use crate::{
  activities::{generate_activity_id, send_lemmy_activity},
  insert_activity,
  protocol::activities::following::{accept::AcceptFollow, follow::Follow},
};
use activitypub_federation::{
  config::Data,
  kinds::activity::AcceptType,
  protocol::verification::verify_urls_match,
  traits::{ActivityHandler, Actor},
};
use lemmy_api_common::{
  community::CommunityResponse,
  context::LemmyContext,
  websocket::{
    handlers::messages::SendUserRoomMessage,
    serialize_websocket_message,
    UserOperation,
  },
};
use lemmy_db_schema::{
  source::{actor_language::CommunityLanguage, community::CommunityFollower},
  traits::Followable,
};
use lemmy_db_views::structs::LocalUserView;
use lemmy_db_views_actor::structs::CommunityView;
use lemmy_utils::error::LemmyError;
use url::Url;

impl AcceptFollow {
  #[tracing::instrument(skip_all)]
  pub async fn send(follow: Follow, context: &Data<LemmyContext>) -> Result<(), LemmyError> {
    let user_or_community = follow.object.dereference_local(context).await?;
    let person = follow.actor.clone().dereference(context).await?;
    let accept = AcceptFollow {
      actor: user_or_community.id().into(),
      object: follow,
      kind: AcceptType::Accept,
      id: generate_activity_id(
        AcceptType::Accept,
        &context.settings().get_protocol_and_hostname(),
      )?,
    };
    let inbox = vec![person.shared_inbox_or_inbox()];
    send_lemmy_activity(context, accept, &user_or_community, inbox, true).await
  }
}

/// Handle accepted follows
#[async_trait::async_trait]
impl ActivityHandler for AcceptFollow {
  type DataType = LemmyContext;
  type Error = LemmyError;

  fn id(&self) -> &Url {
    &self.id
  }

  fn actor(&self) -> &Url {
    self.actor.inner()
  }

  #[tracing::instrument(skip_all)]
  async fn verify(&self, context: &Data<LemmyContext>) -> Result<(), LemmyError> {
    verify_urls_match(self.actor.inner(), self.object.object.inner())?;
    self.object.verify(context).await?;
    Ok(())
  }

  #[tracing::instrument(skip_all)]
  async fn receive(self, context: &Data<LemmyContext>) -> Result<(), LemmyError> {
    insert_activity(&self.id, &self, false, true, context).await?;
    let community = self.actor.dereference(context).await?;
    let person = self.object.actor.dereference(context).await?;
    // This will throw an error if no follow was requested
    let community_id = community.id;
    let person_id = person.id;
    CommunityFollower::follow_accepted(context.pool(), community_id, person_id).await?;

    // Send the Subscribed message over websocket
    // Re-read the community_view to get the new SubscribedType
    let community_view =
      CommunityView::read(context.pool(), community_id, Some(person_id), None).await?;

    // Get the local_user_id
    let local_recipient_id = LocalUserView::read_person(context.pool(), person_id)
      .await?
      .local_user
      .id;
    let discussion_languages = CommunityLanguage::read(context.pool(), community_id).await?;

    let res = CommunityResponse {
      community_view,
      discussion_languages,
    };

    let message = serialize_websocket_message(&UserOperation::FollowCommunity, &res)?;

    context.chat_server().do_send(SendUserRoomMessage {
      recipient_id: local_recipient_id,
      message,
      websocket_id: None,
    });

    Ok(())
  }
}