using System;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Flawless.Client.Remote;

namespace Flawless.Client;

public class AuthHeaderHandler : DelegatingHandler
{
    private string? AuthenticationHeader { get; set; }
    
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        var response = await SendCommandAsync(request, cancellationToken);
        var retryCount = 0;
        
        while (response.Headers.TryGetValues("Token-Expired", out var expired) && expired.Any(s => s == "true"))
        {
            if (retryCount++ > 3)
            {
                AuthenticationHeader = null;
                throw new TimeoutException("Too many retries, login info was cleared");
            }
            
            var refreshRequest = new HttpRequestMessage(HttpMethod.Post, "api/auth/refresh");
            var refresh = await base.SendAsync(refreshRequest, cancellationToken);
            if (!response.IsSuccessStatusCode) throw new ApplicationException("Login is expired and require login!");

            await using var st = await refresh.Content.ReadAsStreamAsync(cancellationToken);
            var tk = await JsonSerializer.DeserializeAsync<TokenInfo>(st, cancellationToken: cancellationToken)
                     ?? throw new ApplicationException("Not able to refresh token, please login again!");

            AuthenticationHeader = tk.Token;
            response = await SendCommandAsync(request, cancellationToken);
        }

        return response;
    }

    private Task<HttpResponseMessage> SendCommandAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        // Prefill this header
        if (AuthenticationHeader != null)
            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", AuthenticationHeader);
        
        return base.SendAsync(request, cancellationToken);
    }
}