/**
 ******************************************************************************
 * 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/kernel/kernel_module.h"

#include "xenia/base/logging.h"
#include "xenia/base/mutex.h"
#include "xenia/cpu/raw_module.h"
#include "xenia/emulator.h"
#include "xenia/kernel/xthread.h"

namespace xe {
namespace kernel {

KernelModule::KernelModule(KernelState* kernel_state, const char* path)
    : XModule(kernel_state, ModuleType::kKernelModule) {
  emulator_ = kernel_state->emulator();
  memory_ = emulator_->memory();
  export_resolver_ = kernel_state->emulator()->export_resolver();

  path_ = path;
  name_ = NameFromPath(path);

  // Persist this object through reloads.
  host_object_ = true;

  // HACK: Allocates memory where xboxkrnl.exe would be!
  // TODO: Need to free this memory when necessary.
  auto heap = memory()->LookupHeap(0x80040000);
  if (heap->AllocRange(0x80040000, 0x801C0000, kTrampolineSize, 16,
                       kMemoryAllocationCommit,
                       kMemoryProtectRead | kMemoryProtectWrite, false,
                       &guest_trampoline_)) {
    guest_trampoline_size_ = kTrampolineSize;

    auto module = std::make_unique<cpu::RawModule>(emulator_->processor());
    guest_trampoline_module_ = module.get();

    module->set_name(name_ + "_trampoline");
    module->SetAddressRange(guest_trampoline_, guest_trampoline_size_);
    emulator_->processor()->AddModule(std::move(module));
  } else {
    XELOGW("KernelModule %s could not allocate trampoline for GetProcAddress!",
           path);
  }

  OnLoad();
}

KernelModule::~KernelModule() {}

uint32_t KernelModule::GetProcAddressByOrdinal(uint16_t ordinal) {
  auto export_entry =
      export_resolver_->GetExportByOrdinal(name().c_str(), ordinal);
  if (!export_entry) {
    // Export (or its parent library) not found.
    return 0;
  }
  if (export_entry->type == cpu::Export::Type::kVariable) {
    if (export_entry->variable_ptr) {
      return export_entry->variable_ptr;
    } else {
      XELOGW(
          "ERROR: var export referenced GetProcAddressByOrdinal(%.4X(%s)) is "
          "not implemented",
          ordinal, export_entry->name);
      return 0;
    }
  } else {
    if (export_entry->function_data.trampoline ||
        export_entry->function_data.shim) {
      global_critical_region_.Acquire();

      // See if the function has been generated already.
      if (guest_trampoline_map_.find(ordinal) != guest_trampoline_map_.end()) {
        auto entry = guest_trampoline_map_.find(ordinal);
        return entry->second;
      }

      // Generate the function.
      assert_true(guest_trampoline_next_ * 8 < guest_trampoline_size_);
      if (guest_trampoline_next_ * 8 >= guest_trampoline_size_) {
        assert_always();  // If you hit this, increase kTrampolineSize
        XELOGE("KernelModule::GetProcAddressByOrdinal trampoline exhausted");
        return 0;
      }

      uint32_t guest_addr = guest_trampoline_ + (guest_trampoline_next_++ * 8);

      auto mem = memory()->TranslateVirtual(guest_addr);
      xe::store_and_swap<uint32_t>(mem + 0x0, 0x44000002);  // sc
      xe::store_and_swap<uint32_t>(mem + 0x4, 0x4E800020);  // blr

      // Declare/define the extern function.
      cpu::Function* function;
      guest_trampoline_module_->DeclareFunction(guest_addr, &function);
      function->set_end_address(guest_addr + 8);
      function->set_name(std::string("__T_") + export_entry->name);

      cpu::GuestFunction::ExternHandler handler = nullptr;
      if (export_entry->function_data.trampoline) {
        handler = (cpu::GuestFunction::ExternHandler)
                      export_entry->function_data.trampoline;
      } else {
        handler =
            (cpu::GuestFunction::ExternHandler)export_entry->function_data.shim;
      }
      static_cast<cpu::GuestFunction*>(function)->SetupExtern(handler,
                                                              export_entry);

      function->set_status(cpu::Symbol::Status::kDeclared);

      // Register the function in our map.
      guest_trampoline_map_[ordinal] = guest_addr;
      return guest_addr;
    } else {
      // Not implemented.
      XELOGW(
          "ERROR: fn export referenced GetProcAddressByOrdinal(%.4X(%s)) is "
          "not implemented",
          ordinal, export_entry->name);
      return 0;
    }
  }
}

uint32_t KernelModule::GetProcAddressByName(const char* name) {
  // TODO: Does this even work for kernel modules?
  XELOGE("KernelModule::GetProcAddressByName not implemented");
  return 0;
}

}  // namespace kernel
}  // namespace xe