from flask import Blueprint, render_template, request, flash, redirect, url_for, current_app
from flask_mail import Message
from itsdangerous import URLSafeTimedSerializer, SignatureExpired, BadSignature
from app.extensions import db, mail, limiter
from app.models import Participant
import traceback

bp = Blueprint('main', __name__)

def get_confirmed_count():
    return Participant.query.filter_by(confirmed=True).count()

def add_user(name, email, looking_for_team, on_waitlist = False):
    new_user = Participant(name=name, email=email, looking_for_team=looking_for_team)
    if on_waitlist:
        new_user.on_waitlist = on_waitlist
    db.session.add(new_user)
    db.session.commit()
    return new_user

def send_verification_email(user, is_new=True):
    if user.num_emails_sent < 5:
        s = URLSafeTimedSerializer(current_app.config['SECRET_KEY'])
        register_token = s.dumps(user.email, salt='email-confirm-h4tum-ctf-2025')
        remove_token = s.dumps(user.email, salt='email-remove-h4tum-ctf-2026')
        register_link = url_for('main.verify_email', token=register_token, _external=True)
        remove_link = url_for('main.remove_registration', token=remove_token, _external=True)
        logo = url_for('static', filename='h4tum_white.png', _external=True)
        
        msg = Message('Verify your CTF Registration', recipients=[user.email])
        msg.html = render_template("email.html", user_name=user.name, register_link=register_link, remove_link=remove_link, logo_url=logo)
        mail.send(msg)
        current_app.logger.info(f"Sent verification email to {user.email}")
        user.num_emails_sent += 1
        db.session.commit()
        if is_new:
            flash("Registration started! Check your email to confirm your spot.", "success")
        else:
            flash("Confirmation email resent. Please check your inbox.", "info")
    else:
        flash("Email limit reached", "error")

def send_waitlist_email(user):
    msg = Message('h4tum CTF 2026 Registration', recipients=[user.email])
    logo = url_for('static', filename='h4tum_white.png', _external=True)
    msg.html = render_template("waitlist_email.html", logo_url=logo, user_name=user.name)
    current_app.logger.info(msg)
    mail.send(msg)

def send_waitlist_newsletter():
    results = db.session.query(Participant.email).filter(Participant.on_waitlist == True).all()
    waitlist_emails = [r[0] for r in results]
    logo = url_for('static', filename='h4tum_white.png', _external=True)
    s = URLSafeTimedSerializer(current_app.config['SECRET_KEY'])
    for email in waitlist_emails:
        register_token = s.dumps(email, salt='email-confirm-h4tum-ctf-2025')
        register_link = url_for('main.verify_email', token=register_token, _external=True)
        remove_token = s.dumps(email, salt='email-remove-h4tum-ctf-2026')
        remove_link = url_for('main.remove_registration', token=remove_token, _external=True)
        msg = Message('h4tum CTF 2026 Free Spot available', recipients=[email])
        msg.html = render_template("waitlist_maillist_email.html", logo_url=logo, register_link=register_link, remove_link=remove_link)
        mail.send(msg)
        current_app.logger.info(f"Sent waitlist newsletter email to {email}")

@bp.route('/', methods=['GET', 'POST'])
@limiter.limit("5 per hour", methods=["POST"])
def index():
    confirmed_count = get_confirmed_count()
    max_spots = current_app.config['MAX_SPOTS']
    spots_left = max_spots - confirmed_count

    if request.method == 'POST':
        name = request.form['name']
        email = request.form['email'].lower().strip()
        looking_for_team = True if request.form.get('looking_for_team') else False
        
        tum_domains = current_app.config['TUM_DOMAINS']
        if not email.endswith(tum_domains):
            domains_str = ", ".join(tum_domains)
            flash(f"Error: You must use one of these email addresses: {domains_str}", "error")
            return redirect(url_for('main.index'))
        existing_user = Participant.query.filter_by(email=email).first()

