#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2011 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.PluginInfrastructure;

namespace HeuristicLab.Clients.Hive {
  [Item("HiveClient", "Hive client.")]
  public sealed class HiveClient : IContent {
    private static HiveClient instance;
    public static HiveClient Instance {
      get {
        if (instance == null) instance = new HiveClient();
        return instance;
      }
    }

    #region Properties
    private ItemCollection<RefreshableHiveExperiment> hiveExperiments;
    public ItemCollection<RefreshableHiveExperiment> HiveExperiments {
      get { return hiveExperiments; }
      set {
        if (value != hiveExperiments) {
          hiveExperiments = value;
          OnHiveExperimentsChanged();
        }
      }
    }

    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

    public HiveClient() { }

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

      try {
        hiveExperiments = new HiveItemCollection<RefreshableHiveExperiment>();
        var he = ServiceLocator.Instance.CallHiveService<IEnumerable<HiveExperiment>>(s => s.GetHiveExperiments());
        hiveExperiments.AddRange(he.Select(x => new RefreshableHiveExperiment(x)).OrderBy(x => x.HiveExperiment.Name));
      }
      catch {
        hiveExperiments = 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 static void Store(IHiveItem item, CancellationToken cancellationToken) {
      if (item.Id == Guid.Empty) {
        if (item is RefreshableHiveExperiment) {
          HiveClient.Instance.UploadExperiment((RefreshableHiveExperiment)item, cancellationToken);
        }
        if (item is HiveExperimentPermission) {
          var hep = (HiveExperimentPermission)item;
          hep.GrantedUserId = ServiceLocator.Instance.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.Instance.CallHiveService((s) => s.GrantPermission(hep.HiveExperimentId, hep.GrantedUserId, hep.Permission));
        }
      } else {
        if (item is HiveExperiment)
          ServiceLocator.Instance.CallHiveService(s => s.UpdateHiveExperiment((HiveExperiment)item));
      }
    }
    public static 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 static void Delete(IHiveItem item) {
      if (item is HiveExperiment)
        ServiceLocator.Instance.CallHiveService(s => s.DeleteHiveExperiment(item.Id));
      if (item is RefreshableHiveExperiment)
        ServiceLocator.Instance.CallHiveService(s => s.DeleteHiveExperiment(item.Id));
      if (item is HiveExperimentPermission) {
        var hep = (HiveExperimentPermission)item;
        ServiceLocator.Instance.CallHiveService(s => s.RevokePermission(hep.HiveExperimentId, 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 HiveExperimentsChanged;
    private void OnHiveExperimentsChanged() {
      var handler = HiveExperimentsChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    #endregion

    public static void StartExperiment(Action<Exception> exceptionCallback, RefreshableHiveExperiment refreshableHiveExperiment, CancellationToken cancellationToken) {
      HiveClient.StoreAsync(
        new Action<Exception>((Exception ex) => {
          refreshableHiveExperiment.HiveExperiment.ExecutionState = ExecutionState.Prepared;
          exceptionCallback(ex);
        }), refreshableHiveExperiment, cancellationToken);
      refreshableHiveExperiment.HiveExperiment.ExecutionState = ExecutionState.Started;
    }

    public static void PauseExperiment(HiveExperiment hiveExperiment) {
      ServiceLocator.Instance.CallHiveService(service => {
        foreach (HiveJob job in hiveExperiment.GetAllHiveJobs()) {
          if (job.Job.State != JobState.Finished && job.Job.State != JobState.Aborted && job.Job.State != JobState.Failed)
            service.PauseJob(job.Job.Id);
        }
      });
      hiveExperiment.ExecutionState = ExecutionState.Paused;
    }

    public static void StopExperiment(HiveExperiment hiveExperiment) {
      ServiceLocator.Instance.CallHiveService(service => {
        foreach (HiveJob job in hiveExperiment.GetAllHiveJobs()) {
          if (job.Job.State != JobState.Finished && job.Job.State != JobState.Aborted && job.Job.State != JobState.Failed)
            service.StopJob(job.Job.Id);
        }
      });
      // execution state does not need to be set. it will be set to Stopped, when all jobs have been downloaded
    }

    #region Upload Experiment
    private Semaphore jobUploadSemaphore = new Semaphore(4, 4); // todo: take magic number into config
    private static object jobCountLocker = new object();
    private static object pluginLocker = new object();
    private void UploadExperiment(RefreshableHiveExperiment refreshableHiveExperiment, CancellationToken cancellationToken) {
      try {
        refreshableHiveExperiment.HiveExperiment.Progress = new Progress("Connecting to server...");
        refreshableHiveExperiment.HiveExperiment.IsProgressing = true;

        IEnumerable<string> resourceNames = ToResourceNameList(refreshableHiveExperiment.HiveExperiment.ResourceNames);
        var resourceIds = new List<Guid>();
        foreach (var resourceName in resourceNames) {
          Guid resourceId = ServiceLocator.Instance.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 (OptimizerHiveJob hiveJob in refreshableHiveExperiment.HiveExperiment.HiveJobs.OfType<OptimizerHiveJob>()) {
          hiveJob.SetIndexInParentOptimizerList(null);
        }

