sigal/src/sigal/gallery.py

# Copyright (c) 2009-2023 - Simon Conseil
# Copyright (c) 2013      - Christophe-Marie Duquesne
# Copyright (c) 2014      - Jonas Kaufmann
# Copyright (c) 2015      - François D.
# Copyright (c) 2017      - Mate Lakat
# Copyright (c) 2018      - Edwin Steele
# Copyright (c) 2021      - Tim AtLee

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.

import fnmatch
import io
import logging
import multiprocessing
import os
import pickle
import random
import sys
from collections import defaultdict
from datetime import datetime
from functools import cached_property
from itertools import cycle
from os.path import isfile, join, splitext
from shutil import get_terminal_size
from urllib.parse import quote as url_quote

from click import progressbar
from natsort import natsort_keygen, ns
from PIL import Image as PILImage

from . import image, signals, video
from .image import get_exif_tags, get_image_metadata, get_size, process_image
from .settings import Status, get_thumb
from .utils import (
    Devnull,
    check_or_create_dir,
    copy,
    get_mime,
    get_mod_date,
    is_valid_html5_audio,
    is_valid_html5_video,
    read_markdown,
    should_reprocess_album,
    url_from_path,
)
from .audio import process_audio
from .video import process_video
from .writer import AlbumListPageWriter, AlbumPageWriter


class Media:
    """Base Class for media files.

    Attributes:

    :var Media.type: ``"image"`` or ``"video"``.
    :var Media.dst_filename: Filename of the resized image.
    :var Media.thumbnail: Location of the corresponding thumbnail image.
    :var Media.big: If not None, location of the unmodified image.
    :var Media.big_url: If not None, url of the unmodified image.

    """

    type = ""
    """Type of media, e.g. ``"image"`` or ``"video"``."""

    def __init__(self, filename, path, settings):
        self.path = path
        self.settings = settings

        self.basename = os.path.splitext(filename)[0]

        self.dst_filename = filename
        """Filename of the resized image."""

        self.src_filename = filename
        """Filename of the input image."""

        self.src_ext = os.path.splitext(filename)[1].lower()
        """Input extension."""

        self.src_path = join(settings["source"], path, self.src_filename)

        self.thumb_name = get_thumb(self.settings, self.dst_filename)

        self.logger = logging.getLogger(__name__)

        signals.media_initialized.send(self)

    def __repr__(self):
        return f"<{self.__class__.__name__}>({str(self)!r})"

    def __str__(self):
        return join(self.path, self.src_filename)

    def __getstate__(self):
        state = self.__dict__.copy()
        # remove un-pickable objects
        state["logger"] = None
        return state

    def __setstate__(self, state):
        for slot, value in state.items():
            setattr(self, slot, value)
        self.logger = logging.getLogger(__name__)

    @property
    def dst_path(self):
        return join(self.settings["destination"], self.path, self.dst_filename)

    @property
    def thumb_path(self):
        return join(self.settings["destination"], self.path, self.thumb_name)

    @property
    def url(self):
        """URL of the media."""
        return url_from_path(self.dst_filename)

    @property
    def big(self):
        """Path to the original image, if ``keep_orig`` is set (relative to the
        album directory). Copy the file if needed.
        """
        if self.settings["keep_orig"]:
            s = self.settings
            if s["use_orig"]:
                # The image *is* the original, just use it
                return self.src_filename
            orig_path = join(s["destination"], self.path, s["orig_dir"])
            check_or_create_dir(orig_path)
            big_path = join(orig_path, self.src_filename)
            if not isfile(big_path):
                copy(
                    self.src_path,
                    big_path,
                    symlink=s["orig_link"],
                    rellink=self.settings["rel_link"],
                )
            return join(s["orig_dir"], self.src_filename)

    @property
    def big_url(self):
        """URL of the original media."""
        if self.big is not None:
            return url_from_path(self.big)

    @property
    def thumbnail(self):
        """Path to the thumbnail image (relative to the album directory)."""

