#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2016 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.Threading;
using HeuristicLab.Common;
using HeuristicLab.Core;
using System.Collections.Generic;
using System.Linq;

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

    #region Properties
    private IItemList<Resource> resources;
    public IItemList<Resource> Resources {
      get { return resources; }
    }

    private IItemList<Downtime> downtimes;
    public IItemList<Downtime> Downtimes {
      get { return downtimes; }
    }

    private Guid downtimeForResourceId;
    public Guid DowntimeForResourceId {
      get { return downtimeForResourceId; }
      set {
        downtimeForResourceId = value;
        if (downtimes != null) {
          downtimes.Clear();
        }
      }
    }

    private IItemList<Project> projects;
    public IItemList<Project> Projects {
      get { return projects; }
    }

    private Dictionary<Guid, HashSet<Project>> projectAncestors;
    public Dictionary<Guid, HashSet<Project>> ProjectAncestors {
      get { return projectAncestors; }
    }

    private Dictionary<Guid, HashSet<Project>> projectDescendants;
    public Dictionary<Guid, HashSet<Project>> ProjectDescendants {
      get { return projectDescendants; }
    }

    private Dictionary<Guid, HashSet<Resource>> resourceAncestors;
    public Dictionary<Guid, HashSet<Resource>> ResourceAncestors {
      get { return resourceAncestors; }
    }

    private Dictionary<Guid, HashSet<Resource>> resourceDescendants;
    public Dictionary<Guid, HashSet<Resource>> ResourceDescendants {
      get { return resourceDescendants; }
    }


    #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);
    }
    #endregion

    private HiveAdminClient() { }

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

      try {
        resources = new ItemList<Resource>();
        projects = new ItemList<Project>();

        projectAncestors = new Dictionary<Guid, HashSet<Project>>();
        projectDescendants = new Dictionary<Guid, HashSet<Project>>();
        resourceAncestors = new Dictionary<Guid, HashSet<Resource>>();
        resourceDescendants = new Dictionary<Guid, HashSet<Resource>>();

        HiveServiceLocator.Instance.CallHiveService(service => {
          service.GetSlaveGroupsForAdministration().ForEach(g => resources.Add(g));
          service.GetSlavesForAdministration().ForEach(s => resources.Add(s));
          service.GetProjectsForAdministration().ForEach(p => projects.Add(p));
        });

        UpdateResourceGenealogy(resources);
        UpdateProjectGenealogy(projects);
      }
      catch {
        throw;
      }
      finally {
        OnRefreshed();
      }
    }

    public void UpdateResourceGenealogy(IItemList<Resource> resources) {
      resourceAncestors.Clear();
      resourceDescendants.Clear();

      foreach (var r in resources) {
        resourceAncestors.Add(r.Id, new HashSet<Resource>());
        resourceDescendants.Add(r.Id, new HashSet<Resource>());
      }

      foreach (var r in resources) {
        var parentResourceId = r.ParentResourceId;
        while (parentResourceId != null) {
          var parent = resources.SingleOrDefault(x => x.Id == parentResourceId);
          if (parent != null) {
            resourceAncestors[r.Id].Add(parent);
            resourceDescendants[parent.Id].Add(r);
            parentResourceId = parent.ParentResourceId;
          } else {
            parentResourceId = null;
          }
        }
      }
    }

    public void UpdateProjectGenealogy(IItemList<Project> projects) {
      projectAncestors.Clear();
      projectDescendants.Clear();

      foreach (var p in projects) {
        projectAncestors.Add(p.Id, new HashSet<Project>());
        projectDescendants.Add(p.Id, new HashSet<Project>());
      }

      foreach (var p in projects) {
        var parentProjectId = p.ParentProjectId;
        while (parentProjectId != null) {
          var parent = projects.SingleOrDefault(x => x.Id == parentProjectId);
          if (parent != null) {
            projectAncestors[p.Id].Add(parent);
            projectDescendants[parent.Id].Add(p);
            parentProjectId = parent.ParentProjectId;
          } else {
            parentProjectId = null;
          }
        }
      }
    }
    #endregion

    #region Refresh downtime calendar
    public void RefreshCalendar() {
      if (downtimeForResourceId != null && downtimeForResourceId != Guid.Empty) {
        OnRefreshing();

        try {
          downtimes = new ItemList<Downtime>();

          HiveServiceLocator.Instance.CallHiveService(service => {
            service.GetDowntimesForResource(downtimeForResourceId).ForEach(d => downtimes.Add(d));
          });
        }
        catch {
          throw;
        }
        finally {
          OnRefreshed();
        }
      }
    }
    #endregion

