# -*- mode: python -*-
# -*- coding: utf-8 -*-

##############################################################################
#
# Gestion scolarite IUT
#
# Copyright (c) 1999 - 2021 Emmanuel Viennet.  All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#   Emmanuel Viennet      emmanuel.viennet@viennet.net
#
##############################################################################

"""Import d'utilisateurs via fichier Excel
"""
import random, time
import re

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.header import Header

from app import db, Departement
from app.scodoc import sco_emails
import app.scodoc.sco_utils as scu
from app.scodoc.notes_log import log
from app.scodoc.sco_exceptions import AccessDenied, ScoValueError, ScoException
from app.scodoc import sco_excel
from app.scodoc import sco_preferences
from app.scodoc import sco_users

from flask import g
from flask_login import current_user
from app.auth.models import User, UserRole

TITLES = ("user_name", "nom", "prenom", "email", "roles", "dept")
COMMENTS = (
    """user_name:
    Composé de lettres (minuscules ou majuscules), de chiffres ou du caractère _
    """,
    """nom:
    Maximum 64 caractères""",
    """prenom:
    Maximum 64 caractères""",
    """email:
    Maximum 120 caractères""",
    """roles:
    un plusieurs rôles séparés par ','
    chaque role est fait de 2 composantes séparées par _:
    1. Le role (Ens, Secr ou Admin)
    2. Le département (en majuscule)
    Exemple: "Ens_RT,Admin_INFO"
    """,
    """dept:
    Le département d'appartenance du l'utillsateur. Laisser vide si l'utilisateur intervient dans plusieurs dépatements
    """,
)


def generate_excel_sample():
    """generates an excel document suitable to import users"""
    style = sco_excel.excel_make_style(bold=True)
    titles = TITLES
    titles_styles = [style] * len(titles)
    return sco_excel.excel_simple_table(
        titles=titles,
        titles_styles=titles_styles,
        sheet_name="Utilisateurs ScoDoc",
        comments=COMMENTS,
    )


def import_excel_file(datafile):
    """
    Import scodoc users from Excel file.
    This method:
        * checks that the current_user has the ability to do so (at the moment only a SuperAdmin). He may thereoff import users with any well formed role into any deprtment (or all)
        * Once the check is done ans successfull, build the list of users (does not check the data)
        * call :func:`import_users` to actually do the job
    history: scodoc7 with no SuperAdmin every Admin_XXX could import users.
    :param datafile:  the stream from to the to be imported
    :return: same as import users
    """
    # Check current user privilege
    auth_dept = current_user.dept
    auth_name = str(current_user)
    if not current_user.is_administrator():
        raise AccessDenied("invalid user (%s) must be SuperAdmin" % auth_name)
    # Récupération des informations sur l'utilisateur courant
    log("sco_import_users.import_excel_file by %s" % auth_name)
    # Read the data from the stream
    exceldata = datafile.read()
    if not exceldata:
        raise ScoValueError("Ficher excel vide ou invalide")
    _, data = sco_excel.excel_bytes_to_list(exceldata)
    if not data:  # probably a bug
        raise ScoException("import_excel_file: empty file !")
    # 1-  --- check title line
    fs = [scu.stripquotes(s).lower() for s in data[0]]
    log("excel: fs='%s'\ndata=%s" % (str(fs), str(data)))
    # check cols
    cols = {}.fromkeys(TITLES)
    unknown = []
    for tit in fs:
        if tit not in cols:
            unknown.append(tit)
        else:
            del cols[tit]
    if cols or unknown:
        raise ScoValueError(
            "colonnes incorrectes (on attend %d, et non %d) <br/> (colonnes manquantes: %s, colonnes invalides: %s)"
            % (len(TITLES), len(fs), list(cols.keys()), unknown)
        )
    # ok, same titles... : build the list of dictionaries
    users = []
    for line in data[1:]:
        d = {}
        for i in range(len(fs)):
            d[fs[i]] = line[i]
        users.append(d)

    return import_users(users)


def import_users(users):
    """
    Import users from a list of users_descriptors.

    descriptors are dictionaries hosting users's data.
    The operation is atomic (all the users are imported or none)

    :param users: list of descriptors to be imported

    :return: a tuple that describe the result of the import:
        * ok: import ok or aborted
        * messages: the list of messages
        * the # of users created
    """
    """ Implémentation:
    Pour chaque utilisateur à créer:
        * vérifier données (y compris que le même nom d'utilisateur n'est pas utilisé plusieurs fois)
        * générer mot de passe aléatoire
        * créer utilisateur et mettre le mot de passe
        * envoyer mot de passe par mail
    Les utilisateurs à créer sont stockés dans un dictionnaire. 
    L'ajout effectif ne se fait qu'en fin de fonction si aucune erreur n'a été détectée
    """

    if len(users) == 0:
        import_ok = False
        msg_list = ["Feuille vide ou illisible"]
    else:
        created = {}  # liste de uid créés
        msg_list = []
        line = 1  # start from excel line #2
        import_ok = True

        def append_msg(msg):
            msg_list.append("Ligne %s : %s" % (line, msg))

