"""
Draftail / contentstate conversion
"""
from draftjs_exporter.dom import DOM

from wagtail.admin.rich_text.converters.contentstate_models import Entity
from wagtail.admin.rich_text.converters.html_to_contentstate import (
    AtomicBlockEntityElementHandler,
)
from wagtail.images import get_image_model
from wagtail.images.formats import get_image_format
from wagtail.images.shortcuts import get_rendition_or_not_found


def image_entity(props):
    """
    Helper to construct elements of the form
    <embed alt="Right-aligned image" embedtype="image" format="right" id="1"/>
    when converting from contentstate data
    """
    return DOM.create_element(
        "embed",
        {
            "embedtype": "image",
            "format": props.get("format"),
            "id": props.get("id"),
            "alt": props.get("alt"),
        },
    )


class ImageElementHandler(AtomicBlockEntityElementHandler):
    """
    Rule for building an image entity when converting from database representation
    to contentstate
    """

    def create_entity(self, name, attrs, state, contentstate):
        Image = get_image_model()
        try:
            image = Image.objects.get(id=attrs["id"])
            image_format = get_image_format(attrs["format"])
            rendition = get_rendition_or_not_found(image, image_format.filter_spec)
            src = rendition.url
        except Image.DoesNotExist:
            src = ""

        return Entity(
            "IMAGE",
            "IMMUTABLE",
            {
                "id": attrs["id"],
                "src": src,
                "alt": attrs.get("alt"),
                "format": attrs["format"],
            },
        )


ContentstateImageConversionRule = {
    "from_database_format": {
        'embed[embedtype="image"]': ImageElementHandler(),
    },
    "to_database_format": {"entity_decorators": {"IMAGE": image_entity}},
}