"""
GambitFlow Bridge API - HuggingFace Space
Unified API gateway with Firebase analytics and rate limiting
"""

from flask import Flask, request, jsonify, Response
from flask_cors import CORS
import requests
import time
import os
from functools import wraps
import firebase_admin
from firebase_admin import credentials, db
import json

app = Flask(__name__)
CORS(app)

# ==================== FIREBASE SETUP ====================

def initialize_firebase():
    """Initialize Firebase Admin SDK"""
    try:
        # Load credentials from environment variable
        firebase_creds = os.getenv('FIREBASE_CREDENTIALS')
        if firebase_creds:
            cred_dict = json.loads(firebase_creds)
            cred = credentials.Certificate(cred_dict)
        else:
            # Fallback to service account file
            cred = credentials.Certificate('firebase-credentials.json')
        
        firebase_admin.initialize_app(cred, {
            'databaseURL': os.getenv('FIREBASE_DATABASE_URL', 'https://chess-web-78351-default-rtdb.asia-southeast1.firebasedatabase.app')
        })
        print("✅ Firebase initialized successfully")
    except Exception as e:
        print(f"⚠️ Firebase initialization failed: {e}")

# Initialize Firebase
initialize_firebase()

# ==================== MODEL CONFIGURATION ====================

MODELS = {
    'nano': {
        'name': 'Nexus-Nano',
        'endpoint': os.getenv('NANO_ENDPOINT', 'https://gambitflow-nexus-nano-inference-api.hf.space'),
        'timeout': 30
    },
    'core': {
        'name': 'Nexus-Core',
        'endpoint': os.getenv('CORE_ENDPOINT', 'https://gambitflow-nexus-core-inference-api.hf.space'),
        'timeout': 40
    },
    'base': {
        'name': 'Synapse-Base',
        'endpoint': os.getenv('BASE_ENDPOINT', 'https://gambitflow-synapse-base-inference-api.hf.space'),
        'timeout': 60
    }
}

# ==================== FIREBASE ANALYTICS ====================

def increment_stats(model_name, stat_type='moves'):
    """
    Increment statistics in Firebase
    stat_type: 'moves' or 'matches'
    """
    try:
        ref = db.reference('stats')
        
        # Increment total stats
        total_ref = ref.child('total').child(stat_type)
        current = total_ref.get() or 0
        total_ref.set(current + 1)
        
        # Increment model-specific stats
        model_ref = ref.child('models').child(model_name).child(stat_type)
        current = model_ref.get() or 0
        model_ref.set(current + 1)
        
        # Update last_updated timestamp
        ref.child('last_updated').set(int(time.time()))
        
    except Exception as e:
        print(f"Firebase stats update error: {e}")

def get_all_stats():
    """Get all statistics from Firebase"""
    try:
        ref = db.reference('stats')
        stats = ref.get() or {}
        
        if not stats:
            # Initialize default structure
            stats = {
                'total': {'moves': 0, 'matches': 0},
                'models': {
                    'nano': {'moves': 0, 'matches': 0},
                    'core': {'moves': 0, 'matches': 0},
                    'base': {'moves': 0, 'matches': 0}
                },
                'last_updated': int(time.time())
            }
            ref.set(stats)
        
        return stats
    except Exception as e:
        print(f"Firebase stats fetch error: {e}")
        return {
            'total': {'moves': 0, 'matches': 0},
            'models': {
                'nano': {'moves': 0, 'matches': 0},
                'core': {'moves': 0, 'matches': 0},
                'base': {'moves': 0, 'matches': 0}
            },
            'last_updated': int(time.time())
        }

# ==================== CACHE ====================

class SimpleCache:
    def __init__(self, ttl=300):
        self.cache = {}
        self.ttl = ttl
    
    def get(self, key):
        if key in self.cache:
            value, timestamp = self.cache[key]
            if time.time() - timestamp < self.ttl:
                return value
            del self.cache[key]
        return None
    
    def set(self, key, value):
        self.cache[key] = (value, time.time())
    
    def clear_old(self):
        current_time = time.time()
        expired = [k for k, (_, t) in self.cache.items() if current_time - t >= self.ttl]
        for k in expired:
            del self.cache[k]

cache = SimpleCache(ttl=300)

# ==================== ROUTES ====================

@app.route('/')
def index():
    """API documentation"""
    return jsonify({
        'name': 'GambitFlow Bridge API',
        'version': '1.0.0',
        'description': 'Unified gateway for all GambitFlow chess engines',
        'endpoints': {
            '/predict': 'POST - Get best move prediction',
            '/health': 'GET - Health check',
            '/stats': 'GET - Get usage statistics',
            '/models': 'GET - List available models'
        },
        'models': list(MODELS.keys())
    })

@app.route('/health')
def health():
    """Health check endpoint"""
    return jsonify({
        'status': 'healthy',
        'timestamp': int(time.time()),
        'models': len(MODELS),
        'cache_size': len(cache.cache)
    })

