#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Threading;
using System.Threading.Tasks;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.MainForm;
using HeuristicLab.PluginInfrastructure;
using TS = System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;

namespace HeuristicLab.Clients.Hive.WebJobManager.Services.Imports
{
    /// <summary>
    /// Rewritten to use the HiveServiceLocatorWeb
    /// </summary>
    [Item("HiveClientWeb", "Hive client.")]
    public sealed class HiveClientWeb : IContent
    {
       
        public IHostingEnvironment CurrentEnv { get; set; } //Current building area
        #region Properties
        private HiveItemCollection<RefreshableJob> jobs;
        public HiveItemCollection<RefreshableJob> Jobs
        {
            get { return jobs; }
            set
            {
                if (value != jobs)
                {
                    jobs = value;
                    OnHiveJobsChanged();
                }
            }
        }

        private List<Plugin> onlinePlugins;
        public List<Plugin> OnlinePlugins
        {
            get { return onlinePlugins; }
            set { onlinePlugins = value; }
        }

        private List<Plugin> alreadyUploadedPlugins;
        public List<Plugin> AlreadyUploadedPlugins
        {
            get { return alreadyUploadedPlugins; }
            set { alreadyUploadedPlugins = value; }
        }
        #endregion

        private HiveServiceLocatorWeb serviceLocator;
        public  Guid UserId { get; set; }
        public HiveClientWeb(HiveServiceLocatorWeb serv, Guid u)
        {
            serviceLocator = serv;
            UserId = u;
        }
        /// <summary>
        /// Reaches to the webloginservice to get the current instance of the servicelocator. 
        /// </summary>
        public void updateServiceLocator()
        {// No idea if needed
            serviceLocator = WebLoginService.Instance.getServiceLocator(UserId);
        }


        public void ClearHiveClientWeb()
        {
            Jobs.ClearWithoutHiveDeletion();
            foreach (var j in Jobs)
            {
                if (j.RefreshAutomatically)
                {
                    j.RefreshAutomatically = false; // stop result polling
                }
                j.Dispose();
            }
            Jobs = null;

            if (onlinePlugins != null)
                onlinePlugins.Clear();
            if (alreadyUploadedPlugins != null)
                alreadyUploadedPlugins.Clear();
        }

        #region Refresh
        public void Refresh()
        {
            OnRefreshing();

            try
            {
                jobs = new HiveItemCollection<RefreshableJob>();
                var jobsLoaded = serviceLocator.CallHiveService<IEnumerable<Job>>(s => s.GetJobs());

                foreach (var j in jobsLoaded)
                {
                    jobs.Add(new RefreshableJob(j));
                }
            }
            catch
            {
                jobs = null;
                throw;
            }
            finally
            {
                OnRefreshed();
            }
        }

        public void RefreshAsync(Action<Exception> exceptionCallback)
        {
            var call = new Func<Exception>(delegate ()
            {
                try
                {
                    Refresh();
                }
                catch (Exception ex)
                {
                    return ex;
                }
                return null;
            });
            call.BeginInvoke(delegate (IAsyncResult result)
            {
                Exception ex = call.EndInvoke(result);
                if (ex != null) exceptionCallback(ex);
            }, null);
        }
        #endregion

        #region Store
        public void Store(IHiveItem item, CancellationToken cancellationToken)
        {
            if (item.Id == Guid.Empty)
            {
                if (item is RefreshableJob)
                {
                    this.UploadJob((RefreshableJob)item, cancellationToken);
                }
                if (item is JobPermission)
                {
                    var hep = (JobPermission)item;
                    hep.GrantedUserId = serviceLocator.CallHiveService((s) => s.GetUserIdByUsername(hep.GrantedUserName));
                    if (hep.GrantedUserId == Guid.Empty)
                    {
                        throw new ArgumentException(string.Format("The user {0} was not found.", hep.GrantedUserName));
                    }
                    serviceLocator.CallHiveService((s) => s.GrantPermission(hep.JobId, hep.GrantedUserId, hep.Permission));
                }
            }
            else {
                if (item is Job)
                    serviceLocator.CallHiveService(s => s.UpdateJob((Job)item));
            }
        }
        public void StoreAsync(Action<Exception> exceptionCallback, IHiveItem item, CancellationToken cancellationToken)
        {
            var call = new Func<Exception>(delegate ()
            {
                try
                {
                    Store(item, cancellationToken);
                }
                catch (Exception ex)
                {
                    return ex;
                }
                return null;
            });
            call.BeginInvoke(delegate (IAsyncResult result)
            {
                Exception ex = call.EndInvoke(result);
                if (ex != null) exceptionCallback(ex);
            }, null);
        }
        #endregion

