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, bool OnDemand = false)
        {
            if (BackupIsRunning) return;
            //get NOW in utc
            DateTime utcNow = DateTime.UtcNow;
            if (!OnDemand)
            {
                log.LogTrace("Checking if backup should run");

                //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)
                {
                    log.LogTrace("Not past backup time yet"); 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))
                {
                    log.LogTrace("Hasn't been 24 hours since last backup yet"); return;//nope//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 RUNNING");

                log.LogDebug("Backup starting");

                //*************
                //DO DATA BACKUP
                //build command
                //this is valid on windows
                //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


                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.LogError($"BACKUP ERROR: {Result}");


                //PRUNE DATA BACKUP SETS NOT KEPT
                FileUtil.DatabaseBackupCleanUp(ServerGlobalOpsSettings.BackupSetsToKeep);


                //DO FILE BACKUP IF ATTACHMENTS BACKED UP
                if (ServerGlobalOpsSettings.BackupAttachments)
                    FileUtil.BackupAttachments();

                //PRUNE DATA BACKUP SETS NOT KEPT
                FileUtil.AttachmentBackupCleanUp(ServerGlobalOpsSettings.BackupSetsToKeep);



                //v.next - COPY TO ONLINE STORAGE

                //***************
                if (!OnDemand)
                {
                    //Update last backup
                    var biz = GlobalOpsSettingsBiz.GetBiz(ct);
                    var OpSet = await biz.GetAsync(false);
                    OpSet.LastBackup = utcNow;
                    await biz.ReplaceAsync(OpSet);
                }
                log.LogDebug("Backup completed");
            }
            catch (Exception ex)
            {
                log.LogError(ex, "Backup failed");
                throw ex;
            }
            finally
            {
                apiServerState.ResumePriorState();
                BackupIsRunning = false;
            }
        }



        /////////////////////////////////////////////////////////////////////
    }//eoc
}//eons