//  This file is part of YamlDotNet - A .NET library for YAML.
//  Copyright (c) Antoine Aubry and contributors

//  Permission is hereby granted, free of charge, to any person obtaining a copy of
//  this software and associated documentation files (the "Software"), to deal in
//  the Software without restriction, including without limitation the rights to
//  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
//  of the Software, and to permit persons to whom the Software is furnished to do
//  so, subject to the following conditions:

//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.

//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.

namespace YamlDotNet.Core.Events
{
    /// <summary>
    /// Base class for parsing events.
    /// </summary>
    public abstract class ParsingEvent
    {
        /// <summary>
        /// Gets a value indicating the variation of depth caused by this event.
        /// The value can be either -1, 0 or 1. For start events, it will be 1,
        /// for end events, it will be -1, and for the remaining events, it will be 0.
        /// </summary>
        public virtual int NestingIncrease
        {
            get { return 0; }
        }

        /// <summary>
        /// Gets the event type, which allows for simpler type comparisons.
        /// </summary>
        internal abstract EventType Type
        {
            get;
        }

        private readonly Mark start;

        /// <summary>
        /// Gets the position in the input stream where the event starts.
        /// </summary>
        public Mark Start
        {
            get
            {
                return start;
            }
        }

        private readonly Mark end;

        /// <summary>
        /// Gets the position in the input stream where the event ends.
        /// </summary>
        public Mark End
        {
            get
            {
                return end;
            }
        }

        /// <summary>
        /// Accepts the specified visitor.
        /// </summary>
        /// <param name="visitor">Visitor to accept, may not be null</param>
        public abstract void Accept(IParsingEventVisitor visitor);

        /// <summary>
        /// Initializes a new instance of the <see cref="ParsingEvent"/> class.
        /// </summary>
        /// <param name="start">The start position of the event.</param>
        /// <param name="end">The end position of the event.</param>
        internal ParsingEvent(Mark start, Mark end)
        {
            this.start = start;
            this.end = end;
        }
    }
}