/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "cuttlefish/host/libs/vm_manager/vm_manager.h"

#include <iomanip>
#include <memory>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include <fruit/fruit.h>
#include "absl/log/check.h"
#include "absl/log/log.h"

#include "cuttlefish/host/libs/config/cuttlefish_config.h"
#include "cuttlefish/host/libs/feature/command_source.h"
#include "cuttlefish/host/libs/feature/inject.h"
#include "cuttlefish/host/libs/vm_manager/crosvm_manager.h"
#include "cuttlefish/host/libs/vm_manager/gem5_manager.h"
#include "cuttlefish/host/libs/vm_manager/qemu_manager.h"
#include "cuttlefish/result/result.h"

namespace cuttlefish {
namespace vm_manager {

static std::unique_ptr<VmManager> Allocate(VmmMode mode, Arch arch) {
  switch (mode) {
    case VmmMode::kCrosvm:
      return std::make_unique<CrosvmManager>();
    case VmmMode::kQemu:
      return std::make_unique<QemuManager>(arch);
    case VmmMode::kGem5:
      return std::make_unique<Gem5Manager>(arch);
    case VmmMode::kUnknown:
      LOG(ERROR) << "Invalid VM manager: " << mode;
      return {};
  }
}

std::unique_ptr<VmManager> GetVmManager(VmmMode vmm_mode, Arch arch) {
  std::unique_ptr<VmManager> vmm = Allocate(vmm_mode, arch);
  if (vmm != nullptr && !vmm->IsSupported()) {
    LOG(ERROR) << "VM manager " << vmm_mode
               << " is not supported on this machine.";
    return {};
  }
  return vmm;
}

Result<std::unordered_map<std::string, std::string>>
ConfigureMultipleBootDevices(const std::string& pci_path, int pci_offset,
                             int num_disks) {
  int num_boot_devices =
      (num_disks < VmManager::kDefaultNumBootDevices) ? num_disks : VmManager::kDefaultNumBootDevices;
  std::string boot_devices_prop_val = "";
  for (int i = 0; i < num_boot_devices; i++) {
    std::stringstream stream;
    stream << std::setfill('0') << std::setw(2) << std::hex
           << pci_offset + i + VmManager::kDefaultNumHvcs + VmManager::kMaxDisks - num_disks;
    boot_devices_prop_val += pci_path + stream.str() + ".0,";
  }
  boot_devices_prop_val.pop_back();
  return {{{"androidboot.boot_devices", boot_devices_prop_val}}};
}

class VmmCommands : public CommandSource, public LateInjected {
 public:
  INJECT(VmmCommands(const CuttlefishConfig& config, VmManager& vmm))
      : config_(config), vmm_(vmm) {}

  // CommandSource
  Result<std::vector<MonitorCommand>> Commands() override {
    return vmm_.StartCommands(config_, dependencyCommands_);
  }

  // SetupFeature
  std::string Name() const override { return "VirtualMachineManager"; }

  // LateInjected
  Result<void> LateInject(fruit::Injector<>& injector) override {
    dependencyCommands_ = injector.getMultibindings<VmmDependencyCommand>();

    return {};
  }

 private:
  std::unordered_set<SetupFeature*> Dependencies() const override { return {}; }
  Result<void> ResultSetup() override { return {}; }

  const CuttlefishConfig& config_;
  VmManager& vmm_;
  std::vector<VmmDependencyCommand*> dependencyCommands_;
};

fruit::Component<fruit::Required<const CuttlefishConfig,
                                 const CuttlefishConfig::InstanceSpecific>,
                 VmManager>
VmManagerComponent() {
  return fruit::createComponent()
      .registerProvider([](const CuttlefishConfig& config,
                           const CuttlefishConfig::InstanceSpecific& instance) {
        auto vmm = GetVmManager(config.vm_manager(), instance.target_arch());
        CHECK(vmm) << "Invalid VMM/Arch: \"" << config.vm_manager() << "\""
                   << (int)instance.target_arch() << "\"";
        return vmm.release();  // fruit takes ownership of raw pointers
      })
      .addMultibinding<CommandSource, VmmCommands>()
      .addMultibinding<LateInjected, VmmCommands>()
      .addMultibinding<SetupFeature, VmmCommands>();
}

} // namespace vm_manager
} // namespace cuttlefish
