Initial Commit

src/utils/index.ts

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+// Utility functions for the Beach Litter Mapping Platform
+
+/**
+ * Validates if coordinates are within Ireland's geographical bounds
+ */
+export function isValidIrishCoordinates(lat: number, lng: number): boolean {
+  // Ireland approximate bounds
+  const MIN_LAT = 51.4;
+  const MAX_LAT = 55.4;
+  const MIN_LNG = -10.5;
+  const MAX_LNG = -5.5;
+
+  return lat >= MIN_LAT && lat <= MAX_LAT && lng >= MIN_LNG && lng <= MAX_LNG;
+}
+
+/**
+ * Formats a date to ISO 8601 format
+ */
+export function formatDateISO(date: Date): string {
+  return date.toISOString();
+}
+
+/**
+ * Calculates distance between two coordinates in meters using Haversine formula
+ */
+export function calculateDistance(
+  lat1: number,
+  lng1: number,
+  lat2: number,
+  lng2: number
+): number {
+  const R = 6371e3; // Earth's radius in meters
+  const φ1 = (lat1 * Math.PI) / 180;
+  const φ2 = (lat2 * Math.PI) / 180;
+  const Δφ = ((lat2 - lat1) * Math.PI) / 180;
+  const Δλ = ((lng2 - lng1) * Math.PI) / 180;
+
+  const a =
+    Math.sin(Δφ / 2) * Math.sin(Δφ / 2) +
+    Math.cos(φ1) * Math.cos(φ2) * Math.sin(Δλ / 2) * Math.sin(Δλ / 2);
+  const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+
+  return R * c;
+}
+
+/**
+ * Validates file type for photo uploads
+ */
+export function isValidImageFile(file: File): boolean {
+  const validTypes = ['image/jpeg', 'image/jpg', 'image/png', 'image/webp'];
+  return validTypes.includes(file.type);
+}
+
+/**
+ * Validates file size (max 5MB)
+ */
+export function isValidFileSize(file: File, maxSizeMB: number = 5): boolean {
+  const maxSizeBytes = maxSizeMB * 1024 * 1024;
+  return file.size <= maxSizeBytes;
+}
+
+/**
+ * Formats bytes to human-readable size
+ */
+export function formatFileSize(bytes: number): string {
+  if (bytes === 0) return '0 Bytes';
+  const k = 1024;
+  const sizes = ['Bytes', 'KB', 'MB', 'GB'];
+  const i = Math.floor(Math.log(bytes) / Math.log(k));
+  return Math.round(bytes / Math.pow(k, i) * 100) / 100 + ' ' + sizes[i];
+}