Mixonomer.NET/Mixonomer.Fire/Extensions/UserRepoExtensions.cs

using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Google.Cloud.Firestore;
using Mixonomer.Fire.Model;

namespace Mixonomer.Fire.Extensions
{
    public static class UserRepoExtensions
    {
        public static async Task<IAsyncEnumerable<DocumentSnapshot>> GetPlaylistDocs(this UserRepo repo, string username)
        {
            var user = await repo.GetUser(username).ConfigureAwait(false);

            return await repo.GetPlaylistDocs(user).ConfigureAwait(false);
        }

        public static async IAsyncEnumerable<Playlist> GetPlaylists(this UserRepo repo, User user)
        {
            var playlists = await repo.GetPlaylistDocs(user).ConfigureAwait(false);

            await foreach (var playlist in playlists)
            {
                yield return playlist.ConvertTo<Playlist>();
            }
        }

        public static async Task<IAsyncEnumerable<DocumentSnapshot>> GetTagDocs(this UserRepo repo, string username)
        {
            var user = await repo.GetUser(username).ConfigureAwait(false);

            return await repo.GetTagDocs(user).ConfigureAwait(false);
        }

        public static async IAsyncEnumerable<Tag> GetTags(this UserRepo repo, User user)
        {
            var tags = await repo.GetTagDocs(user).ConfigureAwait(false);

            await foreach (var tag in tags)
            {
                yield return tag.ConvertTo<Tag>();
            }
        }

        public static async Task<UserContext> GetUserContext(this UserRepo repo, string username)
        {
            var user = new UserContext
            {
                User = await repo.GetUser(username).ConfigureAwait(false)
            };

            var playlists = repo.GetPlaylists(user.User).ToListAsync();
            var tags = repo.GetTags(user.User).ToListAsync();

            await Task.WhenAll(playlists.AsTask(), tags.AsTask()).ConfigureAwait(false);

            user.Playlists = playlists.Result;
            user.Tags = tags.Result;

            return user;
        }
    }
}