use crate::PerformCrud;
use activitypub_federation::core::{object_id::ObjectId, signatures::generate_actor_keypair};
use actix_web::web::Data;
use lemmy_api_common::{
  community::{CommunityResponse, CreateCommunity},
  utils::{blocking, get_local_user_view_from_jwt, is_admin, local_site_to_slur_regex},
};
use lemmy_apub::{
  generate_followers_url,
  generate_inbox_url,
  generate_local_apub_endpoint,
  generate_shared_inbox_url,
  objects::community::ApubCommunity,
  EndpointType,
};
use lemmy_db_schema::{
  source::community::{
    Community,
    CommunityFollower,
    CommunityFollowerForm,
    CommunityInsertForm,
    CommunityModerator,
    CommunityModeratorForm,
  },
  traits::{Crud, Followable, Joinable},
  utils::diesel_option_overwrite_to_url_create,
};
use lemmy_db_views::structs::SiteView;
use lemmy_db_views_actor::structs::CommunityView;
use lemmy_utils::{
  error::LemmyError,
  utils::{check_slurs, check_slurs_opt, is_valid_actor_name},
  ConnectionId,
};
use lemmy_websocket::LemmyContext;

#[async_trait::async_trait(?Send)]
impl PerformCrud for CreateCommunity {
  type Response = CommunityResponse;

  #[tracing::instrument(skip(context, _websocket_id))]
  async fn perform(
    &self,
    context: &Data<LemmyContext>,
    _websocket_id: Option<ConnectionId>,
  ) -> Result<CommunityResponse, LemmyError> {
    let data: &CreateCommunity = self;
    let local_user_view =
      get_local_user_view_from_jwt(&data.auth, context.pool(), context.secret()).await?;
    let site_view = blocking(context.pool(), SiteView::read_local).await??;
    let local_site = site_view.local_site;

    if local_site.community_creation_admin_only && is_admin(&local_user_view).is_err() {
      return Err(LemmyError::from_message(
        "only_admins_can_create_communities",
      ));
    }

    // Check to make sure the icon and banners are urls
    let icon = diesel_option_overwrite_to_url_create(&data.icon)?;
    let banner = diesel_option_overwrite_to_url_create(&data.banner)?;

    let slur_regex = local_site_to_slur_regex(&local_site);
    check_slurs(&data.name, &slur_regex)?;
    check_slurs(&data.title, &slur_regex)?;
    check_slurs_opt(&data.description, &slur_regex)?;

    if !is_valid_actor_name(&data.name, local_site.actor_name_max_length as usize) {
      return Err(LemmyError::from_message("invalid_community_name"));
    }

    // Double check for duplicate community actor_ids
    let community_actor_id = generate_local_apub_endpoint(
      EndpointType::Community,
      &data.name,
      &context.settings().get_protocol_and_hostname(),
    )?;
    let community_actor_id_wrapped = ObjectId::<ApubCommunity>::new(community_actor_id.clone());
    let community_dupe = community_actor_id_wrapped.dereference_local(context).await;
    if community_dupe.is_ok() {
      return Err(LemmyError::from_message("community_already_exists"));
    }

    // When you create a community, make sure the user becomes a moderator and a follower
    let keypair = generate_actor_keypair()?;

    let community_form = CommunityInsertForm::builder()
      .name(data.name.to_owned())
      .title(data.title.to_owned())
      .description(data.description.to_owned())
      .icon(icon)
      .banner(banner)
      .nsfw(data.nsfw)
      .actor_id(Some(community_actor_id.to_owned()))
      .private_key(Some(keypair.private_key))
      .public_key(keypair.public_key)
      .followers_url(Some(generate_followers_url(&community_actor_id)?))
      .inbox_url(Some(generate_inbox_url(&community_actor_id)?))
      .shared_inbox_url(Some(generate_shared_inbox_url(&community_actor_id)?))
      .posting_restricted_to_mods(data.posting_restricted_to_mods)
      .instance_id(site_view.site.instance_id)
      .build();

    let inserted_community = blocking(context.pool(), move |conn| {
      Community::create(conn, &community_form)
    })
    .await?
    .map_err(|e| LemmyError::from_error_message(e, "community_already_exists"))?;

    // The community creator becomes a moderator
    let community_moderator_form = CommunityModeratorForm {
      community_id: inserted_community.id,
      person_id: local_user_view.person.id,
    };

    let join = move |conn: &mut _| CommunityModerator::join(conn, &community_moderator_form);
    blocking(context.pool(), join)
      .await?
      .map_err(|e| LemmyError::from_error_message(e, "community_moderator_already_exists"))?;

    // Follow your own community
    let community_follower_form = CommunityFollowerForm {
      community_id: inserted_community.id,
      person_id: local_user_view.person.id,
      pending: false,
    };

    let follow = move |conn: &mut _| CommunityFollower::follow(conn, &community_follower_form);
    blocking(context.pool(), follow)
      .await?
      .map_err(|e| LemmyError::from_error_message(e, "community_follower_already_exists"))?;

    let person_id = local_user_view.person.id;
    let community_view = blocking(context.pool(), move |conn| {
      CommunityView::read(conn, inserted_community.id, Some(person_id))
    })
    .await??;

    Ok(CommunityResponse { community_view })
  }
}