using System.Windows.Forms;
using HeuristicLab.Core.Views;
using HeuristicLab.MainForm;

using System.Collections.Generic;
using System.Linq;

namespace HeuristicLab.Problems.ProgramSynthesis.Views {
  [View("Push Expression Selection Editor")]
  [Content(typeof(IExpressionsConfiguration), true)]
  public partial class ExpressionSelectionView : ItemView {
    public ExpressionSelectionView() {
      InitializeComponent();

      InitEvents();
      Name = "Push Expression Selection Editor";
    }

    public new IExpressionsConfiguration Content {
      get { return (IExpressionsConfiguration)base.Content; }
      set {
        if (Content != null) Content.EnabledExpressionsChanged -= EnabledExpressionsChanged;
        base.Content = value;
      }
    }

    protected override void OnReadOnlyChanged() {
      base.OnReadOnlyChanged();

      expressionsTreeView.Enabled = !ReadOnly;
    }

    private void InitEvents() {
      expressionsTreeView.AfterCheck += ExpressionsTreeViewAfterCheck;
    }

    private void ExpressionsTreeViewAfterCheck(object sender, TreeViewEventArgs e) {
      if (e.Action == TreeViewAction.Unknown)
        return;

      Content.EnabledExpressionsChanged -= EnabledExpressionsChanged;
      var stackType = (StackTypes)e.Node.Tag;

      if (e.Node.Parent == null) {
        Content.SetStack(stackType, e.Node.Checked);
        SetStackNodeText(e.Node);
        foreach (var subNode in e.Node.Nodes.OfType<TreeNode>().Where(n => n.Checked != e.Node.Checked))
          subNode.Checked = e.Node.Checked;
      } else {
        Content.SetExpression(e.Node.Text, e.Node.Checked);
        SetStackNodeText(e.Node.Parent);

        // enable/disable stack if no or at least one expression is enabled
        if ((e.Node.Checked && !e.Node.Parent.Checked) ||
            (!e.Node.Checked && e.Node.Parent.Nodes.OfType<TreeNode>().All(n => !n.Checked))) {
          e.Node.Parent.Checked = e.Node.Checked;
        }
      }

      Content.EnabledExpressionsChanged += EnabledExpressionsChanged;
    }

    protected override void OnContentChanged() {
      expressionsTreeView.Nodes.Clear();

      if (Content == null) {
        return;
      }

      Content.EnabledExpressionsChanged += EnabledExpressionsChanged;
      UpdateNodes();
    }

    private void EnabledExpressionsChanged(object sender, EnabledExpressionsChangedEventArgs e) {
      if (InvokeRequired) Invoke(new MethodInvoker(UpdateNodes));
      else UpdateNodes();
    }

    private void UpdateNodes() {
      expressionsTreeView.Nodes.Clear();

      var treeNodes = GetTreeNodes(Content.EnabledExpressions)
        .OrderBy(x => x.Text)
        .ToArray();

      expressionsTreeView.Nodes.AddRange(treeNodes);
    }

    private IEnumerable<TreeNode> GetTreeNodes(IReadOnlyList<string> enabledExpressions) {
      foreach (var stackType in ExpressionTable.StackTypeToNamesTable.Keys) {
        if (stackType == StackTypes.None)
          continue;

        var stackTreeNode = new TreeNode {
          Tag = stackType
        };

        var stackExpressions = ExpressionTable.StackTypeToNamesTable[stackType];
        var enabledStackExpressions = enabledExpressions.Intersect(stackExpressions).ToList();

        SetStackNodeText(stackTreeNode);
        stackTreeNode.Checked = enabledStackExpressions.Any();

        var expressionNodes = stackExpressions
          .Where(name => {
            var type = ExpressionTable.NameToTypeTable[name];
            var attribute = ExpressionTable.TypeToAttributeTable[type];

            return !attribute.IsHidden;
          })
          .OrderBy(name => name)
          .Select(name => new TreeNode {
            Text = name,
            Tag = stackType,
            Checked = enabledStackExpressions.Contains(name),
          }).ToArray();

        foreach (var node in expressionNodes) {
          var type = ExpressionTable.NameToTypeTable[node.Text];
          var attribute = ExpressionTable.TypeToAttributeTable[type];

          node.ToolTipText = attribute.Description;
        }

        stackTreeNode.Nodes.AddRange(expressionNodes);

        yield return stackTreeNode;
      }
    }

    private void SetStackNodeText(TreeNode node) {
      var stackTypes = (StackTypes)node.Tag;
      var stackExpressions = ExpressionTable.StackTypeToNamesTable[stackTypes];
      var enabledStackExpressions = Content.EnabledExpressions.Intersect(stackExpressions).ToList();
      var stackNames = string.Join(", ", stackTypes.ToValues().Select(type => type.ToString()).OrderBy(x => x));

      node.Text = string.Format(
                "{0} ({1}/{2})",
                stackNames,
                enabledStackExpressions.Count,
                stackExpressions.Count);
    }
  }
}