#include <llvm/IR/LLVMContext.h>

#include "Lexer.h"
#include "Parser.h"

#include <llvm/Support/CommandLine.h>
#include <llvm/Support/ErrorOr.h>
#include <llvm/Support/MemoryBuffer.h>
#include <llvm/Support/SourceMgr.h>
#include <mlir/IR/OwningOpRef.h>
#include <mlir/Parser/Parser.h>
#include <mlir/Pass/PassManager.h>
#include <mlir/Transforms/Passes.h>
#include <mlir/Dialect/Func/Extensions/AllExtensions.h>
#include <mlir/Dialect/Affine/Passes.h>
#include <mlir/Dialect/Func/IR/FuncOps.h>
#include <mlir/Dialect/LLVMIR/Transforms/InlinerInterfaceImpl.h>
#include <mlir/Target/LLVMIR/Dialect/Builtin/BuiltinToLLVMIRTranslation.h>
#include <mlir/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.h>
#include <mlir/Target/LLVMIR/Export.h>
#include <mlir/ExecutionEngine/ExecutionEngine.h>
#include <mlir/ExecutionEngine/OptUtils.h>
#include <llvm/IR/Module.h>
#include <llvm/ExecutionEngine/Orc/JITTargetMachineBuilder.h>
#include <llvm/Support/TargetSelect.h>

#include "Dialect.h"
#include "MLIRGen.h"
#include "Passes.h"

namespace mlir
{
    class ModuleOp;
}

static llvm::cl::opt<std::string> inputFilename(llvm::cl::Positional,
                                                llvm::cl::desc("<input hello file>"),
                                                llvm::cl::init("-"),
                                                llvm::cl::value_desc("filename"));

namespace
{
    enum Action { None, DumpSyntaxNode, DumpMLIR, DumpAffineMLIR, DumpLLVMMLIR, DumpLLVM, RunJit };

    enum InputType { Hello, MLIR };
}

/// The input file type.
static llvm::cl::opt<InputType> inputType("x", llvm::cl::init(Hello),
                                          llvm::cl::desc("Decided the kind of input desired."),
                                          llvm::cl::values(
                                              clEnumValN(Hello, "hello", "load the input file as a hello source.")),
                                          llvm::cl::values(
                                              clEnumValN(MLIR, "mlir", "load the input file as a mlir source.")));

/// What is the action the compiler will do.
static llvm::cl::opt<Action> emitAction("emit", llvm::cl::desc("Select the kind of output desired"),
                                        llvm::cl::values(clEnumValN(DumpSyntaxNode, "ast", "Dump syntax node")),
                                        llvm::cl::values(clEnumValN(DumpMLIR, "mlir", "Dump mlir code")),
                                        llvm::cl::values(clEnumValN(DumpAffineMLIR, "affine-mlir",
                                                                    "Dump mlir code after lowering to affine loops")),
                                        llvm::cl::values(clEnumValN(DumpLLVMMLIR, "llvm-mlir",
                                                                    "Dump mlir code after lowering to llvm.")),
                                        llvm::cl::values(clEnumValN(DumpLLVM, "llvm",
                                                                    "Dump llvm code.")),
                                        llvm::cl::values(clEnumValN(RunJit, "jit", "Run the input by jitter.")));

/// Whether to enable the optimization.
static llvm::cl::opt<bool> enableOpt("opt", llvm::cl::desc("Enable optimizations"));

std::unique_ptr<hello::Module> parseInputFile(llvm::StringRef filename)
{
    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> fileOrErr =
        llvm::MemoryBuffer::getFileOrSTDIN(filename);
    if (const std::error_code ec = fileOrErr.getError())
    {
        llvm::errs() << "Could not open input file: " << ec.message() << "\n";
        return nullptr;
    }
    auto buffer = fileOrErr.get()->getBuffer();
    hello::LexerBuffer lexer(buffer.begin(), buffer.end(), std::string(filename));
    hello::Parser parser(lexer);
    return parser.parseModule();
}

int loadAndProcessMLIR(mlir::MLIRContext& context, mlir::OwningOpRef<mlir::ModuleOp>& module)
{
    if (inputType != MLIR && !llvm::StringRef(inputFilename).ends_with(".mlir"))
    {
        // The input file is hello language.
        auto syntaxNode = parseInputFile(inputFilename);
        if (syntaxNode == nullptr)
        {
            return 1;
        }
        module = hello::mlirGen(context, *syntaxNode);

        if (!module)
        {
            llvm::errs() << "Failed to convert hello syntax tree to MLIR.\n";
            return 1;
        }
    }
    else
    {
        // The the input file is mlir.
        llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> fileOrErr =
            llvm::MemoryBuffer::getFileOrSTDIN(inputFilename);
        if (std::error_code ec = fileOrErr.getError())
        {
            llvm::errs() << "Could not open input file: " << ec.message() << "\n";
            return 1;
        }

