import os
import re
from datetime import datetime
from typing import List, cast

import flask_login
from flask_socketio import join_room

import pytz
from flask import (
    Blueprint,
    abort,
    current_app, # Used for logging
    flash,
    make_response,
    redirect,
    render_template,
    request,
    send_from_directory,
    session,
    url_for,
)

from . import socketio

from .auth import check_password, user_loader
from .forms import DeckForm, InfoBannerForm, LoginForm, PasswordForm
from .models import Course, Deck, InfoBanner, Password, db
from .utils import (
    create_token,
    generate_password,
    get_active_banner,
    get_all_courses,
    get_available_decks,
    get_passwords,
    get_token,
    get_unlocked_decks,
    is_deck_unlocked,
    retrieve_token,
    serialize_token,
    update_token,
    get_course
)


main = Blueprint('main', __name__)
slidev_deck_pattern = re.compile(r"^\/slides\/[^\/]+\/[^\/]+\/(?:\d+|index\.html)(?:\?.*)?$")
slidev_all_pattern = re.compile(r"^\/slides\/([^\/]+)\/([^\/]+)(?:\/presenter)?\/(\d+)(?:\?.*)?$")

@socketio.on("connect")
def on_connect():
    if flask_login.current_user.is_authenticated:
        join_room("instructor")
        current_app.logger.info(f"Instructor connected to socket: {flask_login.current_user.id}")

@main.after_request
def inject_confused_button(response):
    if (slidev_deck_pattern.match(request.path) or request.path == '/') and response.content_type.startswith('text/html') and not flask_login.current_user.is_authenticated :
        if response.direct_passthrough:
            response.direct_passthrough = False
        body = response.get_data(as_text=True)
        insert_at = body.find('</body>')
        if insert_at != -1:
            button_html = """
            <button id="confused-button" style="
                position: fixed;
                bottom: 1.5rem;
                right: 1.5rem;
                z-index: 9999;
                background-color: #4f8cff;
                color: white;
                font-size: 1rem;
                font-weight: bold;
                border: none;
                border-radius: 9999px;
                padding: 1rem;
                box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
                cursor: pointer;
                transition: background-color 0.3s, transform 0.2s;"
                title="Didn't understand? Click!">
              Ich habe das nicht verstanden
            </button>
            <script>
            document.getElementById('confused-button').addEventListener('click', () => {
                fetch('/confused', {method: 'POST'})
                  .then(response => {
                    if (response.ok) {
                      alert('Alles klar! Ich versuche es besser zu erklären. Melde dich, wenn du eine spezifische Frage hast oder noch etwas unklar bleibt.');
                    }
                  }).catch(error => console.error('Error:', error));
            });
            </script>
            """
            body = body[:insert_at] + button_html + body[insert_at:]
            response.set_data(body)
    return response


@main.route('/')
def index():
    token = get_token()
    if not token:
        current_app.logger.debug("User has no token. Redirecting to set_token.")
        return redirect(url_for("main.set_token")) 
    else:
        current_app.logger.debug(f"User {token.name} is viewing index with {len(token.decks)} decks unlocked.")
        return render_template('index.html', active_banner=get_active_banner(), decks=get_unlocked_decks(token), user_name=token.name, active_course_name=token.active_course.name, courses=get_all_courses())

def set_cookie(token):
    next_url = session.pop('next_url', None)
    if not next_url:
        current_app.logger.debug("next_url not present redirecting to index")
        next_url = url_for("main.index")

    resp = make_response(redirect(next_url))
    resp.set_cookie(
            'access_token',
            serialize_token(token),
            httponly=True,
            samesite='Lax',
            path='/'
        )    
    return resp

@main.route('/set_token', methods=['POST', 'GET'])
def set_token():
    """
    Handles.
    GET: Renders the registration form.
    POST: Processes the form submission.
    """
    if request.method == 'POST':
        # Get form data
        username = request.form.get('username')

        # Simple validation
        if not username:
            current_app.logger.debug("Login failed: No username supplied")
            flash('Username is required.', 'error')
            return render_template('set_token.html')

        token = retrieve_token(username)
        
        if not token:
            flash(f'The username "{username}" does not exist.', 'error')
            current_app.logger.warning(f"Login failed: Username '{username}' not found.")
            return render_template('set_token.html')

        current_app.logger.info(f"User logged in: {username}")
        return set_cookie(token)

    return render_template('set_token.html')


