#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 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 HeuristicLab.Common;
using HeuristicLab.Core;

namespace HeuristicLab.Parameters {
  /// <summary>
  /// A generic parameter representing instances of type T which are collected from the sub-scopes of the current scope.
  /// </summary>
  [Item("SubScopesLookupParameter<T>", "A generic parameter representing instances of type T which are collected from or written to the sub-scopes of the current scope.")]
  public class SubScopesLookupParameter<T> : LookupParameter<ItemArray<T>> where T : class, IItem {
    public SubScopesLookupParameter() : base() { }
    public SubScopesLookupParameter(string name) : base(name) { }
    public SubScopesLookupParameter(string name, string description) : base(name, description) { }

    protected override IItem GetActualValue() {
      string name = LookupParameter<ItemArray<T>>.TranslateName(Name, ExecutionContext);
      IScope scope = ExecutionContext.Scope;
      ItemArray<T> values = new ItemArray<T>(scope.SubScopes.Count);
      IVariable var;
      T value;

      for (int i = 0; i < values.Length; i++) {
        scope.SubScopes[i].Variables.TryGetValue(name, out var);
        if (var != null) {
          value = var.Value as T;
          if ((var.Value != null) && (value == null))
            throw new InvalidOperationException(
              string.Format("Type mismatch. Variable \"{0}\" does not contain a \"{1}\".",
                            name,
                            typeof(T).GetPrettyName())
            );
          values[i] = value;
        }
      }
      return values;
    }
    protected override void SetActualValue(IItem value) {
      ItemArray<T> values = value as ItemArray<T>;
      if (values == null)
        throw new InvalidOperationException(
          string.Format("Type mismatch. Value is not a \"{0}\".",
                        typeof(ItemArray<T>).GetPrettyName())
        );

      string name = LookupParameter<ItemArray<T>>.TranslateName(Name, ExecutionContext);
      IScope scope = ExecutionContext.Scope;
      IVariable var;

      for (int i = 0; i < values.Length; i++) {
        scope.SubScopes[i].Variables.TryGetValue(name, out var);
        if (var != null) var.Value = values[i];
        else scope.SubScopes[i].Variables.Add(new Variable(name, values[i]));
      }
    }
  }
}