import os
import uuid
import smtplib
import pytz
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from itsdangerous import URLSafeTimedSerializer
from werkzeug.security import generate_password_hash, check_password_hash
from flask import Flask, render_template, jsonify, redirect, url_for, request, session, send_from_directory, make_response
from icalendar import Calendar, Event as ICalEvent
from .db import init_db, engine
from . import config, auth, assistant
from sqlmodel import Session, select
from .models import User, Event, GlobalStatus, Project, PortalFile, UserSession, ProjectMember
from datetime import datetime, timezone, timedelta
from functools import wraps

app = Flask(__name__)
app.secret_key = config.WEB_SECRET
serializer = URLSafeTimedSerializer(app.secret_key)

MSK = pytz.timezone("Europe/Moscow")

def to_msk(dt):
    """UTC → Europe/Moscow для отображения в шаблонах и API."""
    if dt is None: return None
    if dt.tzinfo is None: dt = dt.replace(tzinfo=timezone.utc)
    return dt.astimezone(MSK)

@app.template_filter("msk_strftime")
def _msk_strftime(dt, fmt):
    if dt is None: return ""
    return to_msk(dt).strftime(fmt)

UPLOAD_FOLDER = '/var/lib/gitea/portal-files'
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
app.config['MAX_CONTENT_LENGTH'] = 100 * 1024 * 1024 

with app.app_context():
    init_db()
    with Session(engine) as db_session:
        status = db_session.exec(select(GlobalStatus)).first()
        if not status:
            db_session.add(GlobalStatus(status="free", message="Вне расписания"))
            db_session.commit()

@app.before_request
def validate_session():
    if "session_id" in session:
        with Session(engine) as db_session:
            db_sess = db_session.exec(select(UserSession).where(UserSession.session_token == session["session_id"])).first()
            if not db_sess:
                session.clear()
                return redirect(url_for("login"))

def send_email(to_email, subject, body):
    if not config.SMTP_SERVER:
        print("\n" + "="*50, flush=True)
        print(f"📧 EMAIL ДЛЯ: {to_email}", flush=True)
        print(f"Тема: {subject}", flush=True)
        print(body, flush=True)
        print("="*50 + "\n", flush=True)
        return True
    
    try:
        msg = MIMEMultipart()
        msg['From'] = config.SMTP_FROM
        msg['To'] = to_email
        msg['Subject'] = subject
        msg.attach(MIMEText(body, 'plain'))
        
        server = smtplib.SMTP(config.SMTP_SERVER, config.SMTP_PORT)
        server.starttls()
        server.login(config.SMTP_USER, config.SMTP_PASSWORD)
        server.send_message(msg)
        server.quit()
        return True
    except Exception as e:
        print(f"Ошибка отправки email: {e}", flush=True)
        return False

def require_role(allowed_roles):
    if isinstance(allowed_roles, str):
        allowed_roles = [allowed_roles]
    def decorator(f):
        @wraps(f)
        def decorated_function(*args, **kwargs):
            if session.get("role") not in allowed_roles:
                return "403: Доступ запрещен.", 403
            return f(*args, **kwargs)
        return decorated_function
    return decorator

def login_required(f):
    @wraps(f)
    def decorated_function(*args, **kwargs):
        if not session.get("user_id"):
            return redirect(url_for("login"))
        return f(*args, **kwargs)
    return decorated_function

def parse_datetime(dt_str):
    """Ввод из формы — в Europe/Moscow, сохраняем как UTC."""
    if not dt_str: return None
    clean_str = dt_str.replace('T', ' ').strip()
    if len(clean_str) > 16: clean_str = clean_str[:16]
    naive = datetime.strptime(clean_str, "%Y-%m-%d %H:%M")
    return MSK.localize(naive).astimezone(timezone.utc)

@app.route("/healthz")
def healthz():
    try:
        from sqlalchemy import text
        with engine.connect() as conn:
            conn.execute(text("SELECT 1"))
        return jsonify({"status": "ok", "db": "ok"})
    except Exception as e:
        return jsonify({"status": "error", "db": str(e)}), 503

