import os
import logging
import asyncio
from pathlib import Path

from hydrogram import Client, filters
from hydrogram.types import Message
from hydrogram.errors import SessionPasswordNeeded, PhoneCodeInvalid, PhoneNumberInvalid, PasswordHashInvalid

# --- Configuration ---
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')
logger = logging.getLogger(__name__)

# Retrieve Session String from Hugging Face secrets
SESSION_STRING = os.environ.get('SESSION_STRING')

# --- Dynamic Storage Path Initialization ---
# Define potential base directories for storage and a subdirectory name
PERSISTENT_STORAGE_CANDIDATES = [
    Path("/data"),  # Common absolute path for persistent data in containers
    Path("."),      # Current working directory (e.g., /app if WORKDIR is /app)
]
APP_STORAGE_SUBDIR_NAME = "app_template_storage" # Subdirectory to hold our template
TEMPLATE_FILENAME = "user_template_content.txt"

DATA_DIR: Path = None
TEMPLATE_FILE_PATH: Path = None

def initialize_storage_paths():
    """Tries to find/create a writable directory for the template file."""
    global DATA_DIR, TEMPLATE_FILE_PATH

    # 1. Try creating a subdirectory in candidate locations
    for base_candidate in PERSISTENT_STORAGE_CANDIDATES:
        potential_data_dir = base_candidate / APP_STORAGE_SUBDIR_NAME
        try:
            potential_data_dir.mkdir(parents=True, exist_ok=True)
            # Test if we can actually write a dummy file here
            test_file = potential_data_dir / ".writable_test"
            with open(test_file, "w") as f:
                f.write("test")
            test_file.unlink() # Clean up test file

            DATA_DIR = potential_data_dir
            TEMPLATE_FILE_PATH = DATA_DIR / TEMPLATE_FILENAME
            logger.info(f"Successfully established writable data directory: {DATA_DIR}")
            return
        except PermissionError:
            logger.warning(f"Permission denied to create/use directory {potential_data_dir}. Trying next candidate.")
        except Exception as e:
            logger.warning(f"Failed to create/use directory {potential_data_dir} due to {type(e).__name__}: {e}. Trying next candidate.")

    # 2. If subdirectory creation failed, try to place the file directly in a candidate base directory
    logger.warning("Could not create/use a dedicated subdirectory. Attempting to use a base directory directly for the file.")
    for base_candidate in PERSISTENT_STORAGE_CANDIDATES:
        potential_template_file_path = base_candidate / TEMPLATE_FILENAME
        try:
            # Test writability by trying to open the file in append mode (creates if not exists)
            with open(potential_template_file_path, 'a'):
                pass # Just testing if open works without error
            # If we are here, it means we can probably write the file directly.
            DATA_DIR = base_candidate # The "data directory" is now the base itself
            TEMPLATE_FILE_PATH = potential_template_file_path
            logger.info(f"Using base directory {DATA_DIR.resolve()} directly for template file: {TEMPLATE_FILE_PATH}")
            return
        except PermissionError:
            logger.warning(f"Permission denied to write template file directly in {base_candidate.resolve()}. Trying next candidate.")
        except Exception as e:
            logger.warning(f"Failed to write template file in {base_candidate.resolve()} due to {type(e).__name__}: {e}. Trying next candidate.")

    # If all attempts fail
    logger.error("CRITICAL: Unable to find or create a writable location for the template file.")
    # Set paths to None to indicate failure; the app might crash or malfunction later.
    # A more robust solution would be to exit here.
    DATA_DIR = None
    TEMPLATE_FILE_PATH = None
    # Consider exiting: exit("Failed to initialize storage.")

# Call this ONCE at the start of the script
initialize_storage_paths()

# Global variable to hold the loaded template content
current_template_content = None

# --- Helper Functions for Template Management ---
async def load_template_from_file():
    """Loads template content from the persistent file."""
    global current_template_content
    if not TEMPLATE_FILE_PATH:
        logger.error("Template file path is not configured. Cannot load template.")
        current_template_content = None
        return

    if TEMPLATE_FILE_PATH.exists():
        try:
            with open(TEMPLATE_FILE_PATH, "r", encoding="utf-8") as f:
                current_template_content = f.read()
            logger.info(f"Template loaded successfully from {TEMPLATE_FILE_PATH}")
        except Exception as e:
            logger.error(f"Error loading template from {TEMPLATE_FILE_PATH}: {e}")
            current_template_content = None
    else:
        logger.info(f"Template file {TEMPLATE_FILE_PATH} not found. No template loaded.")
        current_template_content = None

async def save_template_to_file(content: str):
    """Saves template content to the persistent file."""
    global current_template_content
    if not TEMPLATE_FILE_PATH:
        logger.error("Template file path is not configured. Cannot save template.")
        return False

    try:
        # Ensure the parent directory exists (it should if initialize_storage_paths worked for a subdir)
        if TEMPLATE_FILE_PATH.parent != Path("."): # Avoid trying to create "." if file is in current dir
             TEMPLATE_FILE_PATH.parent.mkdir(parents=True, exist_ok=True)

        with open(TEMPLATE_FILE_PATH, "w", encoding="utf-8") as f:
            f.write(content)
        current_template_content = content
        logger.info(f"Template saved successfully to {TEMPLATE_FILE_PATH}")
        return True
    except Exception as e:
        logger.error(f"Error saving template to {TEMPLATE_FILE_PATH}: {e}")
        return False

