# -*- coding: utf-8 -*-

import sys
import traceback
from flask import Blueprint
from flask import redirect, render_template, request, flash, url_for
from flask_login import login_required, login_user, current_user
from werkzeug.exceptions import Forbidden
from werkzeug import Response

from accounts.forms import (
    RegisterForm,
    RegisterCompleteForm,
    LostPasswordForm,
    SettingsForm,
)
from accounts.utils import templated
from accounts.utils.confirmation import Confirmation
from accounts.utils.login import logout_required
from accounts.models import Account
from accounts.app import accounts_app

from typing import Union


bp = Blueprint("default", __name__)


@bp.route("/register", methods=["GET", "POST"])
@templated("register.html")
@logout_required
def register() -> Union[dict, Response]:
    form = RegisterForm()
    if form.validate_on_submit():
        accounts_app.mail_backend.send(
            form.mail.data, "mail/register.txt", username=form.username.data
        )

        flash(
            "Es wurde eine E-Mail an die angegebene Adresse geschickt, "
            "um diese zu überprüfen. Bitte folge den Anweisungen in der "
            "E-Mail.",
            "success",
        )

        return redirect(url_for(".index"))

    return {"form": form}


@bp.route("/register/<token>", methods=["GET", "POST"])
@templated("register_complete.html")
@logout_required
def register_complete(token: str):
    # TODO: check for double uids and mail
    username, mail = Confirmation("register").loads_http(
        token, max_age=3 * 24 * 60 * 60
    )

    try:
        accounts_app.user_backend.get_by_uid(username)
        accounts_app.user_backend.get_by_mail(mail)
    except accounts_app.user_backend.NoSuchUserError:
        pass
    else:
        flash(
            "Du hast den Benutzer bereits angelegt! Du kannst dich jetzt einfach einloggen:"
        )
        return redirect(url_for(".index"))

    form = RegisterCompleteForm()
    if form.validate_on_submit():
        user = Account(username, mail, password=form.password.data)
        accounts_app.user_backend.register(user)
        login_user(user)

        accounts_app.mail_backend.send(
            accounts_app.config["MAIL_REGISTER_NOTIFY"],
            "mail/register_notify.txt",
            username=username,
            mail=mail,
        )

        flash("Benutzer erfolgreich angelegt.", "success")
        return redirect(url_for(".index"))

    return {
        "form": form,
        "token": token,
        "username": username,
        "mail": mail,
    }


@bp.route("/lost_password", methods=["GET", "POST"])
@templated("lost_password.html")
@logout_required
def lost_password():
    form = LostPasswordForm()
    if form.validate_on_submit() and form.user:
        # TODO: make the link only usable once (e.g include a hash of the old pw)
        # atm the only thing we do is make the link valid for only little time
        accounts_app.mail_backend.send(
            form.user.mail, "mail/lost_password.txt", username=form.user.uid
        )

        flash(
            "Wir haben dir eine E-Mail mit einem Link zum Passwort ändern "
            "geschickt. Bitte folge den Anweisungen in der E-Mail.",
            "success",
        )

        return redirect(url_for(".index"))

    return {"form": form}


@bp.route("/lost_password/<token>", methods=["GET", "POST"])
@templated("lost_password_complete.html")
@logout_required
def lost_password_complete(token: str):
    (username,) = Confirmation("lost_password").loads_http(
        token, max_age=4 * 60 * 60
    )

    form = RegisterCompleteForm()
    if form.validate_on_submit():
        user = accounts_app.user_backend.get_by_uid(username)
        user.change_password(form.password.data)
        accounts_app.user_backend.update(user, as_admin=True)
        login_user(user)

        flash("Passwort geändert.", "success")
        return redirect(url_for(".index"))

    return {
        "form": form,
        "token": token,
        "username": username,
    }


@bp.route("/", methods=["GET", "POST"])
@templated("index.html")
@login_required
def index() -> Union[Response, dict]:
    form = SettingsForm(mail=current_user.mail)
    if form.validate_on_submit():
        changed = False

        if request.form.get("submit_main"):
            if form.mail.data and form.mail.data != current_user.mail:
                accounts_app.mail_backend.send(
                    form.mail.data,
                    "mail/change_mail.txt",
                    username=current_user.uid,
                )

                flash(
                    "Es wurde eine E-Mail an die angegebene Adresse geschickt, "
                    "um diese zu überprüfen. Bitte folge den Anweisungen in der "
                    "E-Mail.",
                    "success",
                )
                changed = True

            if form.password.data:
                current_user.change_password(
                    form.password.data, form.old_password.data
                )
                flash("Passwort geändert", "success")
                changed = True

        if changed:
            accounts_app.user_backend.update(current_user)
            login_user(current_user)
            return redirect(url_for(".index"))
        else:
            flash("Nichts geändert.")

    return {
        "form": form,
    }


@bp.route("/change_mail/<token>")
@login_required
def change_mail(token: str):
    username, mail = Confirmation("change_mail").loads_http(
        token, max_age=3 * 24 * 60 * 60
    )

    if current_user.uid != username:
        raise Forbidden(
            "Bitte logge dich als der Benutzer ein, dessen E-Mail-Adresse du ändern willst."
        )

    results = accounts_app.user_backend.find_by_mail(mail)
    for user in results:
        if user.uid != current_user.uid:
            raise Forbidden(
                "Diese E-Mail-Adresse wird schon von einem anderen account benutzt!"
            )

    current_user.change_email(mail)
    accounts_app.user_backend.update(current_user)

    flash("E-Mail-Adresse geändert.", "success")
    return redirect(url_for(".index"))


@bp.route("/about")
@templated("about.html")
def about():
    return {
        "app": accounts_app,
    }


@bp.app_errorhandler(Exception)
def exception_handler(e):
    traceback.print_exception(e, file=sys.stderr)
    return (
        render_template(
            "error.html",
            error={
                "message": "Interner Fehler",
                "description": "Bitte melde uns den Fehler an "
                + """<a href="mailto:spline@spline.de">spline@spline.de</a>.""",
            },
        ),
        500,
    )


@bp.app_errorhandler(403)
@bp.app_errorhandler(404)
def errorhandler(e):
    return render_template("error.html", error=e), e.code