@app.route('/stats')
def get_stats():
    """Get usage statistics from Firebase"""
    stats = get_all_stats()
    return jsonify(stats)

@app.route('/models')
def list_models():
    """List all available models"""
    models_info = {}
    for key, config in MODELS.items():
        models_info[key] = {
            'name': config['name'],
            'endpoint': config['endpoint'],
            'timeout': config['timeout']
        }
    return jsonify({'models': models_info})

@app.route('/predict', methods=['POST'])
def predict():
    """
    Main prediction endpoint
    Forwards request to appropriate model and tracks statistics
    """
    try:
        data = request.get_json()
        
        if not data:
            return jsonify({'error': 'No data provided'}), 400
        
        # Extract parameters
        fen = data.get('fen')
        model = data.get('model', 'core')
        depth = data.get('depth', 5)
        time_limit = data.get('time_limit', 3000)
        track_stats = data.get('track_stats', True)  # Allow disabling stats tracking
        
        if not fen:
            return jsonify({'error': 'FEN position required'}), 400
        
        if model not in MODELS:
            return jsonify({'error': f'Invalid model: {model}'}), 400
        
        # Check cache
        cache_key = f"{model}:{fen}:{depth}:{time_limit}"
        cached = cache.get(cache_key)
        if cached:
            cached['from_cache'] = True
            if track_stats:
                increment_stats(model, 'moves')
            return jsonify(cached)
        
        # Forward to model API
        model_config = MODELS[model]
        endpoint = f"{model_config['endpoint']}/predict"
        
        response = requests.post(
            endpoint,
            json={
                'fen': fen,
                'depth': depth,
                'time_limit': time_limit
            },
            timeout=model_config['timeout']
        )
        
        if response.status_code == 200:
            result = response.json()
            
            # Cache the result
            cache.set(cache_key, result)
            
            # Track statistics in Firebase
            if track_stats:
                increment_stats(model, 'moves')
            
            result['from_cache'] = False
            result['model'] = model
            
            return jsonify(result)
        else:
            return jsonify({
                'error': 'Model API error',
                'status_code': response.status_code,
                'details': response.text
            }), response.status_code
    
    except requests.Timeout:
        return jsonify({'error': 'Request timeout'}), 504
    except Exception as e:
        return jsonify({'error': str(e)}), 500

@app.route('/match/start', methods=['POST'])
def start_match():
    """Track match start"""
    try:
        data = request.get_json()
        model = data.get('model', 'core')
        
        if model not in MODELS:
            return jsonify({'error': 'Invalid model'}), 400
        
        increment_stats(model, 'matches')
        
        return jsonify({
            'success': True,
            'model': model,
            'message': 'Match started'
        })
    except Exception as e:
        return jsonify({'error': str(e)}), 500

@app.route('/batch', methods=['POST'])
def batch_predict():
    """
    Batch prediction endpoint for multiple positions
    """
    try:
        data = request.get_json()
        positions = data.get('positions', [])
        model = data.get('model', 'core')
        
        if not positions:
            return jsonify({'error': 'No positions provided'}), 400
        
        if len(positions) > 10:
            return jsonify({'error': 'Maximum 10 positions per batch'}), 400
        
        results = []
        for pos in positions:
            fen = pos.get('fen')
            depth = pos.get('depth', 5)
            time_limit = pos.get('time_limit', 3000)
            
            # Make individual request
            pred_data = {
                'fen': fen,
                'model': model,
                'depth': depth,
                'time_limit': time_limit,
                'track_stats': False  # Don't track for batch
            }
            
            result = predict_single(pred_data)
            results.append(result)
        
        # Track batch as single operation
        increment_stats(model, 'moves')
        
        return jsonify({
            'success': True,
            'count': len(results),
            'results': results
        })
    
    except Exception as e:
        return jsonify({'error': str(e)}), 500

def predict_single(data):
    """Helper function for single prediction"""
    try:
        fen = data.get('fen')
        model = data.get('model', 'core')
        depth = data.get('depth', 5)
        time_limit = data.get('time_limit', 3000)
        
        model_config = MODELS[model]
        endpoint = f"{model_config['endpoint']}/predict"
        
        response = requests.post(
            endpoint,
            json={
                'fen': fen,
                'depth': depth,
                'time_limit': time_limit
            },
            timeout=model_config['timeout']
        )
        
        if response.status_code == 200:
            return response.json()
        else:
            return {'error': 'Prediction failed'}
    except:
        return {'error': 'Request failed'}

# ==================== CLEANUP ====================

@app.before_request
def before_request():
    """Clean old cache entries before each request"""
    cache.clear_old()

# ==================== RUN ====================

if __name__ == '__main__':
    port = int(os.getenv('PORT', 7860))
    app.run(host='0.0.0.0', port=port, debug=False)