#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.Drawing;
using System.Linq;
using System.Windows.Forms;
using HeuristicLab.Clients.Access;
using HeuristicLab.Common.Resources;
using HeuristicLab.Core.Views;
using HeuristicLab.MainForm;

namespace HeuristicLab.Clients.Hive.Administrator.Views {
  [View("ProjectView")]
  [Content(typeof(Project), IsDefaultView = false)]
  public partial class ProjectPermissionsView : ItemView {
    private const int userImageIndex = 0;
    private const int userGroupImageIndex = 1;

    private readonly HashSet<UserGroupBase> assignedPermissions = new HashSet<UserGroupBase>();
    private readonly HashSet<UserGroupBase> inheritedPermissions = new HashSet<UserGroupBase>();

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

    public ProjectPermissionsView() {
      InitializeComponent();

      treeView.ImageList.Images.Add(VSImageLibrary.User);
      treeView.ImageList.Images.Add(VSImageLibrary.UserAccounts);
    }

    #region Overrides
    protected override void OnContentChanged() {
      base.OnContentChanged();
      if (Content == null) {
        assignedPermissions.Clear();
        inheritedPermissions.Clear();
        treeView.Nodes.Clear();
        detailsViewHost.Content = null;
      } else {
        UpdateAssignedPermissions();
        UpdateInheritedPermissions();
        var top = BuildPermissionsList(AccessClient.Instance.UsersAndGroups);
        detailsViewHost.Content = top;
      }
    }
    #endregion

    #region Event Handlers
    private void ProjectPermissionsView_Load(object sender, EventArgs e) {

    }

    private void refreshButton_Click(object sender, EventArgs e) {
      UpdateAssignedPermissions();
      UpdateInheritedPermissions();
      var top = BuildPermissionsList(AccessClient.Instance.UsersAndGroups);
      detailsViewHost.Content = top;
    }

    private void inheritButton_Click(object sender, EventArgs e) {
      SetGrantedProjectPermissions(Content.Id, Enumerable.Empty<Guid>());
      UpdateAssignedPermissions();
      UpdateInheritedPermissions();
      var top = BuildPermissionsList(AccessClient.Instance.UsersAndGroups);
      detailsViewHost.Content = top;
    }

    private async void saveButton_Click(object sender, EventArgs e) {
      await SecurityExceptionUtil.TryAsyncAndReportSecurityExceptions(
        action: () => SetGrantedProjectPermissions(Content.Id, assignedPermissions.Select(x => x.Id)));
    }

    private void treeView_AfterSelect(object sender, TreeViewEventArgs e) {
      var selectedPermission = (UserGroupBase)e.Node.Tag;
      detailsViewHost.Content = selectedPermission;
    }

    private void treeView_BeforeCheck(object sender, TreeViewCancelEventArgs e) {
      var checkedPermission = (UserGroupBase)e.Node.Tag;
      if (e.Node.Parent == null || inheritedPermissions.Contains(checkedPermission) || checkedPermission.Id == Guid.Empty) e.Cancel = true;
    }

    private void treeView_AfterCheck(object sender, TreeViewEventArgs e) {
      var checkedPermission = (UserGroupBase)e.Node.Tag;
      if (e.Node.Checked)
        assignedPermissions.Add(checkedPermission);
      else
        assignedPermissions.Remove(checkedPermission);
    }
    #endregion

    #region Helpers
    private static IEnumerable<UserGroupBase> GetGrantedPermissionsForProject(Guid projectId) {
      var projectPermissions = HiveServiceLocator.Instance.CallHiveService(s => s.GetProjectPermissions(projectId));
      var userIds = new HashSet<Guid>(projectPermissions.Select(x => x.GrantedUserId));
      return AccessClient.Instance.UsersAndGroups.Where(x => userIds.Contains(x.Id));
    }

    private static void SetGrantedProjectPermissions(Guid projectId, IEnumerable<Guid> userIds) {
      HiveServiceLocator.Instance.CallHiveService(s => {
        var currentlyAssignedPermissions = s.GetProjectPermissions(projectId);
        s.RevokeProjectPermissions(projectId, currentlyAssignedPermissions.Select(x => x.GrantedUserId).ToList());
        s.GrantProjectPermissions(projectId, userIds.ToList());
      });
    }

    private void UpdateAssignedPermissions() {
      assignedPermissions.Clear();
      foreach (var r in GetGrantedPermissionsForProject(Content.Id))
        assignedPermissions.Add(r);
    }

    private void UpdateInheritedPermissions() {
      inheritedPermissions.Clear();
      var parentProject = HiveAdminClient.Instance.Projects.SingleOrDefault(x => x.Id == Content.ParentProjectId);
      while (parentProject != null) {
        foreach (var r in GetGrantedPermissionsForProject(parentProject.Id))
          inheritedPermissions.Add(r);
        parentProject = HiveAdminClient.Instance.Projects.SingleOrDefault(x => x.Id == parentProject.ParentProjectId);
      }
    }

    private UserGroupBase BuildPermissionsList(IEnumerable<UserGroupBase> usersAndGroups) {
      treeView.Nodes.Clear();
      if (!usersAndGroups.Any()) return null;

      treeView.BeforeCheck -= treeView_BeforeCheck;
      treeView.AfterCheck -= treeView_AfterCheck;

      var userGroups = new HashSet<UserGroup>(usersAndGroups.OfType<UserGroup>());
      var users = new HashSet<LightweightUser>(usersAndGroups.OfType<LightweightUser>());
      UserGroupBase first = null;

      var groupsNode = new TreeNode("Groups") { ForeColor = SystemColors.GrayText };
      groupsNode.ImageIndex = groupsNode.SelectedImageIndex = userGroupImageIndex;

      foreach (var group in userGroups.OrderBy(x => x.Name)) {
        var node = new TreeNode(group.Name) { Tag = group };
        node.ImageIndex = userGroupImageIndex;
        node.SelectedImageIndex = node.ImageIndex;

        if (inheritedPermissions.Contains(group)) {
          node.Checked = true;
          node.Text += " (Inherited)";
          node.ForeColor = SystemColors.GrayText;
        } else if (assignedPermissions.Contains(group))
          node.Checked = true;

        groupsNode.Nodes.Add(node);
        if (first == null) first = group;
      }

      var usersNode = new TreeNode("Users") { ForeColor = SystemColors.GrayText };
      usersNode.ImageIndex = usersNode.SelectedImageIndex = userImageIndex;

      foreach (var user in users.OrderBy(x => x.ToString())) {
        var node = new TreeNode(user.ToString()) { Tag = user };
        node.ImageIndex = userImageIndex;
        node.SelectedImageIndex = node.ImageIndex;

        if (inheritedPermissions.Contains(user)) {
          node.Checked = true;
          node.Text += " (Inherited)";
          node.ForeColor = SystemColors.GrayText;
        } else if (assignedPermissions.Contains(user))
          node.Checked = true;

        usersNode.Nodes.Add(node);
        if (first == null) first = user;
      }

      treeView.Nodes.Add(groupsNode);
      treeView.Nodes.Add(usersNode);
      treeView.BeforeCheck += treeView_BeforeCheck;
      treeView.AfterCheck += treeView_AfterCheck;
      treeView.ExpandAll();

      return first;
    }
    #endregion
  }
}