/**
 ******************************************************************************
 * Xenia : Xbox 360 Emulator Research Project                                 *
 ******************************************************************************
 * Copyright 2013 Ben Vanik. All rights reserved.                             *
 * Released under the BSD license - see LICENSE in the root for more details. *
 ******************************************************************************
 */

#include <xenia/cpu/processor.h>

#include <llvm/ExecutionEngine/ExecutionEngine.h>
#include <llvm/ExecutionEngine/GenericValue.h>
#include <llvm/ExecutionEngine/Interpreter.h>
#include <llvm/ExecutionEngine/JIT.h>
#include <llvm/IR/LLVMContext.h>
#include <llvm/IR/Module.h>
#include <llvm/Support/ManagedStatic.h>
#include <llvm/Support/TargetSelect.h>

#include "cpu/codegen/emit.h"


using namespace llvm;
using namespace xe;
using namespace xe::cpu;
using namespace xe::kernel;


namespace {
  void InitializeIfNeeded();
  void CleanupOnShutdown();

  void InitializeIfNeeded() {
    static bool has_initialized = false;
    if (has_initialized) {
      return;
    }
    has_initialized = true;

    // TODO(benvanik): only do this once
    LLVMLinkInInterpreter();
    LLVMLinkInJIT();
    InitializeNativeTarget();

    llvm_start_multithreaded();

    // TODO(benvanik): only do this once
    codegen::RegisterEmitCategoryALU();
    codegen::RegisterEmitCategoryControl();
    codegen::RegisterEmitCategoryFPU();
    codegen::RegisterEmitCategoryMemory();

    atexit(CleanupOnShutdown);
  }

  void CleanupOnShutdown() {
    llvm_shutdown();
  }
}


Processor::Processor(xe_pal_ref pal, xe_memory_ref memory) {
  pal_ = xe_pal_retain(pal);
  memory_ = xe_memory_retain(memory);

  InitializeIfNeeded();
}

Processor::~Processor() {
  // Cleanup all modules.
  for (std::vector<ExecModule*>::iterator it = modules_.begin();
       it != modules_.end(); ++it) {
    delete *it;
  }

  engine_.reset();

  xe_memory_release(memory_);
  xe_pal_release(pal_);
}

xe_pal_ref Processor::pal() {
  return xe_pal_retain(pal_);
}

xe_memory_ref Processor::memory() {
  return xe_memory_retain(memory_);
}

int Processor::Setup() {
  XEASSERTNULL(engine_);

  dummy_context_ = auto_ptr<LLVMContext>(new LLVMContext());
  Module* dummy_module = new Module("dummy", *dummy_context_.get());

  std::string error_message;

  EngineBuilder builder(dummy_module);
  builder.setEngineKind(EngineKind::JIT);
  builder.setErrorStr(&error_message);
  builder.setOptLevel(CodeGenOpt::None);
  //builder.setOptLevel(CodeGenOpt::Aggressive);
  //builder.setTargetOptions();
  builder.setAllocateGVsWithCode(false);
  //builder.setUseMCJIT(true);

  engine_ = shared_ptr<ExecutionEngine>(builder.create());
  if (!engine_) {
    return 1;
  }

  return 0;
}

int Processor::PrepareModule(
    const char* module_name, const char* module_path,
    uint32_t start_address, uint32_t end_address,
    shared_ptr<ExportResolver> export_resolver) {
  ExecModule* exec_module = new ExecModule(
      memory_, export_resolver, module_name, module_path, engine_);

  if (exec_module->PrepareRawBinary(start_address, end_address)) {
    delete exec_module;
    return 1;
  }

  exec_module->AddFunctionsToMap(all_fns_);
  modules_.push_back(exec_module);

  exec_module->Dump();

  return 0;
}

int Processor::PrepareModule(UserModule* user_module,
                             shared_ptr<ExportResolver> export_resolver) {
  char name_a[2048];
  char path_a[2048];
  XEIGNORE(xestrnarrow(name_a, XECOUNT(name_a), user_module->name()));
  XEIGNORE(xestrnarrow(path_a, XECOUNT(path_a), user_module->path()));
  ExecModule* exec_module = new ExecModule(
      memory_, export_resolver, name_a, path_a,
      engine_);

  if (exec_module->PrepareUserModule(user_module)) {
    delete exec_module;
    return 1;
  }

  exec_module->AddFunctionsToMap(all_fns_);
  modules_.push_back(exec_module);

  //user_module->Dump(export_resolver.get());
  exec_module->Dump();

  return 0;
}

uint32_t Processor::CreateCallback(void (*callback)(void* data), void* data) {
  // TODO(benvanik): implement callback creation.
  return 0;
}

ThreadState* Processor::AllocThread(uint32_t stack_address,
                                    uint32_t stack_size) {
  ThreadState* thread_state = new ThreadState(
      this, stack_address, stack_size);
  return thread_state;
}

void Processor::DeallocThread(ThreadState* thread_state) {
  delete thread_state;
}

int Processor::Execute(ThreadState* thread_state, uint32_t address) {
  // Find the function to execute.
  Function* f = GetFunction(address);
  if (!f) {
    XELOGCPU(XT("Failed to find function %.8X to execute."), address);
    return 1;
  }

  xe_ppc_state_t* ppc_state = thread_state->ppc_state();

  // This could be set to anything to give us a unique identifier to track
  // re-entrancy/etc.
  uint32_t lr = 0xBEBEBEBE;

  // Setup registers.
  ppc_state->lr = lr;

  // Args:
  // - i8* state
  // - i64 lr
  std::vector<GenericValue> args;
  args.push_back(PTOGV(ppc_state));
  GenericValue lr_arg;
  lr_arg.IntVal = APInt(64, lr);
  args.push_back(lr_arg);
  GenericValue ret = engine_->runFunction(f, args);
  // return (uint32_t)ret.IntVal.getSExtValue();

  // Faster, somewhat.
  // Messes with the stack in such a way as to cause Xcode to behave oddly.
  // typedef void (*fnptr)(xe_ppc_state_t*, uint64_t);
  // fnptr ptr = (fnptr)engine_->getPointerToFunction(f);
  // ptr(ppc_state, lr);

  return 0;
}

Function* Processor::GetFunction(uint32_t address) {
  FunctionMap::iterator it = all_fns_.find(address);
  if (it != all_fns_.end()) {
    return it->second;
  }
  return NULL;
}