using Mindrockets.Helpers;
using Npgsql;
using System;
using System.Configuration;
using System.Threading;

namespace UpdateSentencesDate
{
    internal class Program
    {
        private const int BatchSize = 1000;
        private const int MaxRetries = 3;

        static int Main(string[] args)
        {
            Mindrockets.Helpers.Logger.Instance.Info($"[{DateTime.UtcNow:u}] Job started");

            string connectionString = ConfigurationManager
                .ConnectionStrings["PostgreSQL"]?.ConnectionString;

            if (string.IsNullOrWhiteSpace(connectionString))
            {
                Logger.Instance.Error("Connection string 'PostgreSQL' not found.");
                return 1;
            }

            int totalUpdated = 0;

            try
            {
                while (true)
                {
                    int rows = ExecuteBatch(connectionString);

                    totalUpdated += rows;
                    Logger.Instance.Info($"[{DateTime.UtcNow:u}] Batch updated: {rows}");

                    if (rows < BatchSize)
                        break; // no more rows to process
                }

                Logger.Instance.Info($"[{DateTime.UtcNow:u}] Job completed. Total rows updated: {totalUpdated}");
                return 0;
            }
            catch (Exception ex)
            {
                Logger.Instance.Error($"[{DateTime.UtcNow:u}] FATAL ERROR");
                Logger.Instance.Error(ex);
                return 1;
            }
        }

        private static int ExecuteBatch(string connectionString)
        {
            for (int attempt = 1; attempt <= MaxRetries; attempt++)
            {
                try
                {
                    using (var conn = new NpgsqlConnection(connectionString))
                    {
                        conn.Open();

                        using (var tx = conn.BeginTransaction())
                        {
                            using (var cmd = new NpgsqlCommand(UpdateQuery, conn, tx))
                            {
                                cmd.CommandTimeout = 60;

                                cmd.Parameters.AddWithValue("@now", DateTime.UtcNow);
                                cmd.Parameters.AddWithValue("@batchSize", BatchSize);

                                int affected = cmd.ExecuteNonQuery();

                                tx.Commit();
                                return affected;
                            }
                        }
                    }
                }
                catch (PostgresException pgex)
                {
                    Logger.Instance.Info($"[{DateTime.UtcNow:u}] PostgreSQL error (attempt {attempt}): {pgex.Message}");

                    if (attempt == MaxRetries)
                        throw;

                    Thread.Sleep(2000);
                }
                catch (Exception ex)
                {
                    Logger.Instance.Error($"[{DateTime.UtcNow:u}] Error (attempt {attempt}): {ex.Message}");

                    if (attempt == MaxRetries)
                        throw;

                    Thread.Sleep(2000);
                }
            }

            return 0;
        }

        private static readonly string UpdateQuery = @"
WITH target AS (
    SELECT ""Id""
    FROM dbo.""Translations""
    WHERE ""NeedsReview"" = TRUE
      AND (""TrackerId"" = 3 OR ""TrackerId"" = 6)
      AND ""LastTrackDate"" IS NOT NULL
      AND ""LastTrackDate"" >= (@now - INTERVAL '7 days')
      AND ""LastTrackDate"" <  (@now - INTERVAL '1 day')
    ORDER BY ""LastTrackDate"" ASC
    LIMIT @batchSize
    FOR UPDATE SKIP LOCKED
)
UPDATE dbo.""Translations"" t
SET ""LastTrackDate"" = @now
FROM target
WHERE t.""Id"" = target.""Id"";
";
    }
}