// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Collections.Immutable;
 
namespace Microsoft.CodeAnalysis.Snippets
{
    internal readonly struct SnippetPlaceholder
    {
        /// <summary>
        /// The identifier in the snippet that needs to be renamed.
        /// </summary>
        public readonly string Identifier;
 
        /// <summary>
        /// The positions associated with the identifier that will need to
        /// be converted into LSP formatted strings.
        /// </summary>
        public readonly ImmutableArray<int> PlaceHolderPositions;
 
        /// <summary>
        /// <example> 
        /// For loop would have two placeholders:
        /// <code>
        ///     for (var {1:i} = 0; {1:i} &lt; {2:length}; {1:i}++)
        /// </code>
        /// Identifier: i, 3 associated positions <br/>
        /// Identifier: length, 1 associated position <br/>
        /// </example>
        /// </summary>
        public SnippetPlaceholder(string identifier, ImmutableArray<int> placeholderPositions)
        {
            if (identifier.Length == 0)
            {
                throw new ArgumentException($"{nameof(identifier)} must not be an empty string.");
            }
 
            Identifier = identifier;
            PlaceHolderPositions = placeholderPositions;
        }
    }
}