.featureCollection(polygons.map(p => toTurfPolygon(p))));
}

/**
 *
 * @param {Array<Feature<Polygon | MultiPolygon, GeoJsonProperties>>|undefined} features
 * @returns {Feature<Polygon | MultiPolygon, GeoJsonProperties>|undefined|*}
 */
export function mergePolygonFeatures(features) {

    if (!features || features.length === 0)
        return undefined;

    if (features.length === 1)
        return features[0];

        console.log("3" + features.length)
    return turf.union(turf.featureCollection(features));
}