DbFirst/DbFirst.BlazorWebApp/Services/AuthApiClient.cs

using System.Net;

namespace DbFirst.BlazorWebApp.Services;

public class AuthApiClient(HttpClient httpClient, AuthService authService, CookieContainer cookieContainer) : IAuthApiClient
{
    private const string LoginEndpoint = "api/Auth/db-first/login";
    private const string LogoutEndpoint = "api/Auth/logout";
    private const string CheckEndpoint = "api/Auth/check";

    public async Task<bool> LoginAsync(string username, string password, CancellationToken ct = default)
    {
        var content = new MultipartFormDataContent();
        content.Add(new StringContent(username), "Username");
        content.Add(new StringContent(password), "Password");
        content.Add(new StringContent(string.Empty), "UserId");

        var response = await httpClient.PostAsync(LoginEndpoint, content, ct);
        if (!response.IsSuccessStatusCode)
            return false;

        var rawCookie = ExtractCookies();
        authService.SetAuthenticated(username, rawCookie);
        return true;
    }

    public async Task LogoutAsync(CancellationToken ct = default)
    {
        await httpClient.PostAsync(LogoutEndpoint, null, ct);
        authService.SetUnauthenticated();
    }

    public async Task<bool> RestoreAsync(string username, string rawCookieHeader, CancellationToken ct = default)
    {
        RestoreCookies(rawCookieHeader);
        var response = await httpClient.GetAsync(CheckEndpoint, ct);
        if (response.IsSuccessStatusCode)
        {
            authService.SetAuthenticated(username, rawCookieHeader);
            return true;
        }

        authService.SetUnauthenticated();
        return false;
    }

    private string ExtractCookies()
    {
        if (httpClient.BaseAddress is null) return string.Empty;
        var cookies = cookieContainer.GetCookies(httpClient.BaseAddress);
        return string.Join("; ", cookies.Cast<Cookie>().Select(c => $"{c.Name}={c.Value}"));
    }

    private void RestoreCookies(string rawCookieHeader)
    {
        if (httpClient.BaseAddress is null) return;
        foreach (var part in rawCookieHeader.Split(';', StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries))
        {
            var eqIdx = part.IndexOf('=');
            if (eqIdx > 0)
                cookieContainer.Add(httpClient.BaseAddress, new Cookie(part[..eqIdx].Trim(), part[(eqIdx + 1)..].Trim()));
        }
    }
}