using NHIValidation;
using System.Collections.Generic;
using Xunit;
using Xunit.Abstractions;

namespace TestNhi
{
    public class NHIValidationUnitTests
    {
        private readonly ITestOutputHelper _output;

        public NHIValidationUnitTests(ITestOutputHelper output)
        {
            _output = output;
        }

        [Theory]
        [MemberData(nameof(NHIs))]
        public void TestNHIsPass(string nhi)
        {
            Assert.True(NHIValidator.IsValid(nhi));
        }

        [Theory]
        [MemberData(nameof(NHIs))]
        public void TestOtherNHIChecksumsFail(string nhi)
        {
            char checksum = nhi[6];
            string baseNHI = nhi[0..6];
            char[] possibleChecksums = char.IsDigit(checksum)
                ? new[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' }
                : new[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };

            foreach (var c in possibleChecksums)
            {
                if (c != checksum)
                {
                    var n = baseNHI + c;
                    Assert.False(NHIValidator.IsValid(n), $"NHI: {n} incorrectly found valid");
                    _output.WriteLine($"NHI: {n} correctly found invalid");
                }
            }
        }

        [Theory]
        [InlineData("ZZZ0044")] // no digit can be added to "ZZZ004\d"
        [InlineData("ZZZZ000")] // 3 letters followed by either 4 numbers OR 2 numbers + 2 letters
        [InlineData("ZZZ?000")]
        public void TestNHIsFail(string nhi)
        {
            Assert.False(NHIValidator.IsValid(nhi));
        }

        public static IEnumerable<object[]> NHIs =>
            new List<object[]>
            {
                new object[] { "ZZZ0016" },
                new object[] { "ZZZ0024" },
                new object[] { "ZZZ00AX" },
                new object[] { "ALU18KZ" }
            };
    }
}