"""Reddit data scraping using Selenium for page-based scraping with old.reddit.com."""

import time
from typing import Optional, Dict, Any, List
from selenium import webdriver
from selenium.webdriver.firefox.options import Options
from selenium.webdriver.firefox.service import Service


class RedditScraper:
    """Scrapes OLD Reddit pages (old.reddit.com) using a headless Firefox browser."""

    def __init__(self):
        self.driver = None
        self._initialized = False

    def _ensure_browser(self):
        """Ensure Firefox is running in headless mode."""
        if not self._initialized:
            options = Options()
            options.add_argument('--headless')
            options.set_preference('dom.webdriver.enabled', False)
            
            # Custom user agent to appear more human-like
            options.set_preference('general.useragent.override', 
                'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36')
            
            # Use geckodriver from snap
            service = Service(executable_path='/snap/bin/geckodriver')
            self.driver = webdriver.Firefox(service=service, options=options)
            
            # Anti-detection scripts
            self.driver.execute_script("Object.defineProperty(navigator, 'webdriver', { value: false })")
            self._initialized = True

    def scrape_subreddit_top(
        self,
        subreddit: str,
        limit: int = 10,
        time_range: str = "week",
        depth: int = 3,
        include_comments: bool = True
    ) -> Dict[str, Any]:
        """
        Scrape top posts from a subreddit using Selenium on old.reddit.com.

        Args:
            subreddit: Name of the subreddit (without 'r/')
            limit: Number of top posts to retrieve
            time_range: Time filter ('hour', 'day', 'week', 'month', 'year', 'all')
            depth: Maximum comment nesting depth
            include_comments: Whether to scrape comments

        Returns:
            Dict containing scraped data or error information
        """
        self._ensure_browser()

        try:
            # Navigate to OLD Reddit for cleaner DOM structure
            url = f"https://old.reddit.com/r/{subreddit}/top/?t={time_range}"
            self.driver.get(url)
            
            # Wait for content to load
            time.sleep(4)

            # Extract post data using old.reddit.com specific selectors (tested and working!)
            posts_data = self.driver.execute_script('''
                const posts = [];
                
                const postElements = document.querySelectorAll('.thing');
                
                for (const el of Array.from(postElements)) {
                    if (posts.length >= 10) break;
                    
                    // Title link
                    const titleLink = el.querySelector('a.title.may-blank');
                    if (!titleLink) continue;
                    
                    const title = titleLink.textContent.trim();
                    
                    // Skip ads and very short titles  
                    if (title.length < 3 || 
                        title.includes('Microsoft') || 
                        title.startsWith('r/')) continue;
                    
                    // Score
                    let score = 0;
                    try {
                        const scoreEl = el.querySelector('.score.unvoted');
                        if (scoreEl) {
                            score = parseInt(scoreEl.textContent.replace(/[^0-9]/g, '')) || 0;
                        }
                    } catch(e) {}
                    
                    // Author - try multiple selector patterns
                    let author = null;
                    try {
                        const authorLink = el.querySelector('.midcol .author, .author');
                        if (authorLink && authorLink.textContent.trim()) {
                            author = authorLink.textContent.trim();
                        }
                    } catch(e) {}
                    
                    // URL - clean tracking params
                    let url = titleLink.href || '';
                    try {
                        const cleanUrl = new URL(url);
                        ['utm_source', 'utm_medium', 'utm_campaign'].forEach(param => {
                            cleanUrl.searchParams.delete(param);
                        });
                        url = cleanUrl.toString();
                    } catch(e) {}
                    
                    posts.push({
                        title: title,
                        author: author,
                        score: score,
                        url: url
                    });
                }
                
                return posts;
            ''')

            # Build result structure
            posts = []
            for post in posts_data:
                post_obj = {
                    "title": post['title'],
                    "author": post['author'] or None,
                    "score": post['score'],
                    "created_utc": None,  # Not easily accessible via DOM scraping
                    "url": post['url'].replace('old.reddit.com', 'www.reddit.com'),
                    "permalink": post['url'].replace('https://old.reddit.com', ''),
                    "comments": [] if not include_comments else self._scrape_post_comments(post['url'])
                }
                posts.append(post_obj)

            return {
                "subreddit": subreddit,
                "time_range": time_range,
                "limit": len(posts),
                "posts_count": len(posts),
                "data": posts
            }

        except Exception as e:
            import traceback
            print(f"Error during scraping: {e}")
            print(traceback.format_exc())
            return {"Error": f"Unexpected error during scraping: {str(e)}"}

    def _scrape_post_comments(self, post_url: str) -> List[Dict[str, Any]]:
        """Scrape comments from a specific post using Selenium."""
        try:
            self.driver.get(post_url)
            time.sleep(2)

            # Extract comments using old.reddit.com structure
            rawComments = self.driver.execute_script('''
                const comments = [];
                
                // On old Reddit, find comment containers
                const candidates = document.querySelectorAll('.usertext-body, .md, div.comment');
                
                for (const el of Array.from(candidates)) {
                    if (comments.length >= 10) break;
                    
                    const text = el.textContent.trim();
                    
                    // Skip empty or very short content, and UI elements  
                    const lowerText = text.toLowerCase();
                    if (!text || 
                        text.length < 20 ||
                        text.includes('open menu') ||
                        text.includes('reddit home')) continue;
                        
                    comments.push({
                        author: 'unknown',
                        body: text,
                        score: null,
                        created_utc: null
                    });
                }
                
                return comments.slice(0, 10);
            ''')

            # Clean up comment bodies
            for comment in rawComments:
                comment['body'] = self._clean_text(comment.get('body', ''))

            return rawComments[:10]  # Limit to 10 comments per post

        except Exception as e:
            print(f"Comment scraping error: {e}")
            import traceback
            traceback.print_exc()
            return []

    def _clean_text(self, text: str) -> str:
        """Clean and normalize text content."""
        if not text:
            return ""
        lines = text.split("\n")
        cleaned = [line.strip() for line in lines if line.strip()]
        return " ".join(cleaned)

    def close(self):
        """Close browser resources."""
        if self._initialized and self.driver:
            try:
                self.driver.quit()
            except:
                pass
            self._initialized = False


# Singleton pattern for scraper instance
_scraper_instance = None

def get_scraper():
    """Get singleton scraper instance."""
    global _scraper_instance
    if _scraper_instance is None:
        _scraper_instance = RedditScraper()
    return _scraper_instance