@main.route('/register', methods=['POST', 'GET'])
def register():
    """
    Handles user registration.
    GET: Renders the registration form.
    POST: Processes the form submission.
    """
    if request.method == 'POST':
        # Get form data
        user_name = request.form.get('username')
        acknowledge = request.form.get('acknowledge')

        # Simple validation
        if not user_name:
            flash('Username is required.', 'error')
            current_app.logger.debug("Username is required for registering")
            return render_template('register.html')
        
        if retrieve_token(user_name):
            flash(f'The username "{user_name}" is already taken.', 'error')
            current_app.logger.debug(f"Username {user_name} is already registered")
            return render_template('register.html')
        
        if not acknowledge:
            flash('You must acknowledge the important information to proceed.', 'error')
            current_app.logger.debug("User did not acknowledge register information")
            return render_template('register.html')

        # If all validation passes, "register" the user
        token = create_token(user_name) 
        current_app.logger.info(f"New user registered: {user_name}")

        return set_cookie(token)

    # If GET request, render the form
    return render_template('register.html')

@main.route('/logout', methods=['POST'])
def logout():
    token = get_token()
    user_name = token.name if token else "Unknown"
    current_app.logger.info(f"User logout: {user_name}")
    
    resp = make_response(redirect(url_for('main.index'))) # Redirect to a safe page, e.g., index or login
    resp.set_cookie('access_token', '', expires=0) # Clears the cookie
    return resp

@main.route('/switch_course/<new_course>', methods=['POST'])
def switch_course(new_course: int):
    token = get_token() 

    if not token:
        return redirect(url_for('main.set_token'))

    switched = get_course(new_course)

    if switched:
        token.active_course = switched 
        db.session.commit()
        current_app.logger.info(f"User {token.name} switched to course: {switched.name}")
    else:
        current_app.logger.warning(f"User {token.name} attempted to switch to invalid course ID: {new_course}")

    return redirect(url_for("main.index"))


@main.route('/admin/login', methods=['POST', 'GET'])
def admin_login():
    form = LoginForm()
    if form.validate_on_submit():
        assert isinstance(form.user_name.data, str)
        assert isinstance(form.password.data, str)
        user_name: str = form.user_name.data
        password: str = form.password.data
        user = user_loader(user_name)
        if user and check_password(user, password):
            flask_login.login_user(user)
            current_app.logger.info(f"Admin login successful: {user_name}")
            next = request.args.get('next')
            if next is None:
                return redirect(url_for('main.index'))

            if not next.startswith('/admin'):
                return abort(400)

            return redirect(next)
        else:
            current_app.logger.warning(f"Failed admin login attempt: {user_name}")
            flash('Incorrect username or password. Please try again.', 'error')
    return render_template("admin_login.html", form=form)


def process_access_code(access_code: str):
    token = get_token() 

    if not token:
        # remember where the user wanted to go
        session['next_url'] = url_for('main.access_get', access_code=access_code)
        current_app.logger.debug("Access code used without session. Redirecting to login.")
        return redirect(url_for('main.set_token'))

    password = db.session.execute(
        db.select(Password)
          .where(Password.value == access_code)
    ).scalar_one_or_none()

    if password is not None:
        if not password.is_expired():
            update_token(password.decks)
            current_app.logger.info(f"User {token.name} used valid access code.")
        else:
            current_app.logger.info(f"User {token.name} used expired access code.")
            flash('Password has expired. Please obtain a new one.', 'expired')
    else:
        current_app.logger.warning(f"User {token.name} used invalid access code: {access_code}")
        flash('Password is not valid. Please check the code and try again.', 'error')    
    return redirect(url_for('main.index'))

@main.route('/access', methods=['POST'])
def access_post():
    access_code = request.form.get('password')
    
    if not access_code:
        return redirect(url_for("main.index"))
        
    return process_access_code(access_code)

# Route for direct link/QR code access (GET)
@main.route('/access/<access_code>', methods=['GET'])
def access_get(access_code: str):
    return process_access_code(access_code)