        if not isfile(self.thumb_path):
            self.logger.debug("Generating thumbnail for %r", self)
            path = self.dst_path if os.path.exists(self.dst_path) else self.src_path
            try:
                # if thumbnail is missing (if settings['make_thumbs'] is False)
                s = self.settings
                if self.type == "image":
                    image.generate_thumbnail(
                        path, self.thumb_path, s["thumb_size"], fit=s["thumb_fit"]
                    )
                elif self.type == "video":
                    video.generate_thumbnail(
                        path,
                        self.thumb_path,
                        s["thumb_size"],
                        s["thumb_video_delay"],
                        fit=s["thumb_fit"],
                        converter=s["video_converter"],
                        black_retries=s["thumb_video_black_retries"],
                        black_offset=s["thumb_video_black_retry_offset"],
                        black_max_colors=s["thumb_video_black_max_colors"],
                    )
            except Exception as e:
                self.logger.error("Failed to generate thumbnail: %s", e)
                return
        return url_from_path(self.thumb_name)

    @cached_property
    def description(self):
        """Description extracted from the Markdown <imagename>.md file."""
        return self.markdown_metadata.get("description", "")

    @cached_property
    def title(self):
        """Title extracted from the metadata, or defaults to the filename."""
        title = self.markdown_metadata.get("title", "")
        return title if title else self.basename

    @cached_property
    def meta(self):
        """Other metadata extracted from the Markdown <imagename>.md file."""
        return self.markdown_metadata.get("meta", {})

    @cached_property
    def markdown_metadata(self):
        """Get metadata from filename.md: title, description, meta."""
        return self._get_markdown_metadata()

    @property
    def markdown_metadata_filepath(self):
        return splitext(self.src_path)[0] + ".md"

    def _get_markdown_metadata(self):
        """Get metadata from filename.md."""
        meta = {"title": "", "description": "", "meta": {}}
        if isfile(self.markdown_metadata_filepath):
            meta.update(read_markdown(self.markdown_metadata_filepath))
        return meta

    @cached_property
    def file_metadata(self):
        """Type-specific metadata"""
        return {}

    def _get_file_date(self):
        return datetime.fromtimestamp(get_mod_date(self.src_path))


class Image(Media):
    """Gather all informations on an image file."""

    type = "image"

    def __init__(self, filename, path, settings):
        super().__init__(filename, path, settings)
        imgformat = settings.get("img_format")

        # Register all formats
        PILImage.init()

        if imgformat and PILImage.EXTENSION[self.src_ext] != imgformat.upper():
            # Find the extension that should match img_format
            extensions = {v: k for k, v in PILImage.EXTENSION.items()}
            ext = extensions[imgformat.upper()]
            self.dst_filename = self.basename + ext
            self.thumb_name = get_thumb(self.settings, self.dst_filename)

    @cached_property
    def date(self):
        """The date from the EXIF DateTimeOriginal metadata if available, or
        from the file date."""
        return self.exif and self.exif.get("dateobj", None) or self._get_file_date()

    @cached_property
    def exif(self):
        """If not `None` contains a dict with the most common tags. For more
        information, see :ref:`simple-exif-data`.
        """
        datetime_format = self.settings["datetime_format"]
        return (
            get_exif_tags(self.raw_exif, datetime_format=datetime_format)
            if self.raw_exif and self.src_ext in (".jpg", ".jpeg")
            else None
        )

    @cached_property
    def file_metadata(self):
        """Image file metadata (Exif and IPTC)"""
        return get_image_metadata(self.src_path)

    def _get_markdown_metadata(self):
        """Get metadata from filename.md."""
        meta = super()._get_markdown_metadata()

        # If a title or description hasn't been obtained by other means, look
        #  for the information in IPTC fields
        if not meta["title"]:
            meta["title"] = self.file_metadata["iptc"].get("title", "")
        if not meta["description"]:
            meta["description"] = self.file_metadata["iptc"].get("description", "")

        return meta

    @cached_property
    def raw_exif(self):
        """If not `None`, contains the raw EXIF tags."""
        if self.src_ext in (".jpg", ".jpeg"):
            return self.file_metadata["exif"]

    @cached_property
    def size(self):
        """The dimensions of the resized image."""
        return get_size(self.dst_path)

