PlacesFinder

import tkinter as tk
from tkinter import ttk, messagebox
import urllib.request
import urllib.parse
import urllib.error
import json
import math

# =============================================================================
# Helper Function: Haversine Formula
# =============================================================================
def haversine(lat1, lon1, lat2, lon2):
    """
    Calculate the great-circle distance between two points on Earth (in kilometers).
    """
    R = 6371.0  # Radius of the Earth in kilometers
    phi1 = math.radians(lat1)
    phi2 = math.radians(lat2)
    delta_phi = math.radians(lat2 - lat1)
    delta_lambda = math.radians(lon2 - lon1)

    a = math.sin(delta_phi/2)**2 + \
        math.cos(phi1) * math.cos(phi2) * math.sin(delta_lambda/2)**2
    c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))

    distance = R * c
    return distance

# =============================================================================
# Data Source Base Class & Overpass Implementation Using urllib
# =============================================================================
class PlaceDataSource:
    """
    Abstract interface for a place data source.
    """
    def get_restaurants(self, lat, lon, radius_m):
        raise NotImplementedError

    def get_hotels(self, lat, lon, radius_m):
        raise NotImplementedError


class OverpassSource(PlaceDataSource):
    """
    Data source using the OpenStreetMap Overpass API.
    This queries for restaurants (amenity=restaurant) and hotels (tourism=hotel).
    """
    def __init__(self):
        self.api_url = "http://overpass-api.de/api/interpreter"

    def query_overpass(self, query):
        """
        Submit a query to the Overpass API using urllib and return the JSON result.
        """
        data = urllib.parse.urlencode({'data': query}).encode('utf-8')
        req = urllib.request.Request(self.api_url, data=data, method="POST")
        try:
            with urllib.request.urlopen(req) as response:
                # Check that we received a successful status code (200)
                if response.getcode() == 200:
                    response_data = response.read().decode('utf-8')
                    return json.loads(response_data)
                else:
                    raise Exception(f"Overpass API error: {response.getcode()}")
        except urllib.error.URLError as e:
            raise Exception(f"Overpass API error: {e}")

    def get_restaurants(self, lat, lon, radius_m):
        query = f"""
        [out:json];
        (
          node["amenity"="restaurant"](around:{radius_m},{lat},{lon});
          way["amenity"="restaurant"](around:{radius_m},{lat},{lon});
          relation["amenity"="restaurant"](around:{radius_m},{lat},{lon});
        );
        out center;
        """
        data = self.query_overpass(query)
        return self._parse_elements(data)

    def get_hotels(self, lat, lon, radius_m):
        query = f"""
        [out:json];
        (
          node["tourism"="hotel"](around:{radius_m},{lat},{lon});
          way["tourism"="hotel"](around:{radius_m},{lat},{lon});
          relation["tourism"="hotel"](around:{radius_m},{lat},{lon});
        );
        out center;
        """
        data = self.query_overpass(query)
        return self._parse_elements(data)

    def _parse_elements(self, data):
        """
        Parse the returned JSON data to extract a list of places.
        Each place is a dict with name, coordinates, and address (if available).
        """
        places = []
        for element in data.get("elements", []):
            # For ways and relations, get center coordinates; for nodes, use lat/lon directly.
            if element.get("type") in ["way", "relation"]:
                center = element.get("center", {})
                lat_val = center.get("lat")
                lon_val = center.get("lon")
            else:
                lat_val = element.get("lat")
                lon_val = element.get("lon")

            if lat_val is None or lon_val is None:
                continue

            tags = element.get("tags", {})
            name = tags.get("name", "Unknown")

            # Try to assemble an address from available tags.
            address_parts = []
            if "addr:housenumber" in tags:
                address_parts.append(tags["addr:housenumber"])
            if "addr:street" in tags:
                address_parts.append(tags["addr:street"])
            if "addr:city" in tags:
                address_parts.append(tags["addr:city"])
            address = ", ".join(address_parts)

            places.append({
                "name": name,
                "lat": lat_val,
                "lon": lon_val,
                "address": address,
                "tags": tags
            })
        return places

# =============================================================================
# GUI Functions
# =============================================================================
def update_table(treeview, places):
    """
    Clear the given Treeview and insert rows for each place.
    """
    for row in treeview.get_children():
        treeview.delete(row)
    for place in places:
        treeview.insert("", "end", values=(
            place['name'],
            f"{place['distance']:.2f}",
            place['address']
        ))

def search_places():
    """
    Called when the Search button is pressed.
    Reads the input, queries data sources for restaurants and hotels,
    processes the data, and updates the GUI tables.
    """
    status_label.config(text="Searching...")
    search_button.config(state="disabled")
    try:
        # Validate and parse inputs.
        lat = float(lat_entry.get())
        lon = float(lon_entry.get())
        distance_km = float(distance_entry.get())
        radius_m = int(distance_km * 1000)  # Overpass API expects meters

