#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2017 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.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using HeuristicLab.Clients.Access;
using HeuristicLab.Clients.Hive.Views;
using HeuristicLab.Collections;
using HeuristicLab.Common.Resources;
using HeuristicLab.Core;
using HeuristicLab.Core.Views;
using HeuristicLab.MainForm;

namespace HeuristicLab.Clients.Hive.Administrator.Views {
  [View("Projects View")]
  [Content(typeof(IItemList<Project>), false)]
  public partial class ProjectsView : ItemView, IDisposable {
    private const int greenFlagImageIndex = 0;
    private const int redFlagImageIndex = 1;

    private readonly object locker = new object();

    public new IItemList<Project> Content {
      get { return (IItemList<Project>)base.Content; }
      set { base.Content = value; }
    }

    public ProjectsView() {
      InitializeComponent();

      projectsTreeView.ImageList.Images.Add(VSImageLibrary.FlagGreen);
      projectsTreeView.ImageList.Images.Add(VSImageLibrary.FlagRed);

      HiveAdminClient.Instance.Refreshing += HiveAdminClient_Instance_Refreshing;
      HiveAdminClient.Instance.Refreshed += HiveAdminClient_Instance_Refreshed;
      AccessClient.Instance.Refreshing += AccessClient_Instance_Refreshing;
      AccessClient.Instance.Refreshed += AccessClient_Instance_Refreshed;
    }

    #region Overrides
    protected override void OnClosing(FormClosingEventArgs e) {
      AccessClient.Instance.Refreshed -= AccessClient_Instance_Refreshed;
      AccessClient.Instance.Refreshing -= AccessClient_Instance_Refreshing;
      HiveAdminClient.Instance.Refreshed -= HiveAdminClient_Instance_Refreshed;
      HiveAdminClient.Instance.Refreshing -= HiveAdminClient_Instance_Refreshing;
      base.OnClosing(e);
    }

    protected override void RegisterContentEvents() {
      base.RegisterContentEvents();
      Content.ItemsAdded += Content_ItemsAdded;
      Content.ItemsRemoved += Content_ItemsRemoved;
    }

    protected override void DeregisterContentEvents() {
      Content.ItemsRemoved -= Content_ItemsRemoved;
      Content.ItemsAdded -= Content_ItemsAdded;
      base.DeregisterContentEvents();
    }

    protected override void OnContentChanged() {
      base.OnContentChanged();
      if (Content == null) {
        projectsTreeView.Nodes.Clear();
        projectView.Content = null;
        projectPermissionsView.Content = null;
        projectResourcesView.Content = null;
      } else {
        var top = BuildProjectTree(Content);
        projectView.Content = top;
        projectPermissionsView.Content = top;
        projectResourcesView.Content = top;
      }
    }

    protected override void SetEnabledStateOfControls() {
      base.SetEnabledStateOfControls();
      bool enabled = Content != null && !ReadOnly;
      refreshButton.Enabled = enabled;
      addButton.Enabled = enabled;
      removeButton.Enabled = enabled;
      saveProjectButton.Enabled = enabled;
      projectView.Enabled = enabled;
      projectPermissionsView.Enabled = enabled;
      projectResourcesView.Enabled = enabled;
    }
    #endregion

    #region Event Handlers
    private void Content_ItemsAdded(object sender, CollectionItemsChangedEventArgs<IndexedItem<Project>> e) {
      if (InvokeRequired) Invoke((Action<object, CollectionItemsChangedEventArgs<IndexedItem<Project>>>)Content_ItemsAdded, sender, e);
      else {
        OnContentChanged();
      }
    }

    private void Content_ItemsRemoved(object sender, CollectionItemsChangedEventArgs<IndexedItem<Project>> e) {
      if (InvokeRequired) Invoke((Action<object, CollectionItemsChangedEventArgs<IndexedItem<Project>>>)Content_ItemsRemoved, sender, e);
      else {
        OnContentChanged();
      }
    }

    private void ProjectViewContent_PropertyChanged(object sender, PropertyChangedEventArgs e) {
      if (InvokeRequired) Invoke((Action<object, PropertyChangedEventArgs>)ProjectViewContent_PropertyChanged, sender, e);
      else {
        OnContentChanged();
      }
    }

    private void HiveAdminClient_Instance_Refreshing(object sender, EventArgs e) {
      if (InvokeRequired) Invoke((Action<object, EventArgs>)HiveAdminClient_Instance_Refreshing, sender, e);
      else {
        var mainForm = MainFormManager.GetMainForm<MainForm.WindowsForms.MainForm>();
        mainForm.AddOperationProgressToView(this, "Refreshing ...");
        SetEnabledStateOfControls();
      }
    }

