# -*- 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
#
##############################################################################

"""Système de notification par mail des excès d'absences
(see ticket #147)


Il suffit d'appeler abs_notify() après chaque ajout d'absence.
"""
import datetime
from email.MIMEMultipart import (  # pylint: disable=no-name-in-module,import-error
    MIMEMultipart,
)
from email.MIMEText import MIMEText  # pylint: disable=no-name-in-module,import-error
from email.MIMEBase import MIMEBase  # pylint: disable=no-name-in-module,import-error
from email.Header import Header  # pylint: disable=no-name-in-module,import-error
from email import Encoders  # pylint: disable=no-name-in-module,import-error

import notesdb as ndb
import sco_utils as scu
from notes_log import log
from scolog import logdb
import sco_bulletins
import sco_formsemestre


def abs_notify(context, etudid, date):
    """Check if notifications are requested and send them
    Considère le nombre d'absence dans le semestre courant
    (s'il n'y a pas de semestre courant, ne fait rien,
    car l'etudiant n'est pas inscrit au moment de l'absence!).
    """
    sem = retreive_current_formsemestre(context, etudid, date)
    if not sem:
        return  # non inscrit a la date, pas de notification

    debut_sem = ndb.DateDMYtoISO(sem["date_debut"])
    fin_sem = ndb.DateDMYtoISO(sem["date_fin"])
    nbabs = context.CountAbs(etudid, debut=debut_sem, fin=fin_sem)
    nbabsjust = context.CountAbsJust(etudid, debut=debut_sem, fin=fin_sem)

    do_abs_notify(context, sem, etudid, date, nbabs, nbabsjust)


def do_abs_notify(context, sem, etudid, date, nbabs, nbabsjust):
    """Given new counts of absences, check if notifications are requested and send them."""
    # prefs fallback to global pref if sem is None:
    if sem:
        formsemestre_id = sem["formsemestre_id"]
    else:
        formsemestre_id = None
    prefs = context.get_preferences(formsemestre_id=sem["formsemestre_id"])

    destinations = abs_notify_get_destinations(
        context, sem, prefs, etudid, date, nbabs, nbabsjust
    )
    msg = abs_notification_message(context, sem, prefs, etudid, nbabs, nbabsjust)
    if not msg:
        return  # abort

    # Vérification fréquence (pour ne pas envoyer de mails trop souvent)
    abs_notify_max_freq = context.get_preference("abs_notify_max_freq")
    destinations_filtered = []
    for email_addr in destinations:
        nbdays_since_last_notif = user_nbdays_since_last_notif(
            context, email_addr, etudid
        )
        if (nbdays_since_last_notif is None) or (
            nbdays_since_last_notif >= abs_notify_max_freq
        ):
            destinations_filtered.append(email_addr)

    if destinations_filtered:
        abs_notify_send(
            context,
            destinations_filtered,
            etudid,
            msg,
            nbabs,
            nbabsjust,
            formsemestre_id,
        )


def abs_notify_send(
    context, destinations, etudid, msg, nbabs, nbabsjust, formsemestre_id
):
    """Actually send the notification by email, and register it in database"""
    cnx = context.GetDBConnexion()
    log("abs_notify: sending notification to %s" % destinations)
    cursor = cnx.cursor(cursor_factory=ndb.ScoDocCursor)
    for email in destinations:
        del msg["To"]
        msg["To"] = email
        context.sendEmail(msg)
        ndb.SimpleQuery(
            context,
            """insert into absences_notifications (etudid, email, nbabs, nbabsjust, formsemestre_id) values (%(etudid)s, %(email)s, %(nbabs)s, %(nbabsjust)s, %(formsemestre_id)s)""",
            vars(),
            cursor=cursor,
        )

    logdb(
        cnx=cnx,
        method="abs_notify",
        etudid=etudid,
        msg="sent to %s (nbabs=%d)" % (destinations, nbabs),
    )


def abs_notify_get_destinations(context, sem, prefs, etudid, date, nbabs, nbabsjust):
    """Returns set of destination emails to be notified"""
    formsemestre_id = sem["formsemestre_id"]

    destinations = []  # list of email address to notify

    if abs_notify_is_above_threshold(
        context, etudid, nbabs, nbabsjust, formsemestre_id
    ):
        if sem and prefs["abs_notify_respsem"]:
            # notifie chaque responsable du semestre
            for responsable_id in sem["responsables"]:
                u = context.Users.user_info(responsable_id)
                if u["email"]:
                    destinations.append(u["email"])
        if prefs["abs_notify_chief"] and prefs["email_chefdpt"]:
            destinations.append(prefs["email_chefdpt"])
        if prefs["abs_notify_email"]:
            destinations.append(prefs["abs_notify_email"])
        if prefs["abs_notify_etud"]:
            etud = context.getEtudInfo(etudid=etudid, filled=1)[0]
            if etud["email_default"]:
                destinations.append(etud["email_default"])

    # Notification (à chaque fois) des resp. de modules ayant des évaluations
    # à cette date
    # nb: on pourrait prevoir d'utiliser un autre format de message pour ce cas
    if sem and prefs["abs_notify_respeval"]:
        mods = mod_with_evals_at_date(context, date, etudid)
        for mod in mods:
            u = context.Users.user_info(mod["responsable_id"])
            if u["email"]:
                destinations.append(u["email"])

