from json import load
from os import environ

from flask import Flask, flash, redirect, request, session, url_for
from flask_babel import Babel, gettext
from flask_wtf.csrf import CSRFError, CSRFProtect
from ldap3 import ALL_ATTRIBUTES, MODIFY_ADD, MODIFY_DELETE
from ldap3.core.exceptions import LDAPException
from ldap3.utils.dn import escape_rdn

from .helpers.flask import template
from .helpers.ldap import (
    admin_required,
    get_user,
    login_required,
    try_auth,
    update_user,
    update_user_password,
)

app = Flask(__name__)
app.secret_key = environ.get("FLASK_SECRET_KEY", default="test")
app.config["LANGUAGES"] = {"en": "English", "de": "Deutsch"}

babel = Babel(app)
csrf = CSRFProtect(app)

with open(environ["APP_CONFIG"]) as f:
    APP_CONFIG = load(f)


@babel.localeselector
def get_locale():
    return request.accept_languages.best_match(app.config["LANGUAGES"].keys())


@app.errorhandler(CSRFError)
def handle_csrf_error(e):
    flash(
        gettext("CRSF validation error. For your own safety, you have been logged out.")
    )

    session["is_logged_in"] = False
    session["username"] = ""
    session["password"] = ""

    return redirect(url_for("login"))


@app.route("/")
def slash():
    if session.get("is_logged_in"):
        return redirect(url_for("selfservice"))
    return redirect(url_for("login"))


@app.route("/login", methods=["GET", "POST"])
def login():
    session["is_logged_in"] = False

    if request.method == "POST":
        if try_auth(
            escape_rdn(request.form["username"]),
            request.form["password"],
        ):
            session["is_logged_in"] = True
            session["username"] = escape_rdn(request.form["username"])
            session["password"] = request.form["password"]

            flash(gettext("logged in"))

            return redirect(url_for("selfservice"))
        else:
            flash(gettext("username or password is wrong"))

    return template(None, "login.html")


@app.route("/logout")
def logout():
    session["is_logged_in"] = False
    session["username"] = ""
    session["password"] = ""

    flash(gettext("you have been logged out"))

    return redirect(url_for("login"))


@app.route("/selfservice", methods=["GET", "POST"])
@login_required
def selfservice(ldap):
    if request.method == "POST":
        if request.form.get("userdata"):
            try:
                update_user(
                    ldap,
                    session["username"],
                    {
                        "givenName": request.form["givenName"],
                        "sn": request.form["sn"],
                        "cn": "{} {}".format(
                            request.form["givenName"],
                            request.form["sn"],
                        ),
                        "externalMail": request.form["externalMail"],
                    },
                )
                flash(gettext("user data was updated"))
            except LDAPException as e:
                app.logger.error(
                    "Updating {} failed: {}\n{}".format(
                        APP_CONFIG["template"]["user_dn"].format(session["username"]),
                        repr(e),
                        repr(request.form),
                    ),
                )
                flash(e)
        elif request.form.get("passwordchange"):
            validated = (True,)
            if not try_auth(
                session["username"],
                request.form["current"],
            ):
                validated = False
                flash(gettext("current password does not match the one stored"))

            if request.form["new"] != request.form["repeat"]:
                validated = False
                flash(gettext("new passwords do not match"))

            if len(request.form["new"]) < 12:
                validated = False
                flash(gettext("new password must be atleast 12 characters long"))

            if validated:
                try:
                    update_user_password(
                        ldap,
                        session["username"],
                        request.form["new"],
                    )
                    session["password"] = request.form["new"]
                    flash(gettext("your password was changed"))
                except LDAPException as e:
                    app.logger.error(
                        "Updating {} failed: {}".format(
                            APP_CONFIG["template"]["user_dn"].format(
                                session["username"]
                            ),
                            repr(e),
                        ),
                    )
                    flash(e)

        return redirect(url_for("selfservice"))

    return template(ldap, "selfservice.html")


@app.route("/groups", methods=["GET"])
@login_required
def groups(ldap):
    ldap.search(
        APP_CONFIG["ldap"]["group_base"],
        "(objectclass=groupOfNames)",
        attributes=ALL_ATTRIBUTES,
    )

    return template(
        ldap,
        "groups/list.html",
        groups=ldap.entries,
    )


@app.route("/groups/<ou>", methods=["GET", "POST"])
@admin_required
def group_edit(ldap, ou):
    ou = escape_rdn(ou)

    if request.method == "POST":
        if request.form.get("remove"):
            ldap.modify(
                APP_CONFIG["template"]["group_dn"].format(ou),
                {
                    "member": [
                        (
                            MODIFY_DELETE,
                            APP_CONFIG["template"]["user_dn"].format(
                                escape_rdn(request.form["remove"])
                            ),
                        )
                    ]
                },
            )
            flash(
                gettext(
                    "%(user)s was removed from %(ou)s",
                    user=request.form["remove"],
                    ou=ou,
                )
            )
        elif request.form.get("add"):
            ldap.modify(
                APP_CONFIG["template"]["group_dn"].format(ou),
                {
                    "member": [
                        (
                            MODIFY_ADD,
                            APP_CONFIG["template"]["user_dn"].format(
                                escape_rdn(request.form["add"])
                            ),
                        )
                    ]
                },
            )
            flash(
                gettext(
                    "%(user)s was added to %(ou)s", user=request.form["add"], ou=ou
                )
            )

        return redirect(url_for("group_edit", ou=ou))

    ldap.search(
        APP_CONFIG["ldap"]["user_base"],
        APP_CONFIG["template"]["group_nonmembers"].format(ou),
        attributes=["cn", "uid"],
    )
    users = ldap.entries

    ldap.search(
        APP_CONFIG["ldap"]["user_base"],
        APP_CONFIG["template"]["group_members"].format(ou),
        attributes=ALL_ATTRIBUTES,
    )

    return template(
        ldap,
        "groups/members.html",
        members=ldap.entries,
        ou=ou,
        other_users=users,
    )