#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2018 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.ComponentModel;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using HeuristicLab.Data;
using HeuristicLab.Encodings.SymbolicExpressionTreeEncoding;

namespace HeuristicLab.Problems.DataAnalysis.Symbolic.Views {
  public partial class VariableNodeEditDialog : Form {
    private VariableTreeNode variableTreeNode;
    public VariableTreeNode NewNode {
      get { return variableTreeNode; }
      set {
        if (InvokeRequired) {
          Invoke(new Action<SymbolicExpressionTreeNode>(x =>
          {
            variableTreeNode = (VariableTreeNode) x;
            variableNameTextBox.Text = variableTreeNode.VariableName;
          }), value);
        } else {
          variableTreeNode = value;
          variableNameTextBox.Text = variableTreeNode.VariableName;
        }
      }
    }

    public string SelectedVariableName {
      get { return variableNamesCombo.Visible ? variableNamesCombo.Text : variableNameTextBox.Text; }
    }

    public VariableNodeEditDialog(ISymbolicExpressionTreeNode node) {
      InitializeComponent();
      oldValueTextBox.TabStop = false; // cannot receive focus using tab key
      NewNode = (VariableTreeNode)node; // will throw an invalid cast exception if node is not of the correct type
      InitializeFields();
    }

    private void InitializeFields() {
      if (NewNode == null)
        throw new ArgumentException("Node is not a constant.");
      else {
        this.Text = "Edit variable";
        newValueTextBox.Text = oldValueTextBox.Text = Math.Round(variableTreeNode.Weight, 4).ToString();
        // add a dropbox containing all the available variable names
        variableNameLabel.Visible = true;
        variableNamesCombo.Visible = true;
        if (variableTreeNode.Symbol.VariableNames.Any()) {
          foreach (var name in variableTreeNode.Symbol.VariableNames)
            variableNamesCombo.Items.Add(name);
          variableNamesCombo.SelectedIndex = variableNamesCombo.Items.IndexOf(variableTreeNode.VariableName);
          variableNamesCombo.Visible = true;
          variableNameTextBox.Visible = false;
        } else {
          variableNamesCombo.Visible = false;
          variableNameTextBox.Visible = true;
        }
      }
    }

    #region text box validation and events
    private void newValueTextBox_Validating(object sender, CancelEventArgs e) {
      string errorMessage;
      if (!ValidateNewValue(newValueTextBox.Text, out errorMessage)) {
        e.Cancel = true;
        errorProvider.SetError(newValueTextBox, errorMessage);
        newValueTextBox.SelectAll();
      }
    }

    private void newValueTextBox_Validated(object sender, EventArgs e) {
      errorProvider.SetError(newValueTextBox, string.Empty);
    }

    private static bool ValidateNewValue(string value, out string errorMessage) {
      double val;
      bool valid = double.TryParse(value, out val);
      errorMessage = string.Empty;
      if (!valid) {
        var sb = new StringBuilder();
        sb.Append("Invalid Value (Valid Value Format: \"");
        sb.Append(FormatPatterns.GetDoubleFormatPattern());
        sb.Append("\")");
        errorMessage = sb.ToString();
      }
      return valid;
    }
    #endregion

    #region combo box validation and events
    private void variableNamesCombo_Validating(object sender, CancelEventArgs e) {
      if (variableNamesCombo.Items.Count == 0) return;
      if (variableNamesCombo.Items.Contains(variableNamesCombo.SelectedItem)) return;
      e.Cancel = true;
      errorProvider.SetError(variableNamesCombo, "Invalid variable name");
      variableNamesCombo.SelectAll();
    }

    private void variableNamesCombo_Validated(object sender, EventArgs e) {
      errorProvider.SetError(variableNamesCombo, String.Empty);
    }
    #endregion
    // proxy handler passing key strokes to the parent control
    private void childControl_KeyDown(object sender, KeyEventArgs e) {
      ValueChangeDialog_KeyDown(sender, e);
    }

    private void ValueChangeDialog_KeyDown(object sender, KeyEventArgs e) {
      if ((e.KeyCode == Keys.Enter) || (e.KeyCode == Keys.Return)) {
        if (!ValidateChildren()) return;
        OnDialogValidated(this, e); // emit validated effect
        Close();
      }
    }

    public event EventHandler DialogValidated;
    private void OnDialogValidated(object sender, EventArgs e) {
      double weight = double.Parse(newValueTextBox.Text);
      // we impose an extra validation condition: that the weight/value be different than the original ones
      var variableName = SelectedVariableName;
      if (variableTreeNode.Weight.Equals(weight) && variableTreeNode.VariableName.Equals(variableName)) return;
      variableTreeNode.Weight = weight;
      variableTreeNode.VariableName = variableName;
      DialogResult = DialogResult.OK;
      var dialogValidated = DialogValidated;
      if (dialogValidated != null)
        dialogValidated(sender, e);
    }

    private void cancelButton_Click(object sender, EventArgs e) {
      Close();
    }

    private void okButton_Click(object sender, EventArgs e) {
      if (ValidateChildren()) {
        OnDialogValidated(this, e);
        Close();
      }
    }
  }
}