@app.route("/")
def index():
    return render_template("index.html", username=session.get("username"))

# --- АУТЕНТИФИКАЦИЯ ---
@app.route("/register", methods=["GET", "POST"])
def register():
    if request.method == "POST":
        username = request.form.get("username")
        email = request.form.get("email")
        password = request.form.get("password")
        full_name = request.form.get("full_name")
        organization = request.form.get("organization")
        
        with Session(engine) as db_session:
            if db_session.exec(select(User).where(User.username == username)).first():
                return render_template("register.html", error="Логин уже занят")
            if db_session.exec(select(User).where(User.email == email)).first():
                return render_template("register.html", error="Email уже используется")
                
            new_user = User(username=username, email=email, password_hash=generate_password_hash(password), full_name=full_name, organization=organization, role="student", is_verified=False)
            db_session.add(new_user)
            db_session.commit()
            
            token = serializer.dumps(email, salt='email-confirm')
            confirm_url = url_for('verify_email', token=token, _external=True).replace("127.0.0.1:8000", "portal.morozovka.space").replace("http://", "https://")
            send_email(email, "Подтверждение почты", f"Привет, {full_name}!\nДля подтверждения перейди по ссылке:\n{confirm_url}\n")
            
        return render_template("login.html", msg="Регистрация успешна. Проверьте почту (или логи сервера).")
    return render_template("register.html")

@app.route("/verify_email/<token>")
def verify_email(token):
    try: email = serializer.loads(token, salt='email-confirm', max_age=86400)
    except Exception: return "Ссылка недействительна или устарела.", 400
        
    with Session(engine) as db_session:
        user = db_session.exec(select(User).where(User.email == email)).first()
        if user:
            user.is_verified = True
            db_session.add(user)
            db_session.commit()
            return redirect(url_for("login", msg="Почта подтверждена! Теперь можно войти."))
    return "Пользователь не найден.", 404

@app.route("/login", methods=["GET", "POST"])
def login():
    if request.method == "POST":
        username = request.form.get("username")
        password = request.form.get("password")
        
        with Session(engine) as db_session:
            user = db_session.exec(select(User).where(User.username == username)).first()
            if not user or not user.password_hash or not check_password_hash(user.password_hash, password):
                return render_template("login.html", error="Неверный логин или пароль")
            if not user.is_verified:
                return render_template("login.html", error="Подтвердите почту перед входом")
                
            session_token = str(uuid.uuid4())
            db_session.add(UserSession(session_token=session_token, user_id=user.id, ip_address=request.remote_addr, user_agent=request.user_agent.string))
            db_session.commit()
            
            session["user_id"] = user.id
            session["username"] = user.username
            session["role"] = user.role
            session["session_id"] = session_token
            return redirect(url_for("index"))
            
    msg = request.args.get("msg")
    return render_template("login.html", msg=msg)

@app.route("/login/gitea")
def login_gitea():
    gitea_auth_url = (
        f"{config.GITEA_PUBLIC_URL}/login/oauth/authorize"
        f"?client_id={config.GITEA_CLIENT_ID}&response_type=code"
        f"&redirect_uri={config.GITEA_REDIRECT_URI}"
        f"&scope=read:user"
    )
    return redirect(gitea_auth_url)

@app.route("/auth/callback")
def auth_callback():
    code = request.args.get("code")
    if not code: return "Ошибка авторизации Gitea", 400
    token = auth.get_gitea_token(code)
    if not token: return "Ошибка токена Gitea", 400
    gitea_user = auth.get_gitea_user(token)
    if not gitea_user: return "Ошибка профиля Gitea", 400

    with Session(engine) as db_session:
        user = db_session.exec(select(User).where(User.gitea_id == gitea_user["id"])).first()
        if not user:
            user = db_session.exec(select(User).where(User.email == gitea_user.get("email"))).first()
            if user:
                user.gitea_id = gitea_user["id"]
            else:
                existing_admin = db_session.exec(select(User).where(User.role == "admin")).first()
                bootstrap_role = "admin" if not existing_admin else "student"
                user = User(gitea_id=gitea_user["id"], username=gitea_user["login"], full_name=gitea_user.get("full_name"), email=gitea_user.get("email"), role=bootstrap_role, is_verified=True)
                db_session.add(user)
            db_session.commit()
            
