// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Reflection;
using Aspire.Hosting.ApplicationModel;
using Aspire.Hosting.RemoteHost;
using Aspire.TypeSystem;
using Aspire.Hosting.CodeGeneration.TypeScript.Tests.TestTypes;
 
namespace Aspire.Hosting.CodeGeneration.Rust.Tests;
 
public class AtsRustCodeGeneratorTests
{
    private readonly AtsRustCodeGenerator _generator = new();
 
    // The test types are compiled into this assembly via Compile Include
    private const string TestTypesAssemblyName = "Aspire.Hosting.CodeGeneration.Rust.Tests";
 
    [Fact]
    public void Language_ReturnsRust()
    {
        Assert.Equal("Rust", _generator.Language);
    }
 
    [Fact]
    public async Task GenerateDistributedApplication_WithTestTypes_GeneratesCorrectOutput()
    {
        // Arrange
        var atsContext = CreateContextFromTestAssembly();
 
        // Act
        var files = _generator.GenerateDistributedApplication(atsContext);
 
        // Assert
        Assert.Contains("aspire.rs", files.Keys);
        Assert.Contains("transport.rs", files.Keys);
        Assert.Contains("base.rs", files.Keys);
        Assert.Contains("mod.rs", files.Keys);
 
        await Verify(files["aspire.rs"], extension: "rs")
            .UseFileName("AtsGeneratedAspire");
    }
 
    [Fact]
    public void GenerateDistributedApplication_WithTestTypes_IncludesCapabilities()
    {
        // Arrange
        var capabilities = ScanCapabilitiesFromTestAssembly();
 
        // Assert that capabilities are discovered
        Assert.NotEmpty(capabilities);
 
        // Check for specific capabilities (uses AssemblyName/methodName format)
        Assert.Contains(capabilities, c => c.CapabilityId == $"{TestTypesAssemblyName}/addTestRedis");
        Assert.Contains(capabilities, c => c.CapabilityId == $"{TestTypesAssemblyName}/withPersistence");
        Assert.Contains(capabilities, c => c.CapabilityId == $"{TestTypesAssemblyName}/withOptionalString");
    }
 
    [Fact]
    public void GenerateDistributedApplication_WithTestTypes_DeriveCorrectMethodNames()
    {
        // Arrange
        var capabilities = ScanCapabilitiesFromTestAssembly();
 
        // Assert method names are derived correctly
        var addTestRedis = capabilities.First(c => c.CapabilityId == $"{TestTypesAssemblyName}/addTestRedis");
        Assert.Equal("addTestRedis", addTestRedis.MethodName);
 
        var withPersistence = capabilities.First(c => c.CapabilityId == $"{TestTypesAssemblyName}/withPersistence");
        Assert.Equal("withPersistence", withPersistence.MethodName);
    }
 
    [Fact]
    public void GenerateDistributedApplication_WithTestTypes_CapturesParameters()
    {
        // Arrange
        var capabilities = ScanCapabilitiesFromTestAssembly();
 
        // Assert parameters are captured
        var addTestRedis = capabilities.First(c => c.CapabilityId == $"{TestTypesAssemblyName}/addTestRedis");
        Assert.Equal(2, addTestRedis.Parameters.Count);
        Assert.Equal("Aspire.Hosting/Aspire.Hosting.IDistributedApplicationBuilder", addTestRedis.TargetTypeId);
        Assert.Contains(addTestRedis.Parameters, p => p.Name == "name" && p.Type?.TypeId == "string");
        Assert.Contains(addTestRedis.Parameters, p => p.Name == "port" && p.IsOptional);
    }
 
    [Fact]
    public void Scanner_ReturnsBuilder_TrueForResourceBuilderReturnTypes()
    {
        // Verify that ReturnsBuilder is correctly set to true for methods
        // that return IResourceBuilder<T>
        var capabilities = ScanCapabilitiesFromTestAssembly();
 
        // addTestRedis returns IResourceBuilder<TestRedisResource> - should have ReturnsBuilder = true
        var addTestRedis = capabilities.FirstOrDefault(c => c.CapabilityId == $"{TestTypesAssemblyName}/addTestRedis");
        Assert.NotNull(addTestRedis);
        Assert.True(addTestRedis.ReturnsBuilder,
            "addTestRedis returns IResourceBuilder<T> but ReturnsBuilder is false - fluent chaining won't work");
 