        try:
            for u in users:
                line = line + 1
                user_ok, msg = sco_users.check_modif_user(
                    0,
                    user_name=u["user_name"],
                    nom=u["nom"],
                    prenom=u["prenom"],
                    email=u["email"],
                    roles=u["roles"].split(","),
                )
                if not user_ok:
                    append_msg("identifiant '%s' %s" % (u["user_name"], msg))
                    # raise ScoValueError(
                    #     "données invalides pour %s: %s" % (u["user_name"], msg)
                    # )
                u["passwd"] = generate_password()
                #
                # check identifiant
                if not re.match(r"^[a-zA-Z0-9@\\\-_\\\.]*$", u["user_name"]):
                    user_ok = False
                    append_msg(
                        "identifiant '%s' invalide (pas d'accents ni de caractères spéciaux)"
                        % u["user_name"]
                    )
                if len(u["user_name"]) > 64:
                    user_ok = False
                    append_msg(
                        "identifiant '%s' trop long (64 caractères)" % u["user_name"]
                    )
                if len(u["nom"]) > 64:
                    user_ok = False
                    append_msg("nom '%s' trop long (64 caractères)" % u["nom"])
                if len(u["prenom"]) > 64:
                    user_ok = False
                    append_msg("prenom '%s' trop long (64 caractères)" % u["prenom"])
                if len(u["email"]) > 120:
                    user_ok = False
                    append_msg("email '%s' trop long (120 caractères)" % u["email"])
                # check that tha same user_name has not already been described in this import
                if u["user_name"] in created.keys():
                    user_ok = False
                    append_msg(
                        "l'utilisateur '%s' a déjà été décrit ligne %s"
                        % (u["user_name"], created[u["user_name"]]["line"])
                    )
                # check département
                if u["dept"] != "":
                    dept = Departement.query.filter_by(acronym=u["dept"]).first()
                    if dept is None:
                        user_ok = False
                        append_msg("département '%s' inexistant" % u["dept"])
                # check roles / ignore whitespaces around roles / build roles_string
                # roles_string (expected by User) appears as column 'roles' in excel file
                roles_list = []
                for role in u["roles"].split(","):
                    try:
                        _, _ = UserRole.role_dept_from_string(role.strip())
                        roles_list.append(role.strip())
                    except ScoValueError as value_error:
                        user_ok = False
                        append_msg("role %s : %s" % (role, value_error))
                u["roles_string"] = ",".join(roles_list)
                if user_ok:
                    u["line"] = line
                    created[u["user_name"]] = u
                else:
                    import_ok = False
        except ScoValueError as value_error:
            log("import_users: exception: abort create %s" % str(created.keys()))
            raise ScoValueError(msg)  # re-raise exception
        if import_ok:
            for u in created.values():
                # Création de l'utilisateur (via SQLAlchemy)
                user = User()
                user.from_dict(u, new_user=True)
                db.session.add(user)
                db.session.commit()
                mail_password(u)
        else:
            created = []  # reset # of created users to 0
    return import_ok, msg_list, len(created)


#  --------- Génération du mot de passe initial -----------
# Adapté de http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/440564
# Alphabet tres simple pour des mots de passe simples...


ALPHABET = r"""ABCDEFGHIJKLMNPQRSTUVWXYZ123456789123456789AEIOU"""
PASSLEN = 6
RNG = random.Random(time.time())


def generate_password():
    """This function creates a pseudo random number generator object, seeded with
    the cryptographic hash of the passString. The contents of the character set
    is then shuffled and a selection of passLength words is made from this list.
    This selection is returned as the generated password."""
    l = list(ALPHABET)  # make this mutable so that we can shuffle the characters
    RNG.shuffle(l)  # shuffle the character set
    # pick up only a subset from the available characters:
    return "".join(RNG.sample(l, PASSLEN))


def mail_password(u, context=None, reset=False):
    "Send password by email"
    if not u["email"]:
        return

    u[
        "url"
    ] = (
        scu.ScoURL()
    )  # TODO set auth page URL ? (shared by all departments) ../auth/login

    txt = (
        """
Bonjour %(prenom)s %(nom)s,

"""
        % u
    )
    if reset:
        txt += (
            """
votre mot de passe ScoDoc a été ré-initialisé.

Le nouveau mot de passe est:  %(passwd)s
Votre nom d'utilisateur est %(user_name)s

Vous devrez changer ce mot de passe lors de votre première connexion 
sur %(url)s
"""
            % u
        )
    else:
        txt += (
            """
vous avez été déclaré comme utilisateur du logiciel de gestion de scolarité ScoDoc.

Votre nom d'utilisateur est %(user_name)s
Votre mot de passe est: %(passwd)s

Le logiciel est accessible sur: %(url)s

Vous êtes invité à changer ce mot de passe au plus vite (cliquez sur
votre nom en haut à gauche de la page d'accueil).
"""
            % u
        )

    txt += (
        """
        
ScoDoc est un logiciel libre développé à l'Université Paris 13 par Emmanuel Viennet.
Pour plus d'informations sur ce logiciel, voir %s

"""
        % scu.SCO_WEBSITE
    )
    msg = MIMEMultipart()
    if reset:
        msg["Subject"] = Header("Mot de passe ScoDoc", scu.SCO_ENCODING)
    else:
        msg["Subject"] = Header("Votre accès ScoDoc", scu.SCO_ENCODING)
    msg["From"] = sco_preferences.get_preference("email_from_addr")
    msg["To"] = u["email"]
    msg.epilogue = ""
    txt = MIMEText(txt, "plain", scu.SCO_ENCODING)
    msg.attach(txt)
    # sco_emails.sendEmail(msg)  # TODO ScoDoc9 pending function