import asyncio
import os
import time
import signal
import sys
from datetime import datetime
import traceback
import logging
import requests
import json
from typing import Optional, Dict, Any

from sqlalchemy.future import select
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.exc import SQLAlchemyError

from app.database import AsyncSessionLocal, init_db, close_db
from app.models import VideoUpload
from app.utils import pdf, s3

# Setup logging with UTF-8 encoding for Windows compatibility
logging.basicConfig(
    level=logging.INFO,
    format='[%(asctime)s] %(levelname)s - %(name)s - %(message)s',
    handlers=[
        logging.StreamHandler(sys.stdout),
        logging.FileHandler('ollama_worker.log', encoding='utf-8')
    ]
)
logger = logging.getLogger("worker.ollama_daemon")

# Configuration
POLL_INTERVAL = int(os.getenv("OLLAMA_POLL_INTERVAL_SECONDS", "120"))  # 2 minutes default
MAX_VIDEOS_PER_CYCLE = int(os.getenv("OLLAMA_MAX_VIDEOS_PER_CYCLE", "1"))
OLLAMA_BASE_URL = os.getenv("OLLAMA_BASE_URL", "http://localhost:11434")
OLLAMA_MODEL = os.getenv("OLLAMA_MODEL", "llama3.2:latest")
OLLAMA_WHISPER_MODEL = os.getenv("OLLAMA_WHISPER_MODEL", "whisper:latest")

SHUTDOWN_EVENT = asyncio.Event()

# Global backoff state
_recent_error = False
_error_count = 0
MAX_ERRORS_BEFORE_BACKOFF = 3
BACKOFF_SECONDS = int(os.getenv("OLLAMA_BACKOFF_SECONDS", "300"))  # 5 minutes


def signal_handler(signum, frame):
    """Handle shutdown signals gracefully"""
    logger.info(f"Received signal {signum}, initiating graceful shutdown...")
    SHUTDOWN_EVENT.set()


async def check_ollama_health() -> bool:
    """Check if Ollama service is running and healthy"""
    try:
        response = requests.get(f"{OLLAMA_BASE_URL}/api/tags", timeout=10)
        if response.status_code == 200:
            models = response.json().get("models", [])
            logger.info(f"Ollama is healthy. Available models: {[m['name'] for m in models]}")
            return True
        else:
            logger.warning(f"Ollama health check failed: {response.status_code}")
            return False
    except Exception as e:
        logger.warning(f"Ollama health check failed: {e}")
        return False


async def transcribe_with_ollama(video_url: str) -> str:
    """Transcribe video using existing whisper setup as fallback"""
    try:
        logger.info(f"Starting transcription for video: {video_url}")
        
        # For now, use the existing whisper setup as fallback
        # since Ollama whisper model might not be available
        from app.utils.whisper_llm import analyze as basic_analyze
        from sqlalchemy.ext.asyncio import AsyncSession
        
        # Create a mock session for the analyze function
        async with AsyncSessionLocal() as session:
            # Use the existing whisper analysis but only get transcription
            transcription, _ = await basic_analyze(video_url, 0, session)
            logger.info(f"Transcription completed. Length: {len(transcription)} characters")
            return transcription
                
    except Exception as e:
        logger.error(f"Transcription error: {e}")
        return f"Transcription failed: {str(e)}"


async def summarize_with_ollama(text: str) -> str:
    """Summarize text using Ollama's LLM model"""
    try:
        logger.info(f"Starting Ollama summarization. Text length: {len(text)}")
        
        # Truncate very long text to avoid token limits
        max_chars = 8000  # Adjust based on your model's context length
        if len(text) > max_chars:
            text = text[:max_chars] + "..."
            logger.info(f"Text truncated to {max_chars} characters for summarization")
        
        prompt = f"""Please provide a comprehensive summary of the following text. 
        Focus on key points, main ideas, and important details. 
        Make it clear and well-structured.
        
        Text to summarize:
        {text}
        
        Summary:"""
        
        payload = {
            "model": OLLAMA_MODEL,
            "prompt": prompt,
            "stream": False,
            "options": {
                "temperature": 0.3,
                "top_p": 0.9,
                "max_tokens": 1000
            }
        }
        
        response = requests.post(
            f"{OLLAMA_BASE_URL}/api/generate",
            json=payload,
            timeout=120  # 2 minutes timeout
        )
        
        if response.status_code == 200:
            result = response.json()
            summary = result.get('response', '').strip()
            logger.info(f"Ollama summarization completed. Summary length: {len(summary)}")
            return summary
        else:
            logger.error(f"Ollama summarization failed: {response.status_code} - {response.text}")
            return f"Summarization failed - Ollama service error"
            
    except Exception as e:
        logger.error(f"Ollama summarization error: {e}")
        return f"Summarization failed: {str(e)}"


async def enhanced_analysis_with_ollama(transcription: str, summary: str) -> Dict[str, Any]:
    """Perform enhanced analysis using Ollama's LLM"""
    try:
        logger.info("Starting Ollama enhanced analysis")
        
        prompt = f"""Analyze this video content and provide detailed insights:

TRANSCRIPTION:
{transcription}

SUMMARY:
{summary}

Please provide:
1. Key topics and themes (as a list)
2. Sentiment analysis (positive/negative/neutral percentages)
3. Important insights and takeaways
4. Recommendations for the user
5. Context and implications

Format your response as a JSON object with these keys:
- topics: array of strings
- sentiment: object with positive, negative, neutral percentages
- insights: string
- recommendations: string
- context: string

Response:"""
        
        payload = {
            "model": OLLAMA_MODEL,
            "prompt": prompt,
            "stream": False,
            "options": {
                "temperature": 0.2,
                "top_p": 0.8,
                "max_tokens": 1500
            }
        }
        
        response = requests.post(
            f"{OLLAMA_BASE_URL}/api/generate",
            json=payload,
            timeout=180  # 3 minutes timeout
        )
        
        if response.status_code == 200:
            result = response.json()
            analysis_text = result.get('response', '').strip()
            
            # Try to parse JSON response
            try:
                # Extract JSON from response (in case there's extra text)
                start_idx = analysis_text.find('{')
                end_idx = analysis_text.rfind('}') + 1
                if start_idx != -1 and end_idx > start_idx:
                    json_str = analysis_text[start_idx:end_idx]
                    analysis = json.loads(json_str)
                else:
                    # Fallback if no JSON found
                    analysis = {
                        "topics": ["general"],
                        "sentiment": {"positive": 0.5, "negative": 0.2, "neutral": 0.3},
                        "insights": analysis_text[:500],
                        "recommendations": "Review the content for key insights",
                        "context": "Analysis completed using Ollama"
                    }
                
                logger.info("Ollama enhanced analysis completed successfully")
                return analysis
                
            except json.JSONDecodeError:
                logger.warning("Failed to parse JSON from Ollama response, using fallback")
                return {
                    "topics": ["general"],
                    "sentiment": {"positive": 0.5, "negative": 0.2, "neutral": 0.3},
                    "insights": analysis_text[:500],
                    "recommendations": "Review the content for key insights",
                    "context": "Analysis completed using Ollama (fallback format)"
                }
        else:
            logger.error(f"Ollama enhanced analysis failed: {response.status_code} - {response.text}")
            return None
            
    except Exception as e:
        logger.error(f"Ollama enhanced analysis error: {e}")
        return None


async def process_pending_videos():
    """Process all pending video uploads using Ollama"""
    global _recent_error, _error_count
    
    async with AsyncSessionLocal() as session:
        try:
            # Check Ollama health first
            if not await check_ollama_health():
                logger.warning("Ollama service is not available, skipping this cycle")
                _recent_error = True
                _error_count += 1
                return
            
            # Reset error count on successful health check
            _error_count = 0
            _recent_error = False
            
            # Query for pending videos
            result = await session.execute(
                select(VideoUpload).where(VideoUpload.status == "pending")
            )
            all_pending = result.scalars().all()
            pending_videos = all_pending[:MAX_VIDEOS_PER_CYCLE] if all_pending else []

            if not pending_videos:
                logger.info("No pending videos found")
                return

            logger.info(f"Found {len(pending_videos)} pending videos to process with Ollama")

            for video in pending_videos:
                if SHUTDOWN_EVENT.is_set():
                    logger.info("Shutdown requested, stopping video processing")
                    break

                logger.info(f"Processing video ID {video.id} for user {video.user_id} with Ollama")

                try:
                    # Update status to processing
                    video.status = "processing"
                    video.updated_at = datetime.utcnow()
                    await session.commit()

                    # Step 1: Transcribe with Ollama
                    transcription = await transcribe_with_ollama(video.video_url)
                    if not transcription or "failed" in transcription.lower():
                        raise Exception(f"Transcription failed: {transcription}")

                    # Step 2: Summarize with Ollama
                    summary = await summarize_with_ollama(transcription)
                    if not summary or "failed" in summary.lower():
                        logger.warning("Summarization failed, using transcription as summary")
                        summary = transcription[:1000] + "..." if len(transcription) > 1000 else transcription

                    # Step 3: Enhanced analysis with Ollama
                    enhanced_analysis = await enhanced_analysis_with_ollama(transcription, summary)
                    
                    # Step 4: Generate comprehensive report
                    if enhanced_analysis:
                        report = f"""# 📹 Video Analysis Report (Ollama Enhanced)

## 🎵 Audio Transcription
{transcription}

## 📝 Summary
{summary}

## 🤖 Enhanced Analysis (Ollama {OLLAMA_MODEL})
**Topics**: {', '.join(enhanced_analysis.get('topics', ['General']))}
**Sentiment**: {enhanced_analysis.get('sentiment', {})}
**Insights**: {enhanced_analysis.get('insights', 'No additional insights')}
**Recommendations**: {enhanced_analysis.get('recommendations', 'No specific recommendations')}
**Context**: {enhanced_analysis.get('context', 'Analysis completed')}