    @cached_property
    def input_size(self):
        """The dimensions of the input image."""
        return get_size(self.src_path)

    @cached_property
    def thumb_size(self):
        """The dimensions of the thumbnail image."""
        return get_size(self.thumb_path)

    def has_location(self):
        """True if location information is available for EXIF GPSInfo."""
        return self.exif is not None and "gps" in self.exif


class Video(Media):
    """Gather all informations on a video file."""

    type = "video"

    def __init__(self, filename, path, settings):
        super().__init__(filename, path, settings)

        if not settings["use_orig"] or not is_valid_html5_video(self.src_ext):
            video_format = settings["video_format"]
            ext = "." + video_format
            self.dst_filename = self.basename + ext
            self.mime = get_mime(ext)
        else:
            self.mime = get_mime(self.src_ext)

    @cached_property
    def date(self):
        """The date from the Date metadata if available, or from the file date."""
        if "date" in self.meta:
            try:
                self.logger.debug(
                    "Reading date from image metadata : %s", self.src_filename
                )
                return datetime.fromisoformat(self.meta["date"][0])
            except Exception:
                self.logger.debug(
                    "Reading date from image metadata failed : %s", self.src_filename
                )
        # If no date is found in the metadata, return the file date.
        return self._get_file_date()


class Audio(Media):
    """Gather all informations on an audio file."""

    type = "audio"

    def __init__(self, filename, path, settings):
        super().__init__(filename, path, settings)
        self.mime = get_mime(self.src_ext)

    @cached_property
    def date(self):
        """The date from the Date metadata if available, or from the file date."""
        if "date" in self.meta:
            try:
                self.logger.debug(
                    "Reading date from image metadata : %s", self.src_filename
                )
                return datetime.fromisoformat(self.meta["date"][0])
            except Exception:
                self.logger.debug(
                    "Reading date from image metadata failed : %s", self.src_filename
                )
        # If no date is found in the metadata, return the file date.
        return self._get_file_date()


class Album:
    """Gather all informations on an album.

    Attributes:

    :var description_file: Name of the Markdown file which gives information
        on an album
    :var index_url: URL to the index page.
    :var output_file: Name of the output HTML file
    :var meta: Meta data from the Markdown file.
    :var description: description from the Markdown file.

    For details how to annotate your albums with meta data, see
    :doc:`album_information`.

    """

    description_file = "index.md"

    def __init__(self, path, settings, dirnames, filenames, gallery):
        self.path = path
        self.name = path.split(os.path.sep)[-1]
        self.gallery = gallery
        self.settings = settings
        self.subdirs = dirnames
        self.output_file = settings["output_filename"]
        self._thumbnail = None

        if path == ".":
            self.src_path = settings["source"]
            self.dst_path = settings["destination"]
        else:
            self.src_path = join(settings["source"], path)
            self.dst_path = join(settings["destination"], path)

        self.logger = logging.getLogger(__name__)

        # optionally add index.html to the URLs
        self.url_ext = self.output_file if settings["index_in_url"] else ""

        self.index_url = (
            url_from_path(os.path.relpath(settings["destination"], self.dst_path))
            + "/"
            + self.url_ext
        )

        #: List of all medias in the album (:class:`~sigal.gallery.Image` and
        #: :class:`~sigal.gallery.Video`).
        self.medias = medias = []
        self.medias_count = defaultdict(int)

        for f in filenames:
            ext = splitext(f)[1]
            media = None
            if ext.lower() in settings["img_extensions"]:
                media = Image(f, self.path, settings)
            elif ext.lower() in settings["video_extensions"]:
                media = Video(f, self.path, settings)
            elif ext.lower() in settings["audio_extensions"]:
                media = Audio(f, self.path, settings)

