# Based on https://github.com/richardbarran/django-photologue/
# by Richard Barran, BSD-3 licensed

import logging
import os
import random
import unicodedata
from datetime import datetime
from functools import partial
from importlib import import_module
from inspect import isclass
from io import BytesIO

import exifread
from django.conf import settings
from django.core.exceptions import ValidationError
from django.core.files.base import ContentFile
from django.core.validators import RegexValidator
from django.db import models
from django.template.defaultfilters import slugify
from django.urls import reverse
from django.utils.encoding import filepath_to_uri, force_str, smart_str
from django.utils.safestring import mark_safe
from django.utils.timezone import now
from django.utils.translation import gettext_lazy as _
from PIL import Image, ImageFile, ImageFilter

logger = logging.getLogger("photologue.models")

# Default limit for gallery.latest
LATEST_LIMIT = getattr(settings, "PHOTOLOGUE_GALLERY_LATEST_LIMIT", None)

# max_length setting for the ImageModel ImageField
IMAGE_FIELD_MAX_LENGTH = getattr(settings, "PHOTOLOGUE_IMAGE_FIELD_MAX_LENGTH", 100)

# Modify image file buffer size.
ImageFile.MAXBLOCK = getattr(settings, "PHOTOLOGUE_MAXBLOCK", 256 * 2 ** 10)

# Look for user function to define file paths
PHOTOLOGUE_PATH = getattr(settings, "PHOTOLOGUE_PATH", None)
if PHOTOLOGUE_PATH is not None:
    if callable(PHOTOLOGUE_PATH):
        get_storage_path = PHOTOLOGUE_PATH
    else:
        parts = PHOTOLOGUE_PATH.split(".")
        module_name = ".".join(parts[:-1])
        module = import_module(module_name)
        get_storage_path = getattr(module, parts[-1])
else:

    def get_storage_path(instance, filename):
        fn = (
            unicodedata.normalize("NFKD", force_str(filename))
            .encode("ascii", "ignore")
            .decode("ascii")
        )
        return os.path.join("photos", fn)


# Exif Orientation values
# Value 0thRow	0thColumn
#   1	top     left
#   2	top     right
#   3	bottom	right
#   4	bottom	left
#   5	left	top
#   6	right   top
#   7	right   bottom
#   8	left    bottom

# Image Orientations (according to EXIF informations) that needs to be
# transposed and appropriate action
IMAGE_EXIF_ORIENTATION_MAP = {
    2: Image.FLIP_LEFT_RIGHT,
    3: Image.ROTATE_180,
    6: Image.ROTATE_270,
    8: Image.ROTATE_90,
}

# Quality options for JPEG images
JPEG_QUALITY_CHOICES = (
    (30, _("Very Low")),
    (40, _("Low")),
    (50, _("Medium-Low")),
    (60, _("Medium")),
    (70, _("Medium-High")),
    (80, _("High")),
    (90, _("Very High")),
)

# choices for new crop_anchor field in Photo
CROP_ANCHOR_CHOICES = (
    ("top", _("Top")),
    ("right", _("Right")),
    ("bottom", _("Bottom")),
    ("left", _("Left")),
    ("center", _("Center (Default)")),
)

IMAGE_TRANSPOSE_CHOICES = (
    ("FLIP_LEFT_RIGHT", _("Flip left to right")),
    ("FLIP_TOP_BOTTOM", _("Flip top to bottom")),
    ("ROTATE_90", _("Rotate 90 degrees counter-clockwise")),
    ("ROTATE_270", _("Rotate 90 degrees clockwise")),
    ("ROTATE_180", _("Rotate 180 degrees")),
)

# Prepare a list of image filters
filter_names = []
for n in dir(ImageFilter):
    klass = getattr(ImageFilter, n)
    if (
        isclass(klass)
        and issubclass(klass, ImageFilter.BuiltinFilter)
        and hasattr(klass, "name")
    ):
        filter_names.append(klass.__name__)
IMAGE_FILTERS_HELP_TEXT = _(
    'Chain multiple filters using the following pattern "FILTER_ONE->FILTER_TWO->FILTER_THREE"'
    ". Image filters will be applied in order. The following filters are available: %s."
    % (", ".join(filter_names))
)

size_method_map = {}


class TagField(models.CharField):
    """Tags have been removed from Photologue, but the migrations still refer to them so this
    Tagfield definition is left here.
    """

    def __init__(self, **kwargs):
        default_kwargs = {"max_length": 255, "blank": True}
        default_kwargs.update(kwargs)
        super().__init__(**default_kwargs)

    def get_internal_type(self):
        return "CharField"


