/*
 *
 * (c) Copyright Ascensio System Limited 2010-2020
 *
 * This program is freeware. You can redistribute it and/or modify it under the terms of the GNU 
 * General Public License (GPL) version 3 as published by the Free Software Foundation (https://www.gnu.org/copyleft/gpl.html). 
 * In accordance with Section 7(a) of the GNU GPL its Section 15 shall be amended to the effect that 
 * Ascensio System SIA expressly excludes the warranty of non-infringement of any third-party rights.
 *
 * THIS PROGRAM IS DISTRIBUTED WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE. For more details, see GNU GPL at https://www.gnu.org/copyleft/gpl.html
 *
 * You can contact Ascensio System SIA by email at sales@onlyoffice.com
 *
 * The interactive user interfaces in modified source and object code versions of ONLYOFFICE must display 
 * Appropriate Legal Notices, as required under Section 5 of the GNU GPL version 3.
 *
 * Pursuant to Section 7 § 3(b) of the GNU GPL you must retain the original ONLYOFFICE logo which contains 
 * relevant author attributions when distributing the software. If the display of the logo in its graphic 
 * form is not reasonably feasible for technical reasons, you must include the words "Powered by ONLYOFFICE" 
 * in every copy of the program you distribute. 
 * Pursuant to Section 7 § 3(e) we decline to grant you any rights under trademark law for use of our trademarks.
 *
*/


using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using System.Xml.Linq;

using ASC.Common;
using ASC.Common.Caching;
using ASC.Common.Logging;
using ASC.Common.Utils;
using ASC.Core;
using ASC.Core.Billing;
using ASC.Core.Tenants;
using ASC.Data.Backup.Extensions;
using ASC.Data.Backup.Tasks.Modules;
using ASC.Data.Storage;

using Microsoft.Extensions.Options;

namespace ASC.Data.Backup.Tasks
{
    [Scope]
    public class RestorePortalTask : PortalTaskBase
    {
        private ColumnMapper ColumnMapper { get; set; }

        public string BackupFilePath { get; private set; }
        public string UpgradesPath { get; private set; }
        public bool UnblockPortalAfterCompleted { get; set; }
        public bool ReplaceDate { get; set; }
        public bool Dump { get; set; }
        private CoreBaseSettings CoreBaseSettings { get; set; }
        private LicenseReader LicenseReader { get; set; }
        public TenantManager TenantManager { get; }
        private AscCacheNotify AscCacheNotify { get; set; }
        private IOptionsMonitor<ILog> Options { get; set; }

        public RestorePortalTask(
            DbFactory dbFactory,
            IOptionsMonitor<ILog> options,
            StorageFactory storageFactory,
            StorageFactoryConfig storageFactoryConfig,
            CoreBaseSettings coreBaseSettings,
            LicenseReader licenseReader,
            TenantManager tenantManager,
            AscCacheNotify ascCacheNotify,
            ModuleProvider moduleProvider)
            : base(dbFactory, options, storageFactory, storageFactoryConfig, moduleProvider)
        {
            CoreBaseSettings = coreBaseSettings;
            LicenseReader = licenseReader;
            TenantManager = tenantManager;
            AscCacheNotify = ascCacheNotify;
            Options = options;
        }

        public void Init(string toConfigPath, string fromFilePath, int tenantId = -1, ColumnMapper columnMapper = null, string upgradesPath = null)
        {
            if (fromFilePath == null)
                throw new ArgumentNullException("fromFilePath");

            if (!File.Exists(fromFilePath))
                throw new FileNotFoundException("file not found at given path");

            BackupFilePath = fromFilePath;
            UpgradesPath = upgradesPath;
            ColumnMapper = columnMapper ?? new ColumnMapper();
            Init(tenantId, toConfigPath);
        }

        public override void RunJob()
        {
            Logger.Debug("begin restore portal");

