using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using AyaNova.Models;
using AyaNova.Util;
using System.IO;


namespace AyaNova.Biz
{


    /// <summary>
    /// Backup 
    /// 
    /// </summary>
    internal static class CoreJobBackup
    {
        private static ILogger log = AyaNova.Util.ApplicationLogging.CreateLogger("CoreJobBackup");
        private static bool BackupIsRunning = false;
        ////////////////////////////////////////////////////////////////////////////////////////////////
        // 
        //
        public static async Task DoWorkAsync(AyContext ct)
        {
            if (BackupIsRunning) return;

            //get NOW in utc
            DateTime utcNow = DateTime.UtcNow;
            //what time should we backup today?
            DateTime todayBackupTime = new DateTime(utcNow.Year, utcNow.Month, utcNow.Day, ServerGlobalOpsSettings.BackupTime.Hour, ServerGlobalOpsSettings.BackupTime.Minute, 0, DateTimeKind.Utc);//first start with NOW
            //Are we there yet?
            if (utcNow < todayBackupTime) return;//nope

            //Yes, we've passed into the backup window time, but that's also true if we just ran the backup as well so
            //need to check for that as well...
            //Has last backup run more than 24 hours ago?
            if (ServerGlobalOpsSettings.LastBackup > utcNow.AddHours(-24))
                return;//nope, so we have already run today's backup

            //Ok, we're into backup time and it's been more than 24 hours since it last ran so let's do this...
            AyaNova.Api.ControllerHelpers.ApiServerState apiServerState = null;
            try
            {
                BackupIsRunning = true;
                //LOCK DOWN SERVER
                apiServerState = (AyaNova.Api.ControllerHelpers.ApiServerState)ServiceProviderProvider.Provider.GetService(typeof(AyaNova.Api.ControllerHelpers.ApiServerState));
                apiServerState.SetClosed("BACKUP JOB RUNNING");

                log.LogTrace("Backup starting");

                //*************

                //DO DATA BACKUP
                //build command
                //this is valid:
                //C:\data\code\PostgreSQLPortable_12.0\App\PgSQL\bin\pg_dump --dbname=postgresql://postgres:raven@127.0.0.1:5432/AyaNova -Fc > huge_new.backup
                //"AYANOVA_DB_CONNECTION": "Server=localhost;Username=postgres;Password=raven;Database=AyaNova;",

                Npgsql.NpgsqlConnectionStringBuilder PostgresConnectionString = new Npgsql.NpgsqlConnectionStringBuilder(ServerBootConfig.AYANOVA_DB_CONNECTION);
                var DBNameParameter = $"--dbname=postgresql://{PostgresConnectionString.Username}:{PostgresConnectionString.Password}@{PostgresConnectionString.Host}:{PostgresConnectionString.Port}/{PostgresConnectionString.Database}";

                var DataBackupFile = $"db-{FileUtil.GetSafeDateFileName()}.backup";//presentation issue so don't use UTC for this one
                DataBackupFile = FileUtil.GetFullPathForUtilityFile(DataBackupFile);

                var BackupUtilityCommand = "pg_dump";
                if (!string.IsNullOrWhiteSpace(ServerBootConfig.AYANOVA_BACKUP_PG_DUMP_PATH))
                    BackupUtilityCommand = Path.Combine(ServerBootConfig.AYANOVA_BACKUP_PG_DUMP_PATH, BackupUtilityCommand);

                var Arguments = $"{DBNameParameter} -Fc > {DataBackupFile}";

                var Result = RunProgram.Run(BackupUtilityCommand, Arguments, log);
                if (string.IsNullOrWhiteSpace(Result))
                    log.LogDebug("BACKUP SUCCESSFUL (NO ERROR)");
                else
                    log.LogInformation($"BACKUP ERROR: {Result}");


                //DO FILE BACKUP IF ATTACHMENTS BACKED UP
                log.LogInformation("BACKUP STUB: ATTACHMENTS BACKUP RUNNING NOW");

                //PRUNE BACKUP SETS NOT KEPT
                log.LogInformation("BACKUP STUB: PRUNING RUNNING NOW");


                //v.next - COPY TO ONLINE STORAGE

                //***************

                //Update last backup
                var biz = GlobalOpsSettingsBiz.GetBiz(ct);
                var OpSet = await biz.GetAsync(false);
                OpSet.LastBackup = utcNow;
                await biz.ReplaceAsync(OpSet);

                log.LogTrace("Backup completed");
            }
            catch (Exception ex)
            {
                log.LogError(ex, "BACKUP FAILED!");
                throw ex;
            }
            finally
            {
                apiServerState.ResumePriorState();
                BackupIsRunning = false;
                log.LogInformation("BACKUP STUB: COMPLETELY FINISHED BACKING UP");

            }
        }



        /////////////////////////////////////////////////////////////////////

    }//eoc


}//eons