using Google.Apis.Auth.OAuth2;
using Google.Apis.Http;
using Google.Cloud.BigQuery.V2;
using System.Net.Http.Headers;

namespace Migration.Services;

public class CustomHttpClientFactory : HttpClientFactory
{
    private readonly string userAgent;

    public CustomHttpClientFactory(string userAgent)
    {
        if (string.IsNullOrWhiteSpace(userAgent))
        {
            throw new ArgumentException("User-Agent cannot be null or empty", nameof(userAgent));
        }
        this.userAgent = userAgent;
    }

    public new ConfigurableHttpClient CreateHttpClient(CreateHttpClientArgs args)
    {
        var httpClient = base.CreateHttpClient(args);
        httpClient.DefaultRequestHeaders.UserAgent.Clear();
        httpClient.DefaultRequestHeaders.UserAgent.Add(new ProductInfoHeaderValue(userAgent, "1.0"));
        return httpClient;
    }
}

public class GoogleBigQueryClientFactory : IGoogleBigQueryClientFactory
{
    private readonly Lazy<BigQueryClient> bigqueryClient;

    public GoogleBigQueryClientFactory()
    {
        bigqueryClient = new Lazy<BigQueryClient>(CreateClient);
    }

    public BigQueryClient CreateClient()
    {       
        var projectId =  Environment.GetEnvironmentVariable("GOOGLE_PROJECT_ID") ?? throw new Exception("Brak identyfikatora projektu Google.");
        var userAgent = Environment.GetEnvironmentVariable("USER_AGENT") ?? throw new Exception("Nie podano UserAgent.");
        var credentialFile = Environment.GetEnvironmentVariable("GOOGLE_CREDENTIALS_JSON") ?? throw new Exception("Nie podano ścieżki do pliku GoogleCredentials.");

        var credential = GoogleCredential.FromJson(credentialFile);
        var httpClientFactory = new CustomHttpClientFactory(userAgent);

        return new BigQueryClientBuilder
        {
            ProjectId = projectId,
            Credential = credential,
            HttpClientFactory = httpClientFactory
        }.Build();
    }

    public BigQueryTable GetTable(string datasetId, string tableId)
    {
        return bigqueryClient.Value.GetTable(datasetId, tableId);
    }
}