# -*- coding: utf-8 -*-

#   This file is part of the Calibre-Web (https://github.com/janeczku/calibre-web)
#     Copyright (C) 2020 monkey
#
#   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 3 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, see <http://www.gnu.org/licenses/>.

import os
from shutil import copyfile, copyfileobj
from urllib.request import urlopen
from io import BytesIO
from datetime import datetime, timezone

from .. import constants
from cps import config, db, fs, gdriveutils, logger, ub, app
from cps.services.worker import CalibreTask, STAT_CANCELLED, STAT_ENDED
from sqlalchemy import func, text, or_
from flask_babel import lazy_gettext as N_

try:
    from wand.image import Image
    use_IM = True
except (ImportError, RuntimeError) as e:
    use_IM = False


def get_resize_height(resolution):
    return int(255 * resolution)


def get_resize_width(resolution, original_width, original_height):
    height = get_resize_height(resolution)
    percent = (height / float(original_height))
    width = int((float(original_width) * float(percent)))
    return width if width % 2 == 0 else width + 1


def get_best_fit(width, height, image_width, image_height):
    resize_width = int(width / 2.0)
    resize_height = int(height / 2.0)
    aspect_ratio = image_width / image_height

    # If this image's aspect ratio is different from the first image, then resize this image
    # to fill the width and height of the first image
    if aspect_ratio < width / height:
        resize_width = int(width / 2.0)
        resize_height = image_height * int(width / 2.0) / image_width

    elif aspect_ratio > width / height:
        resize_width = image_width * int(height / 2.0) / image_height
        resize_height = int(height / 2.0)

    return {'width': resize_width, 'height': resize_height}


class TaskGenerateCoverThumbnails(CalibreTask):
    def __init__(self, book_id=-1, task_message=''):
        super(TaskGenerateCoverThumbnails, self).__init__(task_message)
        self.log = logger.create()
        self.book_id = book_id
        self.app_db_session = ub.get_new_session_instance()
        self.cache = fs.FileSystem()
        self.resolutions = [
            constants.COVER_THUMBNAIL_SMALL,
            constants.COVER_THUMBNAIL_MEDIUM,
            constants.COVER_THUMBNAIL_LARGE
        ]

    def run(self, worker_thread):
        if use_IM and self.stat != STAT_CANCELLED and self.stat != STAT_ENDED:
            self.message = 'Scanning Books'
            books_with_covers = self.get_books_with_covers(self.book_id)
            count = len(books_with_covers)

            total_generated = 0
            for i, book in enumerate(books_with_covers):

                # Generate new thumbnails for missing covers
                generated = self.create_book_cover_thumbnails(book)

                # Increment the progress
                self.progress = (1.0 / count) * i

                if generated > 0:
                    total_generated += generated
                    self.message = N_('Generated %(count)s cover thumbnails', count=total_generated)

                # Check if job has been cancelled or ended
                if self.stat == STAT_CANCELLED:
                    self.log.info(f'GenerateCoverThumbnails task has been cancelled.')
                    return

                if self.stat == STAT_ENDED:
                    self.log.info(f'GenerateCoverThumbnails task has been ended.')
                    return

            if total_generated == 0:
                self.self_cleanup = True

        self._handleSuccess()
        self.app_db_session.remove()

    @staticmethod
    def get_books_with_covers(book_id=-1):
        filter_exp = (db.Books.id == book_id) if book_id != -1 else True
        with app.app_context():
            calibre_db = db.CalibreDB(app) #, expire_on_commit=False, init=True)
            books_cover = calibre_db.session.query(db.Books).filter(db.Books.has_cover == 1).filter(filter_exp).all()
            # calibre_db.session.close()
        return books_cover

    def get_book_cover_thumbnails(self, book_id):
        return self.app_db_session \
            .query(ub.Thumbnail) \
            .filter(ub.Thumbnail.type == constants.THUMBNAIL_TYPE_COVER) \
            .filter(ub.Thumbnail.entity_id == book_id) \
            .filter(or_(ub.Thumbnail.expiration.is_(None), ub.Thumbnail.expiration > datetime.now(timezone.utc))) \
            .all()

    def create_book_cover_thumbnails(self, book):
        generated = 0
        book_cover_thumbnails = self.get_book_cover_thumbnails(book.id)