        session_token = str(uuid.uuid4())
        db_session.add(UserSession(session_token=session_token, user_id=user.id, ip_address=request.remote_addr, user_agent=request.user_agent.string))
        db_session.commit()
        
        session["user_id"] = user.id
        session["username"] = user.username
        session["role"] = user.role
        session["session_id"] = session_token
    return redirect(url_for("index"))

@app.route("/logout")
def logout():
    if "session_id" in session:
        with Session(engine) as db_session:
            db_sess = db_session.exec(select(UserSession).where(UserSession.session_token == session["session_id"])).first()
            if db_sess:
                db_session.delete(db_sess)
                db_session.commit()
    session.clear()
    return redirect(url_for("index"))

@app.route("/forgot_password", methods=["GET", "POST"])
def forgot_password():
    if request.method == "POST":
        email = request.form.get("email")
        with Session(engine) as db_session:
            user = db_session.exec(select(User).where(User.email == email)).first()
            if user:
                token = serializer.dumps(email, salt='password-reset')
                reset_url = url_for('reset_password', token=token, _external=True).replace("127.0.0.1:8000", "portal.morozovka.space").replace("http://", "https://")
                send_email(email, "Сброс пароля", f"Для сброса пароля перейди по ссылке:\n{reset_url}\n")
        return render_template("login.html", msg="Если такой email есть, инструкция отправлена.")
    return render_template("forgot_password.html")

@app.route("/reset_password/<token>", methods=["GET", "POST"])
def reset_password(token):
    try: email = serializer.loads(token, salt='password-reset', max_age=3600)
    except Exception: return "Ссылка недействительна или устарела.", 400
        
    if request.method == "POST":
        with Session(engine) as db_session:
            user = db_session.exec(select(User).where(User.email == email)).first()
            if user:
                user.password_hash = generate_password_hash(request.form.get("password"))
                db_session.add(user)
                db_session.commit()
                return redirect(url_for("login", msg="Пароль успешно изменен!"))
    return render_template("reset_password.html", token=token)

@app.route("/sessions")
@login_required
def sessions_list():
    with Session(engine) as db_session:
        sessions = db_session.exec(select(UserSession).where(UserSession.user_id == session.get("user_id")).order_by(UserSession.created_at.desc())).all()
    return render_template("sessions.html", sessions=sessions, current_token=session.get("session_id"))

@app.route("/sessions/logout_all", methods=["POST"])
@login_required
def logout_all():
    with Session(engine) as db_session:
        for s in db_session.exec(select(UserSession).where(UserSession.user_id == session.get("user_id"))).all():
            db_session.delete(s)
        db_session.commit()
    session.clear()
    return redirect(url_for("login", msg="Вы вышли со всех устройств."))

@app.route("/profile")
@login_required
def profile():
    with Session(engine) as db_session:
        user = db_session.get(User, session.get("user_id"))
    return render_template("profile.html", user=user)

# --- РАСПИСАНИЕ (ПУБЛИЧНОЕ И АДМИНКА) ---
@app.route("/schedule")
def public_schedule():
    with Session(engine) as db_session:
        current_status = db_session.exec(select(GlobalStatus)).first()
        now = datetime.now(timezone.utc)
        events = db_session.exec(
            select(Event)
            .where(Event.is_public == True)
            .where(Event.start_time >= now - timedelta(days=180))
            .where(Event.start_time <= now + timedelta(days=365))
            .order_by(Event.start_time)
        ).all()

    events_json = [
        {
            "id": e.id,
            "title": e.title,
            "type": e.event_type,
            "start": to_msk(e.start_time).isoformat(),
            "end": to_msk(e.end_time).isoformat(),
            "location": e.location,
            "description": e.description,
        }
        for e in events
    ]
    return render_template("schedule.html", status=current_status, events_json=events_json)