        // withPersistence also returns IResourceBuilder<T>
        var withPersistence = capabilities.FirstOrDefault(c => c.CapabilityId == $"{TestTypesAssemblyName}/withPersistence");
        Assert.NotNull(withPersistence);
        Assert.True(withPersistence.ReturnsBuilder,
            "withPersistence returns IResourceBuilder<T> but ReturnsBuilder is false - fluent chaining won't work");
    }
 
    [Fact]
    public async Task Scanner_AddTestRedis_HasCorrectTypeMetadata()
    {
        // Verify the entire capability object for addTestRedis
        var capabilities = ScanCapabilitiesFromTestAssembly();
 
        var addTestRedis = capabilities.FirstOrDefault(c => c.CapabilityId == $"{TestTypesAssemblyName}/addTestRedis");
        Assert.NotNull(addTestRedis);
 
        await Verify(addTestRedis).UseFileName("AddTestRedisCapability");
    }
 
    [Fact]
    public async Task Scanner_WithPersistence_HasCorrectExpandedTargets()
    {
        // Verify the entire capability object for withPersistence
        var capabilities = ScanCapabilitiesFromTestAssembly();
 
        var withPersistence = capabilities.FirstOrDefault(c => c.CapabilityId == $"{TestTypesAssemblyName}/withPersistence");
        Assert.NotNull(withPersistence);
 
        await Verify(withPersistence).UseFileName("WithPersistenceCapability");
    }
 
    [Fact]
    public async Task Scanner_WithOptionalString_HasCorrectExpandedTargets()
    {
        // Verify withOptionalString (targets IResource, should expand to TestRedisResource)
        var capabilities = ScanCapabilitiesFromTestAssembly();
 
        var withOptionalString = capabilities.FirstOrDefault(c => c.CapabilityId == $"{TestTypesAssemblyName}/withOptionalString");
        Assert.NotNull(withOptionalString);
 
        await Verify(withOptionalString).UseFileName("WithOptionalStringCapability");
    }
 
    [Fact]
    public async Task Scanner_HostingAssembly_AddContainerCapability()
    {
        // Verify the addContainer capability from the real Aspire.Hosting assembly
        var capabilities = ScanCapabilitiesFromHostingAssembly();
 
        var addContainer = capabilities.FirstOrDefault(c => c.CapabilityId == "Aspire.Hosting/addContainer");
        Assert.NotNull(addContainer);
 
        await Verify(addContainer).UseFileName("HostingAddContainerCapability");
    }
 
    [Fact]
    public void RuntimeType_ContainerResource_IsNotInterface()
    {
        // Verify that ContainerResource.IsInterface returns false using runtime reflection
        var containerResourceType = typeof(ContainerResource);
 
        Assert.NotNull(containerResourceType);
        Assert.False(containerResourceType.IsInterface, "ContainerResource should NOT be an interface");
    }
 
    [Fact]
    public void TwoPassScanning_DeduplicatesCapabilities()
    {
        // Verify that when the same capability appears in multiple assemblies,
        // ScanAssemblies deduplicates by CapabilityId.
        var capabilities = ScanCapabilitiesFromBothAssemblies();
 
        // Each capability ID should appear only once
        var duplicates = capabilities
            .GroupBy(c => c.CapabilityId)
            .Where(g => g.Count() > 1)
            .Select(g => g.Key)
            .ToList();
 
        Assert.Empty(duplicates);
    }
 
    [Fact]
    public void TwoPassScanning_MergesHandleTypesFromAllAssemblies()
    {
        // Verify that ScanAssemblies collects handle types from all assemblies
        var result = CreateContextFromBothAssemblies();
 
        // Should have types from Aspire.Hosting (ContainerResource, etc.)
        var containerResourceType = result.HandleTypes
            .FirstOrDefault(t => t.AtsTypeId.Contains("ContainerResource") && !t.AtsTypeId.Contains("IContainer"));
        Assert.NotNull(containerResourceType);
 
        // Should have types from test assembly (TestRedisResource)
        var testRedisType = result.HandleTypes
            .FirstOrDefault(t => t.AtsTypeId.Contains("TestRedisResource"));
        Assert.NotNull(testRedisType);
 
        // TestRedisResource should have IResourceWithEnvironment in its interfaces
        // (inherited via ContainerResource)
        var hasEnvironmentInterface = testRedisType.ImplementedInterfaces
            .Any(i => i.TypeId.Contains("IResourceWithEnvironment"));
        Assert.True(hasEnvironmentInterface,
            "TestRedisResource should implement IResourceWithEnvironment via ContainerResource");
    }
 