        #region Delete
        public void Delete(IHiveItem item)
        {
            if (item.Id == Guid.Empty && item.GetType() != typeof(JobPermission))
                return;

            if (item is Job)
                serviceLocator.CallHiveService(s => s.DeleteJob(item.Id));
            if (item is RefreshableJob)
            {
                RefreshableJob job = (RefreshableJob)item;
                if (job.RefreshAutomatically)
                {
                    job.StopResultPolling();
                }
                serviceLocator.CallHiveService(s => s.DeleteJob(item.Id));
            }
            if (item is JobPermission)
            {
                var hep = (JobPermission)item;
                serviceLocator.CallHiveService(s => s.RevokePermission(hep.JobId, hep.GrantedUserId));
            }
            item.Id = Guid.Empty;
        }
        #endregion

        #region Events
        public event EventHandler Refreshing;
        private void OnRefreshing()
        {
            EventHandler handler = Refreshing;
            if (handler != null) handler(this, EventArgs.Empty);
        }
        public event EventHandler Refreshed;
        private void OnRefreshed()
        {
            var handler = Refreshed;
            if (handler != null) handler(this, EventArgs.Empty);
        }
        public event EventHandler HiveJobsChanged;
        private void OnHiveJobsChanged()
        {
            var handler = HiveJobsChanged;
            if (handler != null) handler(this, EventArgs.Empty);
        }
        #endregion

        public void StartJob(Action<Exception> exceptionCallback, RefreshableJob refreshableJob, CancellationToken cancellationToken)
        {
            this.StoreAsync(
              new Action<Exception>((Exception ex) =>
              {

                  exceptionCallback(ex);
              }), refreshableJob, cancellationToken);

        }

        public void PauseJob(RefreshableJob refreshableJob)
        {
            serviceLocator.CallHiveService(service =>
            {
                foreach (HiveTask task in refreshableJob.GetAllHiveTasks())
                {
                    if (task.Task.State != TaskState.Finished && task.Task.State != TaskState.Aborted && task.Task.State != TaskState.Failed)
                        service.PauseTask(task.Task.Id);
                }
            });
        }

        public void StopJob(RefreshableJob refreshableJob)
        {
            serviceLocator.CallHiveService(service =>
            {
                foreach (HiveTask task in refreshableJob.GetAllHiveTasks())
                {
                    if (task.Task.State != TaskState.Finished && task.Task.State != TaskState.Aborted && task.Task.State != TaskState.Failed)
                        service.StopTask(task.Task.Id);
                }
            });
        }

        public  void ResumeJob(RefreshableJob refreshableJob)
        {
            serviceLocator.CallHiveService(service =>
            {
                foreach (HiveTask task in refreshableJob.GetAllHiveTasks())
                {
                    if (task.Task.State == TaskState.Paused)
                    {
                        service.RestartTask(task.Task.Id);
                    }
                }
            });
        }

        #region Upload Job
        private Semaphore taskUploadSemaphore = new Semaphore(5, 5);
        private static object jobCountLocker = new object();
        private static object pluginLocker = new object();
        
        private void UploadJob(RefreshableJob refreshableJob, CancellationToken cancellationToken)
        {
            try
            {
                refreshableJob.IsProgressing = true;
                refreshableJob.Progress.Start("Connecting to server...");
                IEnumerable<string> resourceNames = ToResourceNameList(refreshableJob.Job.ResourceNames);
                var resourceIds = new List<Guid>();
                foreach (var resourceName in resourceNames)
                {
                    Guid resourceId = serviceLocator.CallHiveService((s) => s.GetResourceId(resourceName));
                    if (resourceId == Guid.Empty)
                    {
                        throw new ResourceNotFoundException(string.Format("Could not find the resource '{0}'", resourceName));
                    }
                    resourceIds.Add(resourceId);
                }

                foreach (OptimizerHiveTask hiveJob in refreshableJob.HiveTasks.OfType<OptimizerHiveTask>())
                {
                    hiveJob.SetIndexInParentOptimizerList(null);
                }

