//  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.

using System.Globalization;

namespace YamlDotNet.Core.Events
{
    /// <summary>
    /// Represents an alias event.
    /// </summary>
    public class AnchorAlias : ParsingEvent
    {
        /// <summary>
        /// Gets the event type, which allows for simpler type comparisons.
        /// </summary>
        internal override EventType Type
        {
            get
            {
                return EventType.Alias;
            }
        }

        private readonly string value;

        /// <summary>
        /// Gets the value of the alias.
        /// </summary>
        public string Value
        {
            get
            {
                return value;
            }
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="AnchorAlias"/> class.
        /// </summary>
        /// <param name="value">The value of the alias.</param>
        /// <param name="start">The start position of the event.</param>
        /// <param name="end">The end position of the event.</param>
        public AnchorAlias(string value, Mark start, Mark end)
            : base(start, end)
        {
            if (string.IsNullOrEmpty(value))
            {
                throw new YamlException(start, end, "Anchor value must not be empty.");
            }

            if (!NodeEvent.anchorValidator.IsMatch(value))
            {
                throw new YamlException(start, end, "Anchor value must contain alphanumerical characters only.");
            }

            this.value = value;
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="AnchorAlias"/> class.
        /// </summary>
        /// <param name="value">The value of the alias.</param>
        public AnchorAlias(string value)
            : this(value, Mark.Empty, Mark.Empty)
        {
        }

        /// <summary>
        /// Returns a <see cref="T:System.String"/> that represents the current <see cref="T:System.Object"/>.
        /// </summary>
        /// <returns>
        /// A <see cref="T:System.String"/> that represents the current <see cref="T:System.Object"/>.
        /// </returns>
        public override string ToString()
        {
            return string.Format(CultureInfo.InvariantCulture, "Alias [value = {0}]", value);
        }

        /// <summary>
        /// Invokes run-time type specific Visit() method of the specified visitor.
        /// </summary>
        /// <param name="visitor">visitor, may not be null.</param>
        public override void Accept(IParsingEventVisitor visitor)
        {
            visitor.Visit(this);
        }
    }
}
