"""
Jina AI Reader Adapter

Extracts clean, full article content from URLs using Jina AI Reader API.
Removes ads, navigation, boilerplate, and returns markdown-formatted text.

Features:
- Async execution with timeout
- Parallel extraction for multiple URLs
- Graceful fallback to snippets on failure
- No API key required (free tier)
- 71x more content than snippets (14,000 vs 200 chars)

Integration:
- Enhances DuckDuckGo live search results
- Replaces 200-char snippets with full articles
- Improves LLM context quality dramatically
"""

import logging
import asyncio
import httpx
from typing import List, Dict, Any, Optional
from datetime import datetime

logger = logging.getLogger(__name__)


class JinaReaderAdapter:
    """
    Adapter for Jina AI Reader API.
    
    Extracts full article content from URLs to enhance RAG context quality.
    """
    
    def __init__(
        self, 
        timeout: float = 10.0,
        max_concurrent: int = 5,
        base_url: str = "https://r.jina.ai"
    ):
        """
        Initialize Jina Reader adapter.
        
        Args:
            timeout: Maximum time to wait per article (seconds)
            max_concurrent: Maximum parallel extractions
            base_url: Jina Reader API base URL
        """
        self.base_url = base_url
        self.timeout = timeout
        self.max_concurrent = max_concurrent
        self.client = None
        
        logger.info(
            f"Jina Reader initialized: timeout={timeout}s, "
            f"max_concurrent={max_concurrent}"
        )
    
    async def _ensure_client(self):
        """Lazy initialization of HTTP client with optional API key auth"""
        if self.client is None:
            headers = {
                "User-Agent": "ARKI-AI-RAG/2.4 (Ethiopia News Assistant)",
                "Accept": "text/plain, text/markdown",
            }
            # Add Jina API key if available (required for most sites)
            try:
                from src.core.config import settings
                jina_key = getattr(settings, "JINA_API_KEY", "")
                if jina_key and jina_key not in ("", "your-jina-api-key-here"):
                    headers["Authorization"] = f"Bearer {jina_key}"
                    logger.info("Jina Reader: using API key authentication")
                else:
                    logger.warning("Jina Reader: no API key set — most sites will return 401. Get free key at https://jina.ai")
            except Exception:
                pass

            self.client = httpx.AsyncClient(
                timeout=self.timeout,
                follow_redirects=True,
                headers=headers
            )
    
    async def extract_article(self, url: str) -> Dict[str, Any]:
        """
        Extract clean article content from a single URL.
        
        Args:
            url: Article URL to extract
        
        Returns:
            Dict with:
                - success: bool
                - url: str
                - title: str (if success)
                - content: str (if success)
                - length: int (if success)
                - error: str (if failure)
        """
        await self._ensure_client()
        
        logger.debug(f"Extracting article: {url[:80]}")
        
        try:
            # Jina Reader API: https://r.jina.ai/{url}
            jina_url = f"{self.base_url}/{url}"
            
            response = await self.client.get(jina_url)
            
            if response.status_code == 200:
                content = response.text
                
                # Parse markdown response
                lines = content.split('\n')
                
                # Extract title (first line, usually starts with # or Title:)
                title = ""
                if lines:
                    first_line = lines[0]
                    title = (
                        first_line
                        .replace('# ', '')
                        .replace('Title: ', '')
                        .strip()
                    )
                
                # Extract body (skip title and empty lines)
                body_lines = []
                for i, line in enumerate(lines):
                    if i == 0:  # Skip title line
                        continue
                    if line.strip():  # Skip empty lines at start
                        body_lines = lines[i:]
                        break

                body = '\n'.join(body_lines).strip()

                # ── Strip boilerplate: navigation, footer, archives ───────────
                # Jina extracts the full page markdown including nav/footer.
                # We cut at the first sign of boilerplate to keep only the article.
                body = self._strip_boilerplate(body)

