use crate::{
  api::{listing_type_with_default, sort_type_with_default},
  fetcher::resolve_actor_identifier,
  objects::community::ApubCommunity,
};
use activitypub_federation::config::Data;
use actix_web::web::{Json, Query};
use lemmy_api_common::{
  context::LemmyContext,
  post::{GetPosts, GetPostsResponse},
  utils::check_private_instance,
};
use lemmy_db_schema::source::community::Community;
use lemmy_db_views::{
  post_view::PostQuery,
  structs::{LocalUserView, PaginationCursor, SiteView},
};
use lemmy_utils::error::{LemmyError, LemmyErrorExt, LemmyErrorType};

#[tracing::instrument(skip(context))]
pub async fn list_posts(
  data: Query<GetPosts>,
  context: Data<LemmyContext>,
  local_user_view: Option<LocalUserView>,
) -> Result<Json<GetPostsResponse>, LemmyError> {
  let local_site = SiteView::read_local(&mut context.pool()).await?;

  check_private_instance(&local_user_view, &local_site.local_site)?;

  let page = data.page;
  let limit = data.limit;
  let community_id = if let Some(name) = &data.community_name {
    Some(
      resolve_actor_identifier::<ApubCommunity, Community>(name, &context, &local_user_view, true)
        .await?,
    )
    .map(|c| c.id)
  } else {
    data.community_id
  };
  let saved_only = data.saved_only.unwrap_or_default();
  let show_hidden = data.show_hidden.unwrap_or_default();

  let liked_only = data.liked_only.unwrap_or_default();
  let disliked_only = data.disliked_only.unwrap_or_default();
  if liked_only && disliked_only {
    return Err(LemmyError::from(LemmyErrorType::ContradictingFilters));
  }

  let local_user_ref = local_user_view.as_ref().map(|u| &u.local_user);
  let listing_type = Some(listing_type_with_default(
    data.type_,
    local_user_ref,
    &local_site.local_site,
    community_id,
  ));

  let sort = Some(sort_type_with_default(
    data.sort,
    local_user_ref,
    &local_site.local_site,
  ));

  // parse pagination token
  let page_after = if let Some(pa) = &data.page_cursor {
    Some(pa.read(&mut context.pool()).await?)
  } else {
    None
  };

  let posts = PostQuery {
    local_user: local_user_view.as_ref(),
    listing_type,
    sort,
    community_id,
    saved_only,
    liked_only,
    disliked_only,
    page,
    page_after,
    limit,
    show_hidden,
    ..Default::default()
  }
  .list(&local_site.site, &mut context.pool())
  .await
  .with_lemmy_type(LemmyErrorType::CouldntGetPosts)?;

  // if this page wasn't empty, then there is a next page after the last post on this page
  let next_page = posts.last().map(PaginationCursor::after_post);
  Ok(Json(GetPostsResponse { posts, next_page }))
}