        // Parse the input mlir.
        llvm::SourceMgr sourceMgr;
        sourceMgr.AddNewSourceBuffer(std::move(*fileOrErr), llvm::SMLoc());
        module =
            mlir::parseSourceFile<mlir::ModuleOp>(sourceMgr, &context);
        if (!module)
        {
            llvm::errs() << "Error can't load file " << inputFilename << "\n";
            return 1;
        }
    }

    const bool isLoweringToAffine = emitAction >= DumpAffineMLIR;
    const bool isLoweringToLLVM = emitAction >= DumpLLVMMLIR;
    mlir::PassManager manager(module.get()->getName());

    if (mlir::failed(mlir::applyPassManagerCLOptions(manager)))
    {
        return 1;
    }

    if (enableOpt || isLoweringToAffine)
    {
        // To inline all functions except 'main' function.
        manager.addPass(mlir::createInlinerPass());
        // In the canonicalizer pass, we add Transpose Pass and Reshape Pass.
        mlir::OpPassManager& functionPassManager = manager.nest<mlir::hello::FuncOp>();
        functionPassManager.addPass(mlir::createCanonicalizerPass());
        functionPassManager.addPass(mlir::createCSEPass());
        functionPassManager.addPass(mlir::hello::createShapeInferencePass());
    }

    if (isLoweringToAffine)
    {
        manager.addPass(mlir::hello::createLowerToAffineLoopsPass());
        mlir::OpPassManager& functionPassManager = manager.nest<mlir::func::FuncOp>();

        // Add some optimization from the affine dialect.
        if (enableOpt)
        {
            manager.addPass(mlir::affine::createLoopFusionPass());
            functionPassManager.addPass(mlir::affine::createAffineScalarReplacementPass());
        }
    }

    if (isLoweringToLLVM)
    {
        manager.addPass(mlir::hello::createLowerToLLVMPass());
    }

    if (mlir::failed(manager.run(*module)))
    {
        return 1;
    }

    return 0;
}

int dumpLLVMIR(mlir::ModuleOp module)
{
    mlir::registerBuiltinDialectTranslation(*module->getContext());
    mlir::registerLLVMDialectTranslation(*module->getContext());

    // Convert the mlir IR to llvm IR.
    llvm::LLVMContext context;
    const auto llvmModule = mlir::translateModuleToLLVMIR(module, context);
    if (llvmModule == nullptr)
    {
        llvm::errs() << "Could not translate LLVM IR to LLVM IR\n";
        return 1;
    }

    llvm::InitializeNativeTarget();
    llvm::InitializeNativeTargetAsmPrinter();

    auto targetMachineBuilderOrError = llvm::orc::JITTargetMachineBuilder::detectHost();
    if (!targetMachineBuilderOrError)
    {
        llvm::errs() << "Could not detect host machine\n";
        return 1;
    }

    auto targetMachineOrError = targetMachineBuilderOrError->createTargetMachine();
    if (!targetMachineOrError)
    {
        llvm::errs() << "Could not create target machine\n";
        return 1;
    }

    mlir::ExecutionEngine::setupTargetTripleAndDataLayout(llvmModule.get(), targetMachineOrError.get().get());

    const auto optimizationPipeline = mlir::makeOptimizingTransformer(enableOpt ? 3 : 0, 0, nullptr);
    if (auto err = optimizationPipeline(llvmModule.get()))
    {
        llvm::errs() << "Failed to run optimization pipeline for LLVM IR:" << err << "\n";
        return 1;
    }

    llvm::outs() << *llvmModule << "\n";
    return 0;
}

int dumpSyntaxNode()
{
    if (inputType == MLIR)
    {
        llvm::errs() << "Failed to dump hello syntax node when input type is MLIR.";
        return 1;
    }

    auto syntaxNode = parseInputFile(inputFilename);
    if (syntaxNode == nullptr)
    {
        return 1;
    }

    syntaxNode->dump();
    return 0;
}

int runJitter(mlir::ModuleOp module)
{
    llvm::InitializeNativeTarget();
    llvm::InitializeNativeTargetAsmPrinter();

    mlir::registerBuiltinDialectTranslation(*module->getContext());
    mlir::registerLLVMDialectTranslation(*module->getContext());

    auto optimizationPipeline = mlir::makeOptimizingTransformer(enableOpt ? 3 : 0, 0, nullptr);

    mlir::ExecutionEngineOptions options;
    options.transformer = optimizationPipeline;

    auto engineOrError = mlir::ExecutionEngine::create(module, options);
    if (!engineOrError)
    {
        llvm::errs() << "Failed to create execution engine\n";
        return 1;
    }

    const auto& engine = engineOrError.get();

    if (auto invocationResult = engine->invokePacked("main"))
    {
        llvm::errs() << "Failed to run main function by jitter?:" << invocationResult << "\n";
        return 1;
    }

    return 0;
}

int main(int argc, char** argv)
{
    mlir::registerAsmPrinterCLOptions();
    mlir::registerMLIRContextCLOptions();
    mlir::registerPassManagerCLOptions();

    llvm::cl::ParseCommandLineOptions(argc, argv, "Hello MLIR Compiler\n");

    if (emitAction == DumpSyntaxNode)
    {
        return dumpSyntaxNode();
    }

    mlir::DialectRegistry registry;
    mlir::func::registerAllExtensions(registry);
    mlir::LLVM::registerInlinerInterface(registry);

    mlir::MLIRContext context(registry);
    context.getOrLoadDialect<mlir::hello::HelloDialect>();

    mlir::OwningOpRef<mlir::ModuleOp> module;
    if (int error = loadAndProcessMLIR(context, module))
    {
        return error;
    }

    if (emitAction <= DumpLLVMMLIR)
    {
        llvm::outs() << *module << "\n";
        return 0;
    }

    if (emitAction == DumpLLVM)
    {
        return dumpLLVMIR(*module);
    }

    if (emitAction == RunJit)
    {
        return runJitter(*module);
    }

    llvm::errs() << "No action specified (parsing only?), use -emit=<action>\n";
    return -1;
}