using System.Reflection;
using System.Threading.Tasks;
using Translator.Cli.Configuration;
using Translator.Core.Mods;
using Xunit;

namespace Translator.Tests;

public sealed class TranslateRecursiveRuntimeConfigTests
{
    [Fact]
    public void UnsupportedOpcodeFailsStrictTranslation()
    {
        var root = Path.Combine(Path.GetTempPath(), $"translator-unsupported-opcode-{Guid.NewGuid():N}");
        Directory.CreateDirectory(root);
        try
        {
            const uint entry = 0x80001000u;
            File.WriteAllBytes(
                Path.Combine(root, "main.dol"),
                SyntheticDolFactory.CreateBytes(
                    entry,
                    sections: [SyntheticDolFactory.Text(
                        0,
                        entry,
                        0x04000000u, // unassigned primary opcode; deliberately unsupported by the lifter
                        0x4E800020u)])); // blr
            var projectPath = Path.Combine(root, "recomp.yml");
            File.WriteAllText(
                projectPath,
                """
                schema_version: 1
                project:
                  id: unsupported-opcode-test
                memory:
                  sda_base: 0x80002000
                  sda2_base: 0x80003000
                inputs:
                  dol:
                    path: main.dol
                translation:
                  entry_points: [0x80001000]
                output:
                  root: generated
                """);
            Assert.False(TranslationProjectConfig.Load(projectPath).Translation.AllowUnsupportedInstructions);

            var strictError = Assert.Throws<TargetInvocationException>(() => InvokeCli(
                "translate-recursive",
                $"0x{entry:X8}",
                "--project", projectPath,
                "--outdir", Path.Combine(root, "strict", "functions"),
                "--output-metadata", Path.Combine(root, "strict", "metadata.json"),
                "--threads", "1"));
            Assert.Contains("UNIMPLEMENTED", strictError.InnerException?.ToString(), StringComparison.Ordinal);
        }
        finally
        {
            if (Directory.Exists(root)) Directory.Delete(root, recursive: true);
        }
    }

    [Fact]
    public void RepeatedRunsReuseUnchangedOutputsAndPruneStaleFiles()
    {
        var root = Path.Combine(Path.GetTempPath(), $"translator-recursive-prune-{Guid.NewGuid():N}");
        Directory.CreateDirectory(root);
        try
        {
            const uint entry = 0x80001000u;
            File.WriteAllBytes(
                Path.Combine(root, "main.dol"),
                SyntheticDolFactory.CreateBytes(
                    entry,
                    sections: [SyntheticDolFactory.Text(
                        0,
                        entry,
                        0x60000000u, // nop
                        0x60000000u, // nop
                        0x4E800020u)])); // blr
            var projectPath = Path.Combine(root, "recomp.yml");
            File.WriteAllText(
                projectPath,
                """
                schema_version: 1
                project:
                  id: recursive-prune-test
                  display_name: Recursive Prune Test
                memory:
                  sda_base: 0x80002000
                  sda2_base: 0x80003000
                inputs:
                  dol:
                    path: main.dol
                translation:
                  entry_points: [0x80001000]
                output:
                  root: generated
                """);

            var stagedFunctions = Path.Combine(root, "staging", "functions");
            var stagedOutputMetadata = Path.Combine(root, "staging", "functions_metadata.json");
            var exitCode = InvokeCli(
                "translate-recursive",
                $"0x{entry:X8}",
                "--project",
                projectPath,
                "--outdir",
                stagedFunctions,
                "--output-metadata",
                stagedOutputMetadata,
                "--threads",
                "1");

            Assert.Equal(0, exitCode);
            var firstMetadata = BaseTranslationOutputMetadataFile.Read(stagedOutputMetadata);
            Assert.Null(firstMetadata.TranslationIdentityHash);
            Assert.Equal(0, firstMetadata.Quality.UnsupportedInstructionCount);
            Assert.Equal(0, firstMetadata.Quality.InvalidSsaFunctionCount);
            Assert.Single(firstMetadata.Functions);
            Assert.Single(Directory.GetFiles(stagedFunctions, "*.cpp"));
            var generatedPath = Directory.GetFiles(stagedFunctions, "*.cpp").Single();
            var unchangedTimestamp = new DateTime(2004, 5, 6, 7, 8, 10, DateTimeKind.Utc);
            File.SetLastWriteTimeUtc(generatedPath, unchangedTimestamp);
            // A populated output tree is not an input to recursive discovery.
            // This stale filename used to become a synthetic function boundary
            // and truncate the second translation at entry + 4.
            File.WriteAllText(Path.Combine(stagedFunctions, $"func_{entry + 4:X8}.cpp"), "stale output hint");
            var metadataTimestamp = new DateTime(2004, 5, 6, 7, 8, 12, DateTimeKind.Utc);
            File.SetLastWriteTimeUtc(stagedOutputMetadata, metadataTimestamp);

            var secondExitCode = InvokeCli(
                "translate-recursive",
                $"0x{entry:X8}",
                "--project",
                projectPath,
                "--outdir",
                stagedFunctions,
                "--output-metadata",
                stagedOutputMetadata,
                "--threads",
                "1");

            Assert.Equal(0, secondExitCode);
            Assert.Equal(unchangedTimestamp, File.GetLastWriteTimeUtc(generatedPath));
            Assert.Equal(metadataTimestamp, File.GetLastWriteTimeUtc(stagedOutputMetadata));

            var stalePath = Path.Combine(stagedFunctions, "func_80001004.cpp");
            var unlistedPath = Path.Combine(stagedFunctions, "unlisted.cpp");
            File.WriteAllText(stalePath, "// stale");
            File.WriteAllText(unlistedPath, "// not translator-owned");
            BaseTranslationOutputMetadataFile.WriteIfChangedAtomic(
                stagedOutputMetadata,
                BaseTranslationOutputMetadata.Create(
                    firstMetadata.Functions.Concat([
                        new BaseTranslationFunctionMetadata(
                            "func_80001004.cpp",
                            8,
                            new string('e', 64),
                            0x80001004u,
                            [])
                    ]),
                    TranslationQualityMetadata.Clean));

            var pruneExitCode = InvokeCli(
                "translate-recursive",
                $"0x{entry:X8}",
                "--project",
                projectPath,
                "--outdir",
                stagedFunctions,
                "--output-metadata",
                stagedOutputMetadata,
                "--prune-stale",
                "--threads",
                "1");
            Assert.Equal(0, pruneExitCode);
            Assert.False(File.Exists(stalePath));
            Assert.True(File.Exists(unlistedPath));
        }
        finally
        {
            if (Directory.Exists(root))
            {
                Directory.Delete(root, recursive: true);
            }
        }
    }

    private static int InvokeCli(params string[] args)
    {
        var entryPoint = typeof(TranslationProjectConfig).Assembly.EntryPoint;
        Assert.NotNull(entryPoint);
        var result = entryPoint!.Invoke(null, new object?[] { args });
        return result switch
        {
            int exitCode => exitCode,
            Task<int> intTask => intTask.GetAwaiter().GetResult(),
            Task task => CompleteTask(task),
            null => 0,
            _ => throw new InvalidOperationException($"Unexpected CLI entry point result type: {result.GetType().FullName}")
        };
    }

    private static int CompleteTask(Task task)
    {
        task.GetAwaiter().GetResult();
        return 0;
    }
}