                // upload Job
                refreshableJob.Progress.Status = "Uploading Job...";
                refreshableJob.Job.Id = serviceLocator.CallHiveService((s) => s.AddJob(refreshableJob.Job));
                refreshableJob.Job = serviceLocator.CallHiveService((s) => s.GetJob(refreshableJob.Job.Id)); // update owner and permissions
                cancellationToken.ThrowIfCancellationRequested();

                int totalJobCount = refreshableJob.GetAllHiveTasks().Count();
                int[] jobCount = new int[1]; // use a reference type (int-array) instead of value type (int) in order to pass the value via a delegate to task-parallel-library
                cancellationToken.ThrowIfCancellationRequested();

                // upload plugins
                refreshableJob.Progress.Status = "Uploading plugins...";
                this.OnlinePlugins = serviceLocator.CallHiveService((s) => s.GetPlugins());
                this.AlreadyUploadedPlugins = new List<Plugin>();
                Plugin configFilePlugin = serviceLocator.CallHiveService((s) => UploadConfigurationFile(s, onlinePlugins));
                this.alreadyUploadedPlugins.Add(configFilePlugin);
                cancellationToken.ThrowIfCancellationRequested();

                // upload tasks
                refreshableJob.Progress.Status = "Uploading tasks...";

                var tasks = new List<TS.Task>();
                foreach (HiveTask hiveTask in refreshableJob.HiveTasks)
                {
                    var task = TS.Task.Factory.StartNew((hj) =>
                    {
                        UploadTaskWithChildren(refreshableJob.Progress, (HiveTask)hj, null, resourceIds, jobCount, totalJobCount, configFilePlugin.Id, refreshableJob.Job.Id, refreshableJob.Log, cancellationToken);
                    }, hiveTask);
                    task.ContinueWith((x) => refreshableJob.Log.LogException(x.Exception), TaskContinuationOptions.OnlyOnFaulted);
                    tasks.Add(task);
                }
                TS.Task.WaitAll(tasks.ToArray());
            }
            finally
            {
                refreshableJob.IsProgressing = false;
                refreshableJob.Progress.Finish();
            }
        }

        /// <summary>
        /// Uploads the local configuration file as plugin
        /// </summary>
        private Plugin UploadConfigurationFile(IHiveService service, List<Plugin> onlinePlugins)
        {
            string exeFilePath = Path.Combine( CurrentEnv.WebRootPath, "bin"  , HeuristicLab.Clients.Hive.Settings.Default.HLBinaryName);
            string configFileName = Path.GetFileName(ConfigurationManager.OpenExeConfiguration(exeFilePath).FilePath);
            string configFilePath = ConfigurationManager.OpenExeConfiguration(exeFilePath).FilePath;
            byte[] hash;

            byte[] data = File.ReadAllBytes(configFilePath);
            using (SHA1 sha1 = SHA1.Create())
            {
                hash = sha1.ComputeHash(data);
            }

            Plugin configPlugin = new Plugin() { Name = "Configuration", Version = new Version(), Hash = hash };
            PluginData configFile = new PluginData() { FileName = configFileName, Data = data };

            IEnumerable<Plugin> onlineConfig = onlinePlugins.Where(p => p.Hash.SequenceEqual(hash));

            if (onlineConfig.Count() > 0)
            {
                return onlineConfig.First();
            }
            else {
                configPlugin.Id = service.AddPlugin(configPlugin, new List<PluginData> { configFile });
                return configPlugin;
            }
        }

