using Microsoft.TypeSpec.Generator;
using Microsoft.TypeSpec.Generator.ClientModel;
using Microsoft.TypeSpec.Generator.ClientModel.Providers;
using Microsoft.TypeSpec.Generator.Input;
using Microsoft.TypeSpec.Generator.Primitives;
using Microsoft.TypeSpec.Generator.Providers;
using Microsoft.TypeSpec.Generator.SourceInput;
using Moq;
using Moq.Protected;
using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;

namespace OpenAILibraryPlugin.Tests.TestHelpers
{
    internal class MockHelpers
    {
        private static readonly string _configFilePath = Path.Combine(AppContext.BaseDirectory, TestHelpersFolder);
        private const string TestHelpersFolder = "TestHelpers";

        public static Mock<ScmCodeModelGenerator> LoadMockGenerator(
            Func<InputType, TypeProvider, IReadOnlyList<TypeProvider>>? createSerializationsCore = null,
            Func<InputType, CSharpType>? createCSharpTypeCore = null,
            Func<InputApiKeyAuth>? apiKeyAuth = null,
            Func<InputOAuth2Auth>? oauth2Auth = null,
            Func<IReadOnlyList<string>>? apiVersions = null,
            Func<IReadOnlyList<InputLiteralType>>? inputLiterals = null,
            Func<IReadOnlyList<InputEnumType>>? inputEnums = null,
            Func<IReadOnlyList<InputModelType>>? inputModels = null,
            Func<IReadOnlyList<InputClient>>? clients = null,
            Func<InputClient, ClientProvider?>? createClientCore = null,
            ClientResponseApi? clientResponseApi = null,
            ClientPipelineApi? clientPipelineApi = null,
            HttpMessageApi? httpMessageApi = null,
            string? configurationJson = null,
            string? inputNamespace = null)
        {
            IReadOnlyList<string> inputNsApiVersions = apiVersions?.Invoke() ?? [];
            IReadOnlyList<InputLiteralType> inputNsLiterals = inputLiterals?.Invoke() ?? [];
            IReadOnlyList<InputEnumType> inputNsEnums = inputEnums?.Invoke() ?? [];
            IReadOnlyList<InputClient> inputNsClients = clients?.Invoke() ?? [];
            IReadOnlyList<InputModelType> inputNsModels = inputModels?.Invoke() ?? [];
            InputAuth inputNsAuth = new InputAuth(apiKeyAuth?.Invoke(), oauth2Auth?.Invoke());
            var mockInputNs = new Mock<InputNamespace>(
                inputNamespace ?? "Samples",
                inputNsApiVersions,
                inputNsLiterals,
                inputNsEnums,
                inputNsModels,
                inputNsClients,
                inputNsAuth);
            var mockInputLibrary = new Mock<InputLibrary>(_configFilePath);
            mockInputLibrary.Setup(p => p.InputNamespace).Returns(mockInputNs.Object);

            Mock<ScmTypeFactory>? mockTypeFactory = null;
            if (createCSharpTypeCore is not null)
            {
                mockTypeFactory = new Mock<ScmTypeFactory>() { CallBase = true };
                mockTypeFactory.Protected().Setup<CSharpType>("CreateCSharpTypeCore", ItExpr.IsAny<InputType>()).Returns(createCSharpTypeCore);
            }

            if (createClientCore is not null)
            {
                mockTypeFactory ??= new Mock<ScmTypeFactory>() { CallBase = true };
                mockTypeFactory.Protected().Setup<ClientProvider?>("CreateClientCore", ItExpr.IsAny<InputClient>()).Returns(createClientCore);
            }

            // initialize the mock singleton instance of the plugin
            var codeModelInstance = typeof(CodeModelGenerator).GetField("_instance", BindingFlags.Static | BindingFlags.NonPublic);
            // invoke the load method with the config file path
            var loadMethod = typeof(Configuration).GetMethod("Load", BindingFlags.Static | BindingFlags.NonPublic);
            object?[] parameters = [_configFilePath, configurationJson];
            var config = loadMethod?.Invoke(null, parameters);
            var mockGeneratorContext = new Mock<GeneratorContext>(config!);
            var mockGeneratorInstance = new Mock<ScmCodeModelGenerator>(mockGeneratorContext.Object) { CallBase = true };
            codeModelInstance!.SetValue(null, mockGeneratorInstance.Object);
            mockGeneratorInstance.SetupGet(p => p.InputLibrary).Returns(mockInputLibrary.Object);

            if (mockTypeFactory is not null)
            {
                mockGeneratorInstance.SetupGet(p => p.TypeFactory).Returns(mockTypeFactory.Object);
            }

            var sourceInputModel = new Mock<SourceInputModel>(() => new SourceInputModel(null, null)) { CallBase = true };
            mockGeneratorInstance.Setup(p => p.SourceInputModel).Returns(sourceInputModel.Object);
            var configureMethod = typeof(CodeModelGenerator).GetMethod(
                "Configure",
                BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.InvokeMethod
            );
            configureMethod!.Invoke(mockGeneratorInstance.Object, null);
            return mockGeneratorInstance;
        }

        public static void SetCustomCodeView(ModelProvider modelProvider, TypeProvider customCodeTypeProvider)
        {
            modelProvider.GetType().BaseType!.GetField(
                    "_customCodeView",
                    BindingFlags.NonPublic | BindingFlags.Instance)?
                .SetValue(modelProvider, new Lazy<TypeProvider>(() => customCodeTypeProvider));
        }
    }
}