using System;
using Microsoft.Data.SqlClient;
using Serilog;
using SyncEngine.Configuration;

namespace SyncEngine.Sync
{
    public sealed class SoftDeleteTracker
    {
        private readonly SyncOptions _options;
        private readonly ILogger _logger;

        public SoftDeleteTracker(SyncOptions options, ILogger logger)
        {
            _options = options;
            _logger = logger;
        }

        public int MarkMissingRows(SqlConnection connection, string qualifiedTable, string pkColumn, DateTime runStart)
        {
            if (!_options.SoftDeleteEnabled || _options.DryRun)
            {
                return 0;
            }

            // Compare at millisecond precision so stored DATETIME2 values match the runStart written by MarkRowsSeen.
            var sql = string.Format(@"
UPDATE {0}
SET _sync_is_deleted = 1, _sync_updated_at = @now
WHERE _sync_is_deleted = 0
  AND (
    _sync_last_seen_at IS NULL
    OR DATEDIFF(millisecond, _sync_last_seen_at, @runStart) > 0
  )",
                qualifiedTable);

            using (var cmd = new SqlCommand(sql, connection))
            {
                cmd.CommandTimeout = _options.CommandTimeoutSeconds;
                cmd.Parameters.AddWithValue("@now", DateTime.UtcNow);
                cmd.Parameters.AddWithValue("@runStart", runStart);
                var count = cmd.ExecuteNonQuery();
                if (count > 0)
                {
                    _logger.Information("Soft-deleted {Count} rows in {Table}", count, qualifiedTable);
                }

                return count;
            }
        }
    }
}