import io
import logging
import urllib
from datetime import datetime
from mimetypes import guess_type
from typing import IO, Any, BinaryIO, Callable, Iterator, List, Optional, Tuple, Union
from urllib.parse import urljoin

from django.conf import settings
from django.core.files.uploadedfile import UploadedFile
from django.utils.translation import gettext as _

from zerver.lib.exceptions import ErrorCode, JsonableError
from zerver.lib.outgoing_http import OutgoingSession
from zerver.lib.upload.base import ZulipUploadBackend
from zerver.lib.upload.local import LocalUploadBackend
from zerver.lib.upload.s3 import S3UploadBackend
from zerver.models import Attachment, Message, Realm, RealmEmoji, ScheduledMessage, UserProfile


class RealmUploadQuotaError(JsonableError):
    code = ErrorCode.REALM_UPLOAD_QUOTA


def check_upload_within_quota(realm: Realm, uploaded_file_size: int) -> None:
    upload_quota = realm.upload_quota_bytes()
    if upload_quota is None:
        return
    used_space = realm.currently_used_upload_space_bytes()
    if (used_space + uploaded_file_size) > upload_quota:
        raise RealmUploadQuotaError(_("Upload would exceed your organization's upload quota."))


def get_file_info(user_file: UploadedFile) -> Tuple[str, str]:
    uploaded_file_name = user_file.name
    assert uploaded_file_name is not None

    content_type = user_file.content_type
    # It appears Django's UploadedFile.content_type defaults to an empty string,
    # even though the value is documented as `str | None`. So we check for both.
    if content_type is None or content_type == "":
        guessed_type = guess_type(uploaded_file_name)[0]
        if guessed_type is not None:
            content_type = guessed_type
        else:
            # Fallback to application/octet-stream if unable to determine a
            # different content-type from the filename.
            content_type = "application/octet-stream"

    uploaded_file_name = urllib.parse.unquote(uploaded_file_name)

    return uploaded_file_name, content_type


# Common and wrappers
if settings.LOCAL_UPLOADS_DIR is not None:
    upload_backend: ZulipUploadBackend = LocalUploadBackend()
else:
    upload_backend = S3UploadBackend()  # nocoverage

# Message attachment uploads


def get_public_upload_root_url() -> str:
    return upload_backend.get_public_upload_root_url()


def upload_message_attachment(
    uploaded_file_name: str,
    uploaded_file_size: int,
    content_type: Optional[str],
    file_data: bytes,
    user_profile: UserProfile,
    target_realm: Optional[Realm] = None,
) -> str:
    return upload_backend.upload_message_attachment(
        uploaded_file_name,
        uploaded_file_size,
        content_type,
        file_data,
        user_profile,
        target_realm=target_realm,
    )


def claim_attachment(
    user_profile: UserProfile,
    path_id: str,
    message: Union[Message, ScheduledMessage],
    is_message_realm_public: bool,
    is_message_web_public: bool = False,
) -> Attachment:
    attachment = Attachment.objects.get(path_id=path_id)
    if isinstance(message, ScheduledMessage):
        attachment.scheduled_messages.add(message)
        # Setting the is_web_public and is_realm_public flags would be incorrect
        # in the scheduled message case - since the attachment becomes such only
        # when the message is actually posted.
        return attachment

    assert isinstance(message, Message)
    attachment.messages.add(message)
    attachment.is_web_public = attachment.is_web_public or is_message_web_public
    attachment.is_realm_public = attachment.is_realm_public or is_message_realm_public
    attachment.save()
    return attachment


def upload_message_attachment_from_request(
    user_file: UploadedFile, user_profile: UserProfile, user_file_size: int
) -> str:
    uploaded_file_name, content_type = get_file_info(user_file)
    return upload_message_attachment(
        uploaded_file_name, user_file_size, content_type, user_file.read(), user_profile
    )


def save_attachment_contents(path_id: str, filehandle: BinaryIO) -> None:
    return upload_backend.save_attachment_contents(path_id, filehandle)


def delete_message_attachment(path_id: str) -> bool:
    return upload_backend.delete_message_attachment(path_id)


def delete_message_attachments(path_ids: List[str]) -> None:
    return upload_backend.delete_message_attachments(path_ids)


def all_message_attachments() -> Iterator[Tuple[str, datetime]]:
    return upload_backend.all_message_attachments()


