// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Runtime.CompilerServices;
 
namespace Microsoft.NET.Sdk.Razor.Tool.Json;
 
internal static partial class Assumed
{
    [InterpolatedStringHandler]
    public readonly ref struct ThrowIfTrueInterpolatedStringHandler
    {
        private readonly PooledStringBuilderHelper _builder;
 
        public ThrowIfTrueInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool success)
        {
            success = condition;
            _builder = new(literalLength, success);
        }
 
        public void AppendLiteral(string value)
            => _builder.AppendLiteral(value);
 
        public void AppendFormatted<TValue>(TValue value)
            => _builder.AppendFormatted(value);
 
        public void AppendFormatted<TValue>(TValue value, string format)
            where TValue : IFormattable
            => _builder.AppendFormatted(value, format);
 
        public string GetFormattedText()
            => _builder.GetFormattedText();
    }
 
    [InterpolatedStringHandler]
    public readonly ref struct ThrowIfFalseInterpolatedStringHandler
    {
        private readonly PooledStringBuilderHelper _builder;
 
        public ThrowIfFalseInterpolatedStringHandler(int literalLength, int formattedCount, bool condition, out bool success)
        {
            success = !condition;
            _builder = new(literalLength, success);
        }
 
        public void AppendLiteral(string value)
            => _builder.AppendLiteral(value);
 
        public void AppendFormatted<TValue>(TValue value)
            => _builder.AppendFormatted(value);
 
        public void AppendFormatted<TValue>(TValue value, string format)
            where TValue : IFormattable
            => _builder.AppendFormatted(value, format);
 
        public string GetFormattedText()
            => _builder.GetFormattedText();
    }
 
    [InterpolatedStringHandler]
    public readonly ref struct ThrowIfNullInterpolatedStringHandler<T>
    {
        private readonly PooledStringBuilderHelper _builder;
 
        public ThrowIfNullInterpolatedStringHandler(int literalLength, int formattedCount, T? value, out bool success)
        {
            success = value is null;
            _builder = new(literalLength, success);
        }
 
        public void AppendLiteral(string value)
            => _builder.AppendLiteral(value);
 
        public void AppendFormatted<TValue>(TValue value)
            => _builder.AppendFormatted(value);
 
        public void AppendFormatted<TValue>(TValue value, string format)
            where TValue : IFormattable
            => _builder.AppendFormatted(value, format);
 
        public string GetFormattedText()
            => _builder.GetFormattedText();
    }
 
    [InterpolatedStringHandler]
    public readonly ref struct UnreachableInterpolatedStringHandler
    {
        private readonly PooledStringBuilderHelper _builder;
 
        public UnreachableInterpolatedStringHandler(int literalLength, int formattedCount)
        {
            _builder = new(literalLength, condition: true);
        }
 
        public void AppendLiteral(string value)
            => _builder.AppendLiteral(value);
 
        public void AppendFormatted<TValue>(TValue value)
            => _builder.AppendFormatted(value);
 
        public void AppendFormatted<TValue>(TValue value, string format)
            where TValue : IFormattable
            => _builder.AppendFormatted(value, format);
 
        public string GetFormattedText()
            => _builder.GetFormattedText();
    }
 
    private ref struct PooledStringBuilderHelper
    {
        private StringBuilder? _builder;
 
        public PooledStringBuilderHelper(int capacity, bool condition)
        {
            if (condition)
            {
                _builder = new StringBuilder(capacity);
            }
        }
 
        public readonly void AppendLiteral(string value)
            => _builder!.Append(value);
 
        public readonly void AppendFormatted<T>(T value)
            => _builder!.Append(value?.ToString());
 
        public readonly void AppendFormatted<TValue>(TValue value, string format)
            where TValue : IFormattable
            => _builder!.Append(value?.ToString(format, formatProvider: null));
 
        public string GetFormattedText()
        {
            var builder = Interlocked.Exchange(ref _builder, null);
 
            if (builder is not null)
            {
                return builder.ToString();
            }
 
            // GetFormattedText() should never be called if the condition passed in was false.
            return Unreachable<string>();
        }
    }
}