app.py

import streamlit as st
import folium
from geopy.geocoders import Nominatim
import numpy as np
import requests
import polyline
import time
from functools import lru_cache
from concurrent.futures import ThreadPoolExecutor

def held_karp_tsp(dist_matrix: np.ndarray) -> tuple:
    """
    Held-Karp algorithm for solving TSP
    Returns: (minimum cost, optimal route)
    """
    if len(dist_matrix) < 2:
        return 0, []

    n = len(dist_matrix)
    inf = float('inf')
    
    # Use numpy arrays for better performance
    dp = np.full((1 << n, n), inf)
    parent = np.full((1 << n, n), -1, dtype=int)
    
    # Base cases
    for i in range(1, n):
        dp[1 << i][i] = dist_matrix[0][i]
    
    # Main DP loop
    for mask in range(1, 1 << n):
        if bin(mask).count('1') <= 1:
            continue
        for curr in range(n):
            if not (mask & (1 << curr)):
                continue
            prev_mask = mask ^ (1 << curr)
            for prev in range(n):
                if not (prev_mask & (1 << prev)):
                    continue
                candidate = dp[prev_mask][prev] + dist_matrix[prev][curr]
                if candidate < dp[mask][curr]:
                    dp[mask][curr] = candidate
                    parent[mask][curr] = prev

    # Reconstruct path
    mask = (1 << n) - 1
    curr = min(range(n), key=lambda x: dp[mask][x] + dist_matrix[x][0])
    path = []
    while curr != -1:
        path.append(curr)
        new_mask = mask ^ (1 << curr)
        curr = parent[mask][curr]
        mask = new_mask
    
    path.append(0)
    path.reverse()
    
    return dp[(1 << n) - 1][path[-2]] + dist_matrix[path[-2]][0], path

@st.cache_data
def get_route_osrm(start_coords: tuple, end_coords: tuple) -> tuple:
    """
    Get route using OSRM public API
    Returns: (distance in km, encoded polyline of the route)
    """
    try:
        # Format coordinates for OSRM (lon,lat format)
        coords = f"{start_coords[1]},{start_coords[0]};{end_coords[1]},{end_coords[0]}"
        
        # OSRM public API endpoint
        url = f"http://router.project-osrm.org/route/v1/driving/{coords}"
        params = {
            "overview": "full",
            "geometries": "polyline",
            "annotations": "distance"
        }
        
        response = requests.get(url, params=params)
        
        if response.status_code == 200:
            data = response.json()
            if data["code"] == "Ok" and len(data["routes"]) > 0:
                route = data["routes"][0]
                distance = route["distance"] / 1000  # Convert to km
                geometry = route["geometry"]  # Already encoded polyline
                return distance, geometry
            else:
                st.warning("No route found")
                return None, None
        else:
            st.warning(f"OSRM API error: {response.status_code}")
            return None, None
            
    except Exception as e:
        st.error(f"Error getting route: {str(e)}")
        return None, None

@st.cache_data
def cached_geocoding(city_name: str) -> tuple:
    """Cache geocoding results"""
    try:
        geolocator = Nominatim(user_agent="tsp_app")
        location = geolocator.geocode(city_name, timeout=10)
        if location:
            return (location.latitude, location.longitude)
        return None
    except Exception as e:
        st.error(f"Error geocoding {city_name}: {str(e)}")
        return None

def create_distance_matrix_with_routes(coordinates: list) -> tuple:
    """
    Create distance matrix and store routes between all points using OSRM
    """
    valid_coordinates = [c for c in coordinates if c is not None]
    n = len(valid_coordinates)
    
    if n < 2:
        return np.array([]), valid_coordinates, {}
        
    dist_matrix = np.zeros((n, n))
    routes_dict = {}  # Store encoded polylines for routes
    
    def calculate_route(i, j):
        if i != j:
            # Add delay to avoid hitting rate limits
            time.sleep(0.1)  
            distance, route = get_route_osrm(valid_coordinates[i], valid_coordinates[j])
            if distance is not None:
                return i, j, distance, route
        return i, j, 0, None

    with ThreadPoolExecutor(max_workers=5) as executor:  # Limit concurrent requests
        futures = []
        for i in range(n):
            for j in range(i + 1, n):
                futures.append(executor.submit(calculate_route, i, j))
        
        with st.spinner("Calculating routes..."):
            for future in futures:
                i, j, distance, route = future.result()
                if route is not None:
                    dist_matrix[i][j] = distance
                    dist_matrix[j][i] = distance
                    routes_dict[f"{i}-{j}"] = route
                    routes_dict[f"{j}-{i}"] = route
                
    return dist_matrix, valid_coordinates, routes_dict

def plot_route_with_roads(map_obj: folium.Map, coordinates: list, route: list, 
                         city_names: list, routes_dict: dict) -> folium.Map:
    """
    Plot route using actual road paths from OSRM
    """
    route_group = folium.FeatureGroup(name="Route")
    
