Wino-Mail/Wino.Core/Http/GmailClientMessageHandler.cs

using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using Google.Apis.Http;
using Wino.Core.Domain.Entities.Shared;
using Wino.Core.Domain.Interfaces;

namespace Wino.Core.Http;

internal class GmailClientMessageHandler : ConfigurableMessageHandler
{
    private readonly IGmailAuthenticator _gmailAuthenticator;
    private readonly MailAccount _mailAccount;

    public GmailClientMessageHandler(IGmailAuthenticator gmailAuthenticator, MailAccount mailAccount) : base(new HttpClientHandler())
    {
        _gmailAuthenticator = gmailAuthenticator;
        _mailAccount = mailAccount;
    }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        // This call here will automatically trigger Google Auth's interactive login if the token is not found.
        // or refresh the token based on the FileDataStore.

        var tokenInformation = await _gmailAuthenticator.GetTokenInformationAsync(_mailAccount);

        request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", tokenInformation.AccessToken);

        return await base.SendAsync(request, cancellationToken);
    }
}