"""
Clutch-IQ Auto Pipeline
-----------------------
This script continuously monitors the `data/demos` directory for new .dem files.
When a new file appears, it:
1. Waits for the file to be fully written (size stability check).
2. Calls `src/etl/extract_snapshots.py` to process it.
3. Deletes the source .dem file immediately after successful processing.

Usage:
    python src/etl/auto_pipeline.py
    
Stop:
    Press Ctrl+C to stop.
"""

import os
import time
import subprocess
import logging
import sys
import argparse

# Configuration
# Default to project demos folder, but can be overridden via CLI args
DEFAULT_WATCH_DIR = os.path.abspath("data/demos") 

# Target processing directory
OUTPUT_DIR = os.path.abspath("data/processed")

CHECK_INTERVAL = 5  # Check every 5 seconds
STABILITY_WAIT = 2  # Wait 2 seconds to check if file size changes
EXTRACT_SCRIPT = os.path.join(os.path.dirname(__file__), "extract_snapshots.py")

logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - [AutoPipeline] - %(message)s',
    handlers=[logging.StreamHandler(sys.stdout)]
)

def is_file_stable(filepath, wait_seconds=2):
    """Check if file size is constant over a short period (indicates download finished)."""
    try:
        size1 = os.path.getsize(filepath)
        time.sleep(wait_seconds)
        size2 = os.path.getsize(filepath)
        return size1 == size2 and size1 > 0
    except OSError:
        return False

def process_file(filepath):
    """Run extraction script on a single file."""
    logging.info(f"Processing new file: {filepath}")
    
    # We use subprocess to isolate memory usage and ensure clean state per file
    cmd = [
        sys.executable, 
        EXTRACT_SCRIPT,
        "--demo_dir", os.path.dirname(filepath), # Temporarily point to where the file is
        "--output_dir", OUTPUT_DIR,
        "--delete-source" # Critical flag!
    ]
    
    try:
        # Note: extract_snapshots.py currently scans the whole dir.
        # This is inefficient if we monitor a busy Downloads folder.
        # Ideally we should pass the specific file path.
        # But for now, since we only care about .dem files and we delete them, it's okay.
        # However, to avoid processing other .dem files in Downloads that user might want to keep,
        # we should probably move it to a temp folder first?
        # Or better: Update extract_snapshots.py to accept a single file.
        
        # For safety in "Downloads" folder scenario:
        # 1. Move file to data/demos (staging area)
        # 2. Process it there
        
        staging_dir = os.path.abspath("data/demos")
        if not os.path.exists(staging_dir):
            os.makedirs(staging_dir)
            
        filename = os.path.basename(filepath)
        staged_path = os.path.join(staging_dir, filename)
        
        # If we are already in data/demos, no need to move
        if os.path.dirname(filepath) != staging_dir:
            logging.info(f"Moving {filename} to staging area...")
            try:
                os.rename(filepath, staged_path)
            except OSError as e:
                logging.error(f"Failed to move file: {e}")
                return
        else:
            staged_path = filepath

        # Now process from staging
        cmd = [
            sys.executable, 
            EXTRACT_SCRIPT,
            "--demo_dir", staging_dir,
            "--output_dir", OUTPUT_DIR,
            "--delete-source"
        ]
        
        result = subprocess.run(cmd, capture_output=True, text=True)
        
        if result.returncode == 0:
            logging.info(f"Successfully processed batch.")
            logging.info(result.stdout)
        else:
            logging.error(f"Processing failed with code {result.returncode}")
            logging.error(result.stderr)
            
    except Exception as e:
        logging.error(f"Execution error: {e}")

import threading

def monitor_loop(monitor_dir, stop_event=None):
    """Core monitoring loop that can be run in a separate thread."""
    logging.info(f"Monitoring {monitor_dir} for new .dem files...")
    logging.info("Files will be MOVED to staging, PROCESSED, and then DELETED.")
    
    while True:
        if stop_event and stop_event.is_set():
            logging.info("Stopping Auto Pipeline thread...")
            break
            
        # List .dem files
        try:
            if not os.path.exists(monitor_dir):
                # Try to create it if it doesn't exist
                try:
                    os.makedirs(monitor_dir)
                except OSError:
                    pass
                    
            if os.path.exists(monitor_dir):
                files = [f for f in os.listdir(monitor_dir) if f.endswith('.dem')]
            else:
                files = []
                
        except Exception as e:
            logging.error(f"Error accessing watch directory: {e}")
            time.sleep(CHECK_INTERVAL)
            continue
        
        if files:
            logging.info(f"Found {len(files)} files pending in {monitor_dir}...")
            
            # Sort by creation time (process oldest first)
            files.sort(key=lambda x: os.path.getctime(os.path.join(monitor_dir, x)))
            
            for f in files:
                filepath = os.path.join(monitor_dir, f)
                
                if not os.path.exists(filepath):
                    continue 
                    
                if is_file_stable(filepath, STABILITY_WAIT):
                    process_file(filepath)
                else:
                    logging.info(f"File {f} is still being written... skipping.")
        
        time.sleep(CHECK_INTERVAL)

def start_background_monitor(watch_dir=DEFAULT_WATCH_DIR):
    """Start the monitor in a background thread."""
    monitor_thread = threading.Thread(target=monitor_loop, args=(watch_dir,), daemon=True)
    monitor_thread.start()
    logging.info("Auto Pipeline service started in background.")
    return monitor_thread

def main():
    parser = argparse.ArgumentParser(description="Auto Pipeline Monitor")
    parser.add_argument("--watch-dir", default=DEFAULT_WATCH_DIR, help="Directory to monitor for .dem files (e.g. C:/Users/Name/Downloads)")
    args = parser.parse_args()
    
    monitor_dir = os.path.abspath(args.watch_dir)
    
    if not os.path.exists(monitor_dir):
        logging.warning(f"Watch directory {monitor_dir} does not exist. Creating it...")
        os.makedirs(monitor_dir)
        
    try:
        monitor_loop(monitor_dir)
    except KeyboardInterrupt:
        logging.info("Stopping Auto Pipeline...")

if __name__ == "__main__":
    main()