using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using System;
using System.Collections.Immutable;

namespace MakeConst.Test
{
    internal static class CSharpVerifierHelper
    {
        /// <summary>
        /// By default, the compiler reports diagnostics for nullable reference types at
        /// <see cref="DiagnosticSeverity.Warning"/>, and the analyzer test framework defaults to only validating
        /// diagnostics at <see cref="DiagnosticSeverity.Error"/>. This map contains all compiler diagnostic IDs
        /// related to nullability mapped to <see cref="ReportDiagnostic.Error"/>, which is then used to enable all
        /// of these warnings for default validation during analyzer and code fix tests.
        /// </summary>
        internal static ImmutableDictionary<string, ReportDiagnostic> NullableWarnings { get; } = GetNullableWarningsFromCompiler();

        private static ImmutableDictionary<string, ReportDiagnostic> GetNullableWarningsFromCompiler()
        {
            string[] args = { "/warnaserror:nullable" };
            var commandLineArguments = CSharpCommandLineParser.Default.Parse(args, baseDirectory: Environment.CurrentDirectory, sdkDirectory: Environment.CurrentDirectory);
            var nullableWarnings = commandLineArguments.CompilationOptions.SpecificDiagnosticOptions;

            // Workaround for https://github.com/dotnet/roslyn/issues/41610
            nullableWarnings = nullableWarnings
                .SetItem("CS8632", ReportDiagnostic.Error)
                .SetItem("CS8669", ReportDiagnostic.Error);

            return nullableWarnings;
        }
    }
}
