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

"""Gestion des images logos (nouveau ScoDoc 9)

Les logos sont `logo_header.<ext>`  et `logo_footer.<ext>`
avec `ext` membre de LOGOS_IMAGES_ALLOWED_TYPES (= jpg, png)

SCODOC_LOGOS_DIR   /opt/scodoc-data/config/logos
"""
import imghdr
import os
import re
from pathlib import Path

from flask import abort, current_app, url_for
from werkzeug.utils import secure_filename

from app import Departement, ScoValueError
from app.scodoc import sco_utils as scu
import PIL
from PIL import Image as PILImage

GLOBAL = "_SERVER"  # category for server level logos


def find_logo(logoname, dept_id=None, strict=False, prefix=scu.LOGO_FILE_PREFIX):
    """
    "Recherche un logo 'name' existant.
    Deux strategies:
    si strict:
        reherche uniquement dans le département puis si non trouvé au niveau global
    sinon
        On recherche en local au dept d'abord puis si pas trouvé recherche globale
    quelquesoit la stratégie, retourne None si pas trouvé
    :param logoname:  le nom recherche
    :param dept_id:  l'id du département dans lequel se fait la recherche (None si global)
    :param strict: stratégie de recherche (strict = False => dept ou global)
    :param prefix: le prefix utilisé (parmi scu.LOGO_FILE_PREFIX / scu.BACKGROUND_FILE_PREFIX)
    :return: un objet Logo désignant le fichier image trouvé (ou None)
    """
    logo = Logo(logoname, dept_id, prefix).select()
    if logo is None and not strict:
        logo = Logo(logoname=logoname, dept_id=None, prefix=prefix).select()
    return logo


def write_logo(stream, name, dept_id=None):
    Logo(logoname=name, dept_id=dept_id).create(stream)


def replace_logo(name, dept_id):
    logo = find_logo(logoname=name, dept_id=dept_id)
    if logo is not None:
        return logo.filepath


def list_logos():
    inventory = {GLOBAL: _list_dept_logos()}  # logos globaux (header / footer)
    for dept in Departement.query.filter_by(visible=True).all():
        logos_dept = _list_dept_logos(dept_id=dept.id)
        if logos_dept:
            inventory[dept.acronym] = _list_dept_logos(dept.id)
    return inventory


def _list_dept_logos(dept_id=None, prefix=scu.LOGO_FILE_PREFIX):
    "Inventorie tous les logos existants (retourne un dictionnaire de dictionnaires [dept_id][logoname]"
    allowed_ext = "|".join(scu.LOGOS_IMAGES_ALLOWED_TYPES)
    filename_parser = re.compile(f"{prefix}([^.]*).({allowed_ext})")
    logos = {}
    path_dir = Path(scu.SCODOC_LOGOS_DIR)
    if dept_id:
        path_dir = Path(
            os.path.sep.join(
                [scu.SCODOC_LOGOS_DIR, scu.LOGOS_DIR_PREFIX + str(dept_id)]
            )
        )
    if path_dir.exists():
        for entry in path_dir.iterdir():
            if os.access(path_dir.joinpath(entry).absolute(), os.R_OK):
                result = filename_parser.match(entry.name)
                if result:
                    logoname = result.group(1)
                    logos[logoname] = Logo(logoname=logoname, dept_id=dept_id).select()
    return logos if len(logos.keys()) > 0 else None


class Logo:
    """Responsable des opérations (read, create), du calcul des chemins et url
    et de la récupération des informations sur un logp.
    Usage:
        logo existant: Logo(<name>, <dept_id>, ...).read()
        logo en création: Logo(<name>, <dept_id>, ...).create(stream)
        Les attributs filename, filepath, get_url() ne devraient pas être utilisés avant les opérations
            read ou save (le format n'est pas encore connu à ce moement là)
    """

    def __init__(self, logoname, dept_id=None, prefix=scu.LOGO_FILE_PREFIX):
        """Initialisation des noms et département des logos.
        if prefix = None on recherche simplement une image 'logoname.*'
        Le format est renseigné au moment de la lecture (read) ou de la création (create) de l'objet
        """
        self.logoname = secure_filename(logoname)
        self.scodoc_dept_id = dept_id
        self.prefix = prefix or ""
        self.suffix = None
        self.dimensions = None
        if self.scodoc_dept_id:
            self.dirpath = os.path.sep.join(
                [
                    scu.SCODOC_LOGOS_DIR,
                    scu.LOGOS_DIR_PREFIX + secure_filename(str(dept_id)),
                ]
            )
        else:
            self.dirpath = scu.SCODOC_LOGOS_DIR
        self.basepath = os.path.sep.join(
            [self.dirpath, self.prefix + secure_filename(self.logoname)]
        )
        self.filepath = None
        self.filename = None

    def _set_format(self, fmt):
        self.suffix = fmt
        self.filepath = self.basepath + "." + fmt
        self.filename = self.logoname + "." + fmt

    def _ensure_directory_exists(self):
        "create enclosing directory if necessary"
        if not Path(self.dirpath).exists():
            current_app.logger.info(f"sco_logos creating directory %s", self.dirpath)
            os.mkdir(self.dirpath)

    def create(self, stream):
        img_type = guess_image_type(stream)
        if img_type not in scu.LOGOS_IMAGES_ALLOWED_TYPES:
            abort(400, "type d'image invalide")
        self._set_format(img_type)
        self._ensure_directory_exists()
        filename = self.basepath + "." + self.suffix
        with open(filename, "wb") as f:
            f.write(stream.read())
        current_app.logger.info(f"sco_logos.store_image %s", self.filename)
        # erase other formats if they exists
        for suffix in set(scu.LOGOS_IMAGES_ALLOWED_TYPES) - set([img_type]):
            try:
                os.unlink(self.basepath + "." + suffix)
            except IOError:
                pass

    def select(self):
        """
        Récupération des données pour un logo existant (sinon -> Exception)
        il doit exister un et un seul fichier image parmi les types autorisés
        (sinon on considère le premier trouvé)
        permet d'affiner le format d'un logo de format inconnu
        """
        for suffix in scu.LOGOS_IMAGES_ALLOWED_TYPES:
            path = Path(self.basepath + "." + suffix)
            if path.exists():
                self._set_format(suffix)
                with open(self.filepath, "rb") as f:
                    img = PILImage.open(f)
                    self.dimensions = img.size
                return self
        return None

    def get_url(self):
        return url_for(
            "scodoc.get_logo",
            scodoc_dept=self.scodoc_dept_id,
            name=self.logoname,
            global_if_not_found=False,
        )

    def get_url_small(self):
        return url_for(
            "scodoc.get_logo_small",
            scodoc_dept=self.scodoc_dept_id,
            name=self.logoname,
            global_if_not_found=False,
        )


def guess_image_type(stream) -> str:
    "guess image type from header in stream"
    header = stream.read(512)
    stream.seek(0)
    fmt = imghdr.what(None, header)
    if not fmt:
        return None
    return fmt if fmt != "jpeg" else "jpg"