import os
import pandas as pd
import google.generativeai as genai
import PyPDF2 as pdf
import io
import re
import streamlit as st
from transformers import pipeline, AutoModelForSequenceClassification, AutoTokenizer
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.metrics.pairwise import cosine_similarity
import torch

# Set API key for Google API (Make sure it's securely set in your environment variables)
api_key = os.getenv('GOOGLE_API_KEY')
if not api_key:
    raise ValueError("API key not found. Please set GOOGLE_API_KEY in your Hugging Face Space secrets.")

# Initialize the generative AI model
genai.configure(api_key=api_key)

# Load pre-trained models
skill_extractor = pipeline("ner", model="dslim/bert-base-NER", aggregation_strategy="simple")
education_extractor = pipeline("ner", model="dbmdz/bert-large-cased-finetuned-conll03-english", aggregation_strategy="simple")

# Define the task and model for Hugging Face
task = "sentiment-analysis"
model_name = "roberta-base"  # Using RoBERTa
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForSequenceClassification.from_pretrained(model_name)

# Extract text from uploaded PDF file
def input_pdf_text(uploaded_file):
    file_stream = io.BytesIO(uploaded_file.read())
    reader = pdf.PdfReader(file_stream)
    text = ""
    for page in reader.pages:
        text += page.extract_text()
    return text

# Extract candidate name directly from the model response
def extract_name_from_model_response(response_text):
    match = re.search(r"Candidate Name:\s*(.*)", response_text)
    if match:
        return match.group(1)
    return "Not Available"

# Extract email and phone numbers using regex
def extract_contact_info(resume_text):
    email_match = re.search(r"[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}", resume_text)
    email = email_match.group(0) if email_match else "Not Available"

    contact_match = re.search(r"\+?\(?\d{1,3}\)?[-.\s]?\(?\d{1,4}\)?[-.\s]?\d{3}[-.\s]?\d{4}|\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}", resume_text)
    contact = contact_match.group(0) if contact_match else "Not Available"

    return email, contact

# Extract skills using NER model
def extract_skills(resume_text):
    ner_results = skill_extractor(resume_text)
    skills = [entity['word'] for entity in ner_results if entity['entity_group'] == 'SKILL']
    return ", ".join(skills) if skills else "Not Available"

# Extract education information using NER model
def extract_education(resume_text):
    ner_results = education_extractor(resume_text)
    education_entities = [entity['word'] for entity in ner_results if entity['entity_group'] == 'EDUCATION']
    
    if education_entities:
        return ", ".join(education_entities)
    else:
        edu_patterns = [
            r"(Bachelor of .+|Master of .+|PhD|BSc|MSc|MBA|B.A|M.A|B.Tech|M.Tech|Doctorate|Engineering|Computer Science|Information Technology|Data Science)",
            r"(University of [A-Za-z]+.*)"
        ]
        education = []
        for pattern in edu_patterns:
            matches = re.findall(pattern, resume_text)
            education.extend(matches)
        
        return ", ".join(education) if education else "Not Available"

# Extract team leadership and management years from the resume
def extract_experience_years(text):
    years = 0
    patterns = [
        r"(\d{4})\s?[-to]+\s?(\d{4})",  # From year to year
        r"(\d+) years",  # Exact mention of years
        r"since (\d{4})",  # Mentions "since"
        r"(\d+)\s?[\-–]\s?(\d+)",  # Handles year ranges with hyphens (e.g., 2015-2020)
        r"(\d+)\s?[\–]\s?present",  # Present with range (e.g., 2019–present)
    ]
    
    for pattern in patterns:
        matches = re.findall(pattern, text)
        for match in matches:
            if len(match) == 2:
                start_year = int(match[0])
                end_year = int(match[1])
                years += end_year - start_year
            elif len(match) == 1:
                years += int(match[0])

    return years

# Calculate the match percentage using TF-IDF and cosine similarity
def calculate_match_percentage(resume_text, job_description):
    documents = [resume_text, job_description]
    tfidf_vectorizer = TfidfVectorizer(stop_words='english')
    tfidf_matrix = tfidf_vectorizer.fit_transform(documents)
    cosine_sim = cosine_similarity(tfidf_matrix[0:1], tfidf_matrix[1:2])
    match_percentage = cosine_sim[0][0] * 100
    return round(match_percentage, 2)

# Generate the detailed analysis from the Gemini model
def get_gemini_response(input_text, job_description):
    prompt = f"""
    Act as an Applicant Tracking System. Analyze the resume with respect to the job description.
    Candidate Details: {input_text}
    Job Description: {job_description}
    Please extract the following:
    1. Candidate Name
    2. Relevant Skills
    3. Educational Background
    4. Direct Team Leadership Experience (in years)
    5. Direct Management Experience (in years)
    6. Match percentage with the job description
    7. Provide a resume summary in 5 bullet points highlighting the candidate's qualifications.
    """
    model = genai.GenerativeModel('gemini-1.5-flash')
    response = model.generate_content(prompt)
    return response.text.strip()

