using System.Linq;
using Newtonsoft.Json;

namespace Microsoft.AspNetCore.Http
{
	/// <summary>
	/// Extensions for the <see cref="ISession"/> object.
	/// </summary>
	public static class SessionExtensions
	{
		/// <summary>
		/// Sets a strong typed value.
		/// </summary>
		/// <typeparam name="T">The value type.</typeparam>
		/// <param name="session">The current session.</param>
		/// <param name="key">The key.</param>
		/// <param name="value">The value.</param>
		public static void SetValue<T>(this ISession session, string key, T value)
			=> session.SetString(key, JsonConvert.SerializeObject(value));

		/// <summary>
		/// Gets a strong typed value.
		/// </summary>
		/// <typeparam name="T">The value type.</typeparam>
		/// <param name="session">The current session.</param>
		/// <param name="key">The key.</param>
		/// <returns>The value.</returns>
		public static T GetValue<T>(this ISession session, string key)
			=> session.HasKey(key) ? JsonConvert.DeserializeObject<T>(session.GetString(key)) : default;

		/// <summary>
		/// Gets a strong typed value or the fallback value.
		/// </summary>
		/// <typeparam name="T">The value type.</typeparam>
		/// <param name="session">The current session.</param>
		/// <param name="key">The key.</param>
		/// <param name="fallback">A fallback value when the key is not present.</param>
		/// <returns>The value.</returns>
		public static T GetValue<T>(this ISession session, string key, T fallback)
		{
			if (session.HasKey(key))
				return session.GetValue<T>(key);

			return fallback;
		}

		/// <summary>
		/// Checks whether the session has the key available.
		/// </summary>
		/// <param name="session">The current session.</param>
		/// <param name="key">The key.</param>
		/// <returns><c>true</c> when the key was found, otherwise <c>false</c>.</returns>
		public static bool HasKey(this ISession session, string key)
			=> session.Keys.Contains(key);
	}
}