/**
 * Copyright (c) 2008, http://www.snakeyaml.org
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.yaml.snakeyaml.events;

import org.yaml.snakeyaml.error.Mark;

/**
 * Basic unit of output from a {@link org.yaml.snakeyaml.parser.Parser} or input
 * of a {@link org.yaml.snakeyaml.emitter.Emitter}.
 */
public abstract class Event {
    public enum ID {
        Alias, 
        Comment,
        DocumentEnd, 
        DocumentStart, 
        MappingEnd, 
        MappingStart, 
        Scalar, 
        SequenceEnd, 
        SequenceStart, 
        StreamEnd, 
        StreamStart
    }

    private final Mark startMark;
    private final Mark endMark;

    public Event(Mark startMark, Mark endMark) {
        this.startMark = startMark;
        this.endMark = endMark;
    }

    public String toString() {
        return "<" + this.getClass().getName() + "(" + getArguments() + ")>";
    }

    public Mark getStartMark() {
        return startMark;
    }

    public Mark getEndMark() {
        return endMark;
    }

    /**
     * Generate human readable representation of the Event
     * @see "__repr__ for Event in PyYAML"
     * @return representation fore humans
     */
    protected String getArguments() {
        return "";
    }

    /**
     * Check if the Event is of the provided kind
     * @param id - the Event.ID enum
     * @return true then this Event of the provided type
     */
    public boolean is(Event.ID id) {
        return getEventId() == id;
    }

    /**
     * Get the type (kind) if this Event
     * @return the ID of this Event
     */
    public abstract Event.ID getEventId();

    /*
     * for tests only
     */
    @Override
    public boolean equals(Object obj) {
        if (obj instanceof Event) {
            return toString().equals(obj.toString());
        } else {
            return false;
        }
    }

    /*
     * for tests only
     */
    @Override
    public int hashCode() {
        return toString().hashCode();
    }
}