    # uniq
    destinations = set(destinations)

    return destinations


def abs_notify_is_above_threshold(context, etudid, nbabs, nbabsjust, formsemestre_id):
    """True si il faut notifier les absences (indépendemment du destinataire)

    nbabs: nombre d'absence (de tous types, unité de compte = demi-journée)
    nbabsjust: nombre d'absences justifiées

    (nbabs > abs_notify_abs_threshold)
    (nbabs - nbabs_last_notified) > abs_notify_abs_increment
    """
    abs_notify_abs_threshold = context.get_preference(
        "abs_notify_abs_threshold", formsemestre_id
    )
    abs_notify_abs_increment = context.get_preference(
        "abs_notify_abs_increment", formsemestre_id
    )
    nbabs_last_notified = etud_nbabs_last_notified(context, etudid, formsemestre_id)

    if nbabs_last_notified == 0:
        if nbabs > abs_notify_abs_threshold:
            return True  # first notification
        else:
            return False
    else:
        if (nbabs - nbabs_last_notified) >= abs_notify_abs_increment:
            return True
    return False


def etud_nbabs_last_notified(context, etudid, formsemestre_id=None):
    """nbabs lors de la dernière notification envoyée pour cet étudiant dans ce semestre
    ou sans semestre (ce dernier cas est nécessaire pour la transition au nouveau code)"""
    cnx = context.GetDBConnexion()
    cursor = cnx.cursor(cursor_factory=ndb.ScoDocCursor)
    cursor.execute(
        """select * from absences_notifications where etudid = %(etudid)s and (formsemestre_id = %(formsemestre_id)s or formsemestre_id is NULL) order by notification_date desc""",
        vars(),
    )
    res = cursor.dictfetchone()
    if res:
        return res["nbabs"]
    else:
        return 0


def user_nbdays_since_last_notif(context, email_addr, etudid):
    """nb days since last notification to this email, or None if no previous notification"""
    cnx = context.GetDBConnexion()
    cursor = cnx.cursor(cursor_factory=ndb.ScoDocCursor)
    cursor.execute(
        """select * from absences_notifications where email = %(email_addr)s and etudid=%(etudid)s order by notification_date desc""",
        {"email_addr": email_addr, "etudid": etudid},
    )
    res = cursor.dictfetchone()
    if res:
        now = datetime.datetime.now(res["notification_date"].tzinfo)
        return (now - res["notification_date"]).days
    else:
        return None


def abs_notification_message(context, sem, prefs, etudid, nbabs, nbabsjust):
    """Mime notification message based on template.
    returns None if sending should be canceled (emplty template).
    """
    etud = context.getEtudInfo(etudid=etudid, filled=True)[0]

    # Variables accessibles dans les balises du template: %(nom_variable)s :
    values = sco_bulletins.make_context_dict(context, sem, etud)

    values["nbabs"] = nbabs
    values["nbabsjust"] = nbabsjust
    values["nbabsnonjust"] = nbabs - nbabsjust
    values["url_ficheetud"] = context.ScoURL() + "/ficheEtud?etudid=" + etudid

    template = prefs["abs_notification_mail_tmpl"]
    if template:
        txt = prefs["abs_notification_mail_tmpl"] % values
    else:
        log("abs_notification_message: empty template, not sending message")
        return None

    subject = """Trop d'absences pour %(nomprenom)s""" % etud
    #
    msg = MIMEMultipart()
    subj = Header("[ScoDoc] " + subject, scu.SCO_ENCODING)
    msg["Subject"] = subj
    msg["From"] = prefs["email_from_addr"]
    txt = MIMEText(txt, "plain", scu.SCO_ENCODING)
    msg.attach(txt)
    return msg


def retreive_current_formsemestre(context, etudid, cur_date):
    """Get formsemestre dans lequel etudid est (ou était) inscrit a la date indiquée
    date est une chaine au format ISO (yyyy-mm-dd)
    """
    req = """SELECT i.formsemestre_id FROM notes_formsemestre_inscription i, notes_formsemestre sem
    WHERE sem.formsemestre_id = i.formsemestre_id AND i.etudid=%(etudid)s
    AND (%(cur_date)s >= sem.date_debut) AND (%(cur_date)s <= sem.date_fin)"""

    r = ndb.SimpleDictFetch(context, req, {"etudid": etudid, "cur_date": cur_date})
    if not r:
        return None
    # s'il y a plusieurs semestres, prend le premier (rarissime et non significatif):
    sem = sco_formsemestre.get_formsemestre(context, r[0]["formsemestre_id"])
    return sem


def mod_with_evals_at_date(context, date_abs, etudid):
    """Liste des moduleimpls avec des evaluations a la date indiquée"""
    req = """SELECT m.* FROM notes_moduleimpl m, notes_evaluation e, notes_moduleimpl_inscription i
    WHERE m.moduleimpl_id = e.moduleimpl_id AND e.moduleimpl_id = i.moduleimpl_id
    AND i.etudid = %(etudid)s AND e.jour = %(date_abs)s"""
    r = ndb.SimpleDictFetch(context, req, {"etudid": etudid, "date_abs": date_abs})
    return r