@app.route("/schedule/export.ics")
def export_ics():
    with Session(engine) as db_session:
        events = db_session.exec(select(Event).where(Event.is_public == True)).all()

    cal = Calendar()
    cal.add('prodid', '-//Morozovka Portal//mxm.dk//')
    cal.add('version', '2.0')

    for ev in events:
        ievent = ICalEvent()
        ievent.add('summary', ev.title)
        ievent.add('dtstart', ev.start_time.astimezone(pytz.utc))
        ievent.add('dtend', ev.end_time.astimezone(pytz.utc))
        if ev.location:
            ievent.add('location', ev.location)
        if ev.description:
            ievent.add('description', ev.description)
        cal.add_component(ievent)

    response = make_response(cal.to_ical())
    response.headers["Content-Disposition"] = "attachment; filename=morozovka_schedule.ics"
    response.headers["Content-Type"] = "text/calendar; charset=utf-8"
    return response

@app.route("/api/assistant", methods=["POST"])
def api_assistant():
    data = request.get_json()
    if not data or "message" not in data: return jsonify({"error": "Нет сообщения"}), 400
    return jsonify({"reply": assistant.get_response(data["message"])})

@app.route("/admin/schedule")
@require_role(["admin", "professor"])
def admin_schedule():
    with Session(engine) as db_session:
        current_status = db_session.exec(select(GlobalStatus)).first()
        events = db_session.exec(select(Event).order_by(Event.start_time.desc()).limit(50)).all()
    return render_template("admin_schedule.html", status=current_status, events=events)

@app.route("/admin/schedule/status", methods=["POST"])
@require_role(["admin", "professor"])
def update_status():
    status_val = request.form.get("status")
    delay = int(request.form.get("delay_minutes") or 0)
    message = request.form.get("message")
    with Session(engine) as db_session:
        current_status = db_session.exec(select(GlobalStatus)).first()
        if current_status:
            current_status.status = status_val
            current_status.delay_minutes = delay
            current_status.message = message
            current_status.updated_at = datetime.now(timezone.utc)
            db_session.add(current_status)
            db_session.commit()
    return redirect(url_for("admin_schedule"))

@app.route("/admin/schedule/event/add", methods=["POST"])
@require_role(["admin", "professor"])
def add_event():
    title = request.form.get("title")
    event_type = request.form.get("event_type")
    start_time = parse_datetime(request.form.get("start_time"))
    end_time = parse_datetime(request.form.get("end_time"))
    with Session(engine) as db_session:
        db_session.add(Event(title=title, event_type=event_type, start_time=start_time, end_time=end_time, location=request.form.get("location"), description=request.form.get("description"), is_public=request.form.get("is_public") == "on"))
        db_session.commit()
    return redirect(url_for("admin_schedule"))

@app.route("/admin/schedule/event/<int:event_id>/edit", methods=["GET", "POST"])
@require_role(["admin", "professor"])
def edit_event(event_id):
    with Session(engine) as db_session:
        event = db_session.get(Event, event_id)
        if not event: return "Событие не найдено", 404

        if request.method == "POST":
            event.title = request.form.get("title")
            event.event_type = request.form.get("event_type")
            event.start_time = parse_datetime(request.form.get("start_time"))
            event.end_time = parse_datetime(request.form.get("end_time"))
            event.location = request.form.get("location")
            event.description = request.form.get("description")
            event.is_public = request.form.get("is_public") == "on"
            event.manually_edited = True
            db_session.add(event)
            db_session.commit()
            return redirect(url_for("admin_schedule"))

    return render_template("admin_event_edit.html", event=event)

@app.route("/admin/schedule/event/<int:event_id>/delete", methods=["POST"])
@require_role(["admin", "professor"])
def delete_event(event_id):
    with Session(engine) as db_session:
        event = db_session.get(Event, event_id)
        if event:
            db_session.delete(event)
            db_session.commit()
    return redirect(url_for("admin_schedule"))

