"""
Script de migration des données de la base "absences" -> "assiduites"/"justificatifs"

Ecrit par Matthias HARTMANN
"""
from datetime import date, datetime, time, timedelta
from json import dump, dumps
from sqlalchemy import not_

from flask import g

from app import db
from app.models import (
    Absence,
    Assiduite,
    Departement,
    Identite,
    Justificatif,
    ModuleImplInscription,
)
from app.models.assiduites import compute_assiduites_justified
from app.profiler import Profiler
from app.scodoc.sco_utils import (
    EtatAssiduite,
    EtatJustificatif,
    TerminalColor,
    localize_datetime,
    print_progress_bar,
)


class _Merger:
    """pour typage"""


class _glob:
    """variables globales du script"""

    PROBLEMS: dict[int, list[str]] = {}
    CURRENT_ETU: list = []
    MODULES: list[tuple[int, int]] = []
    COMPTE: list[int, int] = []
    ERR_ETU: list[int] = []
    MERGER_ASSI: _Merger = None
    MERGER_JUST: _Merger = None

    MORNING: time = None
    NOON: time = None
    EVENING: time = None


class _Merger:
    def __init__(self, abs_: Absence, est_abs: bool) -> None:
        self.deb = (abs_.jour, abs_.matin)
        self.fin = (abs_.jour, abs_.matin)
        self.moduleimpl = abs_.moduleimpl_id
        self.etudid = abs_.etudid
        self.est_abs = est_abs
        self.raison = abs_.description
        self.entry_date = abs_.entry_date

    def merge(self, abs_: Absence) -> bool:
        """Fusionne les absences"""

        if self.etudid != abs_.etudid:
            return False

        # Cas d'une même absence enregistrée plusieurs fois
        if self.fin == (abs_.jour, abs_.matin):
            self.moduleimpl = None
        else:
            if self.fin[1]:
                if abs_.jour != self.fin[0]:
                    return False
            else:
                day_after: date = abs_.jour - timedelta(days=1) == self.fin[0]
                if not (day_after and abs_.matin):
                    return False

        self.fin = (abs_.jour, abs_.matin)
        return True

    @staticmethod
    def _tuple_to_date(couple: tuple[date, bool], end=False):
        if couple[1]:
            time_ = _glob.NOON if end else _glob.MORNING
            date_ = datetime.combine(couple[0], time_)
        else:
            time_ = _glob.EVENING if end else _glob.NOON
            date_ = datetime.combine(couple[0], time_)
        d = localize_datetime(date_)
        return d

    def _to_justif(self):
        date_deb = _Merger._tuple_to_date(self.deb)
        date_fin = _Merger._tuple_to_date(self.fin, end=True)

        retour = Justificatif.fast_create_justificatif(
            etudid=self.etudid,
            date_debut=date_deb,
            date_fin=date_fin,
            etat=EtatJustificatif.VALIDE,
            raison=self.raison,
            entry_date=self.entry_date,
        )
        return retour

    def _to_assi(self):
        date_deb = _Merger._tuple_to_date(self.deb)
        date_fin = _Merger._tuple_to_date(self.fin, end=True)

        retour = Assiduite.fast_create_assiduite(
            etudid=self.etudid,
            date_debut=date_deb,
            date_fin=date_fin,
            etat=EtatAssiduite.ABSENT,
            moduleimpl_id=self.moduleimpl,
            description=self.raison,
            entry_date=self.entry_date,
        )
        return retour

    def export(self):
        """Génère un nouvel objet Assiduité ou Justificatif"""
        obj: Assiduite or Justificatif = None
        if self.est_abs:
            _glob.COMPTE[0] += 1
            obj = self._to_assi()
        else:
            _glob.COMPTE[1] += 1
            obj = self._to_justif()

        db.session.add(obj)


class _Statistics:
    def __init__(self) -> None:
        self.object: dict[str, dict or int] = {"total": 0}
        self.year: int = None

    def __set_year(self, year: int):
        if year not in self.object:
            self.object[year] = {
                "etuds_inexistant": [],
                "abs_invalide": {},
            }
        self.year = year
        return self

    def __add_etud(self, etudid: int):
        if etudid not in self.object[self.year]["etuds_inexistant"]:
            self.object[self.year]["etuds_inexistant"].append(etudid)
        return self

    def __add_abs(self, abs_: int, err: str):
        if abs_ not in self.object[self.year]["abs_invalide"]:
            self.object[self.year]["abs_invalide"][abs_] = [err]
        else:
            self.object[self.year]["abs_invalide"][abs_].append(err)

        return self

    def add_problem(self, abs_: Absence, err: str):
        """Ajoute un nouveau problème dans les statistiques"""
        abs_.jour: date
        pivot: date = date(abs_.jour.year, 9, 15)
        year: int = abs_.jour.year
        if pivot < abs_.jour:
            year += 1
        self.__set_year(year)

        if err == "Etudiant inexistant":
            self.__add_etud(abs_.etudid)
        else:
            self.__add_abs(abs_.id, err)

        self.object["total"] += 1

    def compute_stats(self) -> dict:
        """Comptage des statistiques"""
        stats: dict = {"total": self.object["total"]}
        for year, item in self.object.items():

            if year == "total":
                continue

            stats[year] = {}
            stats[year]["etuds_inexistant"] = len(item["etuds_inexistant"])
            stats[year]["abs_invalide"] = len(item["abs_invalide"])

        return stats

    def export(self, file):
        """Sérialise les statistiques dans un fichier"""
        dump(self.object, file, indent=2)


def migrate_abs_to_assiduites(
    dept: str = "", morning: str = None, noon: str = None, evening: str = None
):
    """
    une absence à 3 états:

    |.estabs|.estjust|
    |1|0| -> absence non justifiée
    |1|1| -> absence justifiée
    |0|1| -> justifié

    dualité des temps :

