using System;
using System.Globalization;

namespace Org.BouncyCastle.Utilities
{
    internal static class Platform
    {
        private static readonly CompareInfo InvariantCompareInfo = CultureInfo.InvariantCulture.CompareInfo;

        internal static bool EqualsIgnoreCase(string a, string b)
        {
            return string.Equals(a, b, StringComparison.OrdinalIgnoreCase);
        }

        internal static string GetEnvironmentVariable(string variable)
        {
            try
            {
                return Environment.GetEnvironmentVariable(variable);
            }
            catch (System.Security.SecurityException)
            {
                // We don't have the required permission to read this environment variable,
                // which is fine, just act as if it's not set
                return null;
            }
        }

        internal static int IndexOf(string source, char value)
        {
            return InvariantCompareInfo.IndexOf(source, value, CompareOptions.Ordinal);
        }

        internal static int IndexOf(string source, string value)
        {
            return InvariantCompareInfo.IndexOf(source, value, CompareOptions.Ordinal);
        }

        internal static int IndexOf(string source, char value, int startIndex)
        {
            return InvariantCompareInfo.IndexOf(source, value, startIndex, CompareOptions.Ordinal);
        }

        internal static int IndexOf(string source, string value, int startIndex)
        {
            return InvariantCompareInfo.IndexOf(source, value, startIndex, CompareOptions.Ordinal);
        }

        internal static bool Is64BitProcess
        {
#if NETCOREAPP2_0_OR_GREATER || NET40_OR_GREATER || NETSTANDARD2_0_OR_GREATER

            get { return Environment.Is64BitProcess; }
#else
            get { return IntPtr.Size == 8; }
#endif
        }

        internal static int LastIndexOf(string source, string value)
        {
            return InvariantCompareInfo.LastIndexOf(source, value, CompareOptions.Ordinal);
        }

        internal static bool StartsWith(string source, string prefix)
        {
            return InvariantCompareInfo.IsPrefix(source, prefix, CompareOptions.Ordinal);
        }

        internal static bool StartsWithIgnoreCase(string source, string prefix)
        {
            return InvariantCompareInfo.IsPrefix(source, prefix, CompareOptions.OrdinalIgnoreCase);
        }

        internal static bool EndsWith(string source, string suffix)
        {
            return InvariantCompareInfo.IsSuffix(source, suffix, CompareOptions.Ordinal);
        }

        internal static string GetTypeName(object obj)
        {
            return GetTypeName(obj.GetType());
        }

        internal static string GetTypeName(Type t)
        {
            return t.FullName;
        }
    }
}