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 * Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
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 * obtaining a copy of this software and associated documentation
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 *
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 * http://opcfoundation.org/License/MIT/1.00/
 * ======================================================================*/

using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using NUnit.Framework;

namespace Opc.Ua.SourceGeneration.Tests
{
    [TestFixture]
    [Category("SourceGenerator")]
    [SetCulture("en-us")]
    [SetUICulture("en-us")]
    public class StackGenerationAssemblyTests
    {
        /// <summary>
        /// A generator must never fail a compilation it was not meant for. The
        /// stack generator is loaded into every compilation that references it,
        /// so a project that did not opt in has to compile untouched and
        /// silently - which is what the BenchmarkDotNet host project needs.
        /// </summary>
        [Test]
        public void GeneratorWithoutTheOptInGeneratesNothingAndStaysQuiet()
        {
            var generator = new StackSourceGenerator();

            CSharpCompilation compilation = OptimizationLevel.Debug
                .CreateCompilation("BenchmarkDotNet.Autogenerated")
                .AddCode(
                    new Dictionary<string, string>().WithOpcUaCoreStubs(),
                    LanguageVersion.Latest);

            GeneratorDriver driver = CSharpGeneratorDriver.Create(generator);
            driver = driver.RunGeneratorsAndUpdateCompilation(
                compilation,
                out _,
                out _);

            GeneratorDriverRunResult runResult = driver.GetRunResult();
            GeneratorRunResult generatorResult = runResult.Results[0];

            Assert.That(generatorResult.Exception, Is.Null);
            Assert.That(generatorResult.GeneratedSources, Is.Empty);
            Assert.That(generatorResult.Diagnostics, Is.Empty);
        }

        /// <summary>
        /// An opt-in the generator cannot make sense of is a misconfiguration
        /// and must still be reported.
        /// </summary>
        [Test]
        public void GeneratorWithAnUnknownModeReportsError()
        {
            var generator = new StackSourceGenerator();

            CSharpCompilation compilation = OptimizationLevel.Debug
                .CreateCompilation("Opc.Ua.Core")
                .AddCode(
                    new Dictionary<string, string>().WithOpcUaCoreStubs(),
                    LanguageVersion.Latest);

            GeneratorDriver driver = CreateDriver(generator, "Nonsense");
            driver = driver.RunGeneratorsAndUpdateCompilation(
                compilation,
                out _,
                out _);

            GeneratorDriverRunResult runResult = driver.GetRunResult();
            GeneratorRunResult generatorResult = runResult.Results[0];

            Assert.That(generatorResult.Exception, Is.Null);
            Assert.That(generatorResult.Diagnostics.Any(d =>
                d.Id == "STACKGEN001"), Is.True);
            Assert.That(generatorResult.GeneratedSources, Is.Empty);
        }

        /// <summary>
        /// The assembly name must no longer decide what is generated - renaming
        /// a project used to change the output silently.
        /// </summary>
        [Test]
        public void GeneratorHonoursTheModeRegardlessOfAssemblyName()
        {
            var generator = new StackSourceGenerator();

            CSharpCompilation compilation = OptimizationLevel.Debug
                .CreateCompilation("Some.Renamed.Assembly")
                .AddCode(
                    new Dictionary<string, string>().WithOpcUaCoreStubs(),
                    LanguageVersion.Latest);

            GeneratorDriver driver = CreateDriver(generator, "Stack");
            driver = driver.RunGeneratorsAndUpdateCompilation(
                compilation,
                out _,
                out _);

            GeneratorDriverRunResult runResult = driver.GetRunResult();
            GeneratorRunResult generatorResult = runResult.Results[0];

            Assert.That(generatorResult.Exception, Is.Null);
            Assert.That(generatorResult.GeneratedSources, Is.Not.Empty);
        }

        [Test]
        public void GeneratorWithModelsModeProducesModels()
        {
            var generator = new StackSourceGenerator();

