import os
import sys

# Hugging Face safe cache
os.environ["HF_HOME"] = "/tmp/huggingface"
os.environ["TRANSFORMERS_CACHE"] = "/tmp/huggingface/transformers"
os.environ["HUGGINGFACE_HUB_CACHE"] = "/tmp/huggingface/hub"

# Force Flask instance path to a writable temporary folder
safe_instance_path = "/tmp/flask_instance"

# Create the safe instance path after imports
os.makedirs(safe_instance_path, exist_ok=True)

from flask import Flask, render_template, redirect, url_for, flash, request, jsonify
from flask_login import LoginManager, login_required, current_user
from werkzeug.utils import secure_filename
import sys
from datetime import datetime

# Adjust sys.path for import flexibility
current_dir = os.path.dirname(os.path.abspath(__file__))
sys.path.append(current_dir)

# Import and initialize DB
from backend.models.database import db, Job, Application, init_db
from backend.models.user import User
from backend.routes.auth import auth_bp, handle_resume_upload

# Import the resume parsing helper.  This module contains lightweight
# heuristics for extracting information from PDF and DOCX files without
# relying on heavy external libraries.  See
# ``codingo/backend/services/resume_parser.py`` for details.
from backend.services.resume_parser import parse_resume as _parse_resume_helper
from backend.routes.interview_api import interview_api
# Import additional utilities
import re
import json

# -----------------------------------------------------------------------------
# Chatbot integration
#
# Import the chatbot module functions
from backend.services.codingo_chatbot import (
    get_response as _codingo_get_response,
    init_embedder_and_db,
    init_llm
)

# Initialize Flask app
app = Flask(
    __name__,
    static_folder='backend/static',
    static_url_path='/static',
    template_folder='backend/templates',
    instance_path=safe_instance_path
)

app.config['SECRET_KEY'] = 'saadi'

# Cookie configuration for Hugging Face Spaces
app.config['SESSION_COOKIE_SAMESITE'] = 'None'
app.config['SESSION_COOKIE_SECURE'] = True
app.config['REMEMBER_COOKIE_SAMESITE'] = 'None'
app.config['REMEMBER_COOKIE_SECURE'] = True

# Configure the database connection
app.config['SQLALCHEMY_DATABASE_URI'] = os.getenv("DATABASE_URL")
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

# Create necessary directories in writable locations
os.makedirs('/tmp/static/audio', exist_ok=True)
os.makedirs('/tmp/temp', exist_ok=True)

# Initialize DB with app
init_db(app)

# Flask-Login setup
login_manager = LoginManager()
login_manager.login_view = 'auth.login'
login_manager.init_app(app)

@login_manager.user_loader
def load_user(user_id):
    return db.session.get(User, int(user_id))

# Register blueprints
app.register_blueprint(auth_bp)
app.register_blueprint(interview_api, url_prefix="/api")

# Routes
@app.route('/')
def index():
    return render_template('index.html')

@app.route('/jobs')
def jobs():
    all_jobs = Job.query.order_by(Job.date_posted.desc()).all()
    return render_template('jobs.html', jobs=all_jobs)

@app.route('/job/<int:job_id>')
def job_detail(job_id):
    job = Job.query.get_or_404(job_id)
    return render_template('job_detail.html', job=job)

@app.route('/apply/<int:job_id>', methods=['GET', 'POST'])
@login_required
def apply(job_id):
    job = Job.query.get_or_404(job_id)
    if request.method == 'POST':
        file = request.files.get('resume')
        features, error, filepath = handle_resume_upload(file)

        if error:
            flash("Resume upload failed. Please try again.", "danger")
            return render_template('apply.html', job=job)

        def parse_entries(raw_value: str):
            import re
            entries = []
            if raw_value:
                for item in re.split(r'[\n,;]+', raw_value):
                    item = item.strip()
                    if item:
                        entries.append(item)
            return entries

        skills_input = request.form.get('skills', '')
        experience_input = request.form.get('experience', '')
        education_input = request.form.get('education', '')

        manual_features = {
            "skills": parse_entries(skills_input),
            "experience": parse_entries(experience_input),
            "education": parse_entries(education_input)
        }

        application = Application(
            job_id=job_id,
            user_id=current_user.id,
            name=current_user.username,
            email=current_user.email,
            resume_path=filepath,
            extracted_features=json.dumps(manual_features)
        )

        db.session.add(application)
        db.session.commit()

        flash('Your application has been submitted successfully!', 'success')
        return redirect(url_for('jobs'))

    return render_template('apply.html', job=job)

