// s2-geometry is a pure JavaScript port of Google/Niantic's S2 Geometry library
// which is perfect since it works in the browser.
import { toHilbertQuadkey, FromHilbertQuadKey, IJToST, STToUV, FaceUVToXYZ, XYZToLngLat } from "./s2-geometry.js";
import Long from 'long';
/**
 * Given an S2 token this function convert the token to 64 bit id
   https://github.com/google/s2-geometry-library-java/blob/c04b68bf3197a9c34082327eeb3aec7ab7c85da1/src/com/google/common/geometry/S2CellId.java#L439
 * */
function getIdFromToken(token) {
    // pad token with zeros to make the length 16
    const paddedToken = token.padEnd(16, '0');
    return Long.fromString(paddedToken, 16);
}
const MAX_RESOLUTION = 100;
/* Adapted from s2-geometry's S2Cell.getCornerLatLngs */
/* eslint-disable max-statements */
function getGeoBounds({ face, ij, level }) {
    const offsets = [
        [0, 0],
        [0, 1],
        [1, 1],
        [1, 0],
        [0, 0]
    ];
    // The S2 cell edge is curved: http://s2geometry.io/
    // This is more prominent at lower levels
    // resolution is the number of segments to generate per edge.
    // We exponentially reduce resolution as level increases so it doesn't affect perf
    // when there are a large number of cells
    const resolution = Math.max(1, Math.ceil(MAX_RESOLUTION * Math.pow(2, -level)));
    const result = new Float64Array(4 * resolution * 2 + 2);
    let ptIndex = 0;
    let prevLng = 0;
    for (let i = 0; i < 4; i++) {
        const offset = offsets[i].slice(0);
        const nextOffset = offsets[i + 1];
        const stepI = (nextOffset[0] - offset[0]) / resolution;
        const stepJ = (nextOffset[1] - offset[1]) / resolution;
        for (let j = 0; j < resolution; j++) {
            offset[0] += stepI;
            offset[1] += stepJ;
            // Cell can be represented by coordinates IJ, ST, UV, XYZ
            // http://s2geometry.io/devguide/s2cell_hierarchy#coordinate-systems
            const st = IJToST(ij, level, offset);
            const uv = STToUV(st);
            const xyz = FaceUVToXYZ(face, uv);
            const lngLat = XYZToLngLat(xyz);
            // Adjust longitude for Web Mercator projection
            if (Math.abs(lngLat[1]) > 89.999) {
                lngLat[0] = prevLng;
            }
            const deltaLng = lngLat[0] - prevLng;
            lngLat[0] += deltaLng > 180 ? -360 : deltaLng < -180 ? 360 : 0;
            result[ptIndex++] = lngLat[0];
            result[ptIndex++] = lngLat[1];
            prevLng = lngLat[0];
        }
    }
    // close the loop
    result[ptIndex++] = result[0];
    result[ptIndex++] = result[1];
    return result;
}
/* eslint-enable max-statements */
export function getS2QuadKey(token) {
    if (typeof token === 'string') {
        if (token.indexOf('/') > 0) {
            // is Hilbert quad key
            return token;
        }
        // is S2 token
        token = getIdFromToken(token);
    }
    // is Long id
    return toHilbertQuadkey(token.toString());
}
/**
 * Get a polygon with corner coordinates for an s2 cell
 * @param {*} cell - This can be an S2 key or token
 * @return {Float64Array} - a simple polygon in flat array format: [lng0, lat0, lng1, lat1, ...]
 *   - the polygon is closed, i.e. last coordinate is a copy of the first coordinate
 */
export function getS2Polygon(token) {
    const key = getS2QuadKey(token);
    const s2cell = FromHilbertQuadKey(key);
    return getGeoBounds(s2cell);
}