# --- НОВЫЕ РОУТЫ: ИМПОРТ ICS ---
@app.route("/admin/schedule/import", methods=["GET", "POST"])
@require_role(["admin", "professor"])
def import_ics():
    if request.method == "POST":
        if 'file' not in request.files:
            return "Файл не загружен", 400
        file = request.files['file']
        if file.filename == '':
            return "Файл не выбран", 400

        if file and file.filename.endswith('.ics'):
            try:
                cal = Calendar.from_ical(file.read())
                count = 0
                with Session(engine) as db_session:
                    for component in cal.walk():
                        if component.name == "VEVENT":
                            summary = str(component.get('summary', 'Без названия'))
                            dtstart_prop = component.get('dtstart')
                            dtend_prop = component.get('dtend')
                            
                            if not dtstart_prop or not dtend_prop:
                                continue
                                
                            dtstart = dtstart_prop.dt
                            dtend = dtend_prop.dt
                            
                            if not isinstance(dtstart, datetime):
                                dtstart = datetime.combine(dtstart, datetime.min.time())
                            if not isinstance(dtend, datetime):
                                dtend = datetime.combine(dtend, datetime.min.time())

                            if dtstart.tzinfo is None:
                                dtstart = dtstart.replace(tzinfo=timezone.utc)
                            if dtend.tzinfo is None:
                                dtend = dtend.replace(tzinfo=timezone.utc)

                            loc = str(component.get('location', ''))
                            desc = str(component.get('description', ''))

                            new_event = Event(
                                title=summary,
                                event_type='lecture',
                                start_time=dtstart.astimezone(timezone.utc),
                                end_time=dtend.astimezone(timezone.utc),
                                location=loc,
                                description=desc,
                                is_public=True
                            )
                            db_session.add(new_event)
                            count += 1
                    db_session.commit()
                return redirect(url_for("admin_schedule"))
            except Exception as e:
                return f"Ошибка при чтении файла .ics: {e}", 400
    return render_template("admin_schedule_import.html")

# --- ПРОЕКТЫ ---
@app.route("/projects")
def projects_list():
    user_role = session.get("role")
    user_id = session.get("user_id")
    with Session(engine) as db_session:
        projects = db_session.exec(select(Project).order_by(Project.created_at.desc())).all()
        member_project_ids = []
        if user_id:
            memberships = db_session.exec(select(ProjectMember).where(ProjectMember.user_id == user_id)).all()
            member_project_ids = [m.project_id for m in memberships]
            
    filtered_projects = []
    for p in projects:
        if p.visibility == "public":
            filtered_projects.append(p)
        elif p.visibility == "internal" and user_id:
            filtered_projects.append(p)
        elif p.visibility == "private" and user_id and (p.owner_id == user_id or p.id in member_project_ids or user_role == "admin"):
            filtered_projects.append(p)
            
    return render_template("projects.html", projects=filtered_projects, role=user_role, user_id=user_id, member_ids=member_project_ids)

@app.route("/projects/new", methods=["GET", "POST"])
@require_role(["admin", "professor", "lead"])
def project_new():
    if request.method == "POST":
        with Session(engine) as db_session:
            new_proj = Project(
                title=request.form.get("title"), description=request.form.get("description"),
                status=request.form.get("status"), visibility=request.form.get("visibility"),
                gitea_url=request.form.get("gitea_url"), owner_id=session.get("user_id")
            )
            db_session.add(new_proj)
            db_session.commit()
            db_session.refresh(new_proj)
            db_session.add(ProjectMember(project_id=new_proj.id, user_id=session.get("user_id"), role="lead"))
            db_session.commit()
        return redirect(url_for("projects_list"))
    return render_template("project_form.html", project=None, is_edit=False)

@app.route("/projects/<int:project_id>")
def project_detail(project_id):
    user_id = session.get("user_id")
    user_role = session.get("role")
    with Session(engine) as db_session:
        proj = db_session.get(Project, project_id)
        if not proj: return "Проект не найден", 404
        
        members = db_session.exec(select(ProjectMember, User).join(User, ProjectMember.user_id == User.id).where(ProjectMember.project_id == project_id)).all()
        is_member = any(m[0].user_id == user_id for m in members)
        
        if proj.visibility == "private" and not is_member and user_role != "admin":
            return "403: Это приватный проект", 403
        if proj.visibility == "internal" and not user_id:
            return redirect(url_for("login"))
    return render_template("project_detail.html", project=proj, members=members, is_member=is_member, user_id=user_id, role=user_role)