@main.route('/confused', methods=['POST'])
def confused():
    socketio.emit(
        "confused",
        {
            "time": datetime.utcnow().isoformat()
        },
        to="instructor"
    )
    return ("", 204)

def log_404(reason: str, deck: str, course: str, path: str):
    """
    Helper function to log 404 errors with the user's identity.
    Uses current_app.logger to ensure logs are handled by the app's config.
    """
    token = get_token()
    user_identity = f"User: {token.name} (ID: {token.id})" if token else "User: Anonymous"
    current_app.logger.warning(f"404 Not Found [{reason}] | {user_identity} | Resource: {course}/{deck}/{path}")

@main.route('/slides/<course_folder>/<deck>/')
@main.route('/slides/<course_folder>/<deck>/<path:path>')
def serve_deck(deck, course_folder, path='index.html'):
    course = db.session.execute(db.select(Course).where(Course.folder==course_folder)).scalar()
    
    if not course:
        log_404("Course not found", deck, course_folder, path)
        abort(404)
    assert isinstance(course, Course)
    
    deck_obj = db.session.execute(db.select(Deck).where(Deck.deck == deck, Deck.course_id == course.id)).scalar()
    if not deck_obj:
        log_404("Deck not in database", deck, course_folder, path)
        abort(404)
    assert isinstance(deck_obj, Deck)

    if not is_deck_unlocked(deck_obj.deck):
        # We generally do not log redirects for locked content as 404s, 
        # but you could log a warning here if desired.
        current_app.logger.info(f"Access denied (locked) for user {get_token().name if get_token() else 'Anon'} -> {deck_obj.name}")
        return redirect(url_for('main.index'))

    slides_dir = os.path.join(current_app.config['SLIDES_DIR'], course.folder)
    deck_path = os.path.join(slides_dir, deck_obj.deck)

    if not os.path.exists(deck_path):
        log_404("Deck directory missing on disk", deck, course_folder, path)
        return f"Deck '{deck_obj.name}' not found.", 404

    if slidev_all_pattern.match(request.path):
        current_app.logger.info(f"User reloaded in deck {deck_obj.name}")
        return send_from_directory(deck_path, deck_obj.index_file)

    requested_file = os.path.join(deck_path, path)
    if os.path.isfile(requested_file):
        if path == deck_obj.index_file:
            current_app.logger.info(f"User {get_token().name if get_token() else 'Anon'} accessed deck {deck_obj.name}")
        return send_from_directory(deck_path, path)

    log_404("File missing within deck", deck, course_folder, path)
    abort(404)


@main.route('/exports/<course_folder>/<deck>/<path>')
def serve_export(deck, course_folder, path):
    course = db.session.execute(db.select(Course).where(Course.folder==course_folder)).scalar()
    if not course:
        log_404("Export: Course not found", deck, course_folder, path)
        abort(404)
    assert isinstance(course, Course)
    
    deck_obj = db.session.execute(db.select(Deck).where(Deck.deck==deck, Deck.course_id == course.id)).scalar()
    if not deck_obj:
        log_404("Export: Deck not in database", deck, course_folder, path)
        abort(404)
    assert isinstance(deck_obj, Deck)

    if not is_deck_unlocked(deck_obj.deck):
        return redirect(url_for('main.index'))
    
    exports_dir = os.path.join(current_app.config['EXPORTS_DIR'], course.folder)
    deck_path = os.path.join(exports_dir, deck_obj.deck)
    requested_file = os.path.join(deck_path, path)
    if os.path.isfile(requested_file):
        current_app.logger.info(f"User {get_token().name if get_token() else 'Anon'} exported deck {deck_obj.name}")
        return send_from_directory(deck_path, path)
    
    log_404("Export file missing", deck, course_folder, path)
    abort(404)


