// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Text;

namespace System.Globalization
{
    internal static class SurrogateCasing
    {
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        internal static void ToUpper(char h, char l, out char hr, out char lr)
        {
            Debug.Assert(char.IsHighSurrogate(h));
            Debug.Assert(char.IsLowSurrogate(l));

            UnicodeUtility.GetUtf16SurrogatesFromSupplementaryPlaneScalar(CharUnicodeInfo.ToUpper(UnicodeUtility.GetScalarFromUtf16SurrogatePair(h, l)), out hr, out lr);

            Debug.Assert(char.IsHighSurrogate(hr));
            Debug.Assert(char.IsLowSurrogate(lr));
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        internal static void ToLower(char h, char l, out char hr, out char lr)
        {
            Debug.Assert(char.IsHighSurrogate(h));
            Debug.Assert(char.IsLowSurrogate(l));

            UnicodeUtility.GetUtf16SurrogatesFromSupplementaryPlaneScalar(CharUnicodeInfo.ToLower(UnicodeUtility.GetScalarFromUtf16SurrogatePair(h, l)), out hr, out lr);

            Debug.Assert(char.IsHighSurrogate(hr));
            Debug.Assert(char.IsLowSurrogate(lr));
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        internal static bool Equal(char h1, char l1, char h2, char l2)
        {
            ToUpper(h1, l1, out char hr1, out char lr1);
            ToUpper(h2, l2, out char hr2, out char lr2);

            return hr1 == hr2 && lr1 == lr2;
        }
    }
}