@app.route("/projects/<int:project_id>/edit", methods=["GET", "POST"])
@login_required
def project_edit(project_id):
    with Session(engine) as db_session:
        proj = db_session.get(Project, project_id)
        if not proj: return "Проект не найден", 404
        
        membership = db_session.exec(select(ProjectMember).where(ProjectMember.project_id == project_id).where(ProjectMember.user_id == session.get("user_id"))).first()
        is_lead = membership and membership.role == "lead"
        
        if session.get("role") != "admin" and proj.owner_id != session.get("user_id") and not is_lead:
            return "403: У вас нет прав на редактирование", 403

        if request.method == "POST":
            proj.title = request.form.get("title")
            proj.description = request.form.get("description")
            proj.status = request.form.get("status")
            proj.visibility = request.form.get("visibility")
            proj.gitea_url = request.form.get("gitea_url")
            db_session.add(proj)
            db_session.commit()
            return redirect(url_for("project_detail", project_id=proj.id))
    return render_template("project_form.html", project=proj, is_edit=True)

@app.route("/projects/<int:project_id>/members/add", methods=["POST"])
@login_required
def project_add_member(project_id):
    username = request.form.get("username")
    with Session(engine) as db_session:
        proj = db_session.get(Project, project_id)
        if not proj: return "Проект не найден", 404
        
        membership = db_session.exec(select(ProjectMember).where(ProjectMember.project_id == project_id).where(ProjectMember.user_id == session.get("user_id"))).first()
        if session.get("role") != "admin" and proj.owner_id != session.get("user_id") and (not membership or membership.role != "lead"):
            return "403: Нет прав", 403
            
        user_to_add = db_session.exec(select(User).where(User.username == username)).first()
        if not user_to_add: return redirect(url_for("project_detail", project_id=project_id))
            
        existing = db_session.exec(select(ProjectMember).where(ProjectMember.project_id == project_id).where(ProjectMember.user_id == user_to_add.id)).first()
        if not existing:
            db_session.add(ProjectMember(project_id=project_id, user_id=user_to_add.id, role="member"))
            db_session.commit()
    return redirect(url_for("project_detail", project_id=project_id))

@app.route("/projects/<int:project_id>/members/<int:user_id>/remove", methods=["POST"])
@login_required
def project_remove_member(project_id, user_id):
    with Session(engine) as db_session:
        proj = db_session.get(Project, project_id)
        if not proj: return "Проект не найден", 404
        
        membership = db_session.exec(select(ProjectMember).where(ProjectMember.project_id == project_id).where(ProjectMember.user_id == session.get("user_id"))).first()
        if session.get("role") != "admin" and proj.owner_id != session.get("user_id") and (not membership or membership.role != "lead"):
            return "403: Нет прав", 403
            
        if user_id == proj.owner_id: return "Нельзя удалить владельца", 400
            
        to_remove = db_session.exec(select(ProjectMember).where(ProjectMember.project_id == project_id).where(ProjectMember.user_id == user_id)).first()
        if to_remove:
            db_session.delete(to_remove)
            db_session.commit()
    return redirect(url_for("project_detail", project_id=project_id))

@app.route("/projects/<int:project_id>/delete", methods=["POST"])
@login_required
def project_delete(project_id):
    with Session(engine) as db_session:
        proj = db_session.get(Project, project_id)
        if proj and (session.get("role") == "admin" or proj.owner_id == session.get("user_id")):
            for m in db_session.exec(select(ProjectMember).where(ProjectMember.project_id == project_id)).all():
                db_session.delete(m)
            db_session.delete(proj)
            db_session.commit()
    return redirect(url_for("projects_list"))