            # Allow modification of the media, including overriding the class
            # type for the media.
            result = signals.album_file.send(self, filename=f, media=media)
            for recv, ret in result:
                if ret is not None:
                    media = ret

            if media:
                self.medias_count[media.type] += 1
                medias.append(media)

        signals.album_initialized.send(self)

    def __repr__(self):
        return f"<{self.__class__.__name__}>(path={self.path!r}, title={self.title!r})"

    def __str__(self):
        return f"{self.path} : " + ", ".join(
            f"{count} {_type}s" for _type, count in self.medias_count.items()
        )

    def __len__(self):
        return len(self.medias)

    def __iter__(self):
        return iter(self.medias)

    @cached_property
    def description(self):
        """Description extracted from the Markdown index.md file."""
        return self.markdown_metadata.get("description", "")

    @cached_property
    def title(self):
        """Title extracted from the Markdown index.md file."""
        title = self.markdown_metadata.get("title", "")
        path = self.path if self.path != "." else self.src_path
        return title if title else os.path.basename(path)

    @cached_property
    def meta(self):
        """Other metadata extracted from the Markdown index.md file."""
        return self.markdown_metadata.get("meta", {})

    @cached_property
    def author(self):
        """Author extracted from the Markdown index.md file or settings."""
        try:
            return self.meta["author"][0]
        except KeyError:
            return self.settings.get("author")

    @property
    def markdown_metadata_filepath(self):
        return join(self.src_path, self.description_file)

    @cached_property
    def markdown_metadata(self):
        """Get metadata from filename.md: title, description, meta."""
        meta = {"title": "", "description": "", "meta": {}}
        if isfile(self.markdown_metadata_filepath):
            meta.update(read_markdown(self.markdown_metadata_filepath))
        return meta

    def create_output_directories(self):
        """Create output directories for thumbnails and original images."""
        check_or_create_dir(self.dst_path)

        if self.medias:
            check_or_create_dir(join(self.dst_path, self.settings["thumb_dir"]))

        if self.medias and self.settings["keep_orig"]:
            self.orig_path = join(self.dst_path, self.settings["orig_dir"])
            check_or_create_dir(self.orig_path)

    def sort_subdirs(self, albums_sort_attr):
        if self.subdirs:
            if not albums_sort_attr:
                albums_sort_attr = self.settings["albums_sort_attr"]
            reverse = self.settings["albums_sort_reverse"]

            if "sort" in self.meta:
                # override default sort order from settings
                albums_sort_attr = self.meta["sort"][0]
                if albums_sort_attr[0] == "-":
                    albums_sort_attr = albums_sort_attr[1:]
                    reverse = True
                else:
                    reverse = False

            root_path = self.path if self.path != "." else ""

            def sort_key(s):
                sort_attr = albums_sort_attr
                if not isinstance(sort_attr, list):
                    sort_attr = [sort_attr]

                album = self.gallery.albums[join(root_path, s)]

                for k in sort_attr:
                    try:
                        if k.startswith("meta."):
                            meta_key = k.split(".", 1)[1]
                            return album.meta.get(meta_key)[0]
                        else:
                            return getattr(album, k)
                    except AttributeError:
                        continue
                    except TypeError:
                        continue
                return ""

            key = natsort_keygen(key=sort_key, alg=ns.SIGNED|ns.LOCALE)
            self.subdirs.sort(key=key, reverse=reverse)

        signals.albums_sorted.send(self)

    def sort_medias(self, medias_sort_attr):
        if self.medias:
            if medias_sort_attr == "filename":
                medias_sort_attr = "dst_filename"

            if medias_sort_attr == "date":
                key = lambda s: s.date or datetime.now()
            elif medias_sort_attr.startswith("meta."):
                meta_key = medias_sort_attr.split(".", 1)[1]
                key = natsort_keygen(
                    key=lambda s: s.meta.get(meta_key, [""])[0], alg=ns.SIGNED|ns.LOCALE
                )
            else:
                key = natsort_keygen(
                    key=lambda s: getattr(s, medias_sort_attr), alg=ns.SIGNED|ns.LOCALE
                )

            self.medias.sort(key=key, reverse=self.settings["medias_sort_reverse"])

        signals.medias_sorted.send(self)

    @property
    def images(self):
        """List of images (:class:`~sigal.gallery.Image`)."""
        for media in self.medias:
            if media.type == "image":
                yield media