        // upload HiveExperiment
        refreshableHiveExperiment.HiveExperiment.Progress.Status = "Uploading HiveExperiment...";
        refreshableHiveExperiment.HiveExperiment.Id = ServiceLocator.Instance.CallHiveService((s) => s.AddHiveExperiment(refreshableHiveExperiment.HiveExperiment));
        cancellationToken.ThrowIfCancellationRequested();

        int totalJobCount = refreshableHiveExperiment.HiveExperiment.GetAllHiveJobs().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
        refreshableHiveExperiment.HiveExperiment.Progress.Status = "Uploading plugins...";
        this.OnlinePlugins = ServiceLocator.Instance.CallHiveService((s) => s.GetPlugins());
        this.AlreadyUploadedPlugins = new List<Plugin>();
        Plugin configFilePlugin = ServiceLocator.Instance.CallHiveService((s) => UploadConfigurationFile(s, onlinePlugins));
        this.alreadyUploadedPlugins.Add(configFilePlugin);
        cancellationToken.ThrowIfCancellationRequested();

        if (refreshableHiveExperiment.RefreshAutomatically) refreshableHiveExperiment.StartResultPolling();

        // upload jobs
        refreshableHiveExperiment.HiveExperiment.Progress.Status = "Uploading jobs...";

        var tasks = new List<Task>();
        foreach (HiveJob hiveJob in refreshableHiveExperiment.HiveExperiment.HiveJobs) {
          tasks.Add(Task.Factory.StartNew((hj) => {
            UploadJobWithChildren(refreshableHiveExperiment.HiveExperiment.Progress, (HiveJob)hj, null, resourceIds, jobCount, totalJobCount, configFilePlugin.Id, refreshableHiveExperiment.HiveExperiment.Id, refreshableHiveExperiment.Log, refreshableHiveExperiment.HiveExperiment.IsPrivileged, cancellationToken);
          }, hiveJob)
          .ContinueWith((x) => refreshableHiveExperiment.Log.LogException(x.Exception), TaskContinuationOptions.OnlyOnFaulted));
        }
        try {
          Task.WaitAll(tasks.ToArray());
        }
        catch (AggregateException ae) {
          if (!ae.InnerExceptions.All(e => e is TaskCanceledException)) throw ae; // for some reason the WaitAll throws a AggregateException containg a TaskCanceledException. i don't know where it comes from, however the tasks all finish properly, so for now just ignore it
        }
      }
      finally {
        refreshableHiveExperiment.HiveExperiment.IsProgressing = false;
      }
    }

    /// <summary>
    /// Uploads the local configuration file as plugin
    /// </summary>
    private static Plugin UploadConfigurationFile(IHiveService service, List<Plugin> onlinePlugins) {
      string exeFilePath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "HeuristicLab 3.3.exe");
      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 job and all its child-jobs while setting the proper parentJobId values for the childs
    /// </summary>
    /// <param name="parentHiveJob">shall be null if its the root job</param>
    private void UploadJobWithChildren(IProgress progress, HiveJob hiveJob, HiveJob parentHiveJob, IEnumerable<Guid> groups, int[] jobCount, int totalJobCount, Guid configPluginId, Guid hiveExperimentId, ILog log, bool isPrivileged, CancellationToken cancellationToken) {
      jobUploadSemaphore.WaitOne();
      bool semaphoreReleased = false;
      try {
        cancellationToken.ThrowIfCancellationRequested();
        lock (jobCountLocker) {
          jobCount[0]++;
        }
        JobData jobData;
        List<IPluginDescription> plugins;

        if (hiveJob.ItemJob.ComputeInParallel && (hiveJob.ItemJob.Item is Optimization.Experiment || hiveJob.ItemJob.Item is Optimization.BatchRun)) {
          hiveJob.Job.IsParentJob = true;
          hiveJob.Job.FinishWhenChildJobsFinished = true;
          jobData = hiveJob.GetAsJobData(true, out plugins);
        } else {
          hiveJob.Job.IsParentJob = false;
          hiveJob.Job.FinishWhenChildJobsFinished = false;
          jobData = hiveJob.GetAsJobData(false, out plugins);
        }
        cancellationToken.ThrowIfCancellationRequested();

        TryAndRepeat(() => {
          if (!cancellationToken.IsCancellationRequested) {
            lock (pluginLocker) {
              ServiceLocator.Instance.CallHiveService((s) => hiveJob.Job.PluginsNeededIds = PluginUtil.GetPluginDependencies(s, this.onlinePlugins, this.alreadyUploadedPlugins, plugins));
            }
          }
        }, -1, "Failed to upload plugins");
        cancellationToken.ThrowIfCancellationRequested();
        hiveJob.Job.PluginsNeededIds.Add(configPluginId);
        hiveJob.Job.HiveExperimentId = hiveExperimentId;
        hiveJob.Job.IsPrivileged = isPrivileged;

        log.LogMessage(string.Format("Uploading job ({0} kb, {1} objects)", jobData.Data.Count() / 1024, hiveJob.ItemJob.GetObjectGraphObjects().Count()));
        TryAndRepeat(() => {
          if (!cancellationToken.IsCancellationRequested) {
            if (parentHiveJob != null) {
              hiveJob.Job.Id = ServiceLocator.Instance.CallHiveService((s) => s.AddChildJob(parentHiveJob.Job.Id, hiveJob.Job, jobData));
            } else {
              hiveJob.Job.Id = ServiceLocator.Instance.CallHiveService((s) => s.AddJob(hiveJob.Job, jobData, groups.ToList()));
            }
          }
        }, 50, "Failed to add job", log);
        cancellationToken.ThrowIfCancellationRequested();