        /// <summary>
        /// Uploads the given task and all its child-jobs while setting the proper parentJobId values for the childs
        /// </summary>
        /// <param name="parentHiveTask">shall be null if its the root task</param>
        private void UploadTaskWithChildren(IProgress progress, HiveTask hiveTask, HiveTask parentHiveTask, IEnumerable<Guid> groups, int[] taskCount, int totalJobCount, Guid configPluginId, Guid jobId, ILog log, CancellationToken cancellationToken)
        {
            taskUploadSemaphore.WaitOne();
            bool semaphoreReleased = false;
            try
            {
                cancellationToken.ThrowIfCancellationRequested();
                lock (jobCountLocker)
                {
                    taskCount[0]++;
                }
                TaskData taskData;
                List<IPluginDescription> plugins;

                if (hiveTask.ItemTask.ComputeInParallel)
                {
                    hiveTask.Task.IsParentTask = true;
                    hiveTask.Task.FinishWhenChildJobsFinished = true;
                    taskData = hiveTask.GetAsTaskData(true, out plugins);
                }
                else {
                    hiveTask.Task.IsParentTask = false;
                    hiveTask.Task.FinishWhenChildJobsFinished = false;
                    taskData = hiveTask.GetAsTaskData(false, out plugins);
                }
                cancellationToken.ThrowIfCancellationRequested();

                TryAndRepeat(() =>
                {
                    if (!cancellationToken.IsCancellationRequested)
                    {
                        lock (pluginLocker)
                        {
                            serviceLocator.CallHiveService((s) => hiveTask.Task.PluginsNeededIds = PluginUtil.GetPluginDependencies(s, this.onlinePlugins, this.alreadyUploadedPlugins, plugins));
                        }
                    }
                }, 5, "Failed to upload plugins");
                cancellationToken.ThrowIfCancellationRequested();
                hiveTask.Task.PluginsNeededIds.Add(configPluginId);
                hiveTask.Task.JobId = jobId;

                log.LogMessage(string.Format("Uploading task ({0} kb, {1} objects)", taskData.Data.Count() / 1024, hiveTask.ItemTask.GetObjectGraphObjects().Count()));
                TryAndRepeat(() =>
                {
                    if (!cancellationToken.IsCancellationRequested)
                    {
                        if (parentHiveTask != null)
                        {
                            hiveTask.Task.Id = serviceLocator.CallHiveService((s) => s.AddChildTask(parentHiveTask.Task.Id, hiveTask.Task, taskData));
                        }
                        else {
                            hiveTask.Task.Id = serviceLocator.CallHiveService((s) => s.AddTask(hiveTask.Task, taskData, groups.ToList()));
                        }
                    }
                }, 5, "Failed to add task", log);
                cancellationToken.ThrowIfCancellationRequested();

                lock (jobCountLocker)
                {
                    progress.ProgressValue = (double)taskCount[0] / totalJobCount;
                    progress.Status = string.Format("Uploaded task ({0} of {1})", taskCount[0], totalJobCount);
                }

                var tasks = new List<TS.Task>();
                foreach (HiveTask child in hiveTask.ChildHiveTasks)
                {
                    var task = TS.Task.Factory.StartNew((tuple) =>
                    {
                        var arguments = (Tuple<HiveTask, HiveTask>)tuple;
                        UploadTaskWithChildren(progress, arguments.Item1, arguments.Item2, groups, taskCount, totalJobCount, configPluginId, jobId, log, cancellationToken);
                    }, new Tuple<HiveTask, HiveTask>(child, hiveTask));
                    task.ContinueWith((x) => log.LogException(x.Exception), TaskContinuationOptions.OnlyOnFaulted);
                    tasks.Add(task);
                }
                taskUploadSemaphore.Release(); semaphoreReleased = true; // the semaphore has to be release before waitall!
                TS.Task.WaitAll(tasks.ToArray());
            }
            finally
            {
                if (!semaphoreReleased) taskUploadSemaphore.Release();
            }
        }
        #endregion

        #region Download Experiment
        public void LoadJob(RefreshableJob refreshableJob)
        {
            var hiveExperiment = refreshableJob.Job;
            refreshableJob.IsProgressing = true;
            TaskDownloaderWeb downloader = null;

            try
            {
                int totalJobCount = 0;
                IEnumerable<LightweightTask> allTasks;

