using Google.Apis.Auth.OAuth2;
using Google.Apis.Auth.OAuth2.Flows;

namespace Core.Thalos.BFF.Api.Services
{
    public interface IGoogleAuthorization
    {
        string GetAuthorizationUrl();
        Task<UserCredential> ExchangeCodeForToken(string code);
    }

    public class GoogleAuthorizationService(
        IGoogleAuthHelper googleHelper, IConfiguration config) : IGoogleAuthorization
    {
        private string RedirectUrl = config["Authentication:Google:RedirectUri"]!;

        public async Task<UserCredential> ExchangeCodeForToken(string code)
        {
            var flow = new GoogleAuthorizationCodeFlow(
                new GoogleAuthorizationCodeFlow.Initializer
                {
                    ClientSecrets = googleHelper.GetClientSecrets(),
                    Scopes = googleHelper.GetScopes()
                });

            var token = await flow.ExchangeCodeForTokenAsync(
                "user", code, RedirectUrl, CancellationToken.None);

            return new UserCredential(flow, "user", token);
        }

        public string GetAuthorizationUrl() =>
            new GoogleAuthorizationCodeFlow(
                new GoogleAuthorizationCodeFlow.Initializer
                {

                    ClientSecrets = googleHelper.GetClientSecrets(),
                    Scopes = googleHelper.GetScopes(),
                    Prompt = "consent"
                }).CreateAuthorizationCodeRequest(RedirectUrl).Build().ToString();
    }
}