class Gallery(models.Model):
    title = models.CharField(_("title"), max_length=250, unique=True)
    slug = models.SlugField(
        _("title slug"),
        unique=True,
        max_length=250,
        help_text=_('A "slug" is a unique URL-friendly title for an object.'),
    )
    date_start = models.DateField(
        default=now,
        verbose_name=_("start date"),
    )
    date_end = models.DateField(
        blank=True,
        null=True,
        verbose_name=_("end date"),
    )
    description = models.TextField(_("description"), blank=True)
    tags = models.ManyToManyField(
        "photologue.Tag",
        related_name="galleries",
        verbose_name=_("tags"),
        blank=True,
    )
    photos = models.ManyToManyField(
        "photologue.Photo",
        related_name="galleries",
        verbose_name=_("photos"),
        blank=True,
    )

    class Meta:
        ordering = ["-date_start"]
        get_latest_by = "date_start"
        verbose_name = _("gallery")
        verbose_name_plural = _("galleries")

    def __str__(self):
        return f"{ self.title } ({self.date_start})"

    def get_absolute_url(self):
        return reverse("photologue:pl-gallery", args=[self.slug])

    def sample(self, public=True):
        """Return a sample of photos, ordered at random."""
        count = 1
        if count > self.photo_count():
            count = self.photo_count()
        if public:
            photo_set = self.photos.filter(is_public=True)
        else:
            photo_set = self.photos
        return random.sample(set(photo_set), count)

    def photo_count(self, public=True):
        """Return a count of all the photos in this gallery."""
        if public:
            return self.photos.filter(is_public=True).count()
        else:
            return self.photos.count()

    def photo_private_count(self):
        """Return a count of private photos in this gallery."""
        return self.photos.filter(is_public=False).count()

    photo_count.short_description = _("count")
    photo_private_count.short_description = _("private count")


class ImageModel(models.Model):
    image = models.ImageField(
        _("image"), max_length=IMAGE_FIELD_MAX_LENGTH, upload_to=get_storage_path
    )
    date_taken = models.DateTimeField(
        _("date taken"),
        null=True,
        blank=True,
        help_text=_("Date image was taken; is obtained from the image EXIF data."),
    )
    view_count = models.PositiveIntegerField(_("view count"), default=0, editable=False)
    crop_from = models.CharField(
        _("crop from"),
        blank=True,
        max_length=10,
        default="center",
        choices=CROP_ANCHOR_CHOICES,
    )

    class Meta:
        abstract = True

    def exif(self, file=None):
        try:
            if file:
                tags = exifread.process_file(file)
            else:
                with self.image.storage.open(self.image.name, "rb") as file:
                    tags = exifread.process_file(file, details=False)
            return tags
        except Exception:
            return {}

    def admin_thumbnail(self):
        func = getattr(self, "get_admin_thumbnail_url", None)
        if func is None:
            return _('An "admin_thumbnail" photo size has not been defined.')
        else:
            if hasattr(self, "get_absolute_url"):
                return mark_safe(
                    '<a href="{}"><img src="{}"></a>'.format(
                        self.get_absolute_url(), func()
                    )
                )
            else:
                return mark_safe(
                    '<a href="{}"><img src="{}"></a>'.format(self.image.url, func())
                )

    admin_thumbnail.short_description = _("Thumbnail")
    admin_thumbnail.allow_tags = True

    def cache_path(self):
        return os.path.join(os.path.dirname(self.image.name), "cache")

    def cache_url(self):
        if not self.image:
            return ""
        return "/".join([os.path.dirname(self.image.url), "cache"])

    def image_filename(self):
        return os.path.basename(force_str(self.image.name))

    def _get_filename_for_size(self, size):
        size = getattr(size, "name", size)
        base, ext = os.path.splitext(self.image_filename())
        return "".join([base, "_", size, ext])

    def _get_size_photosize(self, size):
        return PhotoSizeCache().sizes.get(size)

    def _get_size_size(self, size):
        photosize = PhotoSizeCache().sizes.get(size)
        if not self.size_exists(photosize):
            self.create_size(photosize)
        try:
            return Image.open(
                self.image.storage.open(self._get_size_filename(size))
            ).size
        except Exception:
            return None

    def _get_size_url(self, size):
        photosize = PhotoSizeCache().sizes.get(size)
        if not self.size_exists(photosize):
            self.create_size(photosize)
        if photosize.increment_count:
            self.increment_count()
        return "/".join(
            [
                self.cache_url(),
                filepath_to_uri(self._get_filename_for_size(photosize.name)),
            ]
        )

