/**
 ******************************************************************************
 * 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 <gflags/gflags.h>

#include "xenia/base/assert.h"
#include "xenia/base/atomic.h"
#include "xenia/base/byte_order.h"
#include "xenia/base/logging.h"
#include "xenia/base/memory.h"
#include "xenia/cpu/cpu-private.h"
#include "xenia/cpu/export_resolver.h"
#include "xenia/cpu/frontend/ppc_frontend.h"
#include "xenia/cpu/module.h"
#include "xenia/cpu/thread_state.h"
#include "xenia/cpu/xex_module.h"
#include "xenia/debug/debugger.h"
#include "xenia/profiling.h"

// TODO(benvanik): based on compiler support
#include "xenia/cpu/backend/x64/x64_backend.h"

namespace xe {
namespace cpu {

// TODO(benvanik): remove when enums converted.
using namespace xe::cpu;
using namespace xe::cpu::backend;

using PPCContext = xe::cpu::frontend::PPCContext;

void InitializeIfNeeded();
void CleanupOnShutdown();

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

  // ppc::RegisterDisasmCategoryAltivec();
  // ppc::RegisterDisasmCategoryALU();
  // ppc::RegisterDisasmCategoryControl();
  // ppc::RegisterDisasmCategoryFPU();
  // ppc::RegisterDisasmCategoryMemory();

  atexit(CleanupOnShutdown);
}

void CleanupOnShutdown() {}

class BuiltinModule : public Module {
 public:
  BuiltinModule(Processor* processor) : Module(processor), name_("builtin") {}
  const std::string& name() const override { return name_; }
  bool ContainsAddress(uint32_t address) override {
    return (address & 0xFFFFFFF0) == 0xFFFFFFF0;
  }

 private:
  std::string name_;
};

Processor::Processor(xe::Memory* memory, ExportResolver* export_resolver)
    : memory_(memory),
      debug_info_flags_(0),
      trace_flags_(0),
      builtin_module_(nullptr),
      next_builtin_address_(0xFFFF0000ul),
      export_resolver_(export_resolver),
      interrupt_thread_state_(nullptr),
      interrupt_thread_block_(0) {
  InitializeIfNeeded();
}

Processor::~Processor() {
  if (interrupt_thread_block_) {
    memory_->SystemHeapFree(interrupt_thread_block_);
    delete interrupt_thread_state_;
  }

  {
    std::lock_guard<std::mutex> guard(modules_lock_);
    modules_.clear();
  }

  debugger_.reset();
  frontend_.reset();
  backend_.reset();
}

bool Processor::Setup() {
  debug_info_flags_ = DEBUG_INFO_DEFAULT;
  trace_flags_ = 0;

  auto frontend = std::make_unique<xe::cpu::frontend::PPCFrontend>(this);
  // TODO(benvanik): set options/etc.

  // Must be initialized by subclass before calling into this.
  assert_not_null(memory_);

  // Create debugger first. Other types hook up to it.
  debugger_.reset(new xe::debug::Debugger(this));

  std::unique_ptr<Module> builtin_module(new BuiltinModule(this));
  builtin_module_ = builtin_module.get();
  modules_.push_back(std::move(builtin_module));

  if (frontend_ || backend_) {
    return false;
  }

  std::unique_ptr<xe::cpu::backend::Backend> backend;
  if (!backend) {
#if defined(XENIA_HAS_X64_BACKEND) && XENIA_HAS_X64_BACKEND
    if (FLAGS_processor_backend == "x64") {
      backend.reset(new xe::cpu::backend::x64::X64Backend(this));
    }
#endif  // XENIA_HAS_X64_BACKEND
    if (FLAGS_processor_backend == "any") {
#if defined(XENIA_HAS_X64_BACKEND) && XENIA_HAS_X64_BACKEND
      if (!backend) {
        backend.reset(new xe::cpu::backend::x64::X64Backend(this));
      }
#endif  // XENIA_HAS_X64_BACKEND
    }
  }

