utils.ts

import { GeoPoint } from './types';

export const calculateBearing = (p1: GeoPoint, p2: GeoPoint): number => {
  const dLon = (p2.lng - p1.lng) * Math.PI / 180;
  const lat1 = p1.lat * Math.PI / 180;
  const lat2 = p2.lat * Math.PI / 180;
  const y = Math.sin(dLon) * Math.cos(lat2);
  const x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(dLon);
  const bearing = Math.atan2(y, x) * 180 / Math.PI;
  return (bearing + 360) % 360;
};

export const formatCoords = (coords: GeoPoint): string => {
  return `${coords.lat.toFixed(6)}°N, ${coords.lng.toFixed(6)}°E`;
};

export const generateId = () => Math.random().toString(36).substr(2, 9);

export function decodeBase64(base64: string): Uint8Array {
  const binaryString = atob(base64);
  const len = binaryString.length;
  const bytes = new Uint8Array(len);
  for (let i = 0; i < len; i++) {
    bytes[i] = binaryString.charCodeAt(i);
  }
  return bytes;
}

export async function decodeAudioData(
  data: Uint8Array,
  ctx: AudioContext,
  sampleRate: number,
  numChannels: number,
): Promise<AudioBuffer> {
  const dataInt16 = new Int16Array(data.buffer);
  const frameCount = dataInt16.length / numChannels;
  const buffer = ctx.createBuffer(numChannels, frameCount, sampleRate);

  for (let channel = 0; channel < numChannels; channel++) {
    const channelData = buffer.getChannelData(channel);
    for (let i = 0; i < frameCount; i++) {
      channelData[i] = dataInt16[i * numChannels + channel] / 32768.0;
    }
  }
  return buffer;
}