#!/usr/bin/env python3
import sys
import os
import time
import argparse
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

class RefreshController:
    def __init__(self, debug_port: int, verbose: bool = False):
        """Initialize connection to Chrome instance"""
        self.verbose = verbose
        options = webdriver.ChromeOptions()
        options.add_experimental_option("debuggerAddress", f"127.0.0.1:{debug_port}")
        self.driver = webdriver.Chrome(options=options)
        
        # Load JavaScript files
        js_dir = os.path.join(os.path.dirname(__file__), "..", "js")
        self.js_code = ""
        with open(os.path.join(js_dir, "viewport.js")) as f:
            self.js_code = f.read()

    def log(self, msg: str):
        """Log message if verbose mode is enabled"""
        if self.verbose:
            print(f"DEBUG: {msg}", file=sys.stderr)

    def get_page_state(self) -> dict:
        """Get current page state for comparison"""
        return {
            'url': self.driver.current_url,
            'title': self.driver.title,
            'scroll_position': self.driver.execute_script(
                self.js_code + "; return getViewportInfo();"
            )
        }

    def wait_for_page_change(self, original_state: dict, timeout: int = 30) -> bool:
        """Wait for page to refresh and stabilize"""
        try:
            start_time = time.time()
            while time.time() - start_time < timeout:
                current_state = self.get_page_state()
                
                # Check if page has reloaded
                if (current_state['url'] == original_state['url'] and
                    current_state['title'] == original_state['title']):
                    
                    # Check if DOM has finished updating
                    is_stable = self.driver.execute_script("""
                        return (typeof window._lastMutation === 'undefined' || 
                                Date.now() - window._lastMutation > 1000);
                    """)
                    
                    if is_stable:
                        return True
                        
                time.sleep(0.1)
            
            self.log("Timeout waiting for page to stabilize")
            return False
            
        except Exception as e:
            self.log(f"Error waiting for page change: {str(e)}")
            return False

    def setup_mutation_tracking(self):
        """Setup mutation observer to track DOM changes"""
        self.driver.execute_script("""
            // Track last mutation time
            window._lastMutation = Date.now();
            
            // Create mutation observer
            const observer = new MutationObserver(() => {
                window._lastMutation = Date.now();
            });
            
            // Observe entire document for any changes
            observer.observe(document, {
                childList: true,
                subtree: true,
                attributes: true,
                characterData: true
            });
        """)

    def refresh(self, hard: bool = False, timeout: int = 30) -> bool:
        """
        Refresh the current page
        
        Args:
            hard (bool): If True, bypass cache with Ctrl+F5
            timeout (int): Maximum time to wait for refresh in seconds
            
        Returns:
            bool: True if refresh was successful
        """
        try:
            # Get initial page state
            original_state = self.get_page_state()
            self.log(f"Original page state: {original_state}")
            
            # Setup mutation tracking
            self.setup_mutation_tracking()
            
            if hard:
                # Force reload bypassing cache
                self.log("Executing hard refresh (Ctrl+F5)")
                self.driver.execute_script("""
                    window.location.reload(true);
                """)
            else:
                # Normal reload
                self.log("Executing normal refresh")
                self.driver.refresh()
            
            # Wait for page to stabilize
            success = self.wait_for_page_change(original_state, timeout)
            
            if success:
                # Restore scroll position
                self.driver.execute_script(
                    "window.scrollTo(arguments[0], arguments[1]);",
                    original_state['scroll_position']['scroll_x'],
                    original_state['scroll_position']['scroll_y']
                )
                
                # Final verification
                new_state = self.get_page_state()
                self.log(f"New page state: {new_state}")
                
                return True
            
            return False
            
        except Exception as e:
            self.log(f"Refresh failed: {str(e)}")
            return False

def main():
    parser = argparse.ArgumentParser(description='Refresh page in Chrome')
    parser.add_argument('debug_port', type=int, help='Chrome debug port')
    parser.add_argument('--hard', action='store_true', help='Force refresh bypassing cache')
    parser.add_argument('--timeout', type=int, default=30, help='Refresh timeout in seconds')
    parser.add_argument('-v', '--verbose', action='store_true', help='Enable debug output')
    
    args = parser.parse_args()
    
    try:
        controller = RefreshController(args.debug_port, args.verbose)
        success = controller.refresh(args.hard, args.timeout)
        sys.exit(0 if success else 1)
        
    except Exception as e:
        if args.verbose:
            print(f"Fatal error: {str(e)}", file=sys.stderr)
        sys.exit(1)

if __name__ == "__main__":
    main()