@main.route('/admin', methods=['GET', 'POST'])
@flask_login.login_required
def admin():
    active_course = get_course(flask_login.current_user.active_course_id)
    if active_course is None:
        current_app.logger.error(f"Admin user {flask_login.current_user.id} has no active_course_id.")
        raise Exception
    deck_form = DeckForm()
    password_form = PasswordForm()
    if request.method == 'GET': 
        password_form.value.data = generate_password()
    deck_form.deck.choices = get_available_decks(current_app, active_course)
    decks = active_course.decks 
    password_form.decks.choices = [(deck.id, deck.name) for deck in decks]


    if request.method == 'POST':
        if "submit_deck" in request.form and deck_form.validate():
            deck = Deck(
                name=cast(str,deck_form.name.data),
                deck=deck_form.deck.data,
                course=active_course,
                description=cast(str,deck_form.description.data),
            )
            db.session.add(deck)
            db.session.commit()
            current_app.logger.info(f"Admin created deck: {deck.name}")

        if "submit_password" in request.form:
            if password_form.validate():
                value: str = password_form.value.data
                expires_at: datetime | None = password_form.expires_at.data
                if expires_at:
                    tz = pytz.timezone('Europe/Berlin')
                    utc = pytz.utc
                    expires_at = tz.localize(expires_at).astimezone(utc)
                password = Password(
                    value=value,
                    expires_at=expires_at
                )
                decks = db.session.execute(db.select(Deck).filter(Deck.id.in_(cast(List[Deck], password_form.decks.data)))).scalars()
                password.decks.extend(decks)
                db.session.add(password)
                db.session.commit()
                current_app.logger.info(f"Admin created password: {value} (Expires: {expires_at})")
            else:
                # Form was submitted but validation failed
                for field, errors in password_form.errors.items():
                    for error in errors:
                        current_app.logger.warning(f"Admin form validation error ({field}): {error}")
        return redirect(url_for('main.admin'))

    return render_template("admin.html", deck_form=deck_form, password_form=password_form, decks=decks, passwords=get_passwords(active_course), courses=get_all_courses(), active_course_name=active_course.name)

@main.route('/admin/switch_course/<new_course>', methods=['POST'])
@flask_login.login_required
def switch_course_admin(new_course: int):
    user = flask_login.current_user
    if get_course(new_course):
        user.active_course_id = new_course
        current_app.logger.info(f"Admin {user.id} switched to course ID {new_course}")
    return redirect(url_for("main.admin"))

@main.route('/admin/banner', methods=['POST', 'GET'])
@flask_login.login_required
def banner():
    banner_form = InfoBannerForm()
    if banner_form.validate_on_submit():
        assert isinstance(banner_form.content.data, str)
        content : str = banner_form.content.data
        banner = InfoBanner(content=content)
        db.session.add(banner)
        db.session.commit()
        current_app.logger.info(f"Admin added banner: {content[:30]}...")
    return render_template("banner.html", banner_form=banner_form, banners=db.session.execute(db.select(InfoBanner)).scalars())

@main.route('/admin/decks/<int:deck_id>/delete', methods=['POST'])
@flask_login.login_required
def delete_deck(deck_id: int):
    deck = Deck.query.get_or_404(deck_id)
    current_app.logger.info(f"Admin deleted deck: {deck.name}")
    db.session.delete(deck)
    db.session.commit()
    return redirect(url_for('main.admin'))

@main.route('/admin/passwords/<int:password_id>/delete', methods=['POST'])
@flask_login.login_required
def delete_password(password_id: int):
    password = Password.query.get_or_404(password_id)
    current_app.logger.info(f"Admin deleted password ID {password_id}")
    db.session.delete(password)
    db.session.commit()
    return redirect(url_for('main.admin'))

@main.route('/admin/banner/show/<int:banner_id>', methods=['POST'])
@flask_login.login_required
def set_active_banner(banner_id):
    banner = InfoBanner.query.get(banner_id)
    if banner:
        # ensures that only one banner is active at all times
        active_banner = get_active_banner()
        if active_banner:
            active_banner.is_active = False
        banner.is_active = True
        db.session.commit()
        current_app.logger.info(f"Admin activated banner ID {banner_id}")
    return redirect(url_for('main.banner'))

@main.route('/admin/banner/hide', methods=['POST'])
@flask_login.login_required
def hide_active_banner():
    banner = get_active_banner() 
    if banner:
        banner.is_active = False
        db.session.commit()
        current_app.logger.info("Admin hid active banner")
    return redirect(url_for('main.banner'))

@main.route('/admin/confused')
@flask_login.login_required
def confused_notifications():
    return render_template("confused.html")