from PIL import Image, ImageOps, ImageEnhance, ExifTags
from dominate.tags import *
import dominate
import glob as g, os
import json
import traceback

class GalleryHTML:
    """A maker of thumbnails, HTML galleries, and simple JSON indices"""

    def __init__(self):
        # Set some defaults:
        self.output_dir = '.'
        self.base_url = ""
        self.extensions = ['JPG', 'jpg', 'jpeg', 'png', 'gif', 'bmp']
        self.image_list = []
        self.x = 200
        self.y = 200
        self.square = False
        self.overwrite = False

    def add_images_from(self, source):
        # Ensure that thumbnail directory exists:
        thumb_directory = self.output_dir + "/Thumbs"
        os.makedirs(thumb_directory, exist_ok=True)

        for image in sorted(self._get_images(source)):
            image_basename = os.path.basename(image)
            thumbnail_src = self.base_url + 'Thumbs/' + image_basename
            image_href = self.base_url + image_basename

            image_size = self._thumbnailize(image, thumb_directory + '/' + image_basename)
            self.image_list.append((thumbnail_src, image_href, image_size))

    def _get_images(self, source):
        """Get a list of images from a source directory or pattern."""
        images = []

        if os.path.isdir(source):
            # Grab things with common file extensions out of dirs:
            for extension in self.extensions:
                images.extend(g.glob(source + '/*.' + extension))
        else:
            # Assume a pattern or single filename:
            images.extend(g.glob(source))

        return images

    def images_html(self):
        """Return HTML for an image list."""
        html_output = ''
        for display_image in self.image_list:
            (x, y) = display_image[2]
            html_output += a(img(src=display_image[0], width=x, height=y),
                             href=display_image[1]).render() + "\n"
        return html_output.strip()

    def images_json(self):
        """Return JSON for an image list."""
        return json.dumps(self.image_list)

    def _handle_exif(self, source_image):
        """
        Handle EXIF rotation data, maybe - per:
        https://stackoverflow.com/questions/4228530/pil-thumbnail-is-rotating-my-image
        """

        # PNG files don't have EXIF data; avoid an exception on _getexif():
        if source_image.format == 'PNG':
            return source_image

        try:
            for tag in ExifTags.TAGS.keys():
                if ExifTags.TAGS[tag] == 'Orientation':
                    break

            if source_image._getexif():
                # We have EXIF metadata to work with:
                exif = dict(source_image._getexif().items())

                orientation = exif.get(tag, False)

                if orientation == 3:
                    source_image = source_image.rotate(180, expand=True)
                elif orientation == 6:
                    source_image = source_image.rotate(270, expand=True)
                elif orientation == 8:
                    source_image = source_image.rotate(90, expand=True)
        except:
            traceback.print_exc()

        return source_image;

    def _thumbnailize(self, image, thumbnail_file):
        """Write thumbnails."""
        image_size = (self.x, self.y)

        if os.path.isfile(thumbnail_file) and (not self.overwrite):
            # Skip existing files, unless we've been told to overwrite, but make
            # sure we know the correct width and height for them:
            with open(thumbnail_file, 'r+b') as f:
                with Image.open(f) as existing_thumbnail:
                    image_size = existing_thumbnail.size
        else:
            # Write a new thumbnail:
            with open(image, 'r+b') as f:
                with Image.open(f) as source_image:
                    source_image = self._handle_exif(source_image);
                    # thumb = ImageEnhance.Sharpness(ImageOps.fit(source_image, (thumb_x, thumb_y))).enhance(0.15)
                    if self.square:
                        # Square things off, then make and save thumbnail
                        smaller_dim = min(source_image.size)
                        thumb = ImageOps.fit(source_image, (smaller_dim, smaller_dim))
                    else:
                        thumb = source_image

                    thumb.thumbnail((self.x, self.y))
                    image_size = thumb.size
                    thumb.save(thumbnail_file, source_image.format)

        return image_size