        if existing_user:
            if existing_user.confirmed:
                flash("You are already registered and confirmed!", "info")
            elif existing_user.on_waitlist:
                if confirmed_count < max_spots:
                    existing_user.on_waitlist = False
                    db.session.commit()
                    send_verification_email(existing_user)
                else:
                    flash("You are already on the waitlist", "info")
            else:
                send_verification_email(existing_user, is_new=False)
            return redirect(url_for('main.index'))
        else:
            new_user = add_user(name, email, looking_for_team) 

            if confirmed_count < max_spots:
                send_verification_email(new_user)
            else:
                new_user.on_waitlist = True
                db.session.commit()
                send_waitlist_email(new_user)
                flash("The event is already full!\nYou have been placed on the waitlist", "info")
            return redirect(url_for('main.index'))

    return render_template('index.html', spots_left=spots_left, max_spots=max_spots)


@bp.route('/verify/<token>')
@limiter.limit("50 per hour")
def verify_email(token):
    s = URLSafeTimedSerializer(current_app.config['SECRET_KEY'])
    try:
        email = s.loads(token, salt='email-confirm-h4tum-ctf-2025', max_age=1209600)
    except SignatureExpired:
        return render_template("error.html", error_message="Token expired. Please register again.")
    except BadSignature:
        return render_template("error.html", error_message="Invalid token.")

    user = Participant.query.filter_by(email=email).first_or_404()

    if get_confirmed_count() >= current_app.config['MAX_SPOTS']:
        if user.confirmed:
            return render_template('success.html', message="You are confirmed", discord_link=current_app.config['DISCORD_LINK'], discord_token=user.discord_token)
        else:
            return render_template("error.html", error_message="Sorry! The event filled up while you were claiming the last spot.")
    else:
        user.confirmed = True
        if user.on_waitlist:
            user.on_waitlist = False
        db.session.commit()

        discord_link = current_app.config['DISCORD_LINK']
        discord_token = user.discord_token
        msg = "You are confirmed!"
        if user.looking_for_team:
            msg += " Since you need a team, please join the #team-search channel."
        
        return render_template('success.html', message=msg, discord_link=discord_link, discord_token=discord_token)

@bp.route('/remove/<token>')
@limiter.limit("5 per hour")
def remove_registration(token):
    s = URLSafeTimedSerializer(current_app.config['SECRET_KEY'])
    try:
        email = s.loads(token, salt='email-remove-h4tum-ctf-2026', max_age=1209600)
    except SignatureExpired:
        return render_template("error.html", error_message="Token expired. Please register again.")
    except BadSignature:
        return render_template("error.html", error_message="Invalid token.")

    user = Participant.query.filter_by(email=email).first_or_404()

    if not user:
        return render_template("error.html", error_message="No user found.")
    db.session.delete(user)
    db.session.commit()

    if get_confirmed_count() == current_app.config['MAX_SPOTS'] - 1:
        send_waitlist_newsletter()

    return render_template("deregistered.html", message="Sad to see you go. Comeback next time :D")

@bp.route('/dsgvo')
@limiter.exempt
def dsgvo():
    return render_template('dsgvo.html')

@bp.route('/impressum')
@limiter.exempt
def impressum():
    return render_template('impressum.html')

@bp.route('/rules')
@limiter.exempt
def rules():
    return render_template('rules.html')

@bp.errorhandler(429)
def ratelimit_handler(e):
    msg = Message('429 Ratelimit hit', recipients=["simon.bussmann@tum.de"])
    msg.body = f"IP {request.remote_addr} triggered the rate limit"
    mail.send(msg)
    return render_template("ratelimit_error.html", error_message=e.description), 429

@bp.errorhandler(500)
def server_error(e):
    msg = Message('500 Error on registration Website', recipients=["simon.bussmann@tum.de"])
    full_traceback = traceback.format_exc()
    
    msg.body = f"An error occurred during registration:\n\n{full_traceback}"
    mail.send(msg)

    return render_template("error.html", error_message="Internal Server Error. Admin has been notified!"), 500