                // fetch all task objects to create the full tree of tree of HiveTask objects
                refreshableJob.Progress.Start("Downloading list of tasks...");
                allTasks = serviceLocator.CallHiveService(s => s.GetLightweightJobTasksWithoutStateLog(hiveExperiment.Id));
                totalJobCount = allTasks.Count();

                refreshableJob.Progress.Status = "Downloading tasks...";
                downloader = new TaskDownloaderWeb(allTasks.Select(x => x.Id), serviceLocator);
                downloader.StartAsync();

                while (!downloader.IsFinished)
                {
                    refreshableJob.Progress.ProgressValue = downloader.FinishedCount / (double)totalJobCount;
                    refreshableJob.Progress.Status = string.Format("Downloading/deserializing tasks... ({0}/{1} finished)", downloader.FinishedCount, totalJobCount);
                    Thread.Sleep(500);

                    if (downloader.IsFaulted)
                    {
                        throw downloader.Exception;
                    }
                }
                IDictionary<Guid, HiveTask> allHiveTasks = downloader.Results;
                var parents = allHiveTasks.Values.Where(x => !x.Task.ParentTaskId.HasValue);

                refreshableJob.Progress.Status = "Downloading/deserializing complete. Displaying tasks...";
                // build child-task tree
                foreach (HiveTask hiveTask in parents)
                {
                    BuildHiveJobTree(hiveTask, allTasks, allHiveTasks);
                }

                refreshableJob.HiveTasks = new ItemCollection<HiveTask>(parents);
                refreshableJob.OnLoaded();
            }
            finally
            {
                refreshableJob.IsProgressing = false;
                refreshableJob.Progress.Finish();
                if (downloader != null)
                {
                    downloader.Dispose();
                }
            }
        }

        private static void BuildHiveJobTree(HiveTask parentHiveTask, IEnumerable<LightweightTask> allTasks, IDictionary<Guid, HiveTask> allHiveTasks)
        {
            IEnumerable<LightweightTask> childTasks = from job in allTasks
                                                      where job.ParentTaskId.HasValue && job.ParentTaskId.Value == parentHiveTask.Task.Id
                                                      orderby job.DateCreated ascending
                                                      select job;
            foreach (LightweightTask task in childTasks)
            {
                HiveTask childHiveTask = allHiveTasks[task.Id];
                BuildHiveJobTree(childHiveTask, allTasks, allHiveTasks);
                parentHiveTask.AddChildHiveTask(childHiveTask);
            }
        }
        #endregion

        /// <summary>
        /// Converts a string which can contain Ids separated by ';' to a enumerable
        /// </summary>
        private static IEnumerable<string> ToResourceNameList(string resourceNames)
        {
            if (!string.IsNullOrEmpty(resourceNames))
            {
                return resourceNames.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
            }
            else {
                return new List<string>();
            }
        }

        public ItemTask LoadItemJob(Guid jobId)
        {
            TaskData taskData = serviceLocator.CallHiveService(s => s.GetTaskData(jobId));
            try
            {
                return PersistenceUtil.Deserialize<ItemTask>(taskData.Data);
            }
            catch
            {
                return null;
            }
        }

        /// <summary>
        /// Executes the action. If it throws an exception it is repeated until repetition-count is reached.
        /// If repetitions is -1, it is repeated infinitely.
        /// </summary>
        public static void TryAndRepeat(Action action, int repetitions, string errorMessage, ILog log = null)
        {
            while (true)
            {
                try { action(); return; }
                catch (Exception e)
                {
                    if (repetitions == 0) throw new HiveException(errorMessage, e);
                    if (log != null) log.LogMessage(string.Format("{0}: {1} - will try again!", errorMessage, e.ToString()));
                    repetitions--;
                }
            }
        }

        public  HiveItemCollection<JobPermission> GetJobPermissions(Guid jobId)
        {
            return serviceLocator.CallHiveService((service) =>
            {
                IEnumerable<JobPermission> jps = service.GetJobPermissions(jobId);
                foreach (var hep in jps)
                {
                    hep.UnmodifiedGrantedUserNameUpdate(service.GetUsernameByUserId(hep.GrantedUserId));
                }
                return new HiveItemCollection<JobPermission>(jps);
            });
        }
    }
}