// 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
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// 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 => 0;

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

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

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

        /// <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 ?? throw new System.ArgumentNullException(nameof(start));
            this.End = end ?? throw new System.ArgumentNullException(nameof(end));
        }
    }
}