using System;
using HeuristicLab.Problems.GrammaticalOptimization;

namespace HeuristicLab.Algorithms.GrammaticalOptimization {
  public class RandomSearch : SolverBase {
    private readonly int maxLen;
    private readonly System.Random random;
    private readonly IProblem problem;

    public RandomSearch(IProblem problem, System.Random random, int maxLen) {
      this.maxLen = maxLen;
      this.random = random;
      this.problem = problem;
    }

    public override void Run(int maxIterations) {
      for (int i = 0; i < maxIterations; i++) {
        var sentence = CreateSentence(problem.Grammar).ToString();
        var quality = problem.Evaluate(sentence) / problem.BestKnownQuality(maxLen);
        OnSolutionEvaluated(sentence, quality);
      }
    }

    private Sequence CreateSentence(IGrammar grammar) {
      var sentence = new Sequence(grammar.SentenceSymbol);
      return grammar.CompleteSentenceRandomly(random, sentence, maxLen);
    }
  }
}