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

#nullable disable

using System.Security;

namespace Microsoft.DotNet.Cli;

/// <summary>
/// A program can change the encoding of the console which would affect other programs.
/// We would prefer to have a pattern where the program does not affect encoding of other programs.
/// Create this class in a function akin to Main and let it manage the console encoding resources to return it to the state before execution upon destruction.
/// </summary>
internal class AutomaticEncodingRestorer : IDisposable
{
    private readonly Encoding _originalOutputEncoding = null;
    private readonly Encoding _originalInputEncoding = null;

    private readonly bool outputEncodingAccessible = false;
    private readonly bool inputEncodingAccessible = false;

    public AutomaticEncodingRestorer()
    {
        try
        {
            if (!OperatingSystem.IsIOS() && !OperatingSystem.IsAndroid() && !OperatingSystem.IsTvOS()) // Output + Input Encoding are unavailable on these platforms per docs.
            {
                _originalOutputEncoding = Console.OutputEncoding;
                outputEncodingAccessible = true;
                if (!OperatingSystem.IsBrowser()) // Input Encoding is also unavailable in this platform.
                {
                    _originalInputEncoding = Console.InputEncoding;
                    inputEncodingAccessible = true;
                }
            }
        }
        catch (Exception ex) when (ex is IOException || ex is SecurityException)
        {
            // The encoding is unavailable. Do nothing.
        }
    }

    public void Dispose()
    {
        try
        {
            if (outputEncodingAccessible)
            {
                Console.OutputEncoding = _originalOutputEncoding;
            }
            if (inputEncodingAccessible)
            {
                Console.InputEncoding = _originalInputEncoding;
            }
        }
        catch (Exception ex) when (ex is IOException || ex is SecurityException)
        {
            // The encoding is unavailable. Do nothing.
        }
    }
}