    def _get_size_filename(self, size):
        photosize = PhotoSizeCache().sizes.get(size)
        return smart_str(
            os.path.join(self.cache_path(), self._get_filename_for_size(photosize.name))
        )

    def increment_count(self):
        self.view_count += 1
        models.Model.save(self)

    def __getattr__(self, name):
        global size_method_map
        if not size_method_map:
            init_size_method_map()
        di = size_method_map.get(name, None)
        if di is not None:
            result = partial(getattr(self, di["base_name"]), di["size"])
            setattr(self, name, result)
            return result
        else:
            # When this attribute error is raised, it's usually because
            # something tried to access a missing attribute on the photo.
            # 99% of the time is due to a typo in the attribute name we are
            # trying to access.
            raise AttributeError

    def size_exists(self, photosize):
        func = getattr(self, "get_%s_filename" % photosize.name, None)
        if func is not None:
            if self.image.storage.exists(func()):
                return True
        return False

    def resize_image(self, im, photosize):
        cur_width, cur_height = im.size
        new_width, new_height = photosize.size
        if photosize.crop:
            ratio = max(float(new_width) / cur_width, float(new_height) / cur_height)
            x = cur_width * ratio
            y = cur_height * ratio
            xd = abs(new_width - x)
            yd = abs(new_height - y)
            x_diff = int(xd / 2)
            y_diff = int(yd / 2)
            if self.crop_from == "top":
                box = (int(x_diff), 0, int(x_diff + new_width), new_height)
            elif self.crop_from == "left":
                box = (0, int(y_diff), new_width, int(y_diff + new_height))
            elif self.crop_from == "bottom":
                # y - yd = new_height
                box = (int(x_diff), int(yd), int(x_diff + new_width), int(y))
            elif self.crop_from == "right":
                # x - xd = new_width
                box = (int(xd), int(y_diff), int(x), int(y_diff + new_height))
            else:
                box = (
                    int(x_diff),
                    int(y_diff),
                    int(x_diff + new_width),
                    int(y_diff + new_height),
                )
            im = im.resize((int(x), int(y)), Image.ANTIALIAS).crop(box)
        else:
            if not new_width == 0 and not new_height == 0:
                ratio = min(
                    float(new_width) / cur_width, float(new_height) / cur_height
                )
            else:
                if new_width == 0:
                    ratio = float(new_height) / cur_height
                else:
                    ratio = float(new_width) / cur_width
            new_dimensions = (
                int(round(cur_width * ratio)),
                int(round(cur_height * ratio)),
            )
            if new_dimensions[0] > cur_width or new_dimensions[1] > cur_height:
                if not photosize.upscale:
                    return im
            im = im.resize(new_dimensions, Image.ANTIALIAS)
        return im

    def create_size(self, photosize, recreate=False):
        if self.size_exists(photosize) and not recreate:
            return
        try:
            im = Image.open(self.image.storage.open(self.image.name))
        except OSError:
            return
        # Save the original format
        im_format = im.format
        # Rotate if found & necessary
        if (
            "Image Orientation" in self.exif()
            and self.exif().get("Image Orientation").values[0]
            in IMAGE_EXIF_ORIENTATION_MAP
        ):
            im = im.transpose(
                IMAGE_EXIF_ORIENTATION_MAP[
                    self.exif().get("Image Orientation").values[0]
                ]
            )
        # Resize/crop image
        if (im.size != photosize.size and photosize.size != (0, 0)) or recreate:
            im = self.resize_image(im, photosize)
        # Save file
        im_filename = getattr(self, "get_%s_filename" % photosize.name)()
        try:
            buffer = BytesIO()
            if im_format != "JPEG":
                im.save(buffer, im_format)
            else:
                # Issue #182 - test fix from https://github.com/bashu/django-watermark/issues/31
                if im.mode.endswith("A"):
                    im = im.convert(im.mode[:-1])
                im.save(buffer, "JPEG", quality=int(photosize.quality), optimize=True)
            buffer_contents = ContentFile(buffer.getvalue())
            self.image.storage.save(im_filename, buffer_contents)
        except OSError as e:
            if self.image.storage.exists(im_filename):
                self.image.storage.delete(im_filename)
            raise e

    def remove_size(self, photosize, remove_dirs=True):
        if not self.size_exists(photosize):
            return
        filename = getattr(self, "get_%s_filename" % photosize.name)()
        if self.image.storage.exists(filename):
            self.image.storage.delete(filename)

    def clear_cache(self):
        cache = PhotoSizeCache()
        for photosize in cache.sizes.values():
            self.remove_size(photosize, False)

    def pre_cache(self, recreate=False):
        cache = PhotoSizeCache()
        if recreate:
            self.clear_cache()
        for photosize in cache.sizes.values():
            if photosize.pre_cache:
                self.create_size(photosize, recreate)

