utils.py

import base64
import numpy as np
from PIL import Image
import io
from math import radians, cos, sin, asin, sqrt

def base64_to_image(base64_string):
    """Convert base64 string to PIL Image"""
    try:
        # Remove data URL prefix if present
        if ',' in base64_string:
            base64_string = base64_string.split(',')[1]
        
        # Decode base64
        image_data = base64.b64decode(base64_string)
        image = Image.open(io.BytesIO(image_data))
        
        # Convert to RGB if necessary
        if image.mode != 'RGB':
            image = image.convert('RGB')
        
        return image
    except Exception as e:
        raise ValueError(f"Failed to decode base64 image: {str(e)}")


def image_to_numpy(image):
    """Convert PIL Image to numpy array"""
    return np.array(image)


def haversine_distance(lat1, lon1, lat2, lon2):
    """
    Calculate the great circle distance between two points 
    on the earth (specified in decimal degrees)
    Returns distance in meters
    """
    # Convert decimal degrees to radians
    lat1, lon1, lat2, lon2 = map(radians, [lat1, lon1, lat2, lon2])
    
    # Haversine formula
    dlat = lat2 - lat1
    dlon = lon2 - lon1
    a = sin(dlat/2)**2 + cos(lat1) * cos(lat2) * sin(dlon/2)**2
    c = 2 * asin(sqrt(a))
    
    # Radius of earth in meters
    r = 6371000
    
    return c * r


def format_error_response(message, code=400):
    """Format error response"""
    return {
        'success': False,
        'error': message
    }, code


def format_success_response(data=None, message=None):
    """Format success response"""
    response = {'success': True}
    if message:
        response['message'] = message
    if data:
        response['data'] = data
    return response, 200


def validate_coordinates(latitude, longitude):
    """Validate GPS coordinates"""
    try:
        lat = float(latitude)
        lon = float(longitude)
        
        if not (-90 <= lat <= 90):
            return False, "Latitude must be between -90 and 90"
        if not (-180 <= lon <= 180):
            return False, "Longitude must be between -180 and 180"
        
        return True, None
    except (ValueError, TypeError):
        return False, "Invalid coordinate format"