# Avatar image uploads


def get_avatar_url(hash_key: str, medium: bool = False) -> str:
    return upload_backend.get_avatar_url(hash_key, medium)


def upload_avatar_image(
    user_file: IO[bytes],
    acting_user_profile: UserProfile,
    target_user_profile: UserProfile,
    content_type: Optional[str] = None,
) -> None:
    upload_backend.upload_avatar_image(
        user_file, acting_user_profile, target_user_profile, content_type=content_type
    )


def copy_avatar(source_profile: UserProfile, target_profile: UserProfile) -> None:
    upload_backend.copy_avatar(source_profile, target_profile)


def delete_avatar_image(user_profile: UserProfile) -> None:
    upload_backend.delete_avatar_image(user_profile)


# Realm icon and logo uploads


def upload_icon_image(user_file: IO[bytes], user_profile: UserProfile) -> None:
    upload_backend.upload_realm_icon_image(user_file, user_profile)


def upload_logo_image(user_file: IO[bytes], user_profile: UserProfile, night: bool) -> None:
    upload_backend.upload_realm_logo_image(user_file, user_profile, night)


# Realm emoji uploads


def upload_emoji_image(
    emoji_file: IO[bytes], emoji_file_name: str, user_profile: UserProfile
) -> bool:
    return upload_backend.upload_emoji_image(emoji_file, emoji_file_name, user_profile)


def get_emoji_file_content(
    session: OutgoingSession, emoji_url: str, emoji_id: int, logger: logging.Logger
) -> bytes:  # nocoverage
    original_emoji_url = emoji_url + ".original"

    logger.info("Downloading %s", original_emoji_url)
    response = session.get(original_emoji_url)
    if response.status_code == 200:
        assert isinstance(response.content, bytes)
        return response.content

    logger.info("Error fetching emoji from URL %s", original_emoji_url)
    logger.info("Trying %s instead", emoji_url)
    response = session.get(emoji_url)
    if response.status_code == 200:
        assert isinstance(response.content, bytes)
        return response.content
    logger.info("Error fetching emoji from URL %s", emoji_url)
    logger.error("Could not fetch emoji %s", emoji_id)
    raise AssertionError(f"Could not fetch emoji {emoji_id}")


def handle_reupload_emojis_event(realm: Realm, logger: logging.Logger) -> None:  # nocoverage
    from zerver.lib.emoji import get_emoji_url

    session = OutgoingSession(role="reupload_emoji", timeout=3, max_retries=3)

    query = RealmEmoji.objects.filter(realm=realm).order_by("id")

    for realm_emoji in query:
        logger.info("Processing emoji %s", realm_emoji.id)
        emoji_filename = realm_emoji.file_name
        assert emoji_filename is not None
        emoji_url = get_emoji_url(emoji_filename, realm_emoji.realm_id)
        if emoji_url.startswith("/"):
            emoji_url = urljoin(realm_emoji.realm.uri, emoji_url)

        emoji_file_content = get_emoji_file_content(session, emoji_url, realm_emoji.id, logger)

        emoji_bytes_io = io.BytesIO(emoji_file_content)

        user_profile = realm_emoji.author
        # When this runs, emojis have already been migrated to always have .author set.
        assert user_profile is not None

        logger.info("Reuploading emoji %s", realm_emoji.id)
        realm_emoji.is_animated = upload_emoji_image(emoji_bytes_io, emoji_filename, user_profile)
        realm_emoji.save(update_fields=["is_animated"])


# Export tarballs


def upload_export_tarball(
    realm: Realm, tarball_path: str, percent_callback: Optional[Callable[[Any], None]] = None
) -> str:
    return upload_backend.upload_export_tarball(
        realm, tarball_path, percent_callback=percent_callback
    )


def delete_export_tarball(export_path: str) -> Optional[str]:
    return upload_backend.delete_export_tarball(export_path)