"""
Personalization API routes for Munich News Daily.
Provides endpoints to test and preview personalized content.
"""

from flask import Blueprint, request, jsonify
from datetime import datetime, timedelta
from database import articles_collection
from services.personalization_service import (
    rank_articles_for_user,
    select_personalized_articles,
    get_personalization_explanation,
    get_personalization_stats
)

personalization_bp = Blueprint('personalization', __name__)


@personalization_bp.route('/api/personalize/preview/<email>', methods=['GET'])
def preview_personalized_newsletter(email):
    """
    Preview personalized newsletter for a user.
    
    Query parameters:
        max_articles: Maximum articles to return (default: 10)
        hours_lookback: Hours of articles to consider (default: 24)
        
    Returns:
        JSON with personalized article selection and statistics
    """
    try:
        max_articles = request.args.get('max_articles', 10, type=int)
        hours_lookback = request.args.get('hours_lookback', 24, type=int)
        
        # Get recent articles
        cutoff_date = datetime.utcnow() - timedelta(hours=hours_lookback)
        articles = list(articles_collection.find({
            'created_at': {'$gte': cutoff_date},
            'summary': {'$exists': True, '$ne': None}
        }).sort('created_at', -1))

        
        # Select personalized articles
        personalized = select_personalized_articles(
            articles,
            email,
            max_articles=max_articles
        )
        
        # Get statistics
        stats = get_personalization_stats(personalized, email)
        
        # Format response
        articles_response = []
        for article in personalized:
            articles_response.append({
                'title': article.get('title', ''),
                'title_en': article.get('title_en'),
                'summary': article.get('summary', ''),
                'link': article.get('link', ''),
                'category': article.get('category', 'general'),
                'keywords': article.get('keywords', []),
                'personalization_score': article.get('personalization_score', 0.0),
                'published_at': article.get('published_at', '')
            })
        
        return jsonify({
            'success': True,
            'email': email,
            'articles': articles_response,
            'statistics': stats
        }), 200
        
    except Exception as e:
        return jsonify({
            'success': False,
            'error': str(e)
        }), 500


@personalization_bp.route('/api/personalize/explain', methods=['POST'])
def explain_recommendation():
    """
    Explain why an article was recommended to a user.
    
    Request body:
        {
            "email": "user@example.com",
            "article_id": "article-id-here"
        }
        
    Returns:
        JSON with explanation of recommendation
    """
    try:
        data = request.get_json()
        
        if not data or 'email' not in data or 'article_id' not in data:
            return jsonify({
                'success': False,
                'error': 'email and article_id required'
            }), 400
        
        email = data['email']
        article_id = data['article_id']
        
        # Get article
        from bson import ObjectId
        article = articles_collection.find_one({'_id': ObjectId(article_id)})
        
        if not article:
            return jsonify({
                'success': False,
                'error': 'Article not found'
            }), 404
        
        # Get user interests
        from services.interest_profiling_service import get_user_interests
        user_interests = get_user_interests(email)
        
        # Generate explanation
        explanation = get_personalization_explanation(article, user_interests)
        
        return jsonify({
            'success': True,
            'email': email,
            'article_title': article.get('title', ''),
            'explanation': explanation
        }), 200
        
    except Exception as e:
        return jsonify({
            'success': False,
            'error': str(e)
        }), 500