# --- ФАЙЛЫ ---
@app.route("/files")
@login_required
def files_list():
    with Session(engine) as db_session:
        files = db_session.exec(select(PortalFile, User.username).join(User, PortalFile.uploaded_by == User.id).order_by(PortalFile.uploaded_at.desc())).all()
    return render_template("files.html", files=files)

@app.route("/files/upload", methods=["POST"])
@login_required
def file_upload():
    if 'file' not in request.files: return redirect(url_for('files_list'))
    file = request.files['file']
    if file.filename == '': return redirect(url_for('files_list'))
    if file:
        original_name = file.filename
        ext = os.path.splitext(original_name)[1]
        stored_name = f"{uuid.uuid4().hex}{ext}"
        filepath = os.path.join(app.config['UPLOAD_FOLDER'], stored_name)
        file.save(filepath)
        with Session(engine) as db_session:
            db_session.add(PortalFile(original_name=original_name, stored_name=stored_name, size_bytes=os.path.getsize(filepath), uploaded_by=session.get("user_id")))
            db_session.commit()
    return redirect(url_for('files_list'))

@app.route("/files/download/<int:file_id>")
@login_required
def file_download(file_id):
    with Session(engine) as db_session:
        db_file = db_session.get(PortalFile, file_id)
        if db_file:
            return send_from_directory(app.config['UPLOAD_FOLDER'], db_file.stored_name, as_attachment=True, download_name=db_file.original_name)
    return "Файл не найден", 404

@app.route("/files/<int:file_id>/delete", methods=["POST"])
@login_required
def file_delete(file_id):
    with Session(engine) as db_session:
        db_file = db_session.get(PortalFile, file_id)
        if db_file and (session.get("role") == "admin" or db_file.uploaded_by == session.get("user_id")):
            filepath = os.path.join(app.config['UPLOAD_FOLDER'], db_file.stored_name)
            if os.path.exists(filepath): os.remove(filepath)
            db_session.delete(db_file)
            db_session.commit()
    return redirect(url_for("files_list"))

# --- АДМИНКА: ПОЛЬЗОВАТЕЛИ ---
@app.route("/admin/users")
@require_role("admin")
def admin_users():
    with Session(engine) as db_session:
        users = db_session.exec(select(User).order_by(User.username)).all()
    return render_template("admin_users.html", users=users)

@app.route("/admin/users/<int:user_id>/role", methods=["POST"])
@require_role("admin")
def change_user_role(user_id):
    new_role = request.form.get("role")
    valid_roles = ["admin", "professor", "lead", "member", "student", "guest"]
    if new_role not in valid_roles: return "Ошибка", 400
    with Session(engine) as db_session:
        user = db_session.get(User, user_id)
        if user:
            if user.id == session.get("user_id") and new_role != "admin": return "Нельзя снять с себя админа", 400
            user.role = new_role
            db_session.add(user)
            db_session.commit()
    return redirect(url_for("admin_users"))

@app.route("/admin/users/<int:user_id>/delete", methods=["POST"])
@require_role("admin")
def delete_user(user_id):
    if user_id == session.get("user_id"): return "Нельзя удалить себя", 400
    with Session(engine) as db_session:
        user = db_session.get(User, user_id)
        if not user:
            return redirect(url_for("admin_users"))

        owned_projects = db_session.exec(select(Project).where(Project.owner_id == user_id)).all()
        uploaded_files = db_session.exec(select(PortalFile).where(PortalFile.uploaded_by == user_id)).all()
        if owned_projects or uploaded_files:
            return (f"Нельзя удалить {user.username}: у него {len(owned_projects)} проект(ов) "
                    f"и {len(uploaded_files)} файл(ов). Сначала передайте их другому пользователю."), 400

        for pm in db_session.exec(select(ProjectMember).where(ProjectMember.user_id == user_id)).all():
            db_session.delete(pm)
        for s in db_session.exec(select(UserSession).where(UserSession.user_id == user_id)).all():
            db_session.delete(s)
        db_session.delete(user)
        db_session.commit()
    return redirect(url_for("admin_users"))