using Google.Ads.Gax.Config;
using Google.Ads.GoogleAds.Config;
using Google.Ads.GoogleAds.Lib;
using GoogleApi.Configuration;
using Microsoft.Extensions.Options;

namespace GoogleApi.Services;

// ✅ Alias the Google library config type to avoid collision with your GoogleApi.Configuration.GoogleAdsConfig
using LibGoogleAdsConfig = Google.Ads.GoogleAds.Config.GoogleAdsConfig;

public sealed class GoogleAdsClientFactory
{
    private readonly GoogleApi.Configuration.GoogleAdsConfig _cfg;
    private readonly ILogger<GoogleAdsClientFactory> _logger;

    public GoogleAdsClientFactory(
        IOptions<GoogleApi.Configuration.GoogleAdsConfig> config,
        ILogger<GoogleAdsClientFactory> logger)
    {
        _cfg = config.Value;
        _logger = logger;
    }

    public bool IsRealApiEnabled =>
        _cfg.EnableRealApi &&
        !string.IsNullOrWhiteSpace(_cfg.DeveloperToken) &&
        !string.IsNullOrWhiteSpace(_cfg.OAuth.ClientId) &&
        !string.IsNullOrWhiteSpace(_cfg.OAuth.ClientSecret) &&
        !string.IsNullOrWhiteSpace(_cfg.OAuth.RefreshToken);

    public GoogleAdsClient CreateClient(GoogleAdsContext context)
    {
        var loginCustomerId = NormalizeCustomerId(
            context.LoginCustomerId ?? _cfg.DefaultLoginCustomerId ?? string.Empty);

        var libConfig = new LibGoogleAdsConfig
        {
            DeveloperToken = _cfg.DeveloperToken,

            // ✅ Headless/server-to-server refresh-token flow
            OAuth2Mode = OAuth2Flow.APPLICATION,
            OAuth2ClientId = _cfg.OAuth.ClientId,
            OAuth2ClientSecret = _cfg.OAuth.ClientSecret,
            OAuth2RefreshToken = context.RefreshToken ?? _cfg.OAuth.RefreshToken,

            // MCC/manager header
            LoginCustomerId = string.IsNullOrWhiteSpace(loginCustomerId) ? null : loginCustomerId,

            // ms
            Timeout = Math.Max(1, _cfg.TimeoutSeconds) * 1000
        };

        _logger.LogDebug(
            "[GoogleAds] CreateClient | RealApi={RealApi} LoginCustomerIdSet={LoginSet}",
            IsRealApiEnabled,
            !string.IsNullOrWhiteSpace(libConfig.LoginCustomerId));

        return new GoogleAdsClient(libConfig);
    }

    public static string NormalizeCustomerId(string customerId)
        => (customerId ?? string.Empty).Replace("-", string.Empty).Trim();

    public static string FormatCustomerId(string customerId)
    {
        var normalized = NormalizeCustomerId(customerId);
        if (normalized.Length != 10) return normalized;
        return $"{normalized[..3]}-{normalized[3..6]}-{normalized[6..]}";
    }
}