    @property
    def videos(self):
        """List of videos (:class:`~sigal.gallery.Video`)."""
        for media in self.medias:
            if media.type == "video":
                yield media

    @property
    def albums(self):
        """List of :class:`~sigal.gallery.Album` objects for each
        sub-directory.
        """
        root_path = self.path if self.path != "." else ""
        return [self.gallery.albums[join(root_path, path)] for path in self.subdirs]

    @property
    def nbmedias(self):
        return len(self.medias) + sum(len(album) for album in self.albums)

    @property
    def url(self):
        """URL of the album, relative to its parent."""
        url = self.name.encode("utf-8")
        return url_quote(url) + "/" + self.url_ext

    @property
    def thumbnail(self):
        """Path to the thumbnail of the album."""

        if self._thumbnail:
            # stop if it is already set
            return self._thumbnail

        # Test the thumbnail from the Markdown file.
        thumbnail = self.meta.get("thumbnail", [""])[0]

        if thumbnail and isfile(join(self.src_path, thumbnail)):
            self._thumbnail = url_from_path(
                join(self.name, get_thumb(self.settings, thumbnail))
            )
            self.logger.debug("Thumbnail for %r : %s", self, self._thumbnail)
            return self._thumbnail
        else:
            # find and return the first landscape image
            for f in self.medias:
                ext = splitext(f.dst_filename)[1]
                if ext.lower() not in self.settings["img_extensions"]:
                    continue

                # Use f.size if available as it is quicker (in cache), but
                # fallback to the size of src_path if dst_path is missing
                size = f.input_size
                if size is None:
                    size = f.file_metadata["size"]

                if size["width"] > size["height"]:
                    try:
                        self._thumbnail = url_quote(self.name) + "/" + f.thumbnail
                    except Exception as e:
                        self.logger.info(
                            "Failed to get thumbnail for %s: %s", f.dst_filename, e
                        )
                    else:
                        self.logger.debug(
                            "Use 1st landscape image as thumbnail for %r : %s",
                            self,
                            self._thumbnail,
                        )
                        return self._thumbnail

            # else simply return the 1st media file
            if not self._thumbnail and self.medias:
                for media in self.medias:
                    if media.thumbnail is not None:
                        try:
                            self._thumbnail = (
                                url_quote(self.name) + "/" + media.thumbnail
                            )
                        except Exception as e:
                            self.logger.info(
                                "Failed to get thumbnail for %s: %s",
                                media.dst_filename,
                                e,
                            )
                        else:
                            break
                else:
                    self.logger.warning("No thumbnail found for %r", self)
                    return

                self.logger.debug(
                    "Use the 1st image as thumbnail for %r : %s", self, self._thumbnail
                )
                return self._thumbnail

            # use the thumbnail of their sub-directories
            if not self._thumbnail:
                for path, album in self.gallery.get_albums(self.path):
                    if album.thumbnail:
                        self._thumbnail = url_quote(self.name) + "/" + album.thumbnail
                        self.logger.debug(
                            "Using thumbnail from sub-directory for %r : %s",
                            self,
                            self._thumbnail,
                        )
                        return self._thumbnail

        self.logger.error("Thumbnail not found for %r", self)

    @property
    def random_thumbnail(self):
        try:
            return url_from_path(join(self.name, random.choice(self.medias).thumbnail))
        except IndexError:
            return self.thumbnail

    @property
    def breadcrumb(self):
        """List of ``(url, title)`` tuples defining the current breadcrumb
        path.
        """
        if self.path == ".":
            return []

        path = self.path
        breadcrumb = [((self.url_ext or "."), self.title)]

        while True:
            path = os.path.normpath(os.path.join(path, ".."))
            if path == ".":
                break

            url = url_from_path(os.path.relpath(path, self.path)) + "/" + self.url_ext
            breadcrumb.append((url, self.gallery.albums[path].title))

        breadcrumb.reverse()
        return breadcrumb

    @property
    def show_map(self):
        """Check if we have at least one photo with GPS location in the album"""
        return any(image.has_location() for image in self.images)

