from __future__ import annotations

import logging
from typing import TYPE_CHECKING

from django.conf import settings
from django.core.exceptions import PermissionDenied
from django.utils import timezone

from wagtail.log_actions import log
from wagtail.permission_policies.base import ModelPermissionPolicy
from wagtail.signals import published
from wagtail.utils.timestamps import ensure_utc

if TYPE_CHECKING:
    from wagtail.models import Revision

logger = logging.getLogger("wagtail")


class PublishPermissionError(PermissionDenied):
    """
    Raised when the publish cannot be performed due to insufficient permissions.
    """

    pass


class PublishRevisionAction:
    """
    Publish or schedule revision for publishing.

    :param revision: revision to publish
    :param user: the publishing user
    :param changed: indicated whether content has changed
    :param log_action:
        flag for the logging action. Pass False to skip logging. Cannot pass an action string as the method
        performs several actions: "publish", "revert" (and publish the reverted revision),
        "schedule publishing with a live revision", "schedule revision reversal publishing, with a live revision",
        "schedule publishing", "schedule revision reversal publishing"
    :param previous_revision: indicates a revision reversal. Should be set to the previous revision instance
    """

    def __init__(
        self,
        revision: Revision,
        user=None,
        changed: bool = True,
        log_action: bool = True,
        previous_revision: Revision | None = None,
    ):
        self.revision = revision
        self.object = self.revision.as_object()
        self.permission_policy = ModelPermissionPolicy(type(self.object))
        self.user = user
        self.changed = changed
        self.log_action = log_action
        self.previous_revision = previous_revision

    def check(self, skip_permission_checks=False):
        if (
            self.user
            and not skip_permission_checks
            and not self.permission_policy.user_has_permission(self.user, "publish")
        ):
            raise PublishPermissionError(
                "You do not have permission to publish this object."
            )

    def log_scheduling_action(self):
        log(
            instance=self.object,
            action="wagtail.publish.schedule",
            user=self.user,
            data={
                "revision": {
                    "id": self.revision.id,
                    "created": ensure_utc(self.revision.created_at),
                    "go_live_at": ensure_utc(self.object.go_live_at),
                    "has_live_version": self.object.live,
                }
            },
            revision=self.revision,
            content_changed=self.changed,
        )

    def _after_publish(self):
        from wagtail.models import WorkflowMixin

        published.send(
            sender=type(self.object),
            instance=self.object,
            revision=self.revision,
        )

        if isinstance(self.object, WorkflowMixin):
            if getattr(settings, "WAGTAIL_WORKFLOW_CANCEL_ON_PUBLISH", True) and (
                workflow_state := self.object.current_workflow_state
            ):
                workflow_state.cancel(user=self.user)

    def _publish_revision(
        self,
        revision: Revision,
        object,
        user,
        changed,
        log_action: bool,
        previous_revision: Revision | None = None,
    ):
        from wagtail.models import Revision

        if object.go_live_at and object.go_live_at > timezone.now():
            object.has_unpublished_changes = True
            # Instead set the approved_go_live_at of this revision
            revision.approved_go_live_at = object.go_live_at
            revision.save(update_fields=["approved_go_live_at"])
            # And clear the approved_go_live_at of any other revisions
            object.revisions.exclude(id=revision.id).update(approved_go_live_at=None)
            # if we are updating a currently live object skip the rest
            if object.live_revision_id:
                # Log scheduled publishing
                if log_action:
                    self.log_scheduling_action()

                return
            # if we have a go_live in the future don't make the object live
            object.live = False
        else:
            object.live = True
            # at this point, the object has unpublished changes if and only if there are newer revisions than this one
            object.has_unpublished_changes = not revision.is_latest_revision()
            # If object goes live clear the approved_go_live_at of all revisions
            object.revisions.update(approved_go_live_at=None)
        object.expired = False  # When a object is published it can't be expired

        # Set first_published_at, last_published_at and live_revision
        # if the object is being published now
        if object.live:
            now = timezone.now()
            object.last_published_at = now
            object.live_revision = revision

            if object.first_published_at is None:
                object.first_published_at = now

            if previous_revision:
                previous_revision_object = previous_revision.as_object()
                old_object_title = (
                    str(previous_revision_object)
                    if str(object) != str(previous_revision_object)
                    else None
                )
            else:
                try:
                    previous = revision.get_previous()
                except Revision.DoesNotExist:
                    previous = None
                old_object_title = (
                    str(previous.content_object)
                    if previous and str(object) != str(previous.content_object)
                    else None
                )
        else:
            # Unset live_revision if the object is going live in the future
            object.live_revision = None

        object.save()

        self._after_publish()

        if object.live:
            if log_action:
                data = None
                if previous_revision:
                    data = {
                        "revision": {
                            "id": previous_revision.id,
                            "created": ensure_utc(previous_revision.created_at),
                        }
                    }

                if old_object_title:
                    data = data or {}
                    data["title"] = {
                        "old": old_object_title,
                        "new": str(object),
                    }

                    log(
                        instance=object,
                        action="wagtail.rename",
                        user=user,
                        data=data,
                        revision=revision,
                    )

                log(
                    instance=object,
                    action=log_action
                    if isinstance(log_action, str)
                    else "wagtail.publish",
                    user=user,
                    data=data,
                    revision=revision,
                    content_changed=changed,
                )

            logger.info(
                'Published: "%s" pk=%s revision_id=%d',
                str(object),
                str(object.pk),
                revision.id,
            )
        elif object.go_live_at:
            logger.info(
                'Scheduled for publish: "%s" pk=%s revision_id=%d go_live_at=%s',
                str(object),
                str(object.pk),
                revision.id,
                object.go_live_at.isoformat(),
            )

            if log_action:
                self.log_scheduling_action()

    def execute(self, skip_permission_checks=False):
        self.check(skip_permission_checks=skip_permission_checks)

        return self._publish_revision(
            self.revision,
            self.object,
            user=self.user,
            changed=self.changed,
            log_action=self.log_action,
            previous_revision=self.previous_revision,
        )