    .matin: bool (0:00 -> time_pref | time_pref->23:59:59)
    .jour : date (jour de l'absence/justificatif)
    .moduleimpl_id: relation -> moduleimpl_id
    description:str -> motif abs / raision justif

    .entry_date: datetime -> timestamp d'entrée de l'abs
    .etudid: relation -> Identite
    """
    Profiler.clear()
    stats: _Statistics = _Statistics()

    time_elapsed: Profiler = Profiler("migration")
    time_elapsed.start()

    if morning is None:
        _glob.MORNING = time(8, 0)
    else:
        morning: list[str] = morning.split("h")
        _glob.MORNING = time(int(morning[0]), int(morning[1]))

    if noon is None:
        _glob.NOON = time(12, 0)
    else:
        noon: list[str] = noon.split("h")
        _glob.NOON = time(int(noon[0]), int(noon[1]))

    if evening is None:
        _glob.EVENING = time(18, 0)
    else:
        evening: list[str] = evening.split("h")
        _glob.EVENING = time(int(evening[0]), int(evening[1]))

    absences_query = Absence.query
    if dept is not None:

        dept: Departement = Departement.query.filter_by(acronym=dept).first()
        if dept is not None:
            etuds_id: list[int] = [etud.id for etud in dept.etudiants]
            absences_query = absences_query.filter(Absence.etudid.in_(etuds_id))
    absences: Absence = absences_query.order_by(
        Absence.etudid, Absence.jour, not_(Absence.matin)
    )

    _glob.CURRENT_ETU = []
    _glob.MODULES = []
    _glob.COMPTE = [0, 0]
    _glob.ERR_ETU = []
    _glob.MERGER_ASSI = None
    _glob.MERGER_JUST = None

    absences_len: int = absences.count()

    print(
        f"{TerminalColor.BLUE}{absences_len} absences vont être migrées{TerminalColor.RESET}"
    )

    print_progress_bar(0, absences_len, "Progression", "effectué", autosize=True)

    for i, abs_ in enumerate(absences):

        try:
            _from_abs_to_assiduite_justificatif(abs_)
        except ValueError as e:
            stats.add_problem(abs_, e.args[0])

        if i % 10 == 0:
            print_progress_bar(
                i,
                absences_len,
                "Progression",
                "effectué",
                autosize=True,
            )

        if i % 1000 == 0:
            print_progress_bar(
                i,
                absences_len,
                "Progression",
                "effectué",
                autosize=True,
            )
            db.session.commit()

    _glob.MERGER_ASSI.export()
    _glob.MERGER_JUST.export()

    db.session.commit()

    justifs: Justificatif = Justificatif.query

    if dept is not None:
        justifs.filter(Justificatif.etudid.in_(etuds_id))

    compute_assiduites_justified(justifs)

    print_progress_bar(
        absences_len,
        absences_len,
        "Progression",
        "effectué",
        autosize=True,
    )

    time_elapsed.stop()

    statistiques: dict = stats.compute_stats()
    print(
        f"{TerminalColor.GREEN}La migration a pris {time_elapsed.elapsed():.2f} secondes {TerminalColor.RESET}"
    )

    print(
        f"{TerminalColor.RED}{statistiques['total']} absences qui n'ont pas pu être migrées."
    )
    print(
        f"Vous retrouverez un fichier json {TerminalColor.GREEN}/opt/scodoc-data/log/scodoc_migration_abs.json{TerminalColor.RED} contenant les problèmes de migrations"
    )
    with open(
        "/opt/scodoc-data/log/scodoc_migration_abs.json", "w", encoding="utf-8"
    ) as file:
        stats.export(file)

    print(
        f"{TerminalColor.CYAN}{_glob.COMPTE[0]} assiduités et {_glob.COMPTE[1]} justificatifs ont été générés.{TerminalColor.RESET}"
    )

    print(dumps(statistiques, indent=2))


def _from_abs_to_assiduite_justificatif(_abs: Absence):

    if _abs.etudid not in _glob.CURRENT_ETU:
        etud: Identite = Identite.query.filter_by(id=_abs.etudid).first()
        if etud is None:
            raise ValueError("Etudiant inexistant")
        _glob.CURRENT_ETU.append(_abs.etudid)

    if _abs.estabs:
        moduleimpl_id: int = _abs.moduleimpl_id
        if (
            moduleimpl_id is not None
            and (_abs.etudid, _abs.moduleimpl_id) not in _glob.MODULES
        ):
            moduleimpl_inscription: ModuleImplInscription = (
                ModuleImplInscription.query.filter_by(
                    moduleimpl_id=_abs.moduleimpl_id, etudid=_abs.etudid
                ).first()
            )
            if moduleimpl_inscription is None:
                raise ValueError("Moduleimpl_id incorrect ou étudiant non inscrit")

        if _glob.MERGER_ASSI is None:
            _glob.MERGER_ASSI = _Merger(_abs, True)
            return True
        elif _glob.MERGER_ASSI.merge(_abs):
            return True
        else:
            _glob.MERGER_ASSI.export()
            _glob.MERGER_ASSI = _Merger(_abs, True)
            return False

    if _glob.MERGER_JUST is None:
        _glob.MERGER_JUST = _Merger(_abs, False)
        return True
    elif _glob.MERGER_JUST.merge(_abs):
        return True
    else:
        _glob.MERGER_JUST.export()
        _glob.MERGER_JUST = _Merger(_abs, False)
        return False