        # Generate new thumbnails for missing covers
        resolutions = list(map(lambda t: t.resolution, book_cover_thumbnails))
        missing_resolutions = list(set(self.resolutions).difference(resolutions))
        for resolution in missing_resolutions:
            generated += 1
            self.create_book_cover_single_thumbnail(book, resolution)

        # Replace outdated or missing thumbnails
        for thumbnail in book_cover_thumbnails:
            if book.last_modified.replace(tzinfo=None) > thumbnail.generated_at:
                generated += 1
                self.update_book_cover_thumbnail(book, thumbnail)

            elif not self.cache.get_cache_file_exists(thumbnail.filename, constants.CACHE_TYPE_THUMBNAILS):
                generated += 1
                self.update_book_cover_thumbnail(book, thumbnail)
        return generated

    def create_book_cover_single_thumbnail(self, book, resolution):
        thumbnail = ub.Thumbnail()
        thumbnail.type = constants.THUMBNAIL_TYPE_COVER
        thumbnail.entity_id = book.id
        thumbnail.format = 'jpeg'
        thumbnail.resolution = resolution

        self.app_db_session.add(thumbnail)
        try:
            self.app_db_session.commit()
            self.generate_book_thumbnail(book, thumbnail)
        except Exception as ex:
            self.log.debug('Error creating book thumbnail: ' + str(ex))
            self._handleError('Error creating book thumbnail: ' + str(ex))
            self.app_db_session.rollback()

    def update_book_cover_thumbnail(self, book, thumbnail):
        thumbnail.generated_at = datetime.now(timezone.utc)

        try:
            self.app_db_session.commit()
            self.cache.delete_cache_file(thumbnail.filename, constants.CACHE_TYPE_THUMBNAILS)
            self.generate_book_thumbnail(book, thumbnail)
        except Exception as ex:
            self.log.debug('Error updating book thumbnail: ' + str(ex))
            self._handleError('Error updating book thumbnail: ' + str(ex))
            self.app_db_session.rollback()

    def generate_book_thumbnail(self, book, thumbnail):
        if book and thumbnail:
            if config.config_use_google_drive:
                if not gdriveutils.is_gdrive_ready():
                    raise Exception('Google Drive is configured but not ready')

                content = gdriveutils.get_cover_via_gdrive(book.path)
                if not content:
                    raise Exception('Google Drive cover url not found')
                try:
                    stream = BytesIO(content)
                    with Image(file=stream) as img:
                        filename = self.cache.get_cache_file_path(thumbnail.filename,
                                                                  constants.CACHE_TYPE_THUMBNAILS)
                        height = get_resize_height(thumbnail.resolution)
                        if img.height > height:
                            width = get_resize_width(thumbnail.resolution, img.width, img.height)
                            img.resize(width=width, height=height, filter='lanczos')
                            img.format = thumbnail.format
                            img.save(filename=filename)
                        else:
                            stream.seek(0)
                            with open(filename, 'wb') as fd:
                                copyfileobj(stream, fd)


                except Exception as ex:
                    # Bubble exception to calling function
                    self.log.debug('Error generating thumbnail file: ' + str(ex))
                    raise ex
                finally:
                    if stream is not None:
                        stream.close()
            else:
                book_cover_filepath = os.path.join(config.get_book_path(), book.path, 'cover.jpg')
                if not os.path.isfile(book_cover_filepath):
                    raise Exception('Book cover file not found')

                with Image(filename=book_cover_filepath) as img:
                    height = get_resize_height(thumbnail.resolution)
                    filename = self.cache.get_cache_file_path(thumbnail.filename, constants.CACHE_TYPE_THUMBNAILS)
                    if img.height > height:
                        width = get_resize_width(thumbnail.resolution, img.width, img.height)
                        img.resize(width=width, height=height, filter='lanczos')
                        img.format = thumbnail.format
                        img.save(filename=filename)
                    else:
                        # take cover as is
                        copyfile(book_cover_filepath, filename)

