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

##############################################################################
#
# Gestion scolarite IUT
#
# Copyright (c) 1999 - 2024 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
#
##############################################################################

"""ScoDoc : gestion des archives des PV et bulletins, et des dossiers etudiants (admission)


 Archives are plain files, stored in
    <SCODOC_VAR_DIR>/archives/<dept_id>
 (where <SCODOC_VAR_DIR> is usually /opt/scodoc-data, and <dept_id> a departement id (int))

 Les PV de jurys et documents associés sont stockées dans un sous-repertoire de la forme
    <archivedir>/<dept>/<formsemestre_id>/<YYYY-MM-DD-HH-MM-SS>
 (formsemestre_id est ici FormSemestre.id)

 Les documents liés à l'étudiant sont dans
    <archivedir>/docetuds/<dept_id>/<etudid>/<YYYY-MM-DD-HH-MM-SS>
(etudid est ici Identite.id)

 Les maquettes Apogée pour l'export des notes sont dans
    <archivedir>/apo_csv/<dept_id>/<annee_scolaire>-<sem_id>/<YYYY-MM-DD-HH-MM-SS>/<code_etape>.csv

 Un répertoire d'archive contient des fichiers quelconques, et un fichier texte
 nommé _description.txt qui est une description (humaine, format libre) de l'archive.

"""
import datetime
import glob
import gzip
import mimetypes
import os
import re
import shutil
import time
import zlib

import chardet

from flask import g

import app.scodoc.sco_utils as scu
from config import Config
from app import log
from app.scodoc.sco_exceptions import ScoException, ScoValueError


class BaseArchiver:
    """Classe de base pour tous les archivers"""

    def __init__(self, archive_type=""):
        self.archive_type = archive_type
        self.initialized = False
        self.root = None
        self.dept_id = None

    def set_dept_id(self, dept_id: int):
        "set dept"
        self.dept_id = dept_id

    def initialize(self, dept_id: int = None):
        """Fixe le département et initialise les répertoires au besoin."""
        # Set departement (à chaque fois car peut changer d'une utilisation à l'autre)
        self.dept_id = getattr(g, "scodoc_dept_id") if dept_id is None else dept_id
        if self.initialized:
            return
        dirs = [Config.SCODOC_VAR_DIR, "archives"]
        if self.archive_type:
            dirs.append(self.archive_type)

        self.root = os.path.join(*dirs)  # /opt/scodoc-data/archives/<type>
        log("initialized archiver, path=" + self.root)
        path = dirs[0]
        for directory in dirs[1:]:
            path = os.path.join(path, directory)
            try:
                scu.GSL.acquire()
                if not os.path.isdir(path):
                    log(f"creating directory {path}")
                    os.mkdir(path)
            finally:
                scu.GSL.release()
                self.initialized = True

    def get_obj_dir(self, oid: int, dept_id: int = None):
        """
        :return: path to directory of archives for this object (eg formsemestre_id or etudid).
        If directory does not yet exist, create it.
        """
        self.initialize(dept_id)
        dept_dir = os.path.join(self.root, str(self.dept_id))
        try:
            scu.GSL.acquire()
            if not os.path.isdir(dept_dir):
                log(f"creating directory {dept_dir}")
                os.mkdir(dept_dir)
            obj_dir = os.path.join(dept_dir, str(oid))
            if not os.path.isdir(obj_dir):
                log(f"creating directory {obj_dir}")
                os.mkdir(obj_dir)
        except FileExistsError as exc:
            raise ScoException(
                f"""BaseArchiver error: obj_dir={obj_dir} exists={
                               os.path.exists(obj_dir)
                               } isdir={os.path.isdir(obj_dir)}"""
            ) from exc
        finally:
            scu.GSL.release()
        return obj_dir

    def list_oids(self, dept_id: int = None):
        """
        :return: list of archive oids
        """
        self.initialize(dept_id)
        base = os.path.join(self.root, str(self.dept_id)) + os.path.sep
        dirs = glob.glob(base + "*")
        return [os.path.split(x)[1] for x in dirs]

    def list_obj_archives(self, oid: int, dept_id: int = None):
        """Returns
        :return: list of archive identifiers for this object (paths to non empty dirs)
        """
        self.initialize(dept_id)
        base = self.get_obj_dir(oid, dept_id=dept_id) + os.path.sep
        dirs = glob.glob(
            base
            + "[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]-[0-9][0-9]"
        )
        dirs = [os.path.join(base, d) for d in dirs]
        dirs = [d for d in dirs if os.path.isdir(d) and os.listdir(d)]  # non empty dirs
        dirs.sort()
        return dirs

    def delete_archive(self, archive_id: str, dept_id: int = None):
        """Delete (forever) this archive"""
        self.initialize(dept_id)
        try:
            scu.GSL.acquire()
            shutil.rmtree(archive_id, ignore_errors=True)
        finally:
            scu.GSL.release()

    def get_archive_date(self, archive_id: str):
        """Returns date (as a DateTime object) of an archive"""
        return datetime.datetime(
            *[int(x) for x in os.path.split(archive_id)[1].split("-")]
        )

