// Creating entities is super easy.
async function createBlogPost(title, body, archived) {
  // BlogPost extends Entity.
  const post = new BlogPost();
  post.title = title;
  post.body = body;
  post.archived = archived;
  await post.$save();
  // The post is now saved in the database.
  return post;
}

// Creating relationships is also easy.
async function createBlogPostComment(post, body) {
  if (!(post instanceof BlogPost)) {
    throw new Error("post should be a BlogPost object!");
  }

  const comment = new Comment();
  comment.post = post;
  comment.body = body;
  await comment.$save();
  return comment;
}

const post = await createBlogPost(
  "My First Post",
  "This is a great blog post!",
  false
);
await createBlogPostComment(post, "It sure is! Wow!");

// Object based queries are easy from the frontend.
async function searchBlogPosts(userQuery, page = 0) {
  // The server will only return entities the user has access to.
  return await Nymph.getEntities(
    {
      class: BlogPost.class,
      limit: 10,
      offset: page * 10,
    },
    {
      type: "&",
      // You can do things like pattern matching.
      like: ["title", "%" + userQuery + "%"],
      // Or strict comparison, etc.
      strict: ["archived", false],
    }
  );
}

// Querying relationships is also easy.
async function getBlogPostComments(post) {
  return await Nymph.getEntities(
    {
      class: BlogPostComment.class,
    },
    {
      type: "&",
      ref: ["post", post],
    }
  );
}

// Complicated queries are easy.
async function getMyLatestCommentsForPosts(posts) {
  return await Nymph.getEntities(
    {
      // Get all comments...
      class: BlogPostComment.class,
    },
    {
      type: "&",
      // ...made in the last day...
      gte: ["cdate", null, "-1 day"],
      // ...where the current user is the author...
      ref: ["user", await User.current()],
    },
    {
      // ...and the comment is on any...
      type: "|",
      // ...of the given posts.
      ref: posts.map((post) => ["post", post]),
    }
  );
}

function watchBlogPostComments(post, component) {
  const comments = component.state.comments || [];

  const subscription = Nymph.getEntities(
    {
      class: BlogPostComment.class,
    },
    {
      type: "&",
      ref: ["post", post],
    }
  ).subscribe((update) => {
    // The PubSub server keeps us up to date on this query.
    PubSub.updateArray(comments, update);
    component.setState({ comments });
  });

  component.onDestroy(() => {
    subscription.unsubscribe();
  });
}