16c787d3f3
- ['shipping','buyer'|'seller'|'split'] tag + create-page selector. - Distance from the viewer's last known location (cache only, no GPS prompt) on both gear cards, and a 'Nearest (local)' sort on GearSwapPage. - HandoffHelper (buyer-only, in ListingTradeActions) opens the trade DM pre-filled: suggest a time & place / share delivery details / use a locker, with anti-scam copy. Details stay in the NIP-17 DM; the app never sees them. - ships deals now nudge safety on all platforms, not just when escrow is ready.
57 lines
1.6 KiB
TypeScript
57 lines
1.6 KiB
TypeScript
/**
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* Sort/geo helpers shared across pages. Kept out of SortDropdown.tsx so that
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* component file exports only a component (React Fast Refresh).
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*/
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import ngeohash from 'ngeohash';
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interface LatLng {
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lat: number;
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lng: number;
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}
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/**
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* Distance in km from `from` to a listing's own geohash, or null when the
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* listing carries no location. Used for the marketplace "Near me" sort + badges.
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*/
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export function itemDistanceKm(item: { geohash?: string }, from: LatLng): number | null {
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if (!item.geohash) return null;
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try {
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const { latitude, longitude } = ngeohash.decode(item.geohash);
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if (!Number.isFinite(latitude) || !Number.isFinite(longitude)) return null;
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return calculateDistance(from.lat, from.lng, latitude, longitude);
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} catch {
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return null;
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}
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}
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/** Weighted popularity score: comments 3x, reactions 1x, zaps 5x. */
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export function calculatePopularity(
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commentCount = 0,
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reactionCount = 0,
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zapCount = 0,
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): number {
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return commentCount * 3 + reactionCount * 1 + zapCount * 5;
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}
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/** Great-circle distance between two coordinates, in kilometres (Haversine). */
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export function calculateDistance(
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lat1: number,
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lon1: number,
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lat2: number,
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lon2: number,
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): number {
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const R = 6371; // Earth's radius in km
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const dLat = toRad(lat2 - lat1);
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const dLon = toRad(lon2 - lon1);
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const a =
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Math.sin(dLat / 2) * Math.sin(dLat / 2) +
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Math.cos(toRad(lat1)) * Math.cos(toRad(lat2)) * Math.sin(dLon / 2) * Math.sin(dLon / 2);
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const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
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return R * c;
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}
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function toRad(degrees: number): number {
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return degrees * (Math.PI / 180);
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}
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