"""
Free geolocation module using OpenStreetMap Nominatim API.
Converts place names to coordinates. No API key required.
Works offline with a fallback dictionary of Indian cities.
"""
import requests
import json
import os

# Offline fallback: major Indian cities + water bodies
OFFLINE_LOCATIONS = {
    'silchar': (24.81, 92.80),
    'guwahati': (26.14, 91.74),
    'delhi': (28.61, 77.23),
    'mumbai': (19.08, 72.88),
    'chennai': (13.08, 80.27),
    'kolkata': (22.57, 88.36),
    'bengaluru': (12.97, 77.59),
    'varanasi': (25.32, 83.01),
    'haridwar': (29.95, 78.16),
    'rishikesh': (30.09, 78.27),
    'srinagar': (34.08, 74.80),
    'dal lake': (34.11, 74.86),
    'barak river': (24.80, 92.82),
    'ganga river varanasi': (25.30, 83.01),
    'yamuna river delhi': (28.66, 77.23),
    'brahmaputra guwahati': (26.18, 91.75),
    'chilika lake': (19.72, 85.31),
    'loktak lake': (24.55, 93.83),
    'vembanad lake': (9.58, 76.42),
}

def search_location(query: str) -> dict:
    """
    Search for a location by name.
    Returns {'name': str, 'lat': float, 'lon': float, 'source': str} or {'error': str}
    """
    query = query.strip().lower()
    
    # Check offline cache first
    if query in OFFLINE_LOCATIONS:
        lat, lon = OFFLINE_LOCATIONS[query]
        return {'name': query.title(), 'lat': lat, 'lon': lon, 'source': 'offline_cache'}
    
    # Partial match in offline cache
    for key, (lat, lon) in OFFLINE_LOCATIONS.items():
        if query in key or key in query:
            return {'name': key.title(), 'lat': lat, 'lon': lon, 'source': 'offline_partial_match'}
    
    # Try OpenStreetMap Nominatim (free, no key needed)
    try:
        url = 'https://nominatim.openstreetmap.org/search'
        params = {
            'q': query,
            'format': 'json',
            'limit': 3,
            'countrycodes': 'in'  # Bias toward India
        }
        headers = {'User-Agent': 'Divine-Earthly-Water-Guardian/1.0'}
        resp = requests.get(url, params=params, headers=headers, timeout=10)
        
        if resp.status_code == 200 and resp.json():
            results = resp.json()
            best = results[0]
            return {
                'name': best.get('display_name', query),
                'lat': float(best['lat']),
                'lon': float(best['lon']),
                'source': 'openstreetmap',
                'all_results': [
                    {'name': r['display_name'], 'lat': float(r['lat']), 'lon': float(r['lon'])}
                    for r in results[:3]
                ]
            }
    except Exception as e:
        pass
    
    return {'error': f'Location "{query}" not found. Try a nearby city or lat/lon manually.'}


if __name__ == '__main__':
    # Test
    for q in ['Silchar', 'Dal Lake', 'Varanasi Ganga', 'NonexistentPlace']:
        print(f'{q}:', search_location(q))