import logging
from typing import Union, Dict
import praw
import random
import string
from tenacity import retry, stop_after_attempt, wait_exponential

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class RedditError(Exception):
    """Custom exception for Reddit API errors"""
    pass

def validate_reddit_credentials(client_id: str, client_secret: str, username: str, password: str) -> bool:
    """Validate Reddit credentials"""
    return all([client_id, client_secret, username, password])

def generate_random_user_agent():
    """Generate a random user agent."""
    prefix = "my_script_by_u/"
    username = "your_reddit_username"  # Replace with your Reddit username
    random_suffix = ''.join(random.choices(string.ascii_letters + string.digits, k=10))
    return f"{prefix}{username}_{random_suffix}"

@retry(
    stop=stop_after_attempt(3),
    wait=wait_exponential(multiplier=1, min=4, max=10),
    reraise=True
)
def reddit_post(
    client_id: str,
    client_secret: str,
    username: str,
    password: str,
    subreddit: str,
    title: str,
    body: str = ""
) -> Union[Dict[str, str], Dict[str, str]]:
    """
    Create a Reddit post with improved error handling and retries
    
    Args:
        client_id (str): Reddit API client ID
        client_secret (str): Reddit API client secret
        username (str): Reddit username
        password (str): Reddit password
        subreddit (str): Target subreddit
        title (str): Post title
        body (str): Post content
        
    Returns:
        dict: Post information if successful
        dict: Error information if failed
    """
    try:
        if not validate_reddit_credentials(client_id, client_secret, username, password):
            return {"error": "Invalid or missing Reddit credentials"}

        if not title:
            return {"error": "Post title is required"}

        if not subreddit:
            return {"error": "Subreddit is required"}

        # Initialize Reddit client
        reddit = praw.Reddit(
            client_id=client_id,
            client_secret=client_secret,
            username=username,
            password=password,
            user_agent=f"python:flowify:v1.0 (by /u/{username})"
        )

        # Verify credentials
        try:
            reddit.user.me()
        except Exception:
            return {"error": "Failed to authenticate with Reddit"}

        # Create post
        try:
            subreddit_instance = reddit.subreddit(subreddit)
            post = subreddit_instance.submit(
                title=title,
                selftext=body,
                send_replies=True
            )

            return {
                "success": True,
                "post_id": post.id,
                "url": f"https://reddit.com{post.permalink}"
            }

        except praw.exceptions.RedditAPIException as e:
            error_messages = [f"{error.error_type}: {error.message}" for error in e.items]
            return {"error": f"Reddit API error: {', '.join(error_messages)}"}

    except praw.exceptions.PRAWException as e:
        logger.error(f"PRAW error: {str(e)}")
        return {"error": f"Reddit error: {str(e)}"}
    except Exception as e:
        logger.error(f"Unexpected error creating Reddit post: {str(e)}")
        return {"error": f"Failed to create post: {str(e)}"}