    private void HiveAdminClient_Instance_Refreshed(object sender, EventArgs e) {
      if (InvokeRequired) Invoke((Action<object, EventArgs>)HiveAdminClient_Instance_Refreshed, sender, e);
      else {
        var mainForm = MainFormManager.GetMainForm<MainForm.WindowsForms.MainForm>();
        mainForm.RemoveOperationProgressFromView(this);
        SetEnabledStateOfControls();
      }
    }

    private void AccessClient_Instance_Refreshing(object sender, EventArgs e) {
      if (InvokeRequired) Invoke((Action<object, EventArgs>)AccessClient_Instance_Refreshing, sender, e);
      else {
        var mainForm = MainFormManager.GetMainForm<MainForm.WindowsForms.MainForm>();
        mainForm.AddOperationProgressToView(this, "Refreshing ...");
        SetEnabledStateOfControls();
      }
    }

    private void AccessClient_Instance_Refreshed(object sender, EventArgs e) {
      if (InvokeRequired) Invoke((Action<object, EventArgs>)AccessClient_Instance_Refreshed, sender, e);
      else {
        var mainForm = MainFormManager.GetMainForm<MainForm.WindowsForms.MainForm>();
        mainForm.RemoveOperationProgressFromView(this);
        SetEnabledStateOfControls();
      }
    }

    private async void ProjectsView_Load(object sender, EventArgs e) {
      await SecurityExceptionUtil.TryAsyncAndReportSecurityExceptions(
        action: () => UpdateProjects(),
        finallyCallback: () => Content = HiveAdminClient.Instance.Projects);
    }

    private async void refreshButton_Click(object sender, EventArgs e) {
      lock (locker) {
        if (!refreshButton.Enabled) return;
        refreshButton.Enabled = false;
      }

      await SecurityExceptionUtil.TryAsyncAndReportSecurityExceptions(
        action: () => UpdateProjects(),
        finallyCallback: () => {
          Content = HiveAdminClient.Instance.Projects;
          refreshButton.Enabled = true;
        });
    }

    private void addButton_Click(object sender, EventArgs e) {
      var project = new Project {
        Name = "New Project",
        OwnerUserId = UserInformation.Instance.User.Id
      };
      Content.Add(project);
    }

    private async void removeButton_Click(object sender, EventArgs e) {
      lock (locker) {
        if (!removeButton.Enabled) return;
        removeButton.Enabled = false;
      }

      var selectedNode = projectsTreeView.SelectedNode;
      if (selectedNode == null || selectedNode.Tag == null) return;

      var project = (Project)selectedNode.Tag;
      var result = MessageBox.Show(
        "Do you really want to delete " + project.Name + "?",
        "HeuristicLab Hive Administrator",
        MessageBoxButtons.YesNo,
        MessageBoxIcon.Question);

      if (result == DialogResult.Yes) {
        if (Content.Any(x => x.ParentProjectId == project.Id)) {
          MessageBox.Show(
            "Only empty projects can be deleted.",
            "HeuristicLab Hive Administrator",
            MessageBoxButtons.OK,
            MessageBoxIcon.Error);
        } else {
          await SecurityExceptionUtil.TryAsyncAndReportSecurityExceptions(
            action: () => RemoveProject(project),
            finallyCallback: () => {
              Content.Remove(project);
              removeButton.Enabled = true;
            });
        }
      }
    }

    private async void saveProjectButton_Click(object sender, EventArgs e) {
      lock (locker) {
        if (!saveProjectButton.Enabled) return;
        saveProjectButton.Enabled = false;
      }

      await SecurityExceptionUtil.TryAsyncAndReportSecurityExceptions(
        action: () => {
          var projectsToSave = Content.Where(x => x.Id == Guid.Empty || x.Modified);
          foreach (var project in projectsToSave)
            project.Store();
        },
        finallyCallback: () => saveProjectButton.Enabled = true);
    }

    private void projectsTreeView_AfterSelect(object sender, TreeViewEventArgs e) {
      var selectedProject = (Project)e.Node.Tag;

      if (projectView.Content != null)
        projectView.Content.PropertyChanged -= ProjectViewContent_PropertyChanged;

      projectView.Content = selectedProject;
      projectPermissionsView.Content = selectedProject;
      projectResourcesView.Content = selectedProject;

      if (selectedProject != null)
        selectedProject.PropertyChanged += ProjectViewContent_PropertyChanged;