@app.route('/my_applications')
@login_required
def my_applications():
    applications = Application.query.filter_by(
        user_id=current_user.id
    ).order_by(Application.date_applied.desc()).all()
    return render_template('my_applications.html', applications=applications)

# Chatbot API endpoint
@app.route('/chatbot', methods=['POST'])
def chatbot_endpoint():
    """Handle chatbot queries from the frontend."""
    try:
        data = request.get_json(silent=True) or {}
        user_input = str(data.get('message', '')).strip()
        
        if not user_input:
            return jsonify({"error": "Empty message"}), 400
        
        # Use the imported function from codingo_chatbot module
        reply = _codingo_get_response(user_input)
        return jsonify({"response": reply})
        
    except Exception as exc:
        print(f"Chatbot endpoint error: {exc}", file=sys.stderr)
        return jsonify({"error": "I'm having trouble right now. Please try again."}), 500

@app.route('/parse_resume', methods=['POST'])
def parse_resume():
    """
    Parse an uploaded resume (PDF or DOCX) and return extracted
    information in JSON format.

    This endpoint is separate from the main application flow.  It saves
    the uploaded file to a temporary location (via ``handle_resume_upload``)
    so that recruiters can review the original document later, then
    invokes a lightweight parser to extract the candidate's name,
    skills, education and experience.  Errors during upload or
    parsing are reported back to the client.
    """
    file = request.files.get('resume')
    if not file or file.filename == '':
        return jsonify({"error": "No file uploaded"}), 400

    # Save the file using the existing helper.  We ignore the
    # ``features`` return value because ``handle_resume_upload`` no
    # longer parses resumes itself; it simply stores the file and
    # returns the path on disk.
    features, error, filepath = handle_resume_upload(file)
    if error or not filepath:
        return jsonify({"error": "Error processing resume. Please try again."}), 400

    try:
        # Parse the stored file.  Pass both the path and the original
        # filename so that the parser can fall back to the filename
        # when inferring the candidate's name.
        parsed = _parse_resume_helper(filepath, file.filename)
    except Exception as exc:
        # Log to stderr for debugging
        print(f"Resume parsing error: {exc}", file=sys.stderr)
        return jsonify({"error": "Failed to parse resume"}), 500

    # Normalise the response to ensure string values for the form
    response = {
        'name': parsed.get('name', ''),
        'skills': parsed.get('skills', ''),
        'education': parsed.get('education', ''),
        'experience': parsed.get('experience', '')
    }
    return jsonify(response), 200

@app.route("/interview/<int:job_id>")
@login_required
def interview_page(job_id):
    job = Job.query.get_or_404(job_id)
    application = Application.query.filter_by(
        user_id=current_user.id, 
        job_id=job_id
    ).first()
    
    if not application or not application.extracted_features:
        flash("Please apply for this job and upload your resume first.", "warning")
        return redirect(url_for('job_detail', job_id=job_id))
    
    cv_data = json.loads(application.extracted_features)
    return render_template("interview.html", job=job, cv=cv_data)

@app.route('/post_job', methods=['GET', 'POST'])
@login_required
def post_job():
    if current_user.role not in ('recruiter', 'admin'):
        flash('You do not have permission to post jobs.', 'warning')
        return redirect(url_for('jobs'))

    if request.method == 'POST':
        role_title = request.form.get('role', '').strip()
        description = request.form.get('description', '').strip()
        seniority = request.form.get('seniority', '').strip()
        skills_input = request.form.get('skills', '').strip()
        company = request.form.get('company', '').strip()
        # New field: number of interview questions.  Recruiters can specify
        # how many questions the interview should contain.  Default to 3 if
        # the value is missing or invalid.  See templates/post_job.html for
        # the corresponding input element.
        num_questions_raw = request.form.get('num_questions', '').strip()