# Extract a detailed resume summary (focusing on leadership roles and team management experience)
def extract_leadership_summary(response_text):
    leadership_summary = "Resume Summary: Leadership and Team Management Experience (in years)\n"
    lines = response_text.strip().split("\n")
    meaningful_lines = [line.strip() for line in lines if line.strip()]
    leadership_experience = []
    
    for line in meaningful_lines:
        if "leadership" in line.lower() or "management" in line.lower() or "team" in line.lower():
            leadership_experience.append(line)
    
    leadership_experience = leadership_experience[-5:] if len(leadership_experience) >= 5 else leadership_experience
    
    for idx, bullet in enumerate(leadership_experience, 1):
        leadership_summary += f"{idx}. {bullet}\n"
    
    return leadership_summary

# Analyze the resume using Hugging Face RoBERTa
def analyze_resume(resume_text):
    # Create input prompts for different aspects
    prompts = [
        f"This resume shows strong managerial responsibilities: {resume_text}",
        f"This resume demonstrates excellent leadership skills: {resume_text}",
        f"This resume indicates significant work experience: {resume_text}",
        f"This resume indicates at least 2 years of relevant experience: {resume_text}"
    ]

    results = []
    for prompt in prompts:
        # Tokenize the prompt with truncation
        inputs = tokenizer(prompt, return_tensors="pt", truncation=True)
        outputs = model(**inputs)
        predicted_class = torch.argmax(outputs.logits).item()
        results.append(predicted_class)

    # Interpret the results
    analysis = {
        "managerial_responsibilities": results[0] == 1,  # Assuming 1 is positive sentiment
        "leadership_skills": results[1] == 1,
        "work_experience": results[2] == 1,
        "relevant_experience": results[3] == 1
    }

    # Check if all criteria are met
    is_suitable = all(analysis.values())

    return analysis, is_suitable

# Streamlit interface to upload files and provide job description
st.title("Resume ATS Analysis Tool")
st.markdown("### Upload Resume and Job Description for Analysis")

# File uploader for resume PDF
uploaded_file = st.file_uploader("Upload Resume PDF", type=["pdf"])

# Job description text input
job_description = st.text_area("Job Description", height=200)

if uploaded_file and job_description:
    analyze_button = st.button("Analyze")

    if analyze_button:
        resume_text = input_pdf_text(uploaded_file)
        response_text = get_gemini_response(resume_text, job_description)

        # Initialize an empty dictionary to hold the dynamic data
        data = {}

        # Extract candidate name
        name = extract_name_from_model_response(response_text)
        data['Candidate_Name'] = name if name != "Not Available" else "Not Available"

        # Extract contact info (email, phone)
        email, contact = extract_contact_info(resume_text)
        data['Email'] = email if email != "Not Available" else "Not Available"
        data['Contact'] = contact if contact != "Not Available" else "Not Available"

        # Extract skills
        skills = extract_skills(resume_text)
        data['Skills'] = skills if skills != "Not Available" else "Not Available"

        # Extract education
        education = extract_education(resume_text)
        data['Education'] = education if education != "Not Available" else "Not Available"

        # Extract team leadership and management experience
        team_leadership_years = extract_experience_years(resume_text)
        data['Team_Leadership_Experience (Years)'] = team_leadership_years
        management_experience_years = extract_experience_years(resume_text)
        data['Management_Experience (Years)'] = management_experience_years

        # Calculate match percentage dynamically
        match_percentage = calculate_match_percentage(resume_text, job_description)
        data['Match_Percentage'] = match_percentage

        # Calculate Job Description Match Score dynamically (based on match percentage)
        if match_percentage >= 80:
            job_description_match_score = "High"
        elif match_percentage >= 60:
            job_description_match_score = "Medium"
        else:
            job_description_match_score = "Low"
        data['Job_Description_Match_Score'] = job_description_match_score

        # Extract leadership and team management summary
        leadership_summary = extract_leadership_summary(response_text)
        data['Leadership_and_Team_Management_Summary'] = leadership_summary

        # Analyze the resume using Hugging Face RoBERTa
        analysis, is_suitable = analyze_resume(resume_text)
        data['Managerial_Responsibilities'] = analysis['managerial_responsibilities']
        data['Leadership_Skills'] = analysis['leadership_skills']
        data['Work_Experience'] = analysis['work_experience']
        data['Relevant_Experience'] = analysis['relevant_experience']
        data['Suitable_for_Role'] = is_suitable

        # Display the results as a table
        df = pd.DataFrame([data])
        st.write(df)

        # Download the results as a CSV file
        csv = df.to_csv(index=False)
        st.download_button(
            label="Download Results as CSV",
            data=csv,
            file_name='resume_analysis_results.csv',
            mime='text/csv'
        )

else:
    st.write("Please upload a resume and provide a job description to analyze.")