  if (!backend) {
    return false;
  }
  if (!backend->Initialize()) {
    return false;
  }
  if (!frontend->Initialize()) {
    return false;
  }

  backend_ = std::move(backend);
  frontend_ = std::move(frontend);

  interrupt_thread_state_ = new ThreadState(this, 0, 0, 16 * 1024, 0);
  interrupt_thread_state_->set_name("Interrupt");
  interrupt_thread_block_ = memory_->SystemHeapAlloc(2048);
  interrupt_thread_state_->context()->r[13] = interrupt_thread_block_;

  return true;
}

bool Processor::AddModule(std::unique_ptr<Module> module) {
  std::lock_guard<std::mutex> guard(modules_lock_);
  modules_.push_back(std::move(module));
  return true;
}

Module* Processor::GetModule(const char* name) {
  std::lock_guard<std::mutex> guard(modules_lock_);
  for (const auto& module : modules_) {
    if (module->name() == name) {
      return module.get();
    }
  }
  return nullptr;
}

std::vector<Module*> Processor::GetModules() {
  std::lock_guard<std::mutex> guard(modules_lock_);
  std::vector<Module*> clone(modules_.size());
  for (const auto& module : modules_) {
    clone.push_back(module.get());
  }
  return clone;
}

FunctionInfo* Processor::DefineBuiltin(const std::string& name,
                                       FunctionInfo::ExternHandler handler,
                                       void* arg0, void* arg1) {
  uint32_t address = next_builtin_address_;
  next_builtin_address_ += 4;

  FunctionInfo* fn_info;
  builtin_module_->DeclareFunction(address, &fn_info);
  fn_info->set_end_address(address + 4);
  fn_info->set_name(name);
  fn_info->SetupExtern(handler, arg0, arg1);
  fn_info->set_status(SymbolInfo::STATUS_DECLARED);

  return fn_info;
}

std::vector<Function*> Processor::FindFunctionsWithAddress(uint32_t address) {
  return entry_table_.FindWithAddress(address);
}

bool Processor::ResolveFunction(uint32_t address, Function** out_function) {
  *out_function = nullptr;
  Entry* entry;
  Entry::Status status = entry_table_.GetOrCreate(address, &entry);
  if (status == Entry::STATUS_NEW) {
    // Needs to be generated. We have the 'lock' on it and must do so now.

    // Grab symbol declaration.
    FunctionInfo* symbol_info;
    if (!LookupFunctionInfo(address, &symbol_info)) {
      return false;
    }

    if (!DemandFunction(symbol_info, &entry->function)) {
      entry->status = Entry::STATUS_FAILED;
      return false;
    }
    entry->end_address = symbol_info->end_address();
    status = entry->status = Entry::STATUS_READY;
  }
  if (status == Entry::STATUS_READY) {
    // Ready to use.
    *out_function = entry->function;
    return true;
  } else {
    // Failed or bad state.
    return false;
  }
}

bool Processor::LookupFunctionInfo(uint32_t address,
                                   FunctionInfo** out_symbol_info) {
  *out_symbol_info = nullptr;

  // TODO(benvanik): fast reject invalid addresses/log errors.

  // Find the module that contains the address.
  Module* code_module = nullptr;
  {
    std::lock_guard<std::mutex> guard(modules_lock_);
    // TODO(benvanik): sort by code address (if contiguous) so can bsearch.
    // TODO(benvanik): cache last module low/high, as likely to be in there.
    for (const auto& module : modules_) {
      if (module->ContainsAddress(address)) {
        code_module = module.get();
        break;
      }
    }
  }
  if (!code_module) {
    // No module found that could contain the address.
    return false;
  }

  return LookupFunctionInfo(code_module, address, out_symbol_info);
}

bool Processor::LookupFunctionInfo(Module* module, uint32_t address,
                                   FunctionInfo** out_symbol_info) {
  // Atomic create/lookup symbol in module.
  // If we get back the NEW flag we must declare it now.
  FunctionInfo* symbol_info = nullptr;
  SymbolInfo::Status symbol_status =
      module->DeclareFunction(address, &symbol_info);
  if (symbol_status == SymbolInfo::STATUS_NEW) {
    // Symbol is undeclared, so declare now.
    if (!frontend_->DeclareFunction(symbol_info)) {
      symbol_info->set_status(SymbolInfo::STATUS_FAILED);
      return false;
    }
    symbol_info->set_status(SymbolInfo::STATUS_DECLARED);
  }