# --- Initialization ---
if not SESSION_STRING:
    logger.error("SESSION_STRING environment variable not found. Please set it in Hugging Face secrets.")
    exit(1)

if not TEMPLATE_FILE_PATH:
    logger.critical("CRITICAL: Template storage path could not be initialized. The application cannot manage templates. Exiting.")
    exit(1)


logger.info("Initializing Hydrogram Client with session string...")
try:
    app = Client(
        name="user_session_hgs", # Changed name slightly to avoid old session file conflicts if any
        session_string=SESSION_STRING,
    )
    logger.info("Hydrogram Client initialized.")
except Exception as e:
    logger.error(f"Failed to initialize Hydrogram Client: {type(e).__name__} - {e}")
    exit(1)


# --- Bot Event Handlers (Unchanged from your previous version) ---
@app.on_message(filters.command("start") & filters.private)
async def start_handler(client: Client, message: Message):
    sender_name = message.from_user.first_name if message.from_user else "User"
    logger.info(f"Received /start command from {sender_name} (ID: {message.from_user.id})")
    welcome_text = f"Hello {sender_name}!\n"
    welcome_text += "I am ready to manage your template.\n"
    welcome_text += "Use /settemplate <your text> to set a new template.\n"
    welcome_text += "Use /gettemplate to view the current template."
    if current_template_content:
        welcome_text += "\n\nA template is currently set."
    else:
        welcome_text += "\n\nNo template is currently set."
    await message.reply_text(welcome_text)

@app.on_message(filters.command("settemplate") & filters.private)
async def set_template_handler(client: Client, message: Message):
    user_id = message.from_user.id
    logger.info(f"Received /settemplate command from User ID: {user_id}")
    if len(message.command) > 1:
        new_template = message.text.split(" ", 1)[1].strip()
        if new_template:
            if await save_template_to_file(new_template):
                await message.reply_text("✅ Template updated successfully!")
            else:
                await message.reply_text("❌ Failed to save the template. Please check the logs.")
        else:
            await message.reply_text("⚠️ Please provide content for the template. Usage: `/settemplate Your template text here`")
    else:
        await message.reply_text("ℹ️ Usage: `/settemplate Your template text here`")

@app.on_message(filters.command("gettemplate") & filters.private)
async def get_template_handler(client: Client, message: Message):
    user_id = message.from_user.id
    logger.info(f"Received /gettemplate command from User ID: {user_id}")
    if current_template_content:
        response_text = f"📜 **Current Template:**\n\n{current_template_content}"
    else:
        response_text = "ℹ️ No template is currently set. Use `/settemplate <your text>` to set one."
    await message.reply_text(response_text)

# --- Main Execution ---
async def main():
    await load_template_from_file()
    logger.info("Attempting to connect and start the bot...")
    try:
        await app.start()
        me = await app.get_me()
        logger.info(f"Bot started successfully as {me.first_name} (ID: {me.id})")
        logger.info("Listening for messages...")
        await asyncio.Event().wait()
    except (SessionPasswordNeeded, PhoneCodeInvalid, PhoneNumberInvalid, PasswordHashInvalid) as e:
        logger.error(f"Authorization error: {type(e).__name__} - {e}. Your SESSION_STRING might be invalid or expired.")
    except ConnectionError as e:
        logger.error(f"Connection error: {e}. Check your network or Telegram's status.")
    except Exception as e:
        logger.error(f"An unexpected error occurred during bot startup or runtime: {type(e).__name__} - {e}", exc_info=True)
    finally:
        if app.is_initialized and app.is_connected: # Check if initialized before checking is_connected
            logger.info("Stopping the bot...")
            await app.stop()
            logger.info("Bot stopped.")
        else:
            logger.info("Bot was not fully connected or already stopped.")

if __name__ == '__main__':
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        logger.info("Bot manually interrupted. Exiting...")
    except SystemExit as e: # Catch explicit exits
        logger.info(f"Application exiting with status: {e.code}")
    except Exception as e:
        logger.critical(f"Critical error in main execution block: {type(e).__name__} - {e}", exc_info=True)