import re
from bs4 import BeautifulSoup
import streamlit as st

# Define patterns that indicate the start of a previous message
PRIOR_MESSAGE_MARKERS = [
    # English patterns
    re.compile(r'^On .* wrote:', re.IGNORECASE),
    re.compile(r'^From:\s', re.IGNORECASE),
    re.compile(r'^Sent:\s', re.IGNORECASE),
    re.compile(r'^Subject:\s', re.IGNORECASE),
    re.compile(r'^To:\s', re.IGNORECASE),
    re.compile(r'^Date:\s', re.IGNORECASE),
    re.compile(r'^----\s?Original Message\s?----$', re.IGNORECASE),
    re.compile(r'^__+', re.IGNORECASE),
    re.compile(r'^-\s?-\s?-\s?Original Message\s?-\s?-\s?-$', re.IGNORECASE),
    re.compile(r'^Begin forwarded message:', re.IGNORECASE),
    re.compile(r'^Forwarded message', re.IGNORECASE),
    
    # Portuguese patterns
    re.compile(r'^Em .* escreveu:', re.IGNORECASE),
    re.compile(r'^De:\s', re.IGNORECASE),
    re.compile(r'^Para:\s', re.IGNORECASE),
    re.compile(r'^Data:\s', re.IGNORECASE),
    re.compile(r'^Assunto:\s', re.IGNORECASE),
    re.compile(r'^Mensagem original', re.IGNORECASE),

    # French patterns
    re.compile(r'^De :\s', re.IGNORECASE),  # "From:"
    re.compile(r'^Le .* a écrit :', re.IGNORECASE),  # "On DATE, NAME wrote:"
    
    # German patterns
    re.compile(r'^Am .* schrieb.*:', re.IGNORECASE),  # "On DATE, NAME wrote:"
    re.compile(r'^Von:\s', re.IGNORECASE),  # "From:"
    
    # Spanish patterns
    re.compile(r'^El .* escribió:', re.IGNORECASE),  # "On DATE, NAME wrote:"
    
    # Chinese patterns
    re.compile(r'^历史邮件$', re.IGNORECASE),  # "Historical Emails"
    
    # Dutch patterns
    re.compile(r'^Op .* schreef.*:', re.IGNORECASE),
    re.compile(r'^Van:\s', re.IGNORECASE),
    re.compile(r'^Aan:\s', re.IGNORECASE),
    re.compile(r'^Onderwerp:\s', re.IGNORECASE),
    re.compile(r'^Verzonden:\s', re.IGNORECASE),
    re.compile(r'^Oorspronkelijk bericht', re.IGNORECASE),
    
    # Italian patterns
    re.compile(r'^Il .* ha scritto:', re.IGNORECASE),
    re.compile(r'^Da:\s', re.IGNORECASE),
    re.compile(r'^A:\s', re.IGNORECASE),
    re.compile(r'^Oggetto:\s', re.IGNORECASE),
    re.compile(r'^Data:\s', re.IGNORECASE),
    re.compile(r'^Messaggio originale', re.IGNORECASE),
]

def remove_quoted_text(soup):
    """Remove quoted text sections from the email HTML content."""
    # Remove Gmail quoted text
    for quote in soup.find_all('div', class_='gmail_quote'):
        quote.decompose()

    # Remove Gmail extra
    for extra in soup.find_all('div', class_='gmail_extra'):
        extra.decompose()

    # Remove Outlook quoted text
    for quote in soup.find_all('div', class_='OutlookMessageHeader'):
        quote.decompose()

    # Remove blockquotes
    for blockquote in soup.find_all('blockquote'):
        blockquote.decompose()

    # Remove Yahoo quoted text
    for quote in soup.find_all('div', class_='yahoo_quoted'):
        quote.decompose()

    # Remove reply intros
    for intro in soup.find_all('div', id='reply-intro'):
        intro.decompose()

    # Remove Mozilla's quoted text
    for cite in soup.find_all('div', class_='moz-cite-prefix'):
        cite.decompose()

    return soup

def extract_latest_message_from_lines(lines):
    """Extract the latest message from the list of lines."""
    latest_message_lines = []
    for line in lines:
        # Clean up the line
        line = line.strip()
        # Check if the line matches any prior message markers
        if any(marker.match(line) for marker in PRIOR_MESSAGE_MARKERS):
            break  # Stop if a prior message marker is found
        latest_message_lines.append(line)
    return '\n'.join(latest_message_lines).strip()

def extract_latest_email_text(email_html):
    """
    Extracts the text of the latest email message from the given HTML content,
    removing any quoted threads or previous messages.
    """
    # Parse the HTML content
    soup = BeautifulSoup(email_html, 'html.parser')

    # Remove quoted text sections
    soup = remove_quoted_text(soup)

    # Extract the text and split into lines
    email_text = soup.get_text(separator='\n', strip=True)
    lines = email_text.split('\n')

    # Extract the latest message
    latest_email_text = extract_latest_message_from_lines(lines)

    return latest_email_text

# Streamlit app
def main():
    st.title("Email Latest Message Extractor")
    
    st.write("""
        This tool extracts the latest message from an HTML email and removes any quoted thread or previous messages.
        Paste the raw HTML of your email in the text area below, and the tool will parse and display the latest message.
    """)
    
    # Input field for the raw HTML email content
    email_html = st.text_area("Paste the HTML email content here", height=300)
    
    # Button to process the input
    if st.button("Extract Latest Message"):
        if email_html.strip():
            try:
                latest_message = extract_latest_email_text(email_html)
                st.subheader("Extracted Latest Message:")
                st.text_area("Latest Message", value=latest_message, height=200)
            except Exception as e:
                st.error(f"An error occurred: {e}")
        else:
            st.warning("Please paste the HTML content of the email.")
    
if __name__ == "__main__":
    main()