        # Initialize our data source.
        data_source = OverpassSource()

        # Query for restaurants and hotels.
        restaurants = data_source.get_restaurants(lat, lon, radius_m)
        hotels = data_source.get_hotels(lat, lon, radius_m)

        # Compute distance from the input coordinate for each result.
        for place in restaurants:
            place['distance'] = haversine(lat, lon, place['lat'], place['lon'])
        for place in hotels:
            place['distance'] = haversine(lat, lon, place['lat'], place['lon'])

        # Sort by distance and select the top 20 results.
        restaurants = sorted(restaurants, key=lambda x: x['distance'])[:20]
        hotels = sorted(hotels, key=lambda x: x['distance'])[:20]

        # Update the tables in the GUI.
        update_table(restaurant_treeview, restaurants)
        update_table(hotel_treeview, hotels)
        status_label.config(text="Search complete.")
    except Exception as e:
        messagebox.showerror("Error", str(e))
        status_label.config(text="Error during search.")
    finally:
        search_button.config(state="normal")

# =============================================================================
# Build the GUI
# =============================================================================
root = tk.Tk()
root.title("Nearby Places Finder")

# --- Input Frame ---
input_frame = ttk.Frame(root, padding="10")
input_frame.pack(pady=10, padx=10, fill="x")

ttk.Label(input_frame, text="Latitude:").grid(row=0, column=0, sticky="e", padx=5, pady=5)
lat_entry = ttk.Entry(input_frame, width=20)
lat_entry.grid(row=0, column=1, padx=5, pady=5)

ttk.Label(input_frame, text="Longitude:").grid(row=1, column=0, sticky="e", padx=5, pady=5)
lon_entry = ttk.Entry(input_frame, width=20)
lon_entry.grid(row=1, column=1, padx=5, pady=5)

ttk.Label(input_frame, text="Distance (km):").grid(row=2, column=0, sticky="e", padx=5, pady=5)
distance_entry = ttk.Entry(input_frame, width=20)
distance_entry.grid(row=2, column=1, padx=5, pady=5)

search_button = ttk.Button(input_frame, text="Search", command=search_places)
search_button.grid(row=3, column=0, columnspan=2, pady=10)

# --- Status Label ---
status_label = ttk.Label(root, text="Ready", relief="sunken", anchor="w")
status_label.pack(fill="x", padx=10, pady=(0, 10))

# --- Results Frame (Two Tables) ---
results_frame = ttk.Frame(root, padding="10")
results_frame.pack(padx=10, pady=10, fill="both", expand=True)

# Frame for Restaurants
restaurants_frame = ttk.Labelframe(results_frame, text="Restaurants", padding="5")
restaurants_frame.pack(side="left", fill="both", expand=True, padx=5)

restaurant_treeview = ttk.Treeview(
    restaurants_frame,
    columns=("Name", "Distance (km)", "Address"),
    show="headings",
    selectmode="browse"
)
restaurant_treeview.heading("Name", text="Name")
restaurant_treeview.heading("Distance (km)", text="Distance (km)")
restaurant_treeview.heading("Address", text="Address")
restaurant_treeview.column("Name", width=150)
restaurant_treeview.column("Distance (km)", width=100, anchor="center")
restaurant_treeview.column("Address", width=200)
restaurant_treeview.pack(fill="both", expand=True, side="left")

# Vertical scrollbar for restaurants table.
restaurant_scrollbar = ttk.Scrollbar(restaurants_frame, orient="vertical", command=restaurant_treeview.yview)
restaurant_treeview.configure(yscrollcommand=restaurant_scrollbar.set)
restaurant_scrollbar.pack(side="right", fill="y")

# Frame for Hotels
hotels_frame = ttk.Labelframe(results_frame, text="Hotels", padding="5")
hotels_frame.pack(side="right", fill="both", expand=True, padx=5)

hotel_treeview = ttk.Treeview(
    hotels_frame,
    columns=("Name", "Distance (km)", "Address"),
    show="headings",
    selectmode="browse"
)
hotel_treeview.heading("Name", text="Name")
hotel_treeview.heading("Distance (km)", text="Distance (km)")
hotel_treeview.heading("Address", text="Address")
hotel_treeview.column("Name", width=150)
hotel_treeview.column("Distance (km)", width=100, anchor="center")
hotel_treeview.column("Address", width=200)
hotel_treeview.pack(fill="both", expand=True, side="left")

# Vertical scrollbar for hotels table.
hotel_scrollbar = ttk.Scrollbar(hotels_frame, orient="vertical", command=hotel_treeview.yview)
hotel_treeview.configure(yscrollcommand=hotel_scrollbar.set)
hotel_scrollbar.pack(side="right", fill="y")

# =============================================================================
# Start the GUI event loop.
# =============================================================================
if __name__ == "__main__":
    root.mainloop()