lemmy/crates/db_views_actor/src/community_view.rs

use crate::structs::{CommunityModeratorView, CommunityView, PersonView};
use diesel::{
  result::Error,
  BoolExpressionMethods,
  ExpressionMethods,
  JoinOnDsl,
  NullableExpressionMethods,
  PgTextExpressionMethods,
  QueryDsl,
};
use diesel_async::RunQueryDsl;
use lemmy_db_schema::{
  aggregates::structs::CommunityAggregates,
  newtypes::{CommunityId, PersonId},
  schema::{community, community_aggregates, community_block, community_follower, local_user},
  source::{
    community::{Community, CommunityFollower},
    community_block::CommunityBlock,
    local_user::LocalUser,
  },
  traits::JoinView,
  utils::{fuzzy_search, get_conn, limit_and_offset, DbPool},
  ListingType,
  SortType,
};

type CommunityViewTuple = (
  Community,
  CommunityAggregates,
  Option<CommunityFollower>,
  Option<CommunityBlock>,
);

impl CommunityView {
  pub async fn read(
    pool: &mut DbPool<'_>,
    community_id: CommunityId,
    my_person_id: Option<PersonId>,
    is_mod_or_admin: Option<bool>,
  ) -> Result<Self, Error> {
    let conn = &mut get_conn(pool).await?;
    // The left join below will return None in this case
    let person_id_join = my_person_id.unwrap_or(PersonId(-1));

    let mut query = community::table
      .find(community_id)
      .inner_join(community_aggregates::table)
      .left_join(
        community_follower::table.on(
          community::id
            .eq(community_follower::community_id)
            .and(community_follower::person_id.eq(person_id_join)),
        ),
      )
      .left_join(
        community_block::table.on(
          community::id
            .eq(community_block::community_id)
            .and(community_block::person_id.eq(person_id_join)),
        ),
      )
      .select((
        community::all_columns,
        community_aggregates::all_columns,
        community_follower::all_columns.nullable(),
        community_block::all_columns.nullable(),
      ))
      .into_boxed();

    // Hide deleted and removed for non-admins or mods
    if !is_mod_or_admin.unwrap_or(false) {
      query = query
        .filter(community::removed.eq(false))
        .filter(community::deleted.eq(false));
    }

    let (community, counts, follower, blocked) = query.first::<CommunityViewTuple>(conn).await?;

    Ok(CommunityView {
      community,
      subscribed: CommunityFollower::to_subscribed_type(&follower),
      blocked: blocked.is_some(),
      counts,
    })
  }

  pub async fn is_mod_or_admin(
    pool: &mut DbPool<'_>,
    person_id: PersonId,
    community_id: CommunityId,
  ) -> Result<bool, Error> {
    let is_mod =
      CommunityModeratorView::is_community_moderator(pool, community_id, person_id).await?;
    if is_mod {
      return Ok(true);
    }

    PersonView::is_admin(pool, person_id).await
  }
}

#[derive(Default)]
pub struct CommunityQuery<'a> {
  pub listing_type: Option<ListingType>,
  pub sort: Option<SortType>,
  pub local_user: Option<&'a LocalUser>,
  pub search_term: Option<String>,
  pub is_mod_or_admin: Option<bool>,
  pub show_nsfw: Option<bool>,
  pub page: Option<i64>,
  pub limit: Option<i64>,
}

impl<'a> CommunityQuery<'a> {
  pub async fn list(self, pool: &mut DbPool<'_>) -> Result<Vec<CommunityView>, Error> {
    use SortType::*;

    let conn = &mut get_conn(pool).await?;

    // The left join below will return None in this case
    let person_id_join = self.local_user.map(|l| l.person_id).unwrap_or(PersonId(-1));

    let mut query = community::table
      .inner_join(community_aggregates::table)
      .left_join(local_user::table.on(local_user::person_id.eq(person_id_join)))
      .left_join(
        community_follower::table.on(
          community::id
            .eq(community_follower::community_id)
            .and(community_follower::person_id.eq(person_id_join)),
        ),
      )
      .left_join(
        community_block::table.on(
          community::id
            .eq(community_block::community_id)
            .and(community_block::person_id.eq(person_id_join)),
        ),
      )
      .select((
        community::all_columns,
        community_aggregates::all_columns,
        community_follower::all_columns.nullable(),
        community_block::all_columns.nullable(),
      ))
      .into_boxed();

    if let Some(search_term) = self.search_term {
      let searcher = fuzzy_search(&search_term);
      query = query
        .filter(community::name.ilike(searcher.clone()))
        .or_filter(community::title.ilike(searcher));
    };

    // Hide deleted and removed for non-admins or mods
    if !self.is_mod_or_admin.unwrap_or(false) {
      query = query
        .filter(community::removed.eq(false))
        .filter(community::deleted.eq(false))
        .filter(
          community::hidden
            .eq(false)
            .or(community_follower::person_id.eq(person_id_join)),
        );
    }
    match self.sort.unwrap_or(Hot) {
      Hot | Active => query = query.order_by(community_aggregates::hot_rank.desc()),
      NewComments | TopDay | TopTwelveHour | TopSixHour | TopHour => {
        query = query.order_by(community_aggregates::users_active_day.desc())
      }
      New => query = query.order_by(community::published.desc()),
      Old => query = query.order_by(community::published.asc()),
      // Controversial is temporary until a CommentSortType is created
      MostComments | Controversial => query = query.order_by(community_aggregates::comments.desc()),
      TopAll | TopYear | TopNineMonths => {
        query = query.order_by(community_aggregates::subscribers.desc())
      }
      TopSixMonths | TopThreeMonths => {
        query = query.order_by(community_aggregates::users_active_half_year.desc())
      }
      TopMonth => query = query.order_by(community_aggregates::users_active_month.desc()),
      TopWeek => query = query.order_by(community_aggregates::users_active_week.desc()),
    };

    if let Some(listing_type) = self.listing_type {
      query = match listing_type {
        ListingType::Subscribed => query.filter(community_follower::person_id.is_not_null()), // TODO could be this: and(community_follower::person_id.eq(person_id_join)),
        ListingType::Local => query.filter(community::local.eq(true)),
        _ => query,
      };
    }

    // Don't show blocked communities or nsfw communities if not enabled in profile
    if self.local_user.is_some() {
      query = query.filter(community_block::person_id.is_null());
      query = query.filter(community::nsfw.eq(false).or(local_user::show_nsfw.eq(true)));
    } else {
      // No person in request, only show nsfw communities if show_nsfw is passed into request
      if !self.show_nsfw.unwrap_or(false) {
        query = query.filter(community::nsfw.eq(false));
      }
    }

    let (limit, offset) = limit_and_offset(self.page, self.limit)?;
    let res = query
      .limit(limit)
      .offset(offset)
      .load::<CommunityViewTuple>(conn)
      .await?;

    Ok(res.into_iter().map(CommunityView::from_tuple).collect())
  }
}

impl JoinView for CommunityView {
  type JoinTuple = CommunityViewTuple;
  fn from_tuple(a: Self::JoinTuple) -> Self {
    Self {
      community: a.0,
      counts: a.1,
      subscribed: CommunityFollower::to_subscribed_type(&a.2),
      blocked: a.3.is_some(),
    }
  }
}