            CSharpCompilation compilation = OptimizationLevel.Debug
                .CreateCompilation("Opc.Ua.Core.Types")
                .AddCode(
                    new Dictionary<string, string>().WithOpcUaCoreStubs(),
                    LanguageVersion.Latest);

            GeneratorDriver driver = CreateDriver(generator, "Models");
            driver = driver.RunGeneratorsAndUpdateCompilation(
                compilation,
                out _,
                out _);

            GeneratorDriverRunResult runResult = driver.GetRunResult();
            GeneratorRunResult generatorResult = runResult.Results[0];

            Assert.That(generatorResult.Exception, Is.Null);
            Assert.That(generatorResult.GeneratedSources, Is.Not.Empty);
        }

        [Test]
        public void GeneratorWithStackModeProducesStack()
        {
            var generator = new StackSourceGenerator();

            CSharpCompilation compilation = OptimizationLevel.Debug
                .CreateCompilation("Opc.Ua.Core")
                .AddCode(
                    new Dictionary<string, string>().WithOpcUaCoreStubs(),
                    LanguageVersion.Latest);

            GeneratorDriver driver = CreateDriver(generator, "Stack");
            driver = driver.RunGeneratorsAndUpdateCompilation(
                compilation,
                out _,
                out _);

            GeneratorDriverRunResult runResult = driver.GetRunResult();
            GeneratorRunResult generatorResult = runResult.Results[0];

            Assert.That(generatorResult.Exception, Is.Null);
            Assert.That(generatorResult.GeneratedSources, Is.Not.Empty);
        }

        [Test]
        public void GeneratorWithOldLanguageVersionReportsError()
        {
            var generator = new StackSourceGenerator();

            CSharpCompilation compilation = OptimizationLevel.Debug
                .CreateCompilation("Opc.Ua.Test")
                .AddCode(
                    new Dictionary<string, string>().WithOpcUaCoreStubs(),
                    LanguageVersion.CSharp12);

            GeneratorDriver driver = CreateDriver(generator, "All");
            driver = driver.RunGeneratorsAndUpdateCompilation(
                compilation,
                out Compilation outputCompilation,
                out ImmutableArray<Diagnostic> diagnostics);

            GeneratorDriverRunResult runResult = driver.GetRunResult();
            GeneratorRunResult generatorResult = runResult.Results[0];

            Assert.That(generatorResult.Exception, Is.Null);
            Assert.That(generatorResult.Diagnostics.Any(d =>
                d.Id == "STACKGEN001"), Is.True);
            Assert.That(generatorResult.GeneratedSources, Is.Empty);
        }

        [Test]
        public void GeneratorWithReleaseOptimizationProducesOutput()
        {
            var generator = new StackSourceGenerator();

            CSharpCompilation compilation = OptimizationLevel.Release
                .CreateCompilation("Opc.Ua.Test")
                .AddCode(
                    new Dictionary<string, string>().WithOpcUaCoreStubs(),
                    LanguageVersion.Latest);

            GeneratorDriver driver = CreateDriver(generator, "All");
            driver = driver.RunGeneratorsAndUpdateCompilation(
                compilation,
                out _,
                out _);

            GeneratorDriverRunResult runResult = driver.GetRunResult();
            GeneratorRunResult generatorResult = runResult.Results[0];

            Assert.That(generatorResult.Exception, Is.Null);
            Assert.That(generatorResult.GeneratedSources, Is.Not.Empty);
        }

        /// <summary>
        /// Builds a driver carrying the opt-in a project declares through the
        /// <c>StackSourceGeneratorMode</c> MSBuild property.
        /// </summary>
        private static CSharpGeneratorDriver CreateDriver(
            StackSourceGenerator generator,
            string mode)
        {
            return CSharpGeneratorDriver.Create(
                [generator.AsSourceGenerator()],
                optionsProvider: new AnalyzerOptionsProvider(
                    new Dictionary<string, string>
                    {
                        ["build_property.stacksourcegeneratormode"] = mode
                    }));
        }
    }
}