    [Fact]
    public async Task TwoPassScanning_GeneratesWithEnvironmentOnTestRedisBuilder()
    {
        // End-to-end test: verify that with_environment appears on TestRedisResource
        // in the generated Rust when using 2-pass scanning.
        var atsContext = CreateContextFromBothAssemblies();
 
        // Generate Rust
        var files = _generator.GenerateDistributedApplication(atsContext);
        var aspireRs = files["aspire.rs"];
 
        // Verify with_environment appears (method should exist for resources that support it)
        Assert.Contains("with_environment", aspireRs);
 
        // Snapshot for detailed verification
        await Verify(aspireRs, extension: "rs")
            .UseFileName("TwoPassScanningGeneratedAspire");
    }
 
    [Fact]
    public void GeneratedCode_UsesSnakeCaseMethodNames()
    {
        // Verify that the generated Rust code uses snake_case for method names
        var atsContext = CreateContextFromBothAssemblies();
 
        var files = _generator.GenerateDistributedApplication(atsContext);
        var aspireRs = files["aspire.rs"];
 
        // Rust uses snake_case for methods
        Assert.Contains("add_container", aspireRs);
        Assert.Contains("with_environment", aspireRs);
        Assert.DoesNotContain("addContainer(", aspireRs);
        Assert.DoesNotContain("withEnvironment(", aspireRs);
    }
 
    [Fact]
    public void GeneratedCode_HasCreateBuilderFunction()
    {
        // Verify that the generated Rust code has a create_builder function
        var atsContext = CreateContextFromBothAssemblies();
 
        var files = _generator.GenerateDistributedApplication(atsContext);
        var aspireRs = files["aspire.rs"];
 
        Assert.Contains("pub fn create_builder", aspireRs);
    }
 
    [Fact]
    public void GeneratedCode_HasModRsFile()
    {
        // Verify that mod.rs file is generated
        var atsContext = CreateContextFromBothAssemblies();
 
        var files = _generator.GenerateDistributedApplication(atsContext);
 
        Assert.Contains("mod.rs", files.Keys);
        Assert.Contains("pub mod aspire", files["mod.rs"]);
    }
 
    private static List<AtsCapabilityInfo> ScanCapabilitiesFromTestAssembly()
    {
        var testAssembly = LoadTestAssembly();
 
        // Scan capabilities from the test assembly
        var result = AtsCapabilityScanner.ScanAssembly(testAssembly);
        return result.Capabilities;
    }
 
    private static AtsContext CreateContextFromTestAssembly()
    {
        var testAssembly = LoadTestAssembly();
 
        // Scan capabilities from the test assembly
        var result = AtsCapabilityScanner.ScanAssembly(testAssembly);
        return result.ToAtsContext();
    }
 
    private static Assembly LoadTestAssembly()
    {
        // Get the test assembly at runtime (TypeScript tests assembly has the TestTypes)
        return typeof(TestRedisResource).Assembly;
    }
 
    private static List<AtsCapabilityInfo> ScanCapabilitiesFromHostingAssembly()
    {
        var hostingAssembly = typeof(DistributedApplication).Assembly;
        var result = AtsCapabilityScanner.ScanAssembly(hostingAssembly);
        return result.Capabilities;
    }
 
    private static List<AtsCapabilityInfo> ScanCapabilitiesFromBothAssemblies()
    {
        var (testAssembly, hostingAssembly) = LoadBothAssemblies();
 
        // Use ScanAssemblies for proper cross-assembly expansion
        var result = AtsCapabilityScanner.ScanAssemblies([hostingAssembly, testAssembly]);
        return result.Capabilities;
    }
 
    private static AtsContext CreateContextFromBothAssemblies()
    {
        var (testAssembly, hostingAssembly) = LoadBothAssemblies();
 
        // Use ScanAssemblies for proper cross-assembly expansion and enum collection
        var result = AtsCapabilityScanner.ScanAssemblies([hostingAssembly, testAssembly]);
        return result.ToAtsContext();
    }
 
    private static (Assembly testAssembly, Assembly hostingAssembly) LoadBothAssemblies()
    {
        var testAssembly = typeof(TestRedisResource).Assembly;
        var hostingAssembly = typeof(DistributedApplication).Assembly;
        return (testAssembly, hostingAssembly);
    }
}