using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;
using Google.Apis.Sheets.v4;
using framework_library;
using System;
using System.IO;

namespace framework_business.handlers
{
    public class GoogleSheetsHelper
    {
        public SheetsService Service { get; set; }
        static readonly string[] Scopes = { SheetsService.Scope.Spreadsheets };

        public GoogleSheetsHelper(string applicationName)
        {
            InitializeService(applicationName);
        }

        private void InitializeService(string applicationName)
        {
            var credential = GetCredentialsFromFile();
            Service = new SheetsService(new BaseClientService.Initializer()
            {
                HttpClientInitializer = credential,
                ApplicationName = applicationName
            });
        }

        private GoogleCredential GetCredentialsFromFile()
        {
            string filePath = Environment.GetEnvironmentVariable("GOOGLE_SHEETS_CREDENTIALS_FILE");
            if (string.IsNullOrEmpty(filePath))
                throw new InvalidOperationException(
                    "GOOGLE_SHEETS_CREDENTIALS_FILE must be set in .env or the process environment.");

            filePath = ResolveCredentialsPath(filePath);
            if (!File.Exists(filePath))
                throw new FileNotFoundException(
                    "Google Sheets credentials file not found at: " + filePath, filePath);

            using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
            {
                return GoogleCredential.FromStream(stream).CreateScoped(Scopes);
            }
        }

        private static string ResolveCredentialsPath(string filePath)
        {
            if (Path.IsPathRooted(filePath))
                return filePath;

            if (EnvBootstrap.IsLoaded && !string.IsNullOrEmpty(EnvBootstrap.LoadedPath))
            {
                string repoRoot = Path.GetDirectoryName(EnvBootstrap.LoadedPath);
                if (!string.IsNullOrEmpty(repoRoot))
                {
                    string fromRepo = Path.GetFullPath(Path.Combine(repoRoot, filePath.TrimStart('.', '/', '\\')));
                    if (File.Exists(fromRepo))
                        return fromRepo;
                }
            }

            return Path.GetFullPath(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, filePath));
        }
    }
}