# logger_config.py
import logging
import tkinter as tk
from tkinter import scrolledtext

# This is the single source of truth for the log file name
LOG_FILE = "git_svn_sync.log"

class TextHandler(logging.Handler):
    """
    A handler class to redirect log messages to a Tkinter Text widget.
    Ensures thread safety for GUI updates from different threads if necessary,
    although current usage seems single-threaded for logging.
    """

    def __init__(self, text_widget):
        """
        Initializes the TextHandler with a Tkinter ScrolledText widget.
        Args:
            text_widget (tkinter.scrolledtext.ScrolledText): The Tkinter widget.
        """
        super().__init__()
        # Ensure we store the actual widget
        if not isinstance(text_widget, tk.Text) and not isinstance(text_widget, scrolledtext.ScrolledText):
             raise ValueError("TextHandler requires a valid Tkinter Text or ScrolledText widget.")
        self.text_widget = text_widget

    def emit(self, record):
        """
        Formats and directs the log record to the Tkinter text widget.
        This method should be thread-safe if logging can occur from multiple threads.
        Tkinter GUI updates must happen in the main thread.
        """
        msg = self.format(record) + "\n"
        # Check if the widget exists and is valid before attempting to update it
        if self.text_widget and self.text_widget.winfo_exists():
            try:
                # Schedule the GUI update in the main Tkinter thread
                # Using after(0, ...) ensures it runs in the main event loop
                self.text_widget.after(0, self._insert_text, msg)
            except Exception as e:
                # Fallback or logging for errors during scheduling
                print(f"Error scheduling log message update in Tkinter: {e}")
        # else:
            # Optional: Log to console if the widget is gone
            # print(f"Log Widget gone: {msg.strip()}")


    def _insert_text(self, msg):
        """Helper method to insert text, intended to be called via 'after'."""
        # Double-check widget existence right before insertion
        if self.text_widget and self.text_widget.winfo_exists():
            try:
                # Store current state, modify, insert, restore state
                current_state = self.text_widget['state']
                self.text_widget.config(state=tk.NORMAL)
                self.text_widget.insert(tk.END, msg)
                self.text_widget.config(state=current_state)
                # Autoscroll to the end
                self.text_widget.see(tk.END)
            except tk.TclError as e:
                 # Handle cases where the widget might be destroyed between checks
                 print(f"TclError inserting log into Text widget: {e}")
            except Exception as e:
                 print(f"Unexpected error inserting log into Text widget: {e}")


def setup_logger(log_text_widget=None):
    """
    Sets up the application logger with optional file and text handlers.

    Args:
        log_text_widget (tkinter.scrolledtext.ScrolledText, optional):
            The Tkinter ScrolledText widget for live log display. Defaults to None.

    Returns:
        logging.Logger: The configured logger instance.
    """
    # Use a specific, consistent name for the application logger
    logger_name = "GitSvnSyncApp"
    logger = logging.getLogger(logger_name)

    # Set the desired logging level (e.g., INFO, DEBUG)
    logger.setLevel(logging.INFO)

    # Prevent adding duplicate handlers if called multiple times
    if not logger.handlers:
        # Define a standard log format
        log_formatter = logging.Formatter(
            "%(asctime)s - %(levelname)s - [%(funcName)s] - %(message)s",
            datefmt="%Y-%m-%d %H:%M:%S"
        )

        # --- File Handler ---
        try:
            # Use the centrally defined LOG_FILE name
            file_handler = logging.FileHandler(LOG_FILE, mode='a', encoding='utf-8') # Append mode
            file_handler.setLevel(logging.INFO) # Log INFO level and above to file
            file_handler.setFormatter(log_formatter)
            logger.addHandler(file_handler)
            print(f"Logging to file: {os.path.abspath(LOG_FILE)}") # Print log file path on setup
        except Exception as e:
            # Fallback to stderr if file logging setup fails
            logging.basicConfig(level=logging.INFO) # Basic config to console
            logger.error(f"Critical: Failed to set up file handler for '{LOG_FILE}': {e}. Logging to console.")

        # --- Text Widget Handler (Optional) ---
        if log_text_widget:
            try:
                text_handler = TextHandler(log_text_widget)
                # Log DEBUG level and above to the GUI for more detail during runtime
                text_handler.setLevel(logging.DEBUG)
                text_handler.setFormatter(log_formatter)
                logger.addHandler(text_handler)
                logger.info("GUI logging handler configured.")
            except ValueError as e:
                 logger.error(f"Error setting up GUI TextHandler: {e}")
            except Exception as e:
                 logger.error(f"Unexpected error setting up GUI TextHandler: {e}")
        else:
            logger.info("No GUI log widget provided. Skipping TextHandler setup.")

        # Initial log message indicating setup is complete
        logger.info("Logger setup complete.")
        # Example debug message (will show in GUI if configured, not in file unless file level is DEBUG)
        logger.debug("Debug logging is active for handlers that support it.")

    else:
        logger.info("Logger already configured. Skipping setup.")

    return logger

# --- Import os for abspath in setup_logger ---
import os