---
*Report generated using Ollama {OLLAMA_MODEL} running locally*
"""
                    else:
                        report = f"""# 📹 Video Analysis Report (Ollama Basic)

## 🎵 Audio Transcription
{transcription}

## 📝 Summary
{summary}

## 📊 Analysis Details
- **Processing Method**: Ollama Local Processing
- **Model**: {OLLAMA_MODEL}
- **Enhanced Features**: Basic analysis only

---
*Report generated using Ollama {OLLAMA_MODEL} running locally*
"""

                    logger.info(f"Ollama analysis completed for video {video.id}")

                except Exception as e:
                    logger.error(f"Ollama processing failed for video {video.id}: {e}")
                    logger.debug(traceback.format_exc())
                    
                    # Update status to failed
                    video.status = "failed"
                    video.updated_at = datetime.utcnow()
                    await session.commit()
                    _error_count += 1
                    continue

                try:
                    # Generate PDF
                    pdf_bytes = pdf.generate(transcription, summary)
                    logger.info(f"PDF generation completed for video {video.id}")
                except Exception as e:
                    logger.error(f"PDF generation failed for video {video.id}: {e}")
                    logger.debug(traceback.format_exc())
                    
                    video.status = "failed"
                    video.updated_at = datetime.utcnow()
                    await session.commit()
                    _error_count += 1
                    continue

                try:
                    # Upload to S3
                    pdf_key = f"pdfs/ollama_{video.id}.pdf"
                    pdf_url = s3.upload_pdf_bytes(pdf_bytes, pdf_key)
                    logger.info(f"S3 upload completed for video {video.id}")
                except Exception as e:
                    logger.error(f"Upload to S3 failed for video {video.id}: {e}")
                    logger.debug(traceback.format_exc())
                    
                    video.status = "failed"
                    video.updated_at = datetime.utcnow()
                    await session.commit()
                    _error_count += 1
                    continue

                try:
                    # Mark as completed
                    video.status = "completed"
                    video.pdf_url = pdf_url
                    video.updated_at = datetime.utcnow()
                    await session.commit()
                    logger.info(f"Successfully completed video {video.id} with Ollama")

                except SQLAlchemyError as e:
                    logger.error(f"DB commit failed for video {video.id}: {e}")
                    logger.debug(traceback.format_exc())
                    await session.rollback()
                    _error_count += 1

        except SQLAlchemyError as e:
            logger.error(f"Database error: {e}")
            logger.debug(traceback.format_exc())
            _error_count += 1
        except Exception as e:
            logger.error(f"Unexpected error in process_pending_videos: {e}")
            logger.debug(traceback.format_exc())
            _error_count += 1


async def run_worker():
    """Main worker loop"""
    logger.info("Ollama worker daemon started...")
    
    # Initialize database
    try:
        await init_db()
        logger.info("Database initialized successfully")
    except Exception as e:
        logger.error(f"Failed to initialize database: {e}")
        return

    cycle_count = 0
    while not SHUTDOWN_EVENT.is_set():
        cycle_count += 1
        logger.info(f"Ollama worker cycle {cycle_count} - Checking for pending videos...")
        
        try:
            await process_pending_videos()
        except Exception as e:
            logger.error(f"Worker loop error: {e}")
            logger.debug(traceback.format_exc())
        
        # Check if we need to back off due to errors
        global _recent_error, _error_count
        if _error_count >= MAX_ERRORS_BEFORE_BACKOFF:
            logger.warning(f"Too many errors ({_error_count}), backing off for {BACKOFF_SECONDS} seconds...")
            try:
                await asyncio.wait_for(SHUTDOWN_EVENT.wait(), timeout=BACKOFF_SECONDS)
            except asyncio.TimeoutError:
                pass
            _error_count = 0  # Reset error count after backoff

        # Wait for next cycle or shutdown
        try:
            await asyncio.wait_for(SHUTDOWN_EVENT.wait(), timeout=POLL_INTERVAL)
        except asyncio.TimeoutError:
            # Normal timeout, continue to next cycle
            pass
        except Exception as e:
            logger.error(f"Error in worker wait: {e}")
            break

    logger.info("Ollama worker loop stopped, cleaning up...")
    
    # Cleanup
    try:
        await close_db()
        logger.info("Database connections closed")
    except Exception as e:
        logger.error(f"Error during cleanup: {e}")


async def main():
    """Main entry point with signal handling"""
    # Setup signal handlers
    signal.signal(signal.SIGINT, signal_handler)
    signal.signal(signal.SIGTERM, signal_handler)
    
    try:
        await run_worker()
    except KeyboardInterrupt:
        logger.info("Keyboard interrupt received")
    except Exception as e:
        logger.error(f"Fatal error in main: {e}")
        logger.debug(traceback.format_exc())
    finally:
        logger.info("Ollama worker daemon shutdown complete")


if __name__ == "__main__":
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        logger.info("Ollama worker daemon interrupted by user")
    except Exception as e:
        logger.error(f"Fatal error: {e}")
        sys.exit(1)