import streamlit as st
import googlemaps
import math
import os
from streamlit_js_eval import get_geolocation

# --- CONFIGURATION ---
# Pulling the key securely from Hugging Face Secrets
MAPS_API_KEY = os.environ.get("MAPS_API_KEY")

if not MAPS_API_KEY:
    st.error("⚠️ MAPS_API_KEY not found. Please add it to your Hugging Face Secrets.")
    st.stop()

gmaps = googlemaps.Client(key=MAPS_API_KEY)

def calculate_haversine(lat1, lon1, lat2, lon2):
    """Calculates the straight-line distance in km."""
    R = 6371.0
    dlat, dlon = math.radians(lat2 - lat1), math.radians(lon2 - lon1)
    a = math.sin(dlat / 2)**2 + math.cos(math.radians(lat1)) * \
        math.cos(math.radians(lat2)) * math.sin(dlon / 2)**2
    return R * 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))

# --- APP UI ---
st.set_page_config(page_title="Pharmacy Finder", page_icon="🏥")
st.title("🏥 Real-Time Pharmacy Locator")

# 1. Get User Location Automatically via Browser
loc = get_geolocation()

if loc:
    user_lat = loc['coords']['latitude']
    user_lng = loc['coords']['longitude']
    st.success(f"📍 Location detected: {user_lat}, {user_lng}")

    query = st.text_input("Which pharmacy are you looking for?", placeholder="e.g. Apollo Pharmacy")

    if query:
        try:
            # 2. Live Search via Google Places API
            # We search specifically 'nearby' the user's coordinates
            places_result = gmaps.places(query=query, location=(user_lat, user_lng))['results']
            
            if places_result:
                # 3. Process and Rank Top 5
                found_pharmacies = []
                for place in places_result[:5]:
                    p_lat = place['geometry']['location']['lat']
                    p_lng = place['geometry']['location']['lng']
                    
                    # Using our math tool to get the distance
                    dist = calculate_haversine(user_lat, user_lng, p_lat, p_lng)
                    
                    found_pharmacies.append({
                        "name": place['name'],
                        "address": place.get('formatted_address', 'No address provided'),
                        "distance": round(dist, 2),
                        "lat": p_lat,
                        "lng": p_lng
                    })

                # Sort results: closest first
                found_pharmacies.sort(key=lambda x: x['distance'])

                # 4. Display as Expandable Cards
                st.subheader(f"Top {len(found_pharmacies)} Results:")
                
                for p in found_pharmacies:
                    with st.expander(f"🏥 {p['name']} — {p['distance']} km away"):
                        st.write(f"**Address:** {p['address']}")
                        st.write(f"**Coordinates:** {p['lat']}, {p['lng']}")
                        
                        # Universal Navigation Link (Works on iOS, Android, and Desktop)
                        nav_url = f"https://www.google.com/maps/dir/?api=1&destination={p['lat']},{p['lng']}"
                        st.link_button("🚀 Open in Navigation", nav_url)
            else:
                st.warning("No pharmacies found for that name nearby.")
        
        except Exception as e:
            st.error(f"An error occurred: {e}")
else:
    st.info("Please allow location access in your browser to find pharmacies near you.")