using BenchmarkDotNet.Attributes;
using System;

namespace RemoveLater
{
    [MemoryDiagnoser]
    public class FormatarCpf
    {
        private string _cpf;

        [GlobalSetup]
        public void Setup()
        {
            _cpf = "12345678901";
        }

        [Benchmark]
        public string FormataComSpan()
        {
            var cpfSpan = _cpf.AsSpan();
            Span<char> cpfFormatado = stackalloc char[14];
            cpfFormatado[3] = '.';
            cpfFormatado[7] = '.';
            cpfFormatado[11] = '-';
            for (var i = (src: 0, dest: 0); i.src < 11;)
            {
                if (i.src == 3 || i.src == 6 || i.src == 9)
                    i.dest++;
                cpfFormatado[i.dest] = cpfSpan[i.src];
                i = (i.src + 1, i.dest + 1);
            }
            return cpfFormatado.ToString();
        }

        [Benchmark]
        public string FormataComSpanSlice()
        {
            var cpfSpan = _cpf.AsSpan();
            Span<char> cpfFormatado = stackalloc char[14];
            cpfFormatado[3] = '.';
            cpfFormatado[7] = '.';
            cpfFormatado[11] = '-';
            cpfSpan.Slice(0, 3).CopyTo(cpfFormatado.Slice(0, 3));
            cpfSpan.Slice(3, 3).CopyTo(cpfFormatado.Slice(4, 3));
            cpfSpan.Slice(6, 3).CopyTo(cpfFormatado.Slice(8, 3));
            cpfSpan.Slice(9, 2).CopyTo(cpfFormatado.Slice(12, 2));
            return cpfFormatado.ToString();
        }

        [Benchmark]
        public string FormataComIndexRange()
        {
            return $"{_cpf[0..2]}.{_cpf[3..5]}.{_cpf[6..8]}-{_cpf[9..10]}";
        }

        [Benchmark(Baseline = true)]
        public string FormataComSubString()
        {
            return $"{_cpf.Substring(0, 3)}.{_cpf.Substring(3, 3)}.{_cpf.Substring(6, 3)}-{_cpf.Substring(9, 2)}";
        }
    }
}