using Microsoft.EntityFrameworkCore;
using SharedLibraryCore.Dtos;
using SharedLibraryCore.Interfaces;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace SharedLibraryCore.Repositories
{
    /// <summary>
    /// implementation if IAuditInformationRepository
    /// </summary>
    public class AuditInformationRepository : IAuditInformationRepository
    {
        private readonly IDatabaseContextFactory _contextFactory;

        public AuditInformationRepository(IDatabaseContextFactory contextFactory)
        {
            _contextFactory = contextFactory;
        }

        /// <inheritdoc/>
        public async Task<IList<AuditInfo>> ListAuditInformation(PaginationRequest paginationInfo)
        {
            await using var ctx = _contextFactory.CreateContext(enableTracking: false);
            var iqItems = (from change in ctx.EFChangeHistory
                           where change.TypeOfChange != Database.Models.EFChangeHistory.ChangeType.Ban
                           orderby change.TimeChanged descending
                           join originClient in ctx.Clients
                           on (change.ImpersonationEntityId ?? change.OriginEntityId) equals originClient.ClientId
                           join targetClient in ctx.Clients
                           on change.TargetEntityId equals targetClient.ClientId
                           into targetChange
                           from targetClient in targetChange.DefaultIfEmpty()
                           select new AuditInfo()
                           {
                               Action = change.TypeOfChange.ToString(),
                               OriginName = originClient.CurrentAlias.Name,
                               OriginId = originClient.ClientId,
                               TargetName = targetClient == null ? "" : targetClient.CurrentAlias.Name,
                               TargetId = targetClient == null ? new int?() : targetClient.ClientId,
                               When = change.TimeChanged,
                               Data = change.Comment,
                               OldValue = change.PreviousValue,
                               NewValue = change.CurrentValue
                           })
                .Skip(paginationInfo.Offset)
                .Take(paginationInfo.Count);

            return await iqItems.ToListAsync();
        }
    }
}