    @cached_property
    def zip(self):
        """Placeholder ZIP method.
        The ZIP logic is controlled by the zip_gallery plugin
        """


class Gallery:
    def __init__(self, settings, ncpu=None, show_progress=False):
        self.settings = settings
        self.logger = logging.getLogger(__name__)
        self.stats = defaultdict(int)
        self.init_pool(ncpu)
        check_or_create_dir(settings["destination"])

        if settings["max_img_pixels"]:
            PILImage.MAX_IMAGE_PIXELS = settings["max_img_pixels"]

        # Build the list of directories with images
        albums = self.albums = {}
        src_path = self.settings["source"]

        ignore_dirs = settings["ignore_directories"]
        ignore_files = settings["ignore_files"]

        progressChars = cycle(["/", "-", "\\", "|"])
        try:
            isatty = os.isatty(sys.stdout.fileno())
        except io.UnsupportedOperation:
            isatty = False

        self.progressbar_target = None if show_progress and isatty else Devnull()

        for path, dirs, files in os.walk(src_path, followlinks=True, topdown=False):
            if show_progress:
                print("\rCollecting albums " + next(progressChars), end="")
            relpath = os.path.relpath(path, src_path)

            # Test if the directory match the ignore_dirs settings
            if ignore_dirs and any(
                fnmatch.fnmatch(relpath, ignore) for ignore in ignore_dirs
            ):
                self.logger.info("Ignoring %s", relpath)
                # Remove sub-directories
                for d in dirs[:]:
                    path = join(relpath, d) if relpath != "." else d
                    if path in albums.keys():
                        del albums[path]
                continue

            # Remove files that match the ignore_files settings
            if ignore_files:
                files_path = {join(relpath, f) for f in files}
                for ignore in ignore_files:
                    files_path -= set(fnmatch.filter(files_path, ignore))

                self.logger.debug("Files before filtering: %r", files)
                files = [os.path.split(f)[1] for f in files_path]
                self.logger.debug("Files after filtering: %r", files)

            # Remove sub-directories that have been ignored in a previous
            # iteration (as topdown=False, sub-directories are processed before
            # their parent
            for d in dirs[:]:
                path = join(relpath, d) if relpath != "." else d
                if path not in albums.keys():
                    dirs.remove(d)

            album = Album(relpath, settings, dirs, files, self)

            if not album.medias and not album.albums:
                self.logger.info("Skip empty album: %r", album)
            else:
                album.create_output_directories()
                albums[relpath] = album

        if show_progress:
            print("\rCollecting albums, done.")

        with progressbar(
            albums.values(),
            label="%16s" % "Sorting albums",
            file=self.progressbar_target,
        ) as progress_albums:
            for album in progress_albums:
                album.sort_subdirs(settings["albums_sort_attr"])

        with progressbar(
            albums.values(),
            label="%16s" % "Sorting media",
            file=self.progressbar_target,
        ) as progress_albums:
            for album in progress_albums:
                album.sort_medias(settings["medias_sort_attr"])

        self.logger.debug("Albums:\n%r", albums.values())
        signals.gallery_initialized.send(self)

    @property
    def title(self):
        """Title of the gallery."""
        return self.settings["title"] or self.albums["."].title

    def init_pool(self, ncpu):
        try:
            cpu_count = multiprocessing.cpu_count()
        except NotImplementedError:
            cpu_count = 1

        if ncpu is None:
            ncpu = cpu_count
        else:
            try:
                ncpu = int(ncpu)
            except ValueError:
                self.logger.error("ncpu should be an integer value")
                ncpu = cpu_count

        self.logger.info("Using %s cores", ncpu)
        if ncpu > 1:
            self.pool = multiprocessing.Pool(
                processes=ncpu,
                initializer=pool_init,
                initargs=(self.settings["max_img_pixels"],),
            )
        else:
            self.pool = None

    def get_albums(self, path):
        """Return the list of all sub-directories of path."""

