#!/usr/bin/env python3
"""
File Watcher
Monitors sheets_output/ directory and triggers CSV-to-JSON conversion on changes
"""

import time
import json
import subprocess
from pathlib import Path
from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

# Paths
BASE_DIR = Path(__file__).parent.parent
CONFIG_FILE = BASE_DIR / "config.json"
CONVERTER_SCRIPT = BASE_DIR / "scripts" / "csv_to_json.py"


class CSVChangeHandler(FileSystemEventHandler):
    """Handles CSV file changes"""
    
    def __init__(self, debounce_seconds=2):
        self.debounce_seconds = debounce_seconds
        self.last_modified = {}
        
    def on_modified(self, event):
        """Called when a file is modified"""
        if event.is_directory:
            return
        
        # Only process CSV files
        if not event.src_path.endswith('.csv'):
            return
        
        # Debounce: ignore rapid consecutive changes
        now = time.time()
        if event.src_path in self.last_modified:
            if now - self.last_modified[event.src_path] < self.debounce_seconds:
                return
        
        self.last_modified[event.src_path] = now
        
        print(f"\n📝 Detected change: {Path(event.src_path).name}")
        self.trigger_conversion()
    
    def on_created(self, event):
        """Called when a file is created"""
        if not event.is_directory and event.src_path.endswith('.csv'):
            print(f"\n📄 New file: {Path(event.src_path).name}")
            self.trigger_conversion()
    
    def trigger_conversion(self):
        """Run the CSV-to-JSON converter"""
        print("🔄 Running CSV-to-JSON conversion...")
        
        try:
            result = subprocess.run(
                ['python3', str(CONVERTER_SCRIPT)],
                capture_output=True,
                text=True,
                cwd=str(BASE_DIR)
            )
            
            if result.returncode == 0:
                print(result.stdout)
            else:
                print(f"❌ Conversion failed:")
                print(result.stderr)
                
        except Exception as e:
            print(f"❌ Error running converter: {e}")


def load_config():
    """Load configuration"""
    if not CONFIG_FILE.exists():
        return {
            'file_watcher': {
                'enabled': True,
                'watch_directory': 'sheets_output',
                'debounce_seconds': 2
            }
        }
    
    with open(CONFIG_FILE, 'r') as f:
        return json.load(f)


def main():
    """Start file watcher"""
    config = load_config()
    watcher_config = config.get('file_watcher', {})
    
    if not watcher_config.get('enabled', True):
        print("⚠️  File watcher is disabled in config.json")
        return
    
    watch_dir = BASE_DIR / watcher_config.get('watch_directory', 'sheets_output')
    debounce = watcher_config.get('debounce_seconds', 2)
    
    if not watch_dir.exists():
        print(f"❌ Watch directory not found: {watch_dir}")
        print(f"Creating directory: {watch_dir}")
        watch_dir.mkdir(parents=True, exist_ok=True)
    
    print("👀 File Watcher Started")
    print(f"📂 Watching: {watch_dir}")
    print(f"⏱️  Debounce: {debounce} seconds")
    print("\nWaiting for CSV file changes... (Press Ctrl+C to stop)\n")
    
    event_handler = CSVChangeHandler(debounce_seconds=debounce)
    observer = Observer()
    observer.schedule(event_handler, str(watch_dir), recursive=False)
    observer.start()
    
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        print("\n\n👋 Stopping file watcher...")
        observer.stop()
    
    observer.join()
    print("✅ File watcher stopped")


if __name__ == "__main__":
    main()