    #region Store
    public static void Store(IHiveItem item, CancellationToken cancellationToken) {
      if (item.Id == Guid.Empty) {
        if (item is SlaveGroup) {
          item.Id = HiveServiceLocator.Instance.CallHiveService((s) => s.AddSlaveGroup((SlaveGroup)item));
        }
        if (item is Slave) {
          item.Id = HiveServiceLocator.Instance.CallHiveService((s) => s.AddSlave((Slave)item));
        }
        if (item is Downtime) {
          item.Id = HiveServiceLocator.Instance.CallHiveService((s) => s.AddDowntime((Downtime)item));
        }
        if (item is Project) {
          item.Id = HiveServiceLocator.Instance.CallHiveService(s => s.AddProject((Project)item));
        }
      } else {
        if (item is SlaveGroup) {
          HiveServiceLocator.Instance.CallHiveService((s) => s.UpdateSlaveGroup((SlaveGroup)item));
        }
        if (item is Slave) {
          HiveServiceLocator.Instance.CallHiveService((s) => s.UpdateSlave((Slave)item));
        }
        if (item is Downtime) {
          HiveServiceLocator.Instance.CallHiveService((s) => s.UpdateDowntime((Downtime)item));
        }
        if (item is Project) {
          HiveServiceLocator.Instance.CallHiveService((s) => s.UpdateProject((Project)item));
        }
      }
    }
    #endregion

    #region Delete
    public static void Delete(IHiveItem item) {
      if (item is SlaveGroup) {
        HiveServiceLocator.Instance.CallHiveService((s) => s.DeleteSlaveGroup(item.Id));
      } else if (item is Slave) {
        HiveServiceLocator.Instance.CallHiveService((s) => s.DeleteSlave(item.Id));
      } else if (item is Downtime) {
        HiveServiceLocator.Instance.CallHiveService((s) => s.DeleteDowntime(item.Id));
      } else if (item is Project) {
        HiveServiceLocator.Instance.CallHiveService((s) => s.DeleteProject(item.Id));
      }
    }
    #endregion

    public void ResetDowntime() {
      downtimeForResourceId = Guid.Empty;
      if (downtimes != null) {
        downtimes.Clear();
      }
    }

    #region Helper
    public bool CheckAccessToAdminAreaGranted() {
      if(projects != null) {
        return projects.Count > 0;
      } else {
        bool accessGranted = false;
        HiveServiceLocator.Instance.CallHiveService(s => {
          accessGranted = s.CheckAccessToAdminAreaGranted();
        });
        return accessGranted;
      }
    }

    public bool CheckOwnershipOfResource(Resource res, Guid userId) {
      if (res == null || userId == Guid.Empty) return false;

      if (res.OwnerUserId == userId) {
        return true;
      } else if(resourceAncestors.ContainsKey(res.Id)) {
        return resourceAncestors[res.Id].Where(x => x.OwnerUserId == userId).Any();
      }

      return false;
    }

    public bool CheckOwnershipOfProject(Project pro, Guid userId) {
      if (pro == null || userId == Guid.Empty) return false;

      if (pro.OwnerUserId == userId) {
        return true;
      } else if (projectAncestors.ContainsKey(pro.Id)) {
        return projectAncestors[pro.Id].Where(x => x.OwnerUserId == userId).Any();
      }

      return false;
    }

    public bool CheckOwnershipOfParentProject(Project pro, Guid userId) {
      if (pro == null || userId == Guid.Empty) return false;

      if(projectAncestors.ContainsKey(pro.Id)) {
        return projectAncestors[pro.Id].Where(x => x.OwnerUserId == userId).Any();
      }

      return false;
    }

    public bool CheckParentChange(Project child, Project parent) {
      bool changePossible = true;

      // change is not possible...
      // ... if the moved project is null
      // ... or the new parent is not stored yet
      // ... or there is not parental change
      if (child == null 
        || (parent != null && parent.Id == Guid.Empty)
        || (parent != null && parent.Id == child.ParentProjectId)) {
        changePossible = false;
      } else if(parent != null && projectDescendants.ContainsKey(child.Id)) {
        // ... if the new parent is among the moved project's descendants
        changePossible = !projectDescendants[child.Id].Where(x => x.Id == parent.Id).Any();
      }

      return changePossible;
    }

    public bool CheckParentChange(Resource child, Resource parent) {
      bool changePossible = true;

      // change is not possisble...
      // ... if the moved resource is null
      // ... or the new parent is not stored yet
      // ... or the new parent is a slave
      // ... or there is not parental change
      if (child == null 
        || (parent != null && parent.Id == Guid.Empty)
        || (parent != null && parent is Slave)
        || (parent != null && parent.Id == child.ParentResourceId)) {
        changePossible = false;
      } else if (parent != null && resourceDescendants.ContainsKey(child.Id)) {
        // ... or if the new parent is among the moved resource's descendants
        changePossible = !resourceDescendants[child.Id].Where(x => x.Id == parent.Id).Any();
      }

      return changePossible;
    }
    #endregion
  }
}