import streamlit as st
from sentence_transformers import SentenceTransformer, util
import re

@st.cache_resource
def load_model():
    return SentenceTransformer('sentence-transformers/all-mpnet-base-v2')

model = load_model()

def keyword_match(job_desc, resume):
    job_keywords = set(re.findall(r'\b\w+\b', job_desc.lower()))
    resume_keywords = set(re.findall(r'\b\w+\b', resume.lower()))
    common_keywords = job_keywords.intersection(resume_keywords)
    return len(common_keywords) / len(job_keywords) * 100 if job_keywords else 0

st.title("Enhanced Resume and Job Description Similarity Checker")

job_description = st.text_area("Paste the job description here:", height=200)
resume_text = st.text_area("Paste your resume here:", height=200)

if st.button("Compare"):
    if job_description.strip() and resume_text.strip():
        # Calculate embeddings-based similarity
        job_description_embedding = model.encode(job_description)
        resume_embedding = model.encode(resume_text)
        similarity_score = util.cos_sim(job_description_embedding, resume_embedding).item() * 100

        # Calculate keyword-based similarity
        keyword_score = keyword_match(job_description, resume_text)
        
        # Combine scores (you could adjust the weights as needed)
        overall_score = (similarity_score * 0.6) + (keyword_score * 0.4)
        
        st.write(f"**Similarity Score:** {overall_score:.2f}%")
        
        # Adjusted grading scale based on combined score
        if overall_score > 80:
            st.success("Excellent match! Your resume closely aligns with the job description.")
        elif overall_score > 65:
            st.info("Strong match! Your resume aligns well, but a few minor tweaks could help.")
        elif overall_score > 50:
            st.warning("Moderate match. Your resume has some relevant information, but consider emphasizing relevant skills.")
        elif overall_score > 35:
            st.error("Low match. Your resume does not align well. Consider revising to highlight key skills.")
        else:
            st.error("Very low match. Your resume is significantly different from the job description. Major revisions may be needed.")
    else:
        st.error("Please paste both the job description and your resume to proceed.")