            Logger.Debug("begin restore data");

            using (var dataReader = new ZipReadOperator(BackupFilePath))
            {
                using (var entry = dataReader.GetEntry(KeyHelper.GetDumpKey()))
                {
                    Dump = entry != null && CoreBaseSettings.Standalone;
                }

                if (Dump)
                {
                    RestoreFromDump(dataReader);
                }
                else
                {
                    var modulesToProcess = GetModulesToProcess().ToList();
                    SetStepsCount(ProcessStorage ? modulesToProcess.Count + 1 : modulesToProcess.Count);

                    foreach (var module in modulesToProcess)
                    {
                        var restoreTask = new RestoreDbModuleTask(Options, module, dataReader, ColumnMapper, DbFactory, ReplaceDate, Dump, StorageFactory, StorageFactoryConfig, ModuleProvider);
                        restoreTask.ProgressChanged += (sender, args) => SetCurrentStepProgress(args.Progress);
                        foreach (var tableName in IgnoredTables)
                        {
                            restoreTask.IgnoreTable(tableName);
                        }
                        restoreTask.RunJob();
                    }
                }

                Logger.Debug("end restore data");

                if (ProcessStorage)
                {
                    if (CoreBaseSettings.Standalone)
                    {
                        Logger.Debug("clear cache");
                        AscCacheNotify.ClearCache();
                    }

                    DoRestoreStorage(dataReader);
                }
                if (UnblockPortalAfterCompleted)
                {
                    SetTenantActive(ColumnMapper.GetTenantMapping());
                }
            }

            if (CoreBaseSettings.Standalone)
            {
                Logger.Debug("refresh license");
                try
                {
                    LicenseReader.RejectLicense();
                }
                catch (Exception ex)
                {
                    Logger.Error(ex);
                }

                Logger.Debug("clear cache");
                AscCacheNotify.ClearCache();
            }

            Logger.Debug("end restore portal");
        }

        private void RestoreFromDump(IDataReadOperator dataReader)
        {
            var keyBase = KeyHelper.GetDatabaseSchema();
            var keys = dataReader.GetEntries(keyBase).Select(r => Path.GetFileName(r)).ToList();
            var upgrades = new List<string>();

            if (!string.IsNullOrEmpty(UpgradesPath) && Directory.Exists(UpgradesPath))
            {
                upgrades = Directory.GetFiles(UpgradesPath).ToList();
            }

            var stepscount = keys.Count * 2 + upgrades.Count;

            SetStepsCount(ProcessStorage ? stepscount + 1 : stepscount);

            if (ProcessStorage)
            {
                var storageModules = StorageFactoryConfig.GetModuleList(ConfigPath).Where(IsStorageModuleAllowed);
                var tenants = TenantManager.GetTenants(false);

                stepscount += storageModules.Count() * tenants.Count;

                SetStepsCount(stepscount + 1);

                DoDeleteStorage(storageModules, tenants);
            }
            else
            {
                SetStepsCount(stepscount);
            }

            for (var i = 0; i < keys.Count; i += TasksLimit)
            {
                var tasks = new List<Task>(TasksLimit * 2);

                for (var j = 0; j < TasksLimit && i + j < keys.Count; j++)
                {
                    var key1 = Path.Combine(KeyHelper.GetDatabaseSchema(), keys[i + j]);
                    tasks.Add(RestoreFromDumpFile(dataReader, key1).ContinueWith(r => RestoreFromDumpFile(dataReader, KeyHelper.GetDatabaseData(key1.Substring(keyBase.Length + 1)))));
                }

                Task.WaitAll(tasks.ToArray());
            }

            var comparer = new SqlComparer();
            foreach (var u in upgrades.OrderBy(Path.GetFileName, comparer))
            {
                RunMysqlFile(u, true);
                SetStepCompleted();
            }
        }

        private async Task RestoreFromDumpFile(IDataReadOperator dataReader, string fileName)
        {
            Logger.DebugFormat("Restore from {0}", fileName);
            using (var stream = dataReader.GetEntry(fileName))
            {
                await RunMysqlFile(stream);
            }
            SetStepCompleted();
        }

        private class SqlComparer : IComparer<string>
        {
            public int Compare(string x, string y)
            {
                if (x == y)
                {
                    return 0;
                }

                if (!string.IsNullOrEmpty(x))
                {
                    var splittedX = x.Split('.');
                    if (splittedX.Length <= 2) return -1;
                    if (splittedX[1] == "upgrade") return 1;

                    if (splittedX[1].StartsWith("upgrade") && !string.IsNullOrEmpty(y))
                    {
                        var splittedY = y.Split('.');
                        if (splittedY.Length <= 2) return 1;
                        if (splittedY[1] == "upgrade") return -1;