        errors = []
        if not role_title:
            errors.append('Job title is required.')
        if not description:
            errors.append('Job description is required.')
        if not seniority:
            errors.append('Seniority level is required.')
        if not skills_input:
            errors.append('Skills are required.')
        if not company:
            errors.append('Company name is required.')
        # Validate number of questions; must be a positive integer.  Store
        # errors if the input is provided but invalid.  Missing values will
        # fall back to the default of 3.
        num_questions = 4
        if num_questions_raw:
            try:
                parsed_nq = int(num_questions_raw)
                if parsed_nq <= 0:
                    raise ValueError()
                num_questions = parsed_nq
            except ValueError:
                errors.append('Number of interview questions must be a positive integer.')

        if errors:
            for err in errors:
                flash(err, 'danger')
            return render_template('post_job.html')

        skills_list = [s.strip() for s in re.split(r'[\n,;]+', skills_input) if s.strip()]
        skills_json = json.dumps(skills_list)

        new_job = Job(
            role=role_title,
            description=description,
            seniority=seniority,
            skills=skills_json,
            company=company,
            recruiter_id=current_user.id,
            num_questions=num_questions
        )
        db.session.add(new_job)
        db.session.commit()

        flash('Job posted successfully!', 'success')
        return redirect(url_for('jobs'))

    return render_template('post_job.html')

@app.route('/dashboard')
@login_required
def dashboard():
    if current_user.role not in ('recruiter', 'admin'):
        flash('You do not have permission to access the dashboard.', 'warning')
        return redirect(url_for('index'))

    posted_jobs = Job.query.filter_by(recruiter_id=current_user.id).all()
    job_ids = [job.id for job in posted_jobs]

    candidates_with_scores = []
    if job_ids:
        candidate_apps = Application.query.filter(Application.job_id.in_(job_ids)).all()

        def compute_score(application):
            try:
                candidate_features = json.loads(application.extracted_features) if application.extracted_features else {}
                candidate_skills = candidate_features.get('skills', [])
                job_skills = json.loads(application.job.skills) if application.job and application.job.skills else []
                if not job_skills:
                    return ('Medium', 2)

                candidate_set = {s.lower() for s in candidate_skills}
                job_set = {s.lower() for s in job_skills}
                common = candidate_set & job_set
                ratio = len(common) / len(job_set) if job_set else 0

                if ratio >= 0.75:
                    return ('Excellent', 4)
                elif ratio >= 0.5:
                    return ('Good', 3)
                elif ratio >= 0.25:
                    return ('Medium', 2)
                else:
                    return ('Poor', 1)
            except Exception:
                return ('Medium', 2)

        for app_record in candidate_apps:
            score_label, score_value = compute_score(app_record)
            candidates_with_scores.append({
                'application': app_record,
                'score_label': score_label,
                'score_value': score_value
            })

        candidates_with_scores.sort(key=lambda item: item['score_value'], reverse=True)

    return render_template('dashboard.html', candidates=candidates_with_scores)

if __name__ == '__main__':
    print("Starting Codingo application...")
    
    # Import torch to check GPU availability
    try:
        import torch
        if torch.cuda.is_available():
            print(f"GPU Available: {torch.cuda.get_device_name(0)}")
            print(f"GPU Memory: {torch.cuda.get_device_properties(0).total_memory / 1024**3:.2f} GB")
        else:
            print("No GPU available, using CPU")
    except ImportError:
        print("PyTorch not installed, chatbot will use CPU")
    
    with app.app_context():
        db.create_all()
        # Pre-initialize chatbot on startup for faster first response
        print("Initializing chatbot...")
        try:
            # Initialize the embedder and database
            init_embedder_and_db()
            print("Embedder and database initialized")
            
            # Initialize the LLM (this will download the model if needed)
            init_llm()
            print("LLM initialized successfully")
        except Exception as e:
            print(f"Chatbot initialization error: {e}")
            import traceback
            traceback.print_exc()
    
    # Use port from environment or default to 7860
    port = int(os.environ.get('PORT', 7860))
    app.run(debug=True, host='0.0.0.0', port=port)