using FrameworkDAL.DTO.ChangeTracking;
using FrameworkDAL.Query.ChangeTracking;
using GB5Shared.ChangeTracking;
using GB5Shared.DTO.Framework.Login;
using GB5Shared.QueryExecutor;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace FrameworkDAL.CustomCode.ChangeTracking
{
    public sealed class ChangeTrackingDAL : IChangeTrackingDAL
    {
        private readonly IQueryExecutor _qe;

        public ChangeTrackingDAL(IQueryExecutor qe) => _qe = qe;

        /// <inheritdoc/>
        public async Task SaveChangesAsync(
            int                           eventLogId,
            IReadOnlyList<ChangeRecordDTO> changes,
            LoginDTO                      login,
            CancellationToken             ct = default)
        {
            if (changes.Count == 0) return;

            // Each change is a separate INSERT — change counts per event are small (<20 typical).
            // BulkInsertAsync is overkill for this volume; individual inserts keep the code simple.
            foreach (var change in changes)
            {
                await _qe.ExecuteAsync(
                    login,
                    ChangeTrackingQB.INSERT_CHANGE,
                    new
                    {
                        EventLogId = eventLogId,
                        change.FieldName,
                        change.OldValue,
                        change.NewValue,
                        TenantId   = login.ClientId
                    },
                    cancellationToken: ct).ConfigureAwait(false);
            }
        }

        /// <inheritdoc/>
        public async Task<List<ChangeTrackingDTO>> GetChangesByEventLogAsync(
            int               eventLogId,
            LoginDTO          login,
            CancellationToken ct = default)
        {
            return (await _qe.QueryAsync<ChangeTrackingDTO>(
                login,
                ChangeTrackingQB.GET_BY_EVENTLOG_ID,
                new { EventLogId = eventLogId, TenantId = login.ClientId },
                cancellationToken: ct).ConfigureAwait(false)).ToList();
        }
    }
}