        for name in self.albums[path].subdirs:
            subdir = os.path.normpath(join(path, name))
            yield subdir, self.albums[subdir]
            for subname, album in self.get_albums(subdir):
                yield subname, self.albums[subdir]

    def build(self, force=False):
        "Create the image gallery"

        if not self.albums:
            self.logger.warning("No albums found.")
            return

        def log_func(x):
            # 63 is the total length of progressbar, label, percentage, etc
            available_length = get_terminal_size()[0] - 64
            if x and available_length > 10:
                return x.name[:available_length]
            else:
                return ""

        try:
            with progressbar(
                self.albums.values(),
                label="Collecting files",
                item_show_func=log_func,
                show_eta=False,
                file=self.progressbar_target,
            ) as albums:
                media_list = [
                    f for album in albums for f in self.process_dir(album, force=force)
                ]
        except KeyboardInterrupt:
            sys.exit("Interrupted")

        bar_opt = {
            "label": "Processing files",
            "show_pos": True,
            "file": self.progressbar_target,
        }

        if self.pool:
            result = []
            try:
                with progressbar(length=len(media_list), **bar_opt) as bar:
                    for status in self.pool.imap_unordered(worker, media_list):
                        result.append(status)
                        bar.update(1)
            except KeyboardInterrupt:
                self.pool.terminate()
                sys.exit("Interrupted")
            except pickle.PicklingError:
                self.logger.critical(
                    "Failed to process files with the multiprocessing feature."
                    " This can be caused by some module import or object "
                    "defined in the settings file, which can't be serialized.",
                    exc_info=True,
                )
                sys.exit("Abort")
            finally:
                self.pool.close()
                self.pool.join()
        else:
            with progressbar(media_list, **bar_opt) as medias:
                result = [process_file(media_item) for media_item in medias]

        if any(result):
            failed_files = [
                media for status, media in zip(result, media_list) if status != 0
            ]
            self.remove_files(failed_files)

        if self.settings["write_html"]:
            album_writer = AlbumPageWriter(self.settings, index_title=self.title)
            album_writer.copy_theme_files()
            album_list_writer = AlbumListPageWriter(
                self.settings, index_title=self.title
            )
            with progressbar(
                self.albums.values(),
                label="%16s" % "Writing files",
                item_show_func=log_func,
                show_eta=False,
                file=self.progressbar_target,
            ) as albums:
                for album in albums:
                    if album.albums:
                        if album.medias:
                            self.logger.warning(
                                "Album '%s' contains sub-albums and images. "
                                "Please move images to their own sub-album. "
                                "Images in album %s will not be visible.",
                                album.title,
                                album.title,
                            )
                        album_list_writer.write(album)
                    else:
                        album_writer.write(album)
        print("")

        signals.gallery_build.send(self)

    def remove_files(self, medias):
        self.logger.error("Some files have failed to be processed:")
        for media in medias:
            self.logger.error("  - %s", media.dst_filename)
            album = self.albums[media.path]
            for f in album.medias:
                if f.dst_filename == media.dst_filename:
                    self.stats[f.type + "_failed"] += 1
                    album.medias.remove(f)
                    break
        self.logger.error(
            'You can run "sigal build" in verbose (--verbose) or'
            " debug (--debug) mode to get more details."
        )

    def process_dir(self, album, force=False):
        """Process a list of images in a directory."""
        for f in album:
            if isfile(f.dst_path) and not should_reprocess_album(
                album.path, album.name, force
            ):
                self.logger.info("%s exists - skipping", f.dst_filename)
                self.stats[f.type + "_skipped"] += 1
            else:
                self.stats[f.type] += 1
                yield f


def pool_init(max_img_pixels):
    if max_img_pixels:
        PILImage.MAX_IMAGE_PIXELS = max_img_pixels


def process_file(media):
    processor = None
    if media.type == "image":
        processor = process_image
    elif media.type == "video":
        processor = process_video
    elif media.type == "audio":
        processor = process_audio

    # Allow overriding of the processor
    result = signals.process_file.send(media, processor=processor)
    for recv, ret in result:
        if ret is not None:
            processor = ret

    if processor:
        return processor(media)
    else:
        logging.warning("Processor not found for media %s", media.path)
        return Status.FAILURE


def worker(args):
    try:
        return process_file(args)
    except KeyboardInterrupt:
        pass