import sys
import os
from bs4 import BeautifulSoup

def sanitize_filename(title: str) -> str:
    return "".join(c if c.isalnum() or c in (' ', '-', '_') else '_' for c in title).strip()[:100]

def convert_chat_html_to_markdown(html_path: str) -> str:
    with open(html_path, "r", encoding="utf-8") as f:
        soup = BeautifulSoup(f, "html.parser")

    title = soup.title.string.strip() if soup.title else "chatgpt_conversation"
    filename = sanitize_filename(title) + ".md"

    # Find the main chat container
    main_content = soup.find("main")
    if not main_content:
        raise ValueError("Could not find <main> in HTML. Is this a valid saved ChatGPT conversation?")

    # Each message: role in h3, content in a sibling div
    h3s = main_content.find_all("h3")
    prose_divs = main_content.find_all("div", class_="prose")

    if len(h3s) != len(prose_divs):
        print("Warning: Number of roles and messages doesn't match. Continuing anyway...")

    messages = []
    for role_elem, content_elem in zip(h3s, prose_divs):
        role = role_elem.get_text(strip=True)
        content = content_elem.get_text(separator="\n", strip=True)
        role_prefix = "**ChatGPT:**" if "chatgpt" in role.lower() else "**You:**"
        messages.append(f"{role_prefix}\n\n{content}")

    markdown = f"# {title}\n\n" + "\n\n---\n\n".join(messages)
    return filename, markdown

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python html_to_markdown.py <path_to_saved_html>")
        sys.exit(1)

    input_html = sys.argv[1]
    if not os.path.isfile(input_html):
        print(f"File not found: {input_html}")
        sys.exit(1)

    output_name, markdown_text = convert_chat_html_to_markdown(input_html)
    output_path = os.path.join(os.path.dirname(input_html), output_name)

    with open(output_path, "w", encoding="utf-8") as f:
        f.write(markdown_text)

    print(f"Markdown saved to: {output_path}")