package geniusweb.progress;

import java.util.Date;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonTypeName;

/**
 * progress in terms of number of rounds. The round has to be updated by the
 * user of this class, calling {@link #advance()}. immutable.
 */
@JsonTypeName("rounds")
public class ProgressRounds implements Progress {

	private final Integer duration;
	private final Integer currentRound;
	private final Date endtime;

	/**
	 * 
	 * @param deadline     length max number of rounds, must be positive (not 0)
	 * @param currentRound the current round number (can be from 0 to deadlne).
	 *                     When = deadline, it means the progress has gone past
	 *                     the deadline.
	 * @param end          the termination time of this session.
	 */
	@JsonCreator
	public ProgressRounds(@JsonProperty("duration") Integer deadline,
			@JsonProperty("currentRound") Integer currentRound,
			@JsonProperty("endtime") Date end) {
		if (deadline <= 0)
			throw new IllegalArgumentException(
					"deadline must be positive but is " + deadline);
		if (currentRound < 0 || currentRound > deadline) {
			throw new IllegalArgumentException(
					"current round must be inside [0," + deadline + "]");
		}
		this.duration = deadline;
		this.currentRound = currentRound;
		this.endtime = end;
	}

	@Override
	public Date getTerminationTime() {
		return endtime;
	}

	/**
	 * 
	 * @return the current round. First round is 0. It is recommended that you
	 *         use the functions in {@link Progress} instead of this, to ensure
	 *         your code works with all implementations of Progress including
	 *         future developments.
	 */
	public Integer getCurrentRound() {
		return currentRound;
	}

	/**
	 * 
	 * @return total number of rounds. It is recommended that you use the
	 *         functions in {@link Progress} instead of this, to ensure your
	 *         code works with all implementations of Progress including future
	 *         developments.
	 */
	public Integer getTotalRounds() {
		return duration;
	}

	@Override
	public Double get(Long currentTimeMs) {
		// deadline and current both are limited to MAXINT is 32 bits; double
		// fits 52
		// bits so this should not result in accuracy issues
		double ratio = (double) currentRound / (double) duration;
		if (ratio > 1d)
			ratio = 1d;
		else if (ratio < 0d)
			ratio = 0d;
		return ratio;
	}

	@Override
	public boolean isPastDeadline(Long currentTimeMs) {
		return currentRound >= duration || currentTimeMs > endtime.getTime();
	}

	/**
	 * 
	 * @return new ProgressRounds with round 1 advanced (or this, if
	 *         currentRound= duration). This is up to the user, as it is up to
	 *         the used protocol what exactly is a round.
	 */
	public ProgressRounds advance() {
		if (duration == currentRound)
			return this;
		return new ProgressRounds(duration, currentRound + 1, endtime);
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result
				+ ((currentRound == null) ? 0 : currentRound.hashCode());
		result = prime * result
				+ ((duration == null) ? 0 : duration.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		ProgressRounds other = (ProgressRounds) obj;
		if (currentRound == null) {
			if (other.currentRound != null)
				return false;
		} else if (!currentRound.equals(other.currentRound))
			return false;
		if (duration == null) {
			if (other.duration != null)
				return false;
		} else if (!duration.equals(other.duration))
			return false;
		return true;
	}

	@Override
	public String toString() {
		return "ProgressRounds[" + currentRound + " of " + duration + "]";
	}

}