    @property
    def name(self):
        return N_('Cover Thumbnails')

    def __str__(self):
        if self.book_id > 0:
            return "Add Cover Thumbnails for Book {}".format(self.book_id)
        else:
            return "Generate Cover Thumbnails"

    @property
    def is_cancellable(self):
        return True


class TaskGenerateSeriesThumbnails(CalibreTask):
    def __init__(self, task_message=''):
        super(TaskGenerateSeriesThumbnails, self).__init__(task_message)
        self.log = logger.create()
        self.app_db_session = ub.get_new_session_instance()
        # self.calibre_db = db.CalibreDB(expire_on_commit=False, init=True)
        self.cache = fs.FileSystem()
        self.resolutions = [
            constants.COVER_THUMBNAIL_SMALL,
            constants.COVER_THUMBNAIL_MEDIUM,
        ]

    def run(self, worker_thread):
        with app.app_context():
            calibre_db = db.CalibreDB(app)
            if calibre_db.session and use_IM and self.stat != STAT_CANCELLED and self.stat != STAT_ENDED:
                self.message = 'Scanning Series'
                all_series = self.get_series_with_four_plus_books(calibre_db)
                count = len(all_series)

                total_generated = 0
                for i, series in enumerate(all_series):
                    generated = 0
                    series_thumbnails = self.get_series_thumbnails(series.id)
                    series_books = self.get_series_books(series.id, calibre_db)

                    # Generate new thumbnails for missing covers
                    resolutions = list(map(lambda t: t.resolution, series_thumbnails))
                    missing_resolutions = list(set(self.resolutions).difference(resolutions))
                    for resolution in missing_resolutions:
                        generated += 1
                        self.create_series_thumbnail(series, series_books, resolution)

                    # Replace outdated or missing thumbnails
                    for thumbnail in series_thumbnails:
                        if any(book.last_modified > thumbnail.generated_at for book in series_books):
                            generated += 1
                            self.update_series_thumbnail(series_books, thumbnail)

                        elif not self.cache.get_cache_file_exists(thumbnail.filename, constants.CACHE_TYPE_THUMBNAILS):
                            generated += 1
                            self.update_series_thumbnail(series_books, thumbnail)

                    # Increment the progress
                    self.progress = (1.0 / count) * i

                    if generated > 0:
                        total_generated += generated
                        self.message = N_('Generated {0} series thumbnails').format(total_generated)

                    # Check if job has been cancelled or ended
                    if self.stat == STAT_CANCELLED:
                        self.log.info(f'GenerateSeriesThumbnails task has been cancelled.')
                        return

                    if self.stat == STAT_ENDED:
                        self.log.info(f'GenerateSeriesThumbnails task has been ended.')
                        return

                if total_generated == 0:
                    self.self_cleanup = True

            self._handleSuccess()
            self.app_db_session.remove()

    def get_series_with_four_plus_books(self, calibre_db):
        return calibre_db.session \
            .query(db.Series) \
            .join(db.books_series_link) \
            .join(db.Books) \
            .filter(db.Books.has_cover == 1) \
            .group_by(text('books_series_link.series')) \
            .having(func.count('book_series_link') > 3) \
            .all()

    def get_series_books(self, series_id, calibre_db):
        return calibre_db.session \
            .query(db.Books) \
            .join(db.books_series_link) \
            .join(db.Series) \
            .filter(db.Books.has_cover == 1) \
            .filter(db.Series.id == series_id) \
            .all()

