from functools import partial

from django.db import models

from core.uploads import upload_namer
from core.uris import ProxyAbsoluteUrl, RelativeAbsoluteUrl
from stator.models import State, StateField, StateGraph, StatorModel


class PostAttachmentStates(StateGraph):
    new = State(externally_progressed=True)
    fetched = State()

    new.transitions_to(fetched)


class PostAttachment(StatorModel):
    """
    An attachment to a Post. Could be an image, a video, etc.
    """

    post = models.ForeignKey(
        "activities.post",
        on_delete=models.CASCADE,
        related_name="attachments",
        blank=True,
        null=True,
    )
    author = models.ForeignKey(
        "users.Identity",
        on_delete=models.CASCADE,
        related_name="attachments",
        blank=True,
        null=True,
    )

    state = StateField(graph=PostAttachmentStates)

    mimetype = models.CharField(max_length=200)

    # Files may not be populated if it's remote and not cached on our side yet
    file = models.FileField(
        upload_to=partial(upload_namer, "attachments"),
        null=True,
        blank=True,
    )
    thumbnail = models.ImageField(
        upload_to=partial(upload_namer, "attachment_thumbnails"),
        null=True,
        blank=True,
    )

    remote_url = models.CharField(max_length=500, null=True, blank=True)

    # This is the description for images, at least
    name = models.TextField(null=True, blank=True)

    width = models.IntegerField(null=True, blank=True)
    height = models.IntegerField(null=True, blank=True)
    focal_x = models.IntegerField(null=True, blank=True)
    focal_y = models.IntegerField(null=True, blank=True)
    blurhash = models.TextField(null=True, blank=True)

    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)

    def is_image(self):
        return self.mimetype in [
            "image/apng",
            "image/avif",
            "image/gif",
            "image/jpeg",
            "image/png",
            "image/webp",
        ]

    def is_video(self):
        return self.mimetype in [
            "video/mp4",
            "video/ogg",
            "video/webm",
        ]

    def thumbnail_url(self) -> RelativeAbsoluteUrl:
        if self.thumbnail:
            return RelativeAbsoluteUrl(self.thumbnail.url)
        elif self.file:
            return RelativeAbsoluteUrl(self.file.url)
        else:
            return ProxyAbsoluteUrl(
                f"/proxy/post_attachment/{self.pk}/",
                remote_url=self.remote_url,
            )

    def full_url(self):
        if self.file:
            return RelativeAbsoluteUrl(self.file.url)
        if self.is_image():
            return ProxyAbsoluteUrl(
                f"/proxy/post_attachment/{self.pk}/",
                remote_url=self.remote_url,
            )
        return RelativeAbsoluteUrl(self.remote_url)

    @property
    def file_display_name(self):
        if self.remote_url:
            return self.remote_url.rsplit("/", 1)[-1]
        if self.file:
            return self.file.name
        return f"attachment ({self.mimetype})"

    ### ActivityPub ###

    def to_ap(self):
        return {
            "url": self.file.url,
            "name": self.name,
            "type": "Document",
            "width": self.width,
            "height": self.height,
            "mediaType": self.mimetype,
            "blurhash": self.blurhash,
        }

    ### Mastodon Client API ###

    def to_mastodon_json(self):
        type_ = "unknown"
        if self.is_image():
            type_ = "image"
        elif self.is_video():
            type_ = "video"
        value = {
            "id": self.pk,
            "type": type_,
            "url": self.full_url().absolute,
            "preview_url": self.thumbnail_url().absolute,
            "remote_url": None,
            "meta": {
                "focus": {
                    "x": self.focal_x or 0,
                    "y": self.focal_y or 0,
                },
            },
            "description": self.name,
            "blurhash": self.blurhash,
        }
        if self.width and self.height:
            value["meta"]["original"] = {
                "width": self.width,
                "height": self.height,
                "size": f"{self.width}x{self.height}",
                "aspect": self.width / self.height,
            }
        return value