// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "garnet/bin/sysmgr/app.h"

#include <fuchsia/io/cpp/fidl.h>
#include <fuchsia/sys/cpp/fidl.h>
#include <lib/async/default.h>
#include <lib/async/dispatcher.h>
#include <lib/fdio/directory.h>
#include <lib/fdio/fd.h>
#include <lib/fdio/fdio.h>
#include <lib/fidl/cpp/clone.h>
#include <lib/fidl/cpp/interface_handle.h>
#include <lib/sys/cpp/service_directory.h>
#include <lib/vfs/cpp/node.h>
#include <lib/vfs/cpp/service.h>
#include <zircon/process.h>
#include <zircon/processargs.h>

#include "src/lib/fxl/logging.h"

namespace sysmgr {

namespace {
constexpr char kDefaultLabel[] = "sys";
#ifdef AUTO_UPDATE_PACKAGES
constexpr bool kAutoUpdatePackages = true;
#else
constexpr bool kAutoUpdatePackages = false;
#endif
}  // namespace

App::App(Config config)
    : component_context_(sys::ComponentContext::Create()),
      auto_updates_enabled_(kAutoUpdatePackages) {
  FXL_DCHECK(component_context_);

  // The set of excluded services below are services that are the transitive
  // closure of dependencies required for auto-updates that must not be resolved
  // via the update service.
  const auto update_dependencies = config.TakeUpdateDependencies();
  const auto optional_services = config.TakeOptionalServices();
  std::unordered_set<std