// 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.Threading;
 
namespace Microsoft.CodeAnalysis.Completion;
 
/// <summary>
/// Provides context information for argument completion.
/// </summary>
internal sealed class ArgumentContext(
    ArgumentProvider provider,
    SemanticModel semanticModel,
    int position,
    IParameterSymbol parameter,
    string? previousValue,
    CancellationToken cancellationToken)
{
    internal ArgumentProvider Provider { get; } = provider ?? throw new ArgumentNullException(nameof(provider));
 
    /// <summary>
    /// Gets the semantic model where argument completion is requested.
    /// </summary>
    public SemanticModel SemanticModel { get; } = semanticModel ?? throw new ArgumentNullException(nameof(semanticModel));
 
    /// <summary>
    /// Gets the position within <see cref="SemanticModel"/> where argument completion is requested.
    /// </summary>
    public int Position { get; } = position;
 
    /// <summary>
    /// Gets the symbol for the parameter for which an argument value is requested.
    /// </summary>
    public IParameterSymbol Parameter { get; } = parameter ?? throw new ArgumentNullException(nameof(parameter));
 
    /// <summary>
    /// Gets the previously-provided argument value for this parameter.
    /// </summary>
    /// <value>
    /// The existing text of the argument value, if the argument is already in code; otherwise,
    /// <see langword="null"/> when requesting a new argument value.
    /// </value>
    public string? PreviousValue { get; } = previousValue;
 
    /// <summary>
    /// Gets a cancellation token that argument providers may observe.
    /// </summary>
    public CancellationToken CancellationToken { get; } = cancellationToken;
 
    /// <summary>
    /// Gets or sets the default argument value.
    /// </summary>
    /// <remarks>
    /// If this value is not set, the argument completion session will insert a language-specific default value for
    /// the argument.
    /// </remarks>
    public string? DefaultValue { get; set; }
}