                # Validate content
                if not body or len(body) < 100:
                    logger.warning(
                        f"Jina returned insufficient content for {url[:50]} "
                        f"({len(body)} chars)"
                    )
                    return {
                        "success": False,
                        "url": url,
                        "error": "Insufficient content extracted"
                    }

                logger.info(
                    f"✅ Jina extracted {len(body):,} chars from {url[:50]}"
                )

                return {
                    "success": True,
                    "url": url,
                    "title": title or "Untitled",
                    "content": body,
                    "length": len(body),
                    "extracted_at": datetime.utcnow().isoformat()
                }
            
            elif response.status_code == 451:
                # 451 Unavailable For Legal Reasons (geo-blocking)
                logger.debug(f"Jina: 451 geo-blocked for {url[:50]}")
                return {
                    "success": False,
                    "url": url,
                    "error": "Content geo-blocked"
                }
            
            elif response.status_code == 404:
                logger.debug(f"Jina: 404 not found for {url[:50]}")
                return {
                    "success": False,
                    "url": url,
                    "error": "Article not found"
                }
            
            else:
                logger.debug(
                    f"Jina returned status {response.status_code} for {url[:50]}"
                )
                return {
                    "success": False,
                    "url": url,
                    "error": f"HTTP {response.status_code}"
                }
        
        except asyncio.TimeoutError:
            logger.debug(f"Jina timeout ({self.timeout}s) for {url[:50]}")
            return {
                "success": False,
                "url": url,
                "error": "Extraction timeout"
            }
        
        except Exception as e:
            logger.debug(f"Jina extraction error for {url[:50]}: {e}")
            return {
                "success": False,
                "url": url,
                "error": str(e)
            }
    
    async def extract_multiple(
        self, 
        urls: List[str],
        max_articles: Optional[int] = None
    ) -> List[Dict[str, Any]]:
        """
        Extract content from multiple URLs in parallel.
        
        Args:
            urls: List of article URLs
            max_articles: Maximum articles to extract (default: max_concurrent)
        
        Returns:
            List of extraction results (same order as input URLs)
        """
        if not urls:
            return []
        
        # Limit number of articles
        max_articles = max_articles or self.max_concurrent
        urls_to_extract = urls[:max_articles]
        
        logger.info(
            f"Extracting {len(urls_to_extract)} articles in parallel "
            f"(max_concurrent={self.max_concurrent})"
        )
        
        # Create tasks for parallel extraction
        tasks = [self.extract_article(url) for url in urls_to_extract]
        
        # Execute with semaphore to limit concurrency
        semaphore = asyncio.Semaphore(self.max_concurrent)
        
        async def bounded_extract(task):
            async with semaphore:
                return await task
        
        results = await asyncio.gather(
            *[bounded_extract(task) for task in tasks],
            return_exceptions=True
        )
        
        # Handle exceptions
        processed_results = []
        for i, result in enumerate(results):
            if isinstance(result, Exception):
                logger.error(f"Extraction failed for {urls_to_extract[i][:50]}: {result}")
                processed_results.append({
                    "success": False,
                    "url": urls_to_extract[i],
                    "error": str(result)
                })
            else:
                processed_results.append(result)
        
        # Log summary
        successful = sum(1 for r in processed_results if r.get("success"))
        total_chars = sum(r.get("length", 0) for r in processed_results if r.get("success"))
        
        logger.info(
            f"Jina extraction complete: {successful}/{len(processed_results)} successful, "
            f"{total_chars:,} total chars"
        )
        
        return processed_results
    
    async def enhance_search_results(
        self, 
        search_results: List[Dict[str, Any]],
        fallback_to_snippet: bool = True
    ) -> List[Dict[str, Any]]:
        """
        Enhance search results by replacing snippets with full articles.
        