    # Plot road segments between consecutive points
    total_distance = 0
    for i in range(len(route)-1):
        start_idx = route[i]
        end_idx = route[i+1]
        route_key = f"{start_idx}-{end_idx}"
        
        if route_key in routes_dict:
            # Decode and plot the polyline
            decoded_path = polyline.decode(routes_dict[route_key])
            folium.PolyLine(
                decoded_path,
                color="blue",
                weight=3,
                opacity=0.8,
                tooltip=f"Segment {i+1}: {city_names[start_idx]} → {city_names[end_idx]}"
            ).add_to(route_group)
    
    # Add markers with custom icons
    for i, point_idx in enumerate(route):
        icon_color = "green" if i == 0 else "red" if i == len(route)-1 else "blue"
        popup_text = f"""
        <div style='font-size: 12px'>
            <b>City:</b> {city_names[point_idx]}<br>
            <b>Stop:</b> {i + 1} of {len(route)}
        </div>
        """
        folium.Marker(
            location=coordinates[point_idx],
            popup=folium.Popup(popup_text, max_width=200),
            tooltip=f'Stop {i + 1}: {city_names[point_idx]}',
            icon=folium.Icon(color=icon_color, icon='info-sign')
        ).add_to(route_group)
    
    route_group.add_to(map_obj)
    
    # Add OpenStreetMap tile layer
    folium.TileLayer(
        tiles='https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
        attr='&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
    ).add_to(map_obj)
    
    return map_obj

def main():
    st.set_page_config(page_title="TSP Route Optimizer", layout="wide")
    
    st.title("🌍 Route Optimizer")
    st.markdown("""
    Temukan rute optimal berkendara antar lokasi.
    Masukkan nama lokasi dibawah dan klik 'Optimize Route' untuk melihat hasilnya.
    """)

    col1, col2 = st.columns([1, 2])

    with col1:
        st.subheader("📍 Masukkan Lokasi")
        city_count = st.number_input("Jumlah lokasi", min_value=2, max_value=10, value=3, step=1,
                                   help="Maksimum 10 lokasi direkomendasikan karena batasan API")
        
        if 'city_inputs' not in st.session_state:
            st.session_state.city_inputs = [''] * city_count
        
        if len(st.session_state.city_inputs) != city_count:
            st.session_state.city_inputs = st.session_state.city_inputs[:city_count] + [''] * max(0, city_count - len(st.session_state.city_inputs))
        
        city_names = []
        city_coords = []
        
        for i in range(city_count):
            city_name = st.text_input(
                f"Kota {i+1}",
                value=st.session_state.city_inputs[i],
                key=f"city_{i}"
            )
            st.session_state.city_inputs[i] = city_name
            
            if city_name:
                coords = cached_geocoding(city_name)
                if coords:
                    city_names.append(city_name)
                    city_coords.append(coords)
                else:
                    st.warning(f"⚠️ Tidak dapat menemukan koordinat untuk '{city_name}'")

    with col2:
        if not city_coords:
            map_center = [-2.548926, 118.014863]  # Center of Indonesia
            zoom_start = 5
        else:
            map_center = city_coords[0]
            zoom_start = 5
            
        map_obj = folium.Map(location=map_center, zoom_start=zoom_start)
        
        if st.button("🔄 Optimize Route", key="optimize"):
            if len(city_coords) < 2:
                st.error("❌ Masukkan minimal 2 lokasi yang valid")
            else:
                with st.spinner("Menghitung rute optimal..."):
                    start_time = time.time()
                    
                    # Get distance matrix and routes
                    dist_matrix, valid_coordinates, routes_dict = create_distance_matrix_with_routes(city_coords)
                    
                    # Calculate optimal route
                    min_cost, optimal_route = held_karp_tsp(dist_matrix)
                    
                    end_time = time.time()
                    
                    if min_cost == float('inf'):
                        st.error("❌ Tidak dapat menemukan rute yang valid")
                    else:
                        # Display results
                        st.success(f"✅ Rute dihitung dalam {end_time - start_time:.2f} detik")
                        st.write(f"🛣️ Total jarak berkendara: {min_cost:.2f} km")
                        st.write("📍 Rute optimal:")
                        route_text = " → ".join([city_names[i] for i in optimal_route])
                        st.code(route_text)
                        
                        # Update map with route
                        map_obj = plot_route_with_roads(map_obj, valid_coordinates, optimal_route, 
                                                      city_names, routes_dict)

        # Display map
        st.components.v1.html(folium.Map._repr_html_(map_obj), height=600)

if __name__ == "__main__":
    main()