import json
import math

def calculate_bearing(lat1, lon1, lat2, lon2):
    d_lon = lon2 - lon1
    x = math.cos(math.radians(lat2)) * math.sin(math.radians(d_lon))
    y = math.cos(math.radians(lat1)) * math.sin(math.radians(lat2)) - \
        math.sin(math.radians(lat1)) * math.cos(math.radians(lat2)) * math.cos(math.radians(d_lon))
    bearing = math.atan2(x, y)
    bearing = math.degrees(bearing)
    bearing = (bearing + 360) % 360
    return bearing

def calculate_distance(lat1, lon1, lat2, lon2):
    R = 6371000  # Earth's radius in meters
    d_lat = math.radians(lat2 - lat1)
    d_lon = math.radians(lon2 - lon1)
    a = math.sin(d_lat / 2) * math.sin(d_lat / 2) + \
        math.cos(math.radians(lat1)) * math.cos(math.radians(lat2)) * \
        math.sin(d_lon / 2) * math.sin(d_lon / 2)
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
    distance = R * c
    return distance

def calculate_timestamp(data, current_index):
    if current_index == 0:
        return 0
    else:
        prev_timestamp = calculate_timestamp(data, current_index - 1)
        return prev_timestamp + data[current_index-1]['distance'] / data[current_index]['speed']

def process_route(input_filename, output_filename):
    with open(input_filename, 'r') as infile:
        data = json.load(infile)

    output_data = []

    for i in range(len(data)):
        if i == len(data) - 1:
            data[i]['bearing'] = calculate_bearing(data[i]['latitude'], data[i]['longitude'],
                                                    data[i-1]['latitude'], data[i-1]['longitude'])
        else:
            bearing = calculate_bearing(data[i]['latitude'], data[i]['longitude'],
                                        data[i+1]['latitude'], data[i+1]['longitude'])
            data[i]['bearing'] = bearing

            data[i]['distance'] = calculate_distance(data[i]['latitude'], data[i]['longitude'],
                                                        data[i+1]['latitude'], data[i+1]['longitude'])

        data[i]['timestamp'] = calculate_timestamp(data, i)

        output_data.append(data[i])
        
    for d in output_data:
        d.pop("distance", None)

    with open(output_filename, 'w') as outfile:
        json.dump(output_data, outfile, indent=2)