                        if (splittedY[1].StartsWith("upgrade"))
                        {
                            return string.Compare(x, y, StringComparison.Ordinal);
                        }

                        return -1;
                    }

                    return -1;
                }

                return string.Compare(x, y, StringComparison.Ordinal);
            }
        }

        private void DoRestoreStorage(IDataReadOperator dataReader)
        {
            Logger.Debug("begin restore storage");

            var fileGroups = GetFilesToProcess(dataReader).GroupBy(file => file.Module).ToList();
            var groupsProcessed = 0;
            foreach (var group in fileGroups)
            {
                foreach (var file in group)
                {
                    var storage = StorageFactory.GetStorage(ConfigPath, Dump ? file.Tenant.ToString() : ColumnMapper.GetTenantMapping().ToString(), group.Key);
                    var quotaController = storage.QuotaController;
                    storage.SetQuotaController(null);

                    try
                    {
                        var adjustedPath = file.Path;
                        var module = ModuleProvider.GetByStorageModule(file.Module, file.Domain);
                        if (module == null || module.TryAdjustFilePath(Dump, ColumnMapper, ref adjustedPath))
                        {
                            var key = file.GetZipKey();
                            if (Dump)
                            {
                                key = CrossPlatform.PathCombine(KeyHelper.GetStorage(), key);
                            }
                            using var stream = dataReader.GetEntry(key);
                            try
                            {
                                storage.SaveAsync(file.Domain, adjustedPath, module != null ? module.PrepareData(key, stream, ColumnMapper) : stream).Wait();
                            }
                            catch (Exception error)
                            {
                                Logger.WarnFormat("can't restore file ({0}:{1}): {2}", file.Module, file.Path, error);
                            }
                        }
                    }
                    finally
                    {
                        if (quotaController != null)
                        {
                            storage.SetQuotaController(quotaController);
                        }
                    }
                }

                SetCurrentStepProgress((int)(++groupsProcessed * 100 / (double)fileGroups.Count));
            }

            if (fileGroups.Count == 0)
            {
                SetStepCompleted();
            }
            Logger.Debug("end restore storage");
        }

        private void DoDeleteStorage(IEnumerable<string> storageModules, IEnumerable<Tenant> tenants)
        {
            Logger.Debug("begin delete storage");

            foreach (var tenant in tenants)
            {
                foreach (var module in storageModules)
                {
                    var storage = StorageFactory.GetStorage(ConfigPath, tenant.TenantId.ToString(), module);
                    var domains = StorageFactoryConfig.GetDomainList(ConfigPath, module).ToList();

                    domains.Add(string.Empty); //instead storage.DeleteFiles("\\", "*.*", true);

                    foreach (var domain in domains)
                    {
                        ActionInvoker.Try(
                            state =>
                            {
                                if (storage.IsDirectoryAsync((string)state).Result)
                                {
                                    storage.DeleteFilesAsync((string)state, "\\", "*.*", true).Wait();
                                }
                            },
                            domain,
                            5,
                            onFailure: error => Logger.WarnFormat("Can't delete files for domain {0}: \r\n{1}", domain, error)
                        );
                    }

                    SetStepCompleted();
                }
            }

            Logger.Debug("end delete storage");
        }

        private IEnumerable<BackupFileInfo> GetFilesToProcess(IDataReadOperator dataReader)
        {
            using var stream = dataReader.GetEntry(KeyHelper.GetStorageRestoreInfoZipKey());
            if (stream == null)
            {
                return Enumerable.Empty<BackupFileInfo>();
            }
            var restoreInfo = XElement.Load(new StreamReader(stream));
            return restoreInfo.Elements("file").Select(BackupFileInfo.FromXElement).ToList();
        }

        private void SetTenantActive(int tenantId)
        {
            using var connection = DbFactory.OpenConnection();
            var commandText = string.Format(
                "update tenants_tenants " +
                "set " +
                "  status={0}, " +
                "  last_modified='{1}', " +
                "  statuschanged='{1}' " +
                "where id = '{2}'",
                (int)TenantStatus.Active,
                DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss"),
                tenantId);

            connection.CreateCommand().WithTimeout(120).ExecuteNonQuery();
        }
    }
}