Unsubscribes from issues that were closed as unplanned. Ripped largely from https://gist.github.com/jaredpar/1605aad9c6b8869c8eaf8868b6c73c25.

UnsubscribeunplannedIssues.cs

// File-based app which unsubscribes from GitHub issues in particular repo which were closed as not planned.

#:package [email protected]
#:package [email protected]
#:package [email protected]

using System.Runtime.CompilerServices;
using Humanizer;
using Microsoft.Extensions.Configuration;
using Octokit;

var config = new ConfigurationBuilder()
    .AddUserSecrets<Program>()
    .Build();

string? token = config["GitHub.Token"];
if (string.IsNullOrEmpty(token))
{
    Console.WriteLine("Required GitHub access token was not found.");
    Console.WriteLine("Go to https://github.com/settings/tokens and generate a **classic PAT** with repo/public and notifications scopes.");
    var filePath = Path.GetRelativePath(Environment.CurrentDirectory, GetCurrentFilePath());
    Console.WriteLine($"""Then run command 'dotnet user-secrets set GitHub.Token "<pat>" --file "{filePath}"'.""");
    return 1;
}

var client = new GitHubClient(new ProductHeaderValue("RikkiGibson.UnsubscribeUnplannedIssues"))
{
    Credentials = new Credentials(token)
};
var user = await client.User.Current();
Console.WriteLine($"Authenticated as: {user.Login}");

await MarkUnplannedAsDone(client);

return 0;

string GetCurrentFilePath([CallerFilePath] string? path = null) => path ?? throw new InvalidOperationException();

static async Task MarkUnplannedAsDone(GitHubClient client)
{
    var notificationsClient = client.Activity.Notifications;
    Console.WriteLine("List a repository to process (e.g., owner/repo):");
    var line = Console.ReadLine()!;
    string owner, repo;

    if (line.Contains("/"))
    {
        var parts = line.Split(['/'], 2);
        owner = parts[0];
        repo = parts[1];
    }
    else
    {
        owner = "dotnet";
        repo = line;
    }

    var apiOptions = new ApiOptions
    {
        PageSize = 10,
        PageCount = 1,
        StartPage = 1
    };

    var request = new NotificationsRequest()
    {
        Since = DateTimeOffset.Now.AddDays(-30)
    };

    while (true)
    {
        var notifications = await notificationsClient.GetAllForRepository(owner, repo, request, apiOptions);
        if (notifications.Count == 0)
        {
            Console.WriteLine("No more notifications to process.");
            break;
        }

        foreach (var notification in notifications)
        {
            if (notification.Subject.Type != "Issue")
            {
                continue;
            }

            var issueNumber = int.Parse(notification.Subject.Url.Split('/').Last());
            var issue = await client.Issue.Get(owner, repo, issueNumber);
            if (issue.StateReason == ItemStateReason.NotPlanned)
            {
                Console.WriteLine($"Marking notification as done: #{issue.Number} (opened {issue.CreatedAt.Humanize()}) - {issue.Title} ({issue.HtmlUrl})");
                await MarkAsDone(notification.Id);
            }
        }

        apiOptions.StartPage++;
    }

    async Task MarkAsDone(string threadId)
    {
        var endPoint = new Uri($"notifications/threads/{threadId}", UriKind.Relative);
        var result = await client.Connection.Delete<object>(
            endPoint,
            null,
            "application/vnd.github+json");
    }
}