use crate::{
  activities::community::announce::AnnounceActivity,
  fetcher::{fetch::fetch_remote_object, object_id::ObjectId},
  objects::community::Group,
};
use activitystreams::collection::{CollectionExt, OrderedCollection};
use anyhow::Context;
use lemmy_api_common::blocking;
use lemmy_apub_lib::ActivityHandler;
use lemmy_db_queries::Joinable;
use lemmy_db_schema::source::{
  community::{Community, CommunityModerator, CommunityModeratorForm},
  person::Person,
};
use lemmy_db_views_actor::community_moderator_view::CommunityModeratorView;
use lemmy_utils::{location_info, LemmyError};
use lemmy_websocket::LemmyContext;
use url::Url;

pub(crate) async fn update_community_mods(
  group: &Group,
  community: &Community,
  context: &LemmyContext,
  request_counter: &mut i32,
) -> Result<(), LemmyError> {
  let new_moderators = fetch_community_mods(context, group, request_counter).await?;
  let community_id = community.id;
  let current_moderators = blocking(context.pool(), move |conn| {
    CommunityModeratorView::for_community(conn, community_id)
  })
  .await??;
  // Remove old mods from database which arent in the moderators collection anymore
  for mod_user in &current_moderators {
    if !new_moderators.contains(&mod_user.moderator.actor_id.clone().into()) {
      let community_moderator_form = CommunityModeratorForm {
        community_id: mod_user.community.id,
        person_id: mod_user.moderator.id,
      };
      blocking(context.pool(), move |conn| {
        CommunityModerator::leave(conn, &community_moderator_form)
      })
      .await??;
    }
  }

  // Add new mods to database which have been added to moderators collection
  for mod_id in new_moderators {
    let mod_id = ObjectId::new(mod_id);
    let mod_user: Person = mod_id.dereference(context, request_counter).await?;

    if !current_moderators
      .clone()
      .iter()
      .map(|c| c.moderator.actor_id.clone())
      .any(|x| x == mod_user.actor_id)
    {
      let community_moderator_form = CommunityModeratorForm {
        community_id: community.id,
        person_id: mod_user.id,
      };
      blocking(context.pool(), move |conn| {
        CommunityModerator::join(conn, &community_moderator_form)
      })
      .await??;
    }
  }

  Ok(())
}

pub(crate) async fn fetch_community_outbox(
  context: &LemmyContext,
  outbox: &Url,
  recursion_counter: &mut i32,
) -> Result<(), LemmyError> {
  let outbox =
    fetch_remote_object::<OrderedCollection>(context.client(), outbox, recursion_counter).await?;
  let outbox_activities = outbox.items().context(location_info!())?.clone();
  let mut outbox_activities = outbox_activities.many().context(location_info!())?;
  if outbox_activities.len() > 20 {
    outbox_activities = outbox_activities[0..20].to_vec();
  }

  for announce in outbox_activities {
    // TODO: instead of converting like this, we should create a struct CommunityOutbox with
    //       AnnounceActivity as inner type, but that gives me stackoverflow
    let ser = serde_json::to_string(&announce)?;
    let announce: AnnounceActivity = serde_json::from_str(&ser)?;
    announce.receive(context, recursion_counter).await?;
  }

  Ok(())
}

async fn fetch_community_mods(
  context: &LemmyContext,
  group: &Group,
  recursion_counter: &mut i32,
) -> Result<Vec<Url>, LemmyError> {
  if let Some(mods_url) = &group.moderators {
    let mods =
      fetch_remote_object::<OrderedCollection>(context.client(), mods_url, recursion_counter)
        .await?;
    let mods = mods
      .items()
      .map(|i| i.as_many())
      .flatten()
      .context(location_info!())?
      .iter()
      .filter_map(|i| i.as_xsd_any_uri())
      .map(|u| u.to_owned())
      .collect();
    Ok(mods)
  } else {
    Ok(vec![])
  }
}