Foxnouns.NET/Foxnouns.Backend/Extensions/KeyCacheExtensions.cs

using Foxnouns.Backend.Database;
using Foxnouns.Backend.Services;
using Foxnouns.Backend.Utils;
using Newtonsoft.Json;
using NodaTime;

namespace Foxnouns.Backend.Extensions;

public static class KeyCacheExtensions
{
    public static async Task<string> GenerateAuthStateAsync(this KeyCacheService keyCacheService,
        CancellationToken ct = default)
    {
        var state = AuthUtils.RandomToken().Replace('+', '-').Replace('/', '_');
        await keyCacheService.SetKeyAsync($"oauth_state:{state}", "", Duration.FromMinutes(10), ct);
        return state;
    }

    public static async Task ValidateAuthStateAsync(this KeyCacheService keyCacheService, string state,
        CancellationToken ct = default)
    {
        var val = await keyCacheService.GetKeyAsync($"oauth_state:{state}", delete: true, ct);
        if (val == null) throw new ApiError.BadRequest("Invalid OAuth state");
    }

    public static async Task<string> GenerateRegisterEmailStateAsync(this KeyCacheService keyCacheService, string email,
        Snowflake? userId = null, CancellationToken ct = default)
    {
        // This state is used in links, not just as JSON values, so make it URL-safe
        var state = AuthUtils.RandomToken().Replace('+', '-').Replace('/', '_');
        await keyCacheService.SetKeyAsync($"email_state:{state}", new RegisterEmailState(email, userId),
            Duration.FromDays(1), ct);
        return state;
    }

    public static async Task<RegisterEmailState?> GetRegisterEmailStateAsync(this KeyCacheService keyCacheService,
        string state, CancellationToken ct = default) =>
        await keyCacheService.GetKeyAsync<RegisterEmailState>($"email_state:{state}", delete: true, ct);
}

public record RegisterEmailState(
    string Email,
    [property: JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
    Snowflake? ExistingUserId);