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

        var tasks = new List<Task>();
        foreach (HiveJob child in hiveJob.ChildHiveJobs) {
          tasks.Add(Task.Factory.StartNew((tuple) => {
            var arguments = (Tuple<HiveJob, HiveJob>)tuple;
            UploadJobWithChildren(progress, arguments.Item1, arguments.Item2, groups, jobCount, totalJobCount, configPluginId, hiveExperimentId, log, isPrivileged, cancellationToken);
          }, new Tuple<HiveJob, HiveJob>(child, hiveJob))
          .ContinueWith((x) => log.LogException(x.Exception), TaskContinuationOptions.OnlyOnFaulted));
        }
        jobUploadSemaphore.Release(); semaphoreReleased = true; // the semaphore has to be release before waitall!
        try {
          Task.WaitAll(tasks.ToArray());
        }
        catch (AggregateException ae) {
          if (!ae.InnerExceptions.All(e => e is TaskCanceledException)) throw ae; // for some reason the WaitAll throws a AggregateException containg a TaskCanceledException. i don't know where it comes from, however the tasks all finish properly, so for now just ignore it
        }
      }
      finally {
        if(!semaphoreReleased) jobUploadSemaphore.Release();
      }
    }
    #endregion

    #region Download Experiment
    public static void LoadExperiment(HiveExperiment hiveExperiment) {
      hiveExperiment.Progress = new Progress();
      try {
        hiveExperiment.IsProgressing = true;
        int totalJobCount = 0;
        IEnumerable<LightweightJob> allJobs;

        hiveExperiment.Progress.Status = "Connecting to Server...";
        // fetch all Job objects to create the full tree of tree of HiveJob objects
        hiveExperiment.Progress.Status = "Downloading list of jobs...";
        allJobs = ServiceLocator.Instance.CallHiveService(s => s.GetLightweightExperimentJobs(hiveExperiment.Id));
        totalJobCount = allJobs.Count();

        HiveJobDownloader downloader = new HiveJobDownloader(allJobs.Select(x => x.Id));
        downloader.StartAsync();

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

          if (downloader.IsFaulted) {
            throw downloader.Exception;
          }
        }
        IDictionary<Guid, HiveJob> allHiveJobs = downloader.Results;

        hiveExperiment.HiveJobs = new ItemCollection<HiveJob>(allHiveJobs.Values.Where(x => !x.Job.ParentJobId.HasValue));

        if (hiveExperiment.IsFinished()) {
          hiveExperiment.ExecutionState = Core.ExecutionState.Stopped;
        } else {
          hiveExperiment.ExecutionState = Core.ExecutionState.Started;
        }

        // build child-job tree
        foreach (HiveJob hiveJob in hiveExperiment.HiveJobs) {
          BuildHiveJobTree(hiveJob, allJobs, allHiveJobs);
        }

        hiveExperiment.OnLoaded();
      }
      finally {
        hiveExperiment.IsProgressing = false;
      }
    }

    private static void BuildHiveJobTree(HiveJob parentHiveJob, IEnumerable<LightweightJob> allJobs, IDictionary<Guid, HiveJob> allHiveJobs) {
      IEnumerable<LightweightJob> childJobs = from job in allJobs
                                              where job.ParentJobId.HasValue && job.ParentJobId.Value == parentHiveJob.Job.Id
                                              orderby job.DateCreated ascending
                                              select job;
      foreach (LightweightJob job in childJobs) {
        HiveJob childHiveJob = allHiveJobs[job.Id];
        parentHiveJob.AddChildHiveJob(childHiveJob);
        BuildHiveJobTree(childHiveJob, allJobs, allHiveJobs);
      }
    }
    #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(';');
      } else {
        return new List<string>();
      }
    }

    public static ItemJob LoadItemJob(Guid jobId) {
      JobData jobData = ServiceLocator.Instance.CallHiveService(s => s.GetJobData(jobId));
      try {
        return PersistenceUtil.Deserialize<ItemJob>(jobData.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 static HiveItemCollection<HiveExperimentPermission> GetHiveExperimentPermissions(Guid hiveExperimentId) {
      return ServiceLocator.Instance.CallHiveService((service) => {
        IEnumerable<HiveExperimentPermission> heps = service.GetHiveExperimentPermissions(hiveExperimentId);
        foreach (var hep in heps) {
          hep.GrantedUserName = service.GetUsernameByUserId(hep.GrantedUserId);
        }
        return new HiveItemCollection<HiveExperimentPermission>(heps);
      });
    }
  }
}