from flask import Blueprint, flash, redirect, render_template, request, url_for
from flask_login import current_user, login_user, logout_user

from app import db
from app.session_service import create_user_session, revoke_current_session
from app.email_service import send_password_reset_email, send_welcome_email
from app.folder_utils import process_pending_invites
from app.models import PasswordResetToken, User, UserGroup

bp = Blueprint("auth", __name__, url_prefix="/auth")


@bp.route("/register", methods=["GET", "POST"])
def register():
    if current_user.is_authenticated:
        return redirect(url_for("cabinet.index"))

    if request.method == "POST":
        username = request.form.get("username", "").strip()
        email = request.form.get("email", "").strip().lower()
        password = request.form.get("password", "")
        password2 = request.form.get("password2", "")

        if len(username) < 3:
            flash("Имя пользователя — минимум 3 символа", "error")
        elif len(password) < 6:
            flash("Пароль — минимум 6 символов", "error")
        elif password != password2:
            flash("Пароли не совпадают", "error")
        elif User.query.filter_by(username=username).first():
            flash("Это имя пользователя уже занято", "error")
        elif User.query.filter_by(email=email).first():
            flash("Этот email уже зарегистрирован", "error")
        else:
            default_group = UserGroup.query.filter_by(is_default=True).first()
            user = User(
                username=username,
                email=email,
                group_id=default_group.id if default_group else None,
            )
            user.set_password(password)
            db.session.add(user)
            db.session.commit()
            login_user(user)
            create_user_session(user)
            accepted = process_pending_invites(user)
            send_welcome_email(user)
            flash("Регистрация успешна. Добро пожаловать!", "success")
            if accepted:
                flash(f"Вам открыт доступ к {accepted} общим папкам", "success")
            return redirect(url_for("cabinet.index"))

    return render_template("auth/register.html")


@bp.route("/login", methods=["GET", "POST"])
def login():
    if current_user.is_authenticated:
        return redirect(url_for("cabinet.index"))

    if request.method == "POST":
        login = request.form.get("login", "").strip()
        password = request.form.get("password", "")
        remember = request.form.get("remember") == "on"

        user = User.query.filter(
            (User.username == login) | (User.email == login.lower())
        ).first()

        if user is None or not user.check_password(password):
            flash("Неверный логин или пароль", "error")
        elif not user.is_active:
            flash("Аккаунт заблокирован", "error")
        else:
            login_user(user, remember=remember)
            create_user_session(user, remember=remember)
            accepted = process_pending_invites(user)
            flash(f"Добро пожаловать, {user.username}!", "success")
            if accepted:
                flash(f"Вам открыт доступ к {accepted} общим папкам", "success")
            next_page = request.args.get("next")
            if next_page:
                return redirect(next_page)
            if user.is_admin:
                return redirect(url_for("admin.dashboard"))
            return redirect(url_for("cabinet.index"))

    return render_template("auth/login.html")


@bp.route("/forgot-password", methods=["GET", "POST"])
def forgot_password():
    if current_user.is_authenticated:
        return redirect(url_for("cabinet.index"))

    if request.method == "POST":
        email = request.form.get("email", "").strip().lower()
        user = User.query.filter_by(email=email).first()
        if user:
            token = PasswordResetToken.create_for_user(user)
            db.session.add(token)
            db.session.commit()
            ok, msg = send_password_reset_email(user, token.token)
            if not ok:
                flash(f"Не удалось отправить email: {msg}", "error")
                return redirect(url_for("auth.forgot_password"))

        flash("Если email зарегистрирован, на него отправлена ссылка для сброса пароля", "success")
        return redirect(url_for("auth.login"))

    return render_template("auth/forgot_password.html")


@bp.route("/reset-password/<token>", methods=["GET", "POST"])
def reset_password(token):
    if current_user.is_authenticated:
        return redirect(url_for("cabinet.index"))

    reset_token = PasswordResetToken.query.filter_by(token=token).first()
    if reset_token is None or not reset_token.is_valid():
        flash("Ссылка для сброса пароля недействительна или истекла", "error")
        return redirect(url_for("auth.forgot_password"))

    if request.method == "POST":
        password = request.form.get("password", "")
        password2 = request.form.get("password2", "")
        if len(password) < 6:
            flash("Пароль — минимум 6 символов", "error")
        elif password != password2:
            flash("Пароли не совпадают", "error")
        else:
            reset_token.user.set_password(password)
            reset_token.used = True
            db.session.commit()
            flash("Пароль успешно изменён. Войдите в аккаунт.", "success")
            return redirect(url_for("auth.login"))

    return render_template("auth/reset_password.html", token=token)


@bp.route("/logout")
def logout():
    revoke_current_session()
    logout_user()
    flash("Вы вышли из аккаунта", "success")
    return redirect(url_for("main.index"))