#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 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.Linq;
using HeuristicLab.Algorithms.GeneticAlgorithm;
using HeuristicLab.Data;
using HeuristicLab.Operators;
using HeuristicLab.Optimization;
using HeuristicLab.Optimization.Operators;
using HeuristicLab.Parameters;
using HeuristicLab.Selection;

namespace HeuristicLab.Algorithms.ALPS {
  public static class AlpsGeneticAlgorithmMainOperator {
    public static GeneticAlgorithmMainLoop Create() {
      var mainLoop = new GeneticAlgorithmMainLoop();

      var selector = mainLoop.OperatorGraph.Iterate().OfType<Placeholder>().First(o => o.OperatorParameter.ActualName == "Selector");
      var crossover = mainLoop.OperatorGraph.Iterate().OfType<Placeholder>().First(o => o.OperatorParameter.ActualName == "Crossover");
      var subScopesCounter = mainLoop.OperatorGraph.Iterate().OfType<SubScopesCounter>().First();
      var elitesMerger = mainLoop.OperatorGraph.Iterate().OfType<MergingReducer>().First();

      // Operator starts with calculating number of selected scopes base on plus/comma-selection replacement scheme
      var numberOfSubScopesBranch = new ConditionalBranch() { Name = "PlusSelection?" };
      var numberOfSelectedSubScopesPlusCalculator = new ExpressionCalculator() { Name = "NumberOfSelectedSubScopes = PopulationSize * 2" };
      var numberOfSelectedSubScopesCalculator = new ExpressionCalculator() { Name = "NumberOfSelectedSubScopes = (PopulationSize - Elites) * 2" };
      var replacementBranch = new ConditionalBranch() { Name = "PlusSelection?" };

      // Set new initial operator
      mainLoop.OperatorGraph.InitialOperator = numberOfSubScopesBranch;

      numberOfSubScopesBranch.ConditionParameter.ActualName = "PlusSelection";
      numberOfSubScopesBranch.TrueBranch = numberOfSelectedSubScopesPlusCalculator;
      numberOfSubScopesBranch.FalseBranch = numberOfSelectedSubScopesCalculator;
      numberOfSubScopesBranch.Successor = selector;

      numberOfSelectedSubScopesPlusCalculator.CollectedValues.Add(new LookupParameter<IntValue>("PopulationSize"));
      numberOfSelectedSubScopesPlusCalculator.ExpressionResultParameter.ActualName = "NumberOfSelectedSubScopes";
      numberOfSelectedSubScopesPlusCalculator.ExpressionParameter.Value = new StringValue("PopulationSize 2 * toint");

      numberOfSelectedSubScopesCalculator.CollectedValues.Add(new LookupParameter<IntValue>("PopulationSize"));
      numberOfSelectedSubScopesCalculator.CollectedValues.Add(new LookupParameter<IntValue>("Elites"));
      numberOfSelectedSubScopesCalculator.ExpressionResultParameter.ActualName = "NumberOfSelectedSubScopes";
      numberOfSelectedSubScopesCalculator.ExpressionParameter.Value = new StringValue("PopulationSize Elites - 2 * toint");

      // Use Elitism or Plus-Selection as replacement strategy
      var selectedProcessor = (SubScopesProcessor)selector.Successor;
      var elitismReplacement = selectedProcessor.Successor;
      selectedProcessor.Successor = replacementBranch;
      replacementBranch.ConditionParameter.ActualName = "PlusSelection";
      replacementBranch.FalseBranch = elitismReplacement;

      // Plus selection replacement
      var replacementMergingReducer = new MergingReducer();
      var replacementBestSelector = new BestSelector();
      var replacementRightReducer = new RightReducer();
      replacementBranch.TrueBranch = replacementMergingReducer;

      replacementMergingReducer.Successor = replacementBestSelector;

      replacementBestSelector.NumberOfSelectedSubScopesParameter.ActualName = "PopulationSize";
      replacementBestSelector.CopySelected = new BoolValue(false);
      replacementBestSelector.Successor = replacementRightReducer;

      replacementRightReducer.Successor = null;

      // Increment ages of all individuals after replacement
      var incrementAgeProcessor = new UniformSubScopesProcessor();
      var ageIncrementor = new DoubleCounter() { Name = "Increment Age" };
      replacementBranch.Successor = incrementAgeProcessor;
      incrementAgeProcessor.Operator = ageIncrementor;
      incrementAgeProcessor.Successor = null;
      ageIncrementor.ValueParameter.ActualName = "Age";
      ageIncrementor.Increment = new DoubleValue(1.0);

      // Insert AgeCalculator between crossover and its successor
      var crossoverSuccessor = crossover.Successor;
      var ageCalculator = new WeightingReducer() { Name = "Calculate Age" };
      crossover.Successor = ageCalculator;

      ageCalculator.ParameterToReduce.ActualName = "Age";
      ageCalculator.TargetParameter.ActualName = "Age";
      ageCalculator.WeightParameter.ActualName = "AgeInheritance";
      ageCalculator.Successor = crossoverSuccessor;

      // When counting the evaluated solutions, write in LayerEvaluatedSolutions
      subScopesCounter.ValueParameter.ActualName = "LayerEvaluatedSolutions";
      subScopesCounter.AccumulateParameter.Value = new BoolValue(false);

      // Instead of generational loop after merging of elites, stop
      elitesMerger.Successor = null;

      // Parameterize
      foreach (var stochasticOperator in mainLoop.OperatorGraph.Iterate().OfType<IStochasticOperator>())
        stochasticOperator.RandomParameter.ActualName = "LocalRandom";
      foreach (var stochasticBranch in mainLoop.OperatorGraph.Iterate().OfType<StochasticBranch>())
        stochasticBranch.RandomParameter.ActualName = "LocalRandom";

      // Remove unused operators
      var usedOperators = mainLoop.OperatorGraph.Iterate();
      var unusedOperators = mainLoop.OperatorGraph.Operators.Except(usedOperators);
      foreach (var op in unusedOperators.ToList())
        mainLoop.OperatorGraph.Operators.Remove(op);

      return mainLoop;
    }
  }
}