inabox/inabox.wpf/DynamicGrid/Editors/ScriptEditor/ManualOnlyCompletionProvider.cs

using System.Threading;
using System.Threading.Tasks;
using RoslynPad.Editor;

public sealed class ManualOnlyCompletionProvider : ICodeEditorCompletionProvider
{
    private readonly ICodeEditorCompletionProvider _inner;

    // 0 = blocked, 1 = allow exactly one completion request
    private int _allowOnce;

    public ManualOnlyCompletionProvider(ICodeEditorCompletionProvider inner)
        => _inner = inner;

    /// <summary>
    /// Call this immediately before letting the editor execute its completion action (Ctrl + Space).
    /// </summary>
    public void AllowNextCompletionOnce()
        => Interlocked.Exchange(ref _allowOnce, 1);

    /// <summary>
    /// If false, blocks signature help popups (parameter hints).
    /// </summary>
    public bool AllowSignatureHelp { get; set; } = false;

    /// <summary>
    /// If true, a request with triggerChar == null is treated as a manual invoke
    /// even if you didn't call AllowNextCompletionOnce().
    /// </summary>
    public bool TreatNullTriggerAsManualInvoke { get; set; } = true;

    /// <summary>
    /// If true, allows '.' to trigger completion while typing (classic IDE feel),
    /// while still blocking letter-by-letter popups.
    /// </summary>
    public bool AllowDotTrigger { get; set; } = false;

    public Task<CompletionResult> GetCompletionData(int position, char? triggerChar, bool useSignatureHelp)
    {
        // No results object for this build:
        static CompletionResult EmptyResult() => new CompletionResult(null, null, useHardSelection: false);

        // 1) Signature help requested?
        if (useSignatureHelp && !AllowSignatureHelp)
            return Task.FromResult(EmptyResult());

        // 2) Typed character triggers (auto popup on keystrokes)
        if (triggerChar is not null)
        {
            if (!(AllowDotTrigger && triggerChar == '.'))
                return Task.FromResult(EmptyResult());
        }

        // 3) Manual gating: either explicitly armed once, or inferred from null trigger
        if (Interlocked.Exchange(ref _allowOnce, 0) == 1)
            return _inner.GetCompletionData(position, triggerChar, useSignatureHelp);

        if (TreatNullTriggerAsManualInvoke && triggerChar is null && !useSignatureHelp)
            return _inner.GetCompletionData(position, triggerChar, useSignatureHelp);

        return Task.FromResult(EmptyResult());
    }
}