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._old_image = self.image

    def save(self, *args, **kwargs):
        recreate = kwargs.pop("recreate", False)
        image_has_changed = False
        if self._get_pk_val() and (self._old_image != self.image):
            image_has_changed = True
            # If we have changed the image, we need to clear from the cache all instances of the old
            # image; clear_cache() works on the current (new) image, and in turn calls several other methods.
            # Changing them all to act on the old image was a lot of changes, so instead we temporarily swap old
            # and new images.
            new_image = self.image
            self.image = self._old_image
            self.clear_cache()
            self.image = new_image  # Back to the new image.
            self._old_image.storage.delete(
                self._old_image.name
            )  # Delete (old) base image.
        if self.date_taken is None or image_has_changed:
            # Attempt to get the date the photo was taken from the EXIF data.
            try:
                exif_date = self.exif(self.image.file).get(
                    "EXIF DateTimeOriginal", None
                )
                if exif_date is not None:
                    d, t = exif_date.values.split()
                    year, month, day = d.split(":")
                    hour, minute, second = t.split(":")
                    self.date_taken = datetime(
                        int(year),
                        int(month),
                        int(day),
                        int(hour),
                        int(minute),
                        int(second),
                    )
            except Exception:
                logger.error("Failed to read EXIF DateTimeOriginal", exc_info=True)
        super().save(*args, **kwargs)
        self.pre_cache(recreate)

    def delete(self):
        assert (
            self._get_pk_val() is not None
        ), "%s object can't be deleted because its %s attribute is set to None." % (
            self._meta.object_name,
            self._meta.pk.attname,
        )
        self.clear_cache()
        # Files associated to a FileField have to be manually deleted:
        # https://docs.djangoproject.com/en/dev/releases/1.3/#deleting-a-model-doesn-t-delete-associated-files
        # http://haineault.com/blog/147/
        # The data loss scenarios mentioned in the docs hopefully do not apply
        # to Photologue!
        super().delete()
        self.image.storage.delete(self.image.name)


class Photo(ImageModel):
    title = models.CharField(_("title"), max_length=250, unique=True)
    slug = models.SlugField(
        _("slug"),
        unique=True,
        max_length=250,
        help_text=_('A "slug" is a unique URL-friendly title for an object.'),
    )
    caption = models.TextField(_("caption"), blank=True)
    date_added = models.DateTimeField(_("date added"), default=now)
    owner = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        verbose_name=_("owner"),
    )
    license = models.CharField(
        max_length=255,
        blank=True,
        verbose_name=_("license"),
    )
    is_public = models.BooleanField(
        _("is public"),
        default=True,
        help_text=_("Public photographs will be displayed in the default views."),
    )

    class Meta:
        # We do not have a reliable date for ordering, so let's use
        # the title which is incremented by most cameras
        ordering = ["title"]
        get_latest_by = "date_added"
        verbose_name = _("photo")
        verbose_name_plural = _("photos")

    def __str__(self):
        return self.title

    def save(self, *args, **kwargs):
        # If crop_from property has been changed on existing image,
        # update kwargs to force image recreation in parent class
        current = Photo.objects.get(pk=self.pk) if self.pk else None
        if current and (current.crop_from != self.crop_from):
            kwargs.update(recreate=True)

        if self.slug is None:
            self.slug = slugify(self.title)
        super().save(*args, **kwargs)

    def get_absolute_url(self):
        return reverse("photologue:pl-photo", args=[self.pk])

    def public_galleries(self):
        """Return the public galleries to which this photo belongs."""
        return self.galleries

    def get_previous_in_gallery(self, gallery):
        """Find the neighbour of this photo in the supplied gallery.
        We assume that the gallery and all its photos are on the same site.
        """
        if not self.is_public:
            raise ValueError("Cannot determine neighbours of a non-public photo.")
        photos = gallery.photos.filter(is_public=True)
        if self not in photos:
            raise ValueError("Photo does not belong to gallery.")
        previous = None
        for photo in photos:
            if photo == self:
                return previous
            previous = photo

    def get_next_in_gallery(self, gallery):
        """Find the neighbour of this photo in the supplied gallery.
        We assume that the gallery and all its photos are on the same site.
        """
        if not self.is_public:
            raise ValueError("Cannot determine neighbours of a non-public photo.")
        photos = gallery.photos.filter(is_public=True)
        if self not in photos:
            raise ValueError("Photo does not belong to gallery.")
        matched = False
        for photo in photos:
            if matched:
                return photo
            if photo == self:
                matched = True
        return None


class PhotoSize(models.Model):
    """About the Photosize name: it's used to create get_PHOTOSIZE_url() methods,
    so the name has to follow the same restrictions as any Python method name,
    e.g. no spaces or non-ascii characters."""