    def get_series_thumbnails(self, series_id):
        return (self.app_db_session
            .query(ub.Thumbnail)
            .filter(ub.Thumbnail.type == constants.THUMBNAIL_TYPE_SERIES)
            .filter(ub.Thumbnail.entity_id == series_id)
            .filter(or_(ub.Thumbnail.expiration.is_(None), ub.Thumbnail.expiration > datetime.now(timezone.utc)))
            .all())

    def create_series_thumbnail(self, series, series_books, resolution):
        thumbnail = ub.Thumbnail()
        thumbnail.type = constants.THUMBNAIL_TYPE_SERIES
        thumbnail.entity_id = series.id
        thumbnail.format = 'jpeg'
        thumbnail.resolution = resolution

        self.app_db_session.add(thumbnail)
        try:
            self.app_db_session.commit()
            self.generate_series_thumbnail(series_books, thumbnail)
        except Exception as ex:
            self.log.debug('Error creating book thumbnail: ' + str(ex))
            self._handleError('Error creating book thumbnail: ' + str(ex))
            self.app_db_session.rollback()

    def update_series_thumbnail(self, series_books, thumbnail):
        thumbnail.generated_at = datetime.now(timezone.utc)

        try:
            self.app_db_session.commit()
            self.cache.delete_cache_file(thumbnail.filename, constants.CACHE_TYPE_THUMBNAILS)
            self.generate_series_thumbnail(series_books, thumbnail)
        except Exception as ex:
            self.log.debug('Error updating book thumbnail: ' + str(ex))
            self._handleError('Error updating book thumbnail: ' + str(ex))
            self.app_db_session.rollback()

    def generate_series_thumbnail(self, series_books, thumbnail):
        # Get the last four books in the series based on series_index
        books = sorted(series_books, key=lambda b: float(b.series_index), reverse=True)[:4]

        top = 0
        left = 0
        width = 0
        height = 0
        with Image() as canvas:
            for book in books:
                if config.config_use_google_drive:
                    if not gdriveutils.is_gdrive_ready():
                        raise Exception('Google Drive is configured but not ready')

                    web_content_link = gdriveutils.get_cover_via_gdrive(book.path)
                    if not web_content_link:
                        raise Exception('Google Drive cover url not found')

                    stream = None
                    try:
                        stream = urlopen(web_content_link)
                        with Image(file=stream) as img:
                            # Use the first image in this set to determine the width and height to scale the
                            # other images in this set
                            if width == 0 or height == 0:
                                width = get_resize_width(thumbnail.resolution, img.width, img.height)
                                height = get_resize_height(thumbnail.resolution)
                                canvas.blank(width, height)

                            dimensions = get_best_fit(width, height, img.width, img.height)

                            # resize and crop the image
                            img.resize(width=int(dimensions['width']), height=int(dimensions['height']),
                                       filter='lanczos')
                            img.crop(width=int(width / 2.0), height=int(height / 2.0), gravity='center')

                            # add the image to the canvas
                            canvas.composite(img, left, top)

                    except Exception as ex:
                        self.log.debug('Error generating thumbnail file: ' + str(ex))
                        raise ex
                    finally:
                        if stream is not None:
                            stream.close()

                book_cover_filepath = os.path.join(config.get_book_path(), book.path, 'cover.jpg')
                if not os.path.isfile(book_cover_filepath):
                    raise Exception('Book cover file not found')

                with Image(filename=book_cover_filepath) as img:
                    # Use the first image in this set to determine the width and height to scale the
                    # other images in this set
                    if width == 0 or height == 0:
                        width = get_resize_width(thumbnail.resolution, img.width, img.height)
                        height = get_resize_height(thumbnail.resolution)
                        canvas.blank(width, height)

                    dimensions = get_best_fit(width, height, img.width, img.height)