  *out_symbol_info = symbol_info;
  return true;
}

bool Processor::DemandFunction(FunctionInfo* symbol_info,
                               Function** out_function) {
  *out_function = nullptr;

  // Lock function for generation. If it's already being generated
  // by another thread this will block and return DECLARED.
  Module* module = symbol_info->module();
  SymbolInfo::Status symbol_status = module->DefineFunction(symbol_info);
  if (symbol_status == SymbolInfo::STATUS_NEW) {
    // Symbol is undefined, so define now.
    Function* function = nullptr;
    if (!frontend_->DefineFunction(symbol_info, debug_info_flags_, trace_flags_,
                                   &function)) {
      symbol_info->set_status(SymbolInfo::STATUS_FAILED);
      return false;
    }
    symbol_info->set_function(function);

    // Before we give the symbol back to the rest, let the debugger know.
    debugger_->OnFunctionDefined(symbol_info, function);

    symbol_info->set_status(SymbolInfo::STATUS_DEFINED);
    symbol_status = symbol_info->status();
  }

  if (symbol_status == SymbolInfo::STATUS_FAILED) {
    // Symbol likely failed.
    return false;
  }

  *out_function = symbol_info->function();

  return true;
}

bool Processor::Execute(ThreadState* thread_state, uint32_t address) {
  SCOPE_profile_cpu_f("cpu");

  // Attempt to get the function.
  Function* fn;
  if (!ResolveFunction(address, &fn)) {
    // Symbol not found in any module.
    XELOGCPU("Execute(%.8X): failed to find function", address);
    return false;
  }

  PPCContext* context = thread_state->context();

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

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

  // Execute the function.
  return fn->Call(thread_state, lr);
}

uint64_t Processor::Execute(ThreadState* thread_state, uint32_t address,
                            uint64_t args[], size_t arg_count) {
  SCOPE_profile_cpu_f("cpu");

  PPCContext* context = thread_state->context();
  assert_true(arg_count <= 5);
  for (size_t i = 0; i < arg_count; ++i) {
    context->r[3 + i] = args[i];
  }
  if (!Execute(thread_state, address)) {
    return 0xDEADBABE;
  }
  return context->r[3];
}

Irql Processor::RaiseIrql(Irql new_value) {
  return static_cast<Irql>(
      xe::atomic_exchange(static_cast<uint32_t>(new_value),
                          reinterpret_cast<volatile uint32_t*>(&irql_)));
}

void Processor::LowerIrql(Irql old_value) {
  xe::atomic_exchange(static_cast<uint32_t>(old_value),
                      reinterpret_cast<volatile uint32_t*>(&irql_));
}

uint64_t Processor::ExecuteInterrupt(uint32_t cpu, uint32_t address,
                                     uint64_t args[], size_t arg_count) {
  SCOPE_profile_cpu_f("cpu");

  // Acquire lock on interrupt thread (we can only dispatch one at a time).
  std::lock_guard<std::mutex> lock(interrupt_thread_lock_);

  // Set 0x10C(r13) to the current CPU ID.
  xe::store_and_swap<uint8_t>(
      memory_->TranslateVirtual(interrupt_thread_block_ + 0x10C), cpu);

  // Execute interrupt.
  uint64_t result = Execute(interrupt_thread_state_, address, args, arg_count);

  return result;
}

}  // namespace cpu
}  // namespace xe