    name = models.CharField(
        _("name"),
        max_length=40,
        unique=True,
        help_text=_(
            "Photo size name should contain only letters, numbers and underscores. Examples: "
            '"thumbnail", "display", "small", "main_page_widget".'
        ),
        validators=[
            RegexValidator(
                regex="^[a-z0-9_]+$",
                message="Use only plain lowercase letters (ASCII), numbers and "
                "underscores.",
            )
        ],
    )
    width = models.PositiveIntegerField(
        _("width"),
        default=0,
        help_text=_(
            'If width is set to "0" the image will be scaled to the supplied height.'
        ),
    )
    height = models.PositiveIntegerField(
        _("height"),
        default=0,
        help_text=_(
            'If height is set to "0" the image will be scaled to the supplied width'
        ),
    )
    quality = models.PositiveIntegerField(
        _("quality"),
        choices=JPEG_QUALITY_CHOICES,
        default=70,
        help_text=_("JPEG image quality."),
    )
    upscale = models.BooleanField(
        _("upscale images?"),
        default=False,
        help_text=_(
            "If selected the image will be scaled up if necessary to fit the "
            "supplied dimensions. Cropped sizes will be upscaled regardless of this "
            "setting."
        ),
    )
    crop = models.BooleanField(
        _("crop to fit?"),
        default=False,
        help_text=_(
            "If selected the image will be scaled and cropped to fit the supplied "
            "dimensions."
        ),
    )
    pre_cache = models.BooleanField(
        _("pre-cache?"),
        default=False,
        help_text=_(
            "If selected this photo size will be pre-cached as photos are added."
        ),
    )
    increment_count = models.BooleanField(
        _("increment view count?"),
        default=False,
        help_text=_(
            'If selected the image\'s "view_count" will be incremented when '
            "this photo size is displayed."
        ),
    )

    class Meta:
        ordering = ["width", "height"]
        verbose_name = _("photo size")
        verbose_name_plural = _("photo sizes")

    def __str__(self):
        return self.name

    def clear_cache(self):
        for cls in ImageModel.__subclasses__():
            for obj in cls.objects.all():
                obj.remove_size(self)
                if self.pre_cache:
                    obj.create_size(self)
        PhotoSizeCache().reset()

    def clean(self):
        if self.crop is True:
            if self.width == 0 or self.height == 0:
                raise ValidationError(
                    _(
                        "Can only crop photos if both width and height dimensions are set."
                    )
                )

    def save(self, *args, **kwargs):
        super().save(*args, **kwargs)
        PhotoSizeCache().reset()
        self.clear_cache()

    def delete(self):
        assert (
            self._get_pk_val() is not None
        ), "%s object can't be deleted because its %s attribute is set to None." % (
            self._meta.object_name,
            self._meta.pk.attname,
        )
        self.clear_cache()
        super().delete()

    def _get_size(self):
        return (self.width, self.height)

    def _set_size(self, value):
        self.width, self.height = value

    size = property(_get_size, _set_size)


class PhotoSizeCache:
    __state = {"sizes": {}}

    def __init__(self):
        self.__dict__ = self.__state
        if not len(self.sizes):
            sizes = PhotoSize.objects.all()
            for size in sizes:
                self.sizes[size.name] = size

    def reset(self):
        global size_method_map
        size_method_map = {}
        self.sizes = {}


def init_size_method_map():
    global size_method_map
    for size in PhotoSizeCache().sizes.keys():
        size_method_map["get_%s_size" % size] = {
            "base_name": "_get_size_size",
            "size": size,
        }
        size_method_map["get_%s_photosize" % size] = {
            "base_name": "_get_size_photosize",
            "size": size,
        }
        size_method_map["get_%s_url" % size] = {
            "base_name": "_get_size_url",
            "size": size,
        }
        size_method_map["get_%s_filename" % size] = {
            "base_name": "_get_size_filename",
            "size": size,
        }


class Tag(models.Model):
    name = models.CharField(
        max_length=250,
        unique=True,
        verbose_name=_("name"),
    )
    slug = models.SlugField(
        unique=True,
        max_length=250,
        verbose_name=_("slug"),
        help_text=_('A "slug" is a unique URL-friendly title for an object.'),
    )

    class Meta:
        ordering = ["name"]
        verbose_name = _("tag")
        verbose_name_plural = _("tags")

    def __str__(self):
        return self.name