using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;

namespace UtopiaCanteenSystem.Services;

/// <summary>
/// Admin authentication service via UIND portal API (plain-text response).
/// </summary>
public class AuthService : IAuthService
{
    private static readonly HttpClient HttpClient = new();
    private readonly string _baseUrl;

    public AuthService(string authenticationUrl)
    {
        _baseUrl = (authenticationUrl ?? string.Empty).Trim();
        if (!string.IsNullOrEmpty(_baseUrl) && !_baseUrl.EndsWith("/"))
            _baseUrl += "/";
    }

    public async Task<AuthResult> LoginAsync(string username, string password, CancellationToken cancellationToken = default)
    {
        var user = username?.Trim() ?? string.Empty;
        var pass = password ?? string.Empty;
        if (string.IsNullOrWhiteSpace(_baseUrl))
            return new AuthResult(false, string.Empty);

        if (string.IsNullOrWhiteSpace(user) || string.IsNullOrEmpty(pass))
            return new AuthResult(false, string.Empty);

        // Build URL:
        // {baseUrl}{username}/{password}
        // Must URL-encode both values.
        var url = $"{_baseUrl}{Uri.EscapeDataString(user)}/{Uri.EscapeDataString(pass)}";

        try
        {
            using var resp = await HttpClient.GetAsync(url, cancellationToken).ConfigureAwait(false);
            var body = (await resp.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false)).Trim();

            // Portal returns plain text:
            // "NOT FOUND" => failure
            // otherwise => success and body contains EmployeeId (or user identifier)
            if (body.Equals("NOT FOUND", StringComparison.OrdinalIgnoreCase))
                return new AuthResult(false, string.Empty);

            return new AuthResult(true, body);
        }
        catch
        {
            return new AuthResult(false, string.Empty);
        }
    }
}