package org.opt4j.addons;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.StringTokenizer;

import org.opt4j.benchmark.DoubleString;
import org.opt4j.benchmark.M;
import org.opt4j.core.Objective;
import org.opt4j.core.Objectives;
import org.opt4j.core.problem.Evaluator;
import org.opt4j.start.Constant;

import com.google.inject.Inject;

public class ExternalRuntimeEvaluator implements Evaluator<DoubleString> {

	protected final String command;
	protected final double upperBound;
	protected final double lowerBound;
	protected final List<Objective> objectives = new ArrayList<Objective>();

	@Inject
	public ExternalRuntimeEvaluator(
			@Constant(namespace = ExternalRuntimeEvaluator.class, value = "command") String command,
			@Constant(namespace = ExternalRuntimeEvaluator.class, value = "lowerBound") double lowerBound,
			@Constant(namespace = ExternalRuntimeEvaluator.class, value = "upperBound") double upperBound,
			@Constant(namespace = ExternalRuntimeEvaluator.class, value = "sign") Objective.Sign sign,
			@M int nObjectives) {
		this.command = command;
		this.lowerBound = lowerBound;
		this.upperBound = upperBound;
		for (int i = 0; i < nObjectives; i++) {
			objectives.add(new Objective("objective " + i, sign));
		}
	}

	@Override
	public Objectives evaluate(DoubleString doubleString) {
		String cmd = command.trim();
		for (double value : doubleString) {
			double v = lowerBound + value * (upperBound - lowerBound);
			cmd += " " + v;
		}

		try {
			Process process = Runtime.getRuntime().exec(cmd);
			process.waitFor();
			
			String instr = "";
			InputStream in = process.getInputStream();
			int c;
			while ((c = in.read()) != -1) {
				instr += ((char) c);
			}
			in.close();

			StringTokenizer tokenizer = new StringTokenizer(instr);

			Objectives objectives = new Objectives();

			for (Objective obj : this.objectives) {
				objectives.add(obj, Double.parseDouble(tokenizer.nextToken()));
			}

			return objectives;

		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	@Override
	public Collection<Objective> getObjectives() {
		return objectives;
	}

}