// 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;

namespace Microsoft.CodeAnalysis.Completion;

/// <summary>
/// The action that triggered completion to start.
/// </summary>
/// <remarks>
/// NOTE: Roslyn's LSP completion implementation uses this struct. If a new property is added, either:
///     1: The property's type must be serializable
///     OR
///     2. LSP will need to be updated to not use CompletionTrigger - see
///        Features\LanguageServer\Protocol\Handler\Completion\CompletionResolveData.cs
/// </remarks>
public readonly struct CompletionTrigger
{
    /// <summary>
    /// The reason that completion was started.
    /// </summary>
    public CompletionTriggerKind Kind { get; }

    /// <summary>
    /// The character associated with the triggering action.
    /// </summary>
    public char Character { get; }

    internal CompletionTrigger(CompletionTriggerKind kind, char character = (char)0)
        : this()
    {
        Kind = kind;
        Character = character;
    }

    /// <summary>
    /// Do not use.  Use <see cref="Invoke"/> instead.
    /// </summary>
    [Obsolete("Use 'Invoke' instead.")]
    public static readonly CompletionTrigger Default =
        new(CompletionTriggerKind.Other);

    /// <summary>
    /// The default <see cref="CompletionTrigger"/> when none is specified.
    /// </summary>
    public static readonly CompletionTrigger Invoke =
        new(CompletionTriggerKind.Invoke);

    /// <summary>
    /// Creates a new instance of a <see cref="CompletionTrigger"/> association with the insertion of a typed character into the document.
    /// </summary>
    public static CompletionTrigger CreateInsertionTrigger(char insertedCharacter)
        => new(CompletionTriggerKind.Insertion, insertedCharacter);

    /// <summary>
    /// Creates a new instance of a <see cref="CompletionTrigger"/> association with the deletion of a character from the document.
    /// </summary>
    public static CompletionTrigger CreateDeletionTrigger(char deletedCharacter)
        => new(CompletionTriggerKind.Deletion, deletedCharacter);
}