                    # resize and crop the image
                    img.resize(width=int(dimensions['width']), height=int(dimensions['height']), filter='lanczos')
                    img.crop(width=int(width / 2.0), height=int(height / 2.0), gravity='center')

                    # add the image to the canvas
                    canvas.composite(img, left, top)

                # set the coordinates for the next iteration
                if left == 0 and top == 0:
                    left = int(width / 2.0)
                elif left == int(width / 2.0) and top == 0:
                    left = 0
                    top = int(height / 2.0)
                else:
                    left = int(width / 2.0)

            canvas.format = thumbnail.format
            filename = self.cache.get_cache_file_path(thumbnail.filename, constants.CACHE_TYPE_THUMBNAILS)
            canvas.save(filename=filename)

    @property
    def name(self):
        return N_('Cover Thumbnails')

    def __str__(self):
        return "GenerateSeriesThumbnails"

    @property
    def is_cancellable(self):
        return True


class TaskClearCoverThumbnailCache(CalibreTask):
    def __init__(self, book_id, task_message=N_('Clearing cover thumbnail cache')):
        super(TaskClearCoverThumbnailCache, self).__init__(task_message)
        self.log = logger.create()
        self.book_id = book_id
        self.app_db_session = ub.get_new_session_instance()
        self.cache = fs.FileSystem()

    def run(self, worker_thread):
        if self.app_db_session:
            # delete superfluous thumbnails
            if self.book_id == 0:
                with app.app_context():
                    calibre_db = db.CalibreDB(app)
                    thumbnails = (calibre_db.session.query(ub.Thumbnail)
                                  .join(db.Books, ub.Thumbnail.entity_id == db.Books.id, isouter=True)
                                  .filter(db.Books.id==None)
                                  .all())
                    # calibre_db.session.close()
            elif self.book_id > 0:  # make sure single book is selected
                thumbnails = self.get_thumbnails_for_book(self.book_id)
            if self.book_id < 0:
                self.delete_all_thumbnails()
            else:
                for thumbnail in thumbnails:
                    self.delete_thumbnail(thumbnail)
        self._handleSuccess()
        self.app_db_session.remove()

    def get_thumbnails_for_book(self, book_id):
        return self.app_db_session \
            .query(ub.Thumbnail) \
            .filter(ub.Thumbnail.type == constants.THUMBNAIL_TYPE_COVER) \
            .filter(ub.Thumbnail.entity_id == book_id) \
            .all()

    def delete_thumbnail(self, thumbnail):
        try:
            self.cache.delete_cache_file(thumbnail.filename, constants.CACHE_TYPE_THUMBNAILS)
            self.app_db_session \
                .query(ub.Thumbnail) \
                .filter(ub.Thumbnail.type == constants.THUMBNAIL_TYPE_COVER) \
                .filter(ub.Thumbnail.entity_id == thumbnail.entity_id) \
                .delete()
            self.app_db_session.commit()
        except Exception as ex:
            self.log.debug('Error deleting book thumbnail: ' + str(ex))
            self._handleError('Error deleting book thumbnail: ' + str(ex))

    def delete_all_thumbnails(self):
        try:
            self.app_db_session.query(ub.Thumbnail).filter(ub.Thumbnail.type == constants.THUMBNAIL_TYPE_COVER).delete()
            self.app_db_session.commit()
            self.cache.delete_cache_dir(constants.CACHE_TYPE_THUMBNAILS)
        except Exception as ex:
            self.log.debug('Error deleting thumbnail directory: ' + str(ex))
            self._handleError('Error deleting thumbnail directory: ' + str(ex))

    @property
    def name(self):
        return N_('Cover Thumbnails')

    # needed for logging
    def __str__(self):
        if self.book_id > 0:
            return "Replace/Delete Cover Thumbnails for book " + str(self.book_id)
        else:
            return "Delete Thumbnail cache directory"

    @property
    def is_cancellable(self):
        return False