namespace Microsoft.AspNetCore.Identity
{
	/// <summary>
	/// Provides password hashing and verification methods.
	/// </summary>
	public static class PasswordHelper
	{
		/// <summary>
		/// Hashes a password.
		/// </summary>
		/// <param name="plainPassword">The plain password.</param>
		/// <returns></returns>
		public static string HashPassword(string plainPassword)
		{
			if (string.IsNullOrWhiteSpace(plainPassword))
				return plainPassword?.Trim();

			var ph = new PasswordHasher<object>();
			return ph.HashPassword(null, plainPassword.Trim());
		}

		/// <summary>
		/// Verifies a password with a hashed version.
		/// </summary>
		/// <param name="plainPassword">The plain password.</param>
		/// <param name="hashedPassword">The password hash.</param>
		/// <param name="rehashNeeded">A value indicating whether the password needs a rehash.</param>
		/// <returns></returns>
		public static bool VerifyPassword(string plainPassword, string hashedPassword, out bool rehashNeeded)
		{
			rehashNeeded = false;
			if (string.IsNullOrWhiteSpace(plainPassword) || string.IsNullOrWhiteSpace(hashedPassword))
				return false;

			var ph = new PasswordHasher<object>();
			var result = ph.VerifyHashedPassword(null, hashedPassword, plainPassword);
			switch (result)
			{
				case PasswordVerificationResult.Success:
					return true;

				case PasswordVerificationResult.SuccessRehashNeeded:
					rehashNeeded = true;
					return true;

				case PasswordVerificationResult.Failed:
				default:
					return false;
			}
		}
	}
}