    def list_archive(self, archive_id: str, dept_id: int = None) -> str:
        """Return list of filenames (without path) in archive"""
        self.initialize(dept_id)
        try:
            scu.GSL.acquire()
            files = os.listdir(archive_id)
        finally:
            scu.GSL.release()
        files.sort()
        return [f for f in files if f and f[0] != "_"]

    def get_archive_name(self, archive_id: str):
        """name identifying archive, to be used in web URLs"""
        return os.path.split(archive_id)[1]

    def is_valid_archive_name(self, archive_name: str):
        """check if name is valid."""
        return re.match(
            "^[0-9]{4}-[0-9]{2}-[0-9]{2}-[0-9]{2}-[0-9]{2}-[0-9]{2}$", archive_name
        )

    def get_id_from_name(self, oid, archive_name: str, dept_id: int = None):
        """returns archive id (check that name is valid)"""
        self.initialize(dept_id)
        if not self.is_valid_archive_name(archive_name):
            raise ScoValueError(f"Archive {archive_name} introuvable")
        archive_id = os.path.join(self.get_obj_dir(oid, dept_id=dept_id), archive_name)
        if not os.path.isdir(archive_id):
            log(
                f"invalid archive name: {archive_name}, oid={oid}, archive_id={archive_id}"
            )
            raise ScoValueError(f"Archive {archive_name} introuvable")
        return archive_id

    def get_archive_description(self, archive_id: str, dept_id: int = None) -> str:
        """Return description of archive"""
        self.initialize(dept_id)
        filename = os.path.join(archive_id, "_description.txt")
        try:
            with open(filename, encoding=scu.SCO_ENCODING) as f:
                descr = f.read()
        except UnicodeDecodeError:
            # some (old) files may have saved under exotic encodings
            with open(filename, "rb") as f:
                data = f.read()
                descr = data.decode(chardet.detect(data)["encoding"])

        return descr

    def create_obj_archive(self, oid: int, description: str, dept_id: int = None):
        """Creates a new archive for this object and returns its id."""
        # id suffixé par YYYY-MM-DD-hh-mm-ss
        archive_id = (
            self.get_obj_dir(oid, dept_id=dept_id)
            + os.path.sep
            + "-".join([f"{x:02d}" for x in time.localtime()[:6]])
        )
        log(f"creating archive: {archive_id}")
        try:
            scu.GSL.acquire()
            os.mkdir(archive_id)
        except FileExistsError:  # directory already exists !
            pass
        finally:
            scu.GSL.release()
        self.store(archive_id, "_description.txt", description)
        return archive_id

    def store(
        self,
        archive_id: str,
        filename: str,
        data: str | bytes,
        dept_id: int = None,
        compress=False,
    ):
        """Store data in archive, under given filename.
        Filename may be modified (sanitized): return used filename
        The file is created or replaced.
        data may be str or bytes
        If compress, data is gziped and filename suffix ".gz" added.
        """
        if isinstance(data, str):
            data = data.encode(scu.SCO_ENCODING)
        self.initialize(dept_id)
        filename = scu.sanitize_filename(filename)
        log(f"storing {filename} ({len(data)} bytes) in {archive_id}")
        try:
            scu.GSL.acquire()
            fname = os.path.join(archive_id, filename)
            if compress:
                if not fname.endswith(".gz"):
                    fname += ".gz"
                with gzip.open(fname, "wb") as f:
                    f.write(data)
            else:
                with open(fname, "wb") as f:
                    f.write(data)
        except FileNotFoundError as exc:
            raise ScoValueError(
                f"Erreur stockage archive (dossier inexistant, chemin {fname})"
            ) from exc
        finally:
            scu.GSL.release()
        return filename

    def get(self, archive_id: str, filename: str, dept_id: int = None):
        """Retreive data"""
        self.initialize(dept_id)
        if not scu.is_valid_filename(filename):
            log(f"""Archiver.get: invalid filename '{filename}'""")
            raise ScoValueError("archive introuvable (déjà supprimée ?)")
        fname = os.path.join(archive_id, filename)
        log(f"reading archive file {fname}")
        try:
            if fname.endswith(".gz"):
                try:
                    with gzip.open(fname) as f:
                        data = f.read()
                except (OSError, EOFError, zlib.error) as exc:
                    raise ScoValueError(
                        f"Erreur lecture archive ({fname} invalide)"
                    ) from exc
            else:
                with open(fname, "rb") as f:
                    data = f.read()
        except FileNotFoundError as exc:
            raise ScoValueError(
                f"Erreur lecture archive (inexistant, chemin {fname})"
            ) from exc
        return data

    def get_archived_file(self, oid, archive_name, filename, dept_id: int = None):
        """Recupère les donnees du fichier indiqué et envoie au client.
        Returns: Response
        """
        archive_id = self.get_id_from_name(oid, archive_name, dept_id=dept_id)
        data = self.get(archive_id, filename)
        if filename.endswith(".gz"):
            filename = filename[:-3]
        mime = mimetypes.guess_type(filename)[0]
        if mime is None:
            mime = "application/octet-stream"

        return scu.send_file(data, filename, mime=mime)