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Maurice
254a214b7d
computeTourMetrics indexed points[i - 1] and points[i], which the shared package's noUncheckedIndexedAccess reads as possibly undefined, so the shared typecheck in CI failed since the metrics moved there. It walks the points pairwise from the first one now; the numbers are the same.
53 lines
1.9 KiB
TypeScript
53 lines
1.9 KiB
TypeScript
import { haversineMetres } from '../geo/haversine';
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/** One decoded `route_geometry` point: `[lat, lng]` or `[lat, lng, ele]`. */
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export type GeometryPoint = [number, number] | [number, number, number];
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export interface TourMetrics {
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/** Sum of segment haversine distances, in km. */
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distanceKm: number;
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/** Sum of positive elevation deltas, in metres. Null when the track carries no elevation. */
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elevationGainM: number | null;
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/** Sum of negative elevation deltas (as a positive number), in metres. Null when no elevation. */
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elevationLossM: number | null;
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/** Whether every point in the geometry carried a 3rd (elevation) value. */
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hasElevation: boolean;
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}
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/**
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* Derives distance/elevation from a parsed `route_geometry` array. Never throws:
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* a track with fewer than 2 points, or with missing/mixed elevation, still
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* yields a usable (if partial) result rather than blocking import.
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*
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* The server stores these numbers on every tour; the client computes the same
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* ones for a tour saved offline, so both read them from here.
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*/
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export function computeTourMetrics(points: readonly GeometryPoint[]): TourMetrics {
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const [first, ...rest] = points;
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if (!first || rest.length === 0) {
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return { distanceKm: 0, elevationGainM: null, elevationLossM: null, hasElevation: false };
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}
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const hasElevation = points.every((p) => p.length === 3 && Number.isFinite(p[2]));
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let distanceKm = 0;
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let gain = 0;
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let loss = 0;
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let prev = first;
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for (const point of rest) {
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distanceKm += haversineMetres(prev[0], prev[1], point[0], point[1]) / 1000;
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if (hasElevation) {
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const delta = (point[2] as number) - (prev[2] as number);
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if (delta > 0) gain += delta;
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else loss += -delta;
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}
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prev = point;
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}
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return {
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distanceKm,
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elevationGainM: hasElevation ? gain : null,
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elevationLossM: hasElevation ? loss : null,
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hasElevation,
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};
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}
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