      if (IsAuthorized(selectedProject)) {
        if (!tabControl.TabPages.Contains(permissionsTabPage))
          tabControl.TabPages.Add(permissionsTabPage);
        if (!tabControl.TabPages.Contains(resourcesTabPage))
          tabControl.TabPages.Add(resourcesTabPage);
      } else {
        if (tabControl.TabPages.Contains(permissionsTabPage))
          tabControl.TabPages.Remove(permissionsTabPage);
        if (tabControl.TabPages.Contains(resourcesTabPage))
          tabControl.TabPages.Remove(resourcesTabPage);
      }
    }

    private void projectsTreeView_DragDrop(object sender, DragEventArgs e) {
      var sourceNode = (TreeNode)e.Data.GetData(typeof(TreeNode));
      if (sourceNode == null) return;

      var treeView = (TreeView)sender;
      if (sourceNode.TreeView != treeView) return;

      var targetPoint = treeView.PointToClient(new Point(e.X, e.Y));
      var targetNode = treeView.GetNodeAt(targetPoint);

      if (sourceNode == targetNode) return;

      if (sourceNode.Parent == null)
        treeView.Nodes.Remove(sourceNode);
      else {
        sourceNode.Parent.Nodes.Remove(sourceNode);
        ((Project)sourceNode.Tag).ParentProjectId = null;
      }

      if (targetNode == null) {
        treeView.Nodes.Add(sourceNode);
      } else {
        targetNode.Nodes.Add(sourceNode);
        ((Project)sourceNode.Tag).ParentProjectId = ((Project)targetNode.Tag).Id;
      }
    }

    private void projectsTreeView_ItemDrag(object sender, ItemDragEventArgs e) {
      var sourceNode = (TreeNode)e.Item;
      if (IsAuthorized((Project)sourceNode.Tag))
        DoDragDrop(sourceNode, DragDropEffects.All);
    }

    private void projectsTreeView_DragEnter(object sender, DragEventArgs e) {
      e.Effect = DragDropEffects.Move;
    }

    private void projectsTreeView_DragOver(object sender, DragEventArgs e) {
      e.Effect = DragDropEffects.Move;
    }

    private void projectsTreeView_QueryContinueDrag(object sender, QueryContinueDragEventArgs e) {
      e.Action = DragAction.Continue;
    }
    #endregion

    #region Helpers
    private Project BuildProjectTree(IEnumerable<Project> projects) {
      projectsTreeView.Nodes.Clear();
      if (!projects.Any()) return null;

      var mainProjects = new HashSet<Project>(projects.Where(x => x.ParentProjectId == null));
      var subProbjects = new HashSet<Project>(projects.Except(mainProjects));

      var stack = new Stack<Project>(mainProjects.OrderByDescending(x => x.Name));
      var top = stack.Peek();

      TreeNode currentNode = null;
      Project currentProject = null;

      while (stack.Any()) {
        var newProject = stack.Pop();
        var newNode = new TreeNode(newProject.Name) { Tag = newProject };

        while (currentNode != null && newProject.ParentProjectId != currentProject.Id) {
          currentNode = currentNode.Parent;
          currentProject = currentNode == null ? null : (Project)currentNode.Tag;
        }

        if (currentNode == null) {
          projectsTreeView.Nodes.Add(newNode);
          newNode.ImageIndex = greenFlagImageIndex;
        } else {
          currentNode.Nodes.Add(newNode);
          newNode.ImageIndex = redFlagImageIndex;
        }

        newNode.SelectedImageIndex = newNode.ImageIndex;

        var childProjects = subProbjects.Where(x => x.ParentProjectId == newProject.Id);
        if (childProjects.Any()) {
          foreach (var project in childProjects.OrderByDescending(x => x.Name)) {
            subProbjects.Remove(project);
            stack.Push(project);
          }
          currentNode = newNode;
          currentProject = newProject;
        }
      }

      projectsTreeView.ExpandAll();

      return top;
    }

    private void UpdateProjects() {
      try {
        HiveAdminClient.Instance.Refresh();
      } catch (AnonymousUserException) {
        ShowHiveInformationDialog();
      }
    }

    private void RemoveProject(Project project) {
      try {
        HiveAdminClient.Delete(project);
      } catch (AnonymousUserException) {
        ShowHiveInformationDialog();
      }
    }

    private bool IsAuthorized(Project project) {
      return project != null
          && UserInformation.Instance.UserExists
          && (project.OwnerUserId == UserInformation.Instance.User.Id || HiveRoles.CheckAdminUserPermissions());
    }

    private void ShowHiveInformationDialog() {
      if (InvokeRequired) Invoke((Action)ShowHiveInformationDialog);
      else {
        using (HiveInformationDialog dialog = new HiveInformationDialog()) {
          dialog.ShowDialog(this);
        }
      }
    }
    #endregion
  }
}