package envoy.client.data.commands;

import java.util.*;
import java.util.function.*;

/**
 * This class is the base class of all {@code SystemCommands} and contains an
 * action and a number of arguments that should be used as input for this
 * function.
 * No {@code SystemCommand} can return anything.
 * Every {@code SystemCommand} must have as argument type {@code List<String>} so
 * that the words following the indicator String can be used as input of the
 * function. This approach has one limitation:<br>
 * <b>Order matters!</b> Changing the order of arguments will likely result in
 * unexpected behavior.
 *
 * @author Leon Hofmeister
 * @since Envoy Client v0.2-beta
 */
public final class SystemCommand implements OnCall {

	protected int relevance;

	/**
	 * The argument count of the command.
	 */
	protected final int numberOfArguments;

	/**
	 * This function takes a {@code List<String>} as argument because automatically
	 * {@code SystemCommand#numberOfArguments} words following the necessary command
	 * will be put into this list.
	 *
	 * @see String#split(String)
	 */
	protected final Consumer<List<String>> action;

	protected final String description;

	protected final List<String> defaults;

	/**
	 * Constructs a new {@code SystemCommand}.
	 *
	 * @param action            the action performed by the command
	 * @param numberOfArguments the argument count accepted by the action
	 * @param defaults          the default values for the corresponding arguments
	 * @param description       the description of this {@code SystemCommand}
	 * @since Envoy Client v0.2-beta
	 */
	public SystemCommand(Consumer<List<String>> action, int numberOfArguments, List<String> defaults, String description) {
		this.numberOfArguments	= numberOfArguments;
		this.action				= action;
		this.defaults			= defaults == null ? new ArrayList<>() : defaults;
		this.description		= description;
	}

	/**
	 * @return the action that should be performed
	 * @since Envoy Client v0.2-beta
	 */
	public Consumer<List<String>> getAction() { return action; }

	/**
	 * @return the argument count of the command
	 * @since Envoy Client v0.2-beta
	 */
	public int getNumberOfArguments() { return numberOfArguments; }

	/**
	 * @return the description
	 * @since Envoy Client v0.2-beta
	 */
	public String getDescription() { return description; }

	/**
	 * @return the relevance
	 * @since Envoy Client v0.2-beta
	 */
	public int getRelevance() { return relevance; }

	/**
	 * @param relevance the relevance to set
	 * @since Envoy Client v0.2-beta
	 */
	public void setRelevance(int relevance) { this.relevance = relevance; }

	/**
	 * Increments the relevance of this {@code SystemCommand}.
	 */
	@Override
	public void onCall() { relevance++; }

	/**
	 * Increments the relevance of this {@code SystemCommand} and executes the
	 * supplier.
	 */
	@Override
	public void onCall(Supplier<Void> consumer) {
		onCall();
		consumer.get();
	}

	/**
	 * @return the defaults
	 * @since Envoy Client v0.2-beta
	 */
	public List<String> getDefaults() { return defaults; }

	@Override
	public int hashCode() { return Objects.hash(action); }

	@Override
	public boolean equals(Object obj) {
		if (this == obj) return true;
		if (obj == null) return false;
		if (getClass() != obj.getClass()) return false;
		final SystemCommand other = (SystemCommand) obj;
		return Objects.equals(action, other.action);
	}

	@Override
	public String toString() {
		return "SystemCommand [relevance=" + relevance + ", numberOfArguments=" + numberOfArguments + ", "
				+ (action != null ? "action=" + action + ", " : "") + (description != null ? "description=" + description + ", " : "")
				+ (defaults != null ? "defaults=" + defaults : "") + "]";
	}
}