using Microsoft.Extensions.Configuration;

namespace Core.Configurations
{
	public class AzureConfigurationManager
	{
		private static IConfigurationBuilder _configurationBuilder;

		/// <summary>
		/// This AppConfigBuilder assumes that AppConfigEndpoint and AppConfigLabelFilter are configured as Settings on Azure for the Application that needs them.
		/// AppConfigEndpoint would look like this: Endpoint=https://config-dec-test.azconfig.io;Id=0-l9-s0:foo;Secret=somesecret/bar
		/// </summary>
		/// <param name="localSettingsFile">
		///     Path relative to the base path stored in Microsoft.Extensions.Configuration.IConfigurationBuilder.Properties of builder.
		///  </param>
		public static IConfigurationBuilder AppConfigBuilder(string localSettingsFile)
		{
			if (_configurationBuilder == null)
			{
				var envConfiguration = new Microsoft.Extensions.Configuration.ConfigurationBuilder()
					.AddEnvironmentVariables()
					.Build();

				System.Diagnostics.Trace.Listeners.Add(new System.Diagnostics.TextWriterTraceListener(Console.Out));

				var appConfigEndpoint = envConfiguration["AppConfigEndpoint"];
				var appConfigLabel = envConfiguration["AppConfigLabelFilter"];

				_configurationBuilder = new Microsoft.Extensions.Configuration.ConfigurationBuilder();
				if (!string.IsNullOrEmpty(appConfigEndpoint))
				{
					_configurationBuilder
						.AddAzureAppConfiguration(options =>
						{
							options.Connect(appConfigEndpoint);
							options.Select(keyFilter: "*", labelFilter: appConfigLabel);
						})
						.AddEnvironmentVariables();
				}
				else
				{
					_configurationBuilder.SetBasePath(Directory.GetCurrentDirectory());
					_configurationBuilder.AddJsonFile(localSettingsFile, optional: false);
				}
			}
			return _configurationBuilder;
		}
	}
}