using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using BuildFeed.Model.View;
using MongoDB.Bson;
using MongoDB.Driver;

namespace BuildFeed.Model
{
    public partial class BuildRepository
    {
        public async Task<FrontBuildGroup[]> SelectAllGroups(int limit = -1, int skip = 0)
        {
            IAggregateFluent<BsonDocument> query = _buildCollection.Aggregate().Group(new BsonDocument
            {
                new BsonElement("_id",
                    new BsonDocument
                    {
                        new BsonElement(nameof(BuildGroup.Major), $"${nameof(Build.MajorVersion)}"),
                        new BsonElement(nameof(BuildGroup.Minor), $"${nameof(Build.MinorVersion)}"),
                        new BsonElement(nameof(BuildGroup.Build), $"${nameof(Build.Number)}"),
                        new BsonElement(nameof(BuildGroup.Revision), $"${nameof(Build.Revision)}")
                    }),
                new BsonElement("date", new BsonDocument("$max", $"${nameof(Build.BuildTime)}")),
                new BsonElement("count", new BsonDocument("$sum", 1))
            }).Sort(new BsonDocument
            {
                new BsonElement($"_id.{nameof(BuildGroup.Major)}", -1),
                new BsonElement($"_id.{nameof(BuildGroup.Minor)}", -1),
                new BsonElement($"_id.{nameof(BuildGroup.Build)}", -1),
                new BsonElement($"_id.{nameof(BuildGroup.Revision)}", -1)
            }).Skip(skip);

            if (limit > 0)
            {
                query = query.Limit(limit);
            }

            List<BsonDocument> grouping = await query.ToListAsync();

            return (from g in grouping
                    select new FrontBuildGroup
                    {
                        Key = new BuildGroup
                        {
                            Major = (uint)g["_id"].AsBsonDocument[nameof(BuildGroup.Major)].AsInt32,
                            Minor = (uint)g["_id"].AsBsonDocument[nameof(BuildGroup.Minor)].AsInt32,
                            Build = (uint)g["_id"].AsBsonDocument[nameof(BuildGroup.Build)].AsInt32,
                            Revision = (uint?)g["_id"].AsBsonDocument[nameof(BuildGroup.Revision)].AsNullableInt32
                        },
                        LastBuild = g["date"].ToNullableUniversalTime(),
                        BuildCount = g["count"].AsInt32
                    }).ToArray();
        }

        public async Task<long> SelectAllGroupsCount()
        {
            List<BsonDocument> grouping = await _buildCollection.Aggregate().Group(new BsonDocument
            {
                new BsonElement("_id",
                    new BsonDocument
                    {
                        new BsonElement(nameof(BuildGroup.Major), $"${nameof(Build.MajorVersion)}"),
                        new BsonElement(nameof(BuildGroup.Minor), $"${nameof(Build.MinorVersion)}"),
                        new BsonElement(nameof(BuildGroup.Build), $"${nameof(Build.Number)}"),
                        new BsonElement(nameof(BuildGroup.Revision), $"${nameof(Build.Revision)}")
                    })
            }).ToListAsync();
            return grouping.Count;
        }

        public async Task<List<Build>> SelectGroup(BuildGroup group, int limit = -1, int skip = 0)
        {
            IFindFluent<Build, Build> query = _buildCollection.Find(new BsonDocument
            {
                new BsonElement(nameof(Build.MajorVersion), group.Major),
                new BsonElement(nameof(Build.MinorVersion), group.Minor),
                new BsonElement(nameof(Build.Number), group.Build),
                new BsonElement(nameof(Build.Revision), group.Revision)
            }).Sort(new BsonDocument
            {
                new BsonElement(nameof(Build.BuildTime), 1)
            }).Skip(skip);

            if (limit > 0)
            {
                query = query.Limit(limit);
            }

            return await query.ToListAsync();
        }

        public async Task<long> SelectGroupCount(BuildGroup group) => await _buildCollection.CountAsync(new BsonDocument
        {
            new BsonElement(nameof(Build.MajorVersion), group.Major),
            new BsonElement(nameof(Build.MinorVersion), group.Minor),
            new BsonElement(nameof(Build.Number), group.Build),
            new BsonElement(nameof(Build.Revision), group.Revision)
        });
    }
}