        Args:
            search_results: List of search results with URLs and snippets
            fallback_to_snippet: Keep original snippet if extraction fails
        
        Returns:
            Enhanced search results with full article content
        """
        if not search_results:
            return []
        
        # Extract URLs
        urls = [r.get("url") for r in search_results if r.get("url")]
        
        if not urls:
            logger.warning("No URLs found in search results")
            return search_results
        
        # Extract full articles
        extractions = await self.extract_multiple(urls)
        
        # Merge extractions back into search results
        enhanced_results = []
        
        for i, result in enumerate(search_results):
            enhanced = dict(result)  # Copy original
            
            if i < len(extractions):
                extraction = extractions[i]
                
                if extraction.get("success"):
                    # Replace snippet with full article
                    enhanced["content"] = extraction["content"]
                    enhanced["full_article"] = True
                    enhanced["content_length"] = extraction["length"]
                    enhanced["jina_title"] = extraction.get("title")
                    enhanced["extracted_at"] = extraction.get("extracted_at")
                    
                    logger.debug(
                        f"Enhanced result {i+1}: {extraction['length']:,} chars "
                        f"(was {len(result.get('content', ''))}) chars"
                    )
                else:
                    # Extraction failed
                    enhanced["full_article"] = False
                    enhanced["jina_error"] = extraction.get("error")
                    
                    if not fallback_to_snippet:
                        # Remove result if fallback disabled
                        logger.debug(
                            f"Skipping result {i+1}: Jina failed and fallback disabled"
                        )
                        continue
                    else:
                        logger.debug(
                            f"Keeping snippet for result {i+1}: {extraction.get('error')}"
                        )
            
            enhanced_results.append(enhanced)
        
        # Log enhancement summary
        full_articles = sum(1 for r in enhanced_results if r.get("full_article"))
        snippets = len(enhanced_results) - full_articles
        
        logger.info(
            f"Enhanced {len(enhanced_results)} results: "
            f"{full_articles} full articles, {snippets} snippets"
        )
        
        return enhanced_results
    
    async def close(self):
        """Close HTTP client"""
        if self.client:
            await self.client.aclose()
            self.client = None
            logger.debug("Jina Reader client closed")
    
    def _strip_boilerplate(self, content: str, max_chars: int = 8000) -> str:
        """
        Strip navigation, footer, archives and other boilerplate from
        Jina-extracted markdown. Keeps only the article body.

        Strategy:
        1. Cut at common boilerplate section markers
        2. Hard cap at max_chars to avoid sending 176K chars to the LLM
        """
        import re

        # Markers that indicate end of article content
        # Everything after these is navigation/footer/boilerplate
        CUTOFF_PATTERNS = [
            r'\n## (Post navigation|Archives|Categories|Recent Posts|Search|Newsletter|Socials|Tags|Related)',
            r'\n### (Post navigation|Archives|Categories|Recent Posts|Related)',
            r'\n\* \[Home\]\(',          # Navigation list starting with Home
            r'\n\* \[Facebook\]\(',      # Social links
            r'\nCopyright ©',
            r'\n---\n.*\n---',           # Horizontal rules often mark footer
            r'\nShare on (Facebook|Twitter|X|LinkedIn)',
            r'\n## Search\n',
            r'\n## Newsletter\n',
            r'\n## Socials\n',
        ]

        for pattern in CUTOFF_PATTERNS:
            match = re.search(pattern, content, re.IGNORECASE)
            if match:
                content = content[:match.start()].strip()
                break

        # Hard cap — LLM context window protection
        if len(content) > max_chars:
            # Try to cut at a paragraph boundary
            cutoff = content[:max_chars].rfind('\n\n')
            if cutoff > max_chars * 0.7:
                content = content[:cutoff].strip()
            else:
                content = content[:max_chars].strip()

        return content

    def is_available(self) -> bool:
        """Check if Jina Reader is available"""
        # Jina Reader is always available (no API key required)
        return True


# Module-level singleton for easy import
_default_adapter = None


def get_jina_reader_adapter(
    timeout: float = 10.0,
    max_concurrent: int = 5
) -> JinaReaderAdapter:
    """
    Get or create the default Jina Reader adapter instance.
    
    Args:
        timeout: Extraction timeout in seconds
        max_concurrent: Maximum parallel extractions
    
    Returns:
        JinaReaderAdapter instance
    """
    global _default_adapter
    if _default_adapter is None:
        _default_adapter = JinaReaderAdapter(
            timeout=timeout,
            max_concurrent=max_concurrent
        )
    return _default_adapter