using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MongoDB.Bson;
using MongoDB.Driver;
using MongoDB.Driver.Core.Bindings;
using MongoDB.Driver.Core.Clusters;
using MongoDB.Driver.Core.Servers;
using MongoDB.Driver.Core.WireProtocol.Messages.Encoders;
using MongoDB.Driver.Linq;
using xDataService.Mongo;

namespace xDataService.Extensions {
    public static class XMongoDbExtensions {
        public static Guid ToGuid (this ObjectId source) {
            //
            var bytes = source
                .ToByteArray ()
                .Concat (new byte[] { 5, 5, 5, 5 })
                .ToArray ();

            //
            var result = new Guid (bytes);

            //
            return result;
        }

        public static ObjectId ToObjectId (this Guid source) {
            //
            var bytes = source
                .ToByteArray ()
                .Take (12)
                .ToArray ();

            //
            var result = new ObjectId (bytes);

            //
            return result;
        }

        public static IAsyncEnumerable<T> ToAsyncEnumerable<T> (this IAsyncCursorSource<T> asyncCursorSource) {
            return new XAsyncEnumerableAdapter<T> (asyncCursorSource);
        }

        public static async IAsyncEnumerable<T> ToAsyncEnumerable<T> (this IAsyncCursor<T> source) {
            while (await source.MoveNextAsync ()) {
                foreach (var current in source.Current) {
                    yield return current;
                }
            }
        }

        public static XMongoAsyncCursor<T> ToAsyncCursor<T> (this IQueryable<T> source) {
            return new XMongoAsyncCursor<T> (source);
        }
    }
}