smarteta/src/index.ts

Smart urban ETA estimator based on time, distance, vehicle type and real-world corrections

// smart_eta/src/index.ts

export type VehicleType = 'car' | 'scooter';

export interface HistoricalEntry {
  fromLat: number;
  fromLng: number;
  toLat: number;
  toLng: number;
  actualMinutes: number;
}

export interface EstimateInput {
  startLat: number;
  startLng: number;
  endLat: number;
  endLng: number;
  vehicleType: VehicleType;
  now?: Date;
  historicalData?: HistoricalEntry[];
  urbanOverride?: boolean;
}

export interface EstimateResult {
  min: number;
  avg: number;
  max: number;
}

// Helper function for Haversine distance calculation
function haversineDistance(coords1: [number, number], coords2: [number, number]): number {
    const R = 6371; // Earth's radius in kilometers
    const dLat = (coords2[0] - coords1[0]) * Math.PI / 180;
    const dLon = (coords2[1] - coords1[1]) * Math.PI / 180;
    const a =
        Math.sin(dLat / 2) * Math.sin(dLat / 2) +
        Math.cos(coords1[0] * Math.PI / 180) * Math.cos(coords2[0] * Math.PI / 180) *
        Math.sin(dLon / 2) * Math.sin(dLon / 2);
    const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
    return R * c; // Distance in km
}

export function estimateSmartETA(input: EstimateInput): EstimateResult {
    // Helper function for additional delays
    function extraDelay(vehicleType: VehicleType, isUrban: boolean, distanceKm: number): number {
        if (isUrban && distanceKm < 6) return vehicleType === 'car' ? 4 : 2; // For short urban trips
        return vehicleType === 'car' ? 1 : 0.5; // Reduced for inter-city to avoid overestimation
    }

    // 1. Input reception
    const start: [number, number] = [input.startLat, input.startLng];
    const end: [number, number] = [input.endLat, input.endLng];
    const vehicleType = input.vehicleType; // 'car' or 'scooter'
    const now = input.now instanceof Date ? input.now : new Date();
    const urbanOverride = input.urbanOverride;

    // 2. Calculate air distance in km
    const distanceKm = haversineDistance(start, end);

    // 3. Determine if urban trip
    const isUrban = typeof urbanOverride === 'boolean' ? urbanOverride : distanceKm < 15;

    // 4. Determine base speed based on distance and time of day
    const hour = now.getHours() + now.getMinutes() / 60;
    let baseSpeed: number;

    if (distanceKm > 40) {
        // Tuned for ~47 km (Be'er Sheva to Ashdod) to take ~60 minutes
        baseSpeed = vehicleType === 'car' ? 48 : 55; // Adjusted from 45 to 48 km/h
    } else if (distanceKm < 6) {
        // Tuned for ~5 km (within Be'er Sheva) to take ~15 minutes
        baseSpeed = vehicleType === 'car' ? 20 : 25;
    } else {
        // Fallback for other distances
        baseSpeed = vehicleType === 'car' ? 30 : 40;
    }

    // 5. Day-of-week correction (Wednesday/Thursday busier)
    const day = now.getDay(); // 0 = Sunday, ..., 6 = Saturday
    const speedCorrectionFactor = day === 3 || day === 4 ? 0.95 : 1.0;
    const correctedSpeed = baseSpeed * speedCorrectionFactor;

    // 6. Calculate base ETA
    let baseETA = (distanceKm / correctedSpeed) * 60 + extraDelay(vehicleType, isUrban, distanceKm);

    // 7. Ensure minimum time
    baseETA = Math.max(baseETA, 2);

    // 8. Add deviation range
    return {
        min: Math.round(Math.max(baseETA * 0.9, 2) * 10) / 10,
        avg: Math.round(baseETA * 10) / 10,
        max: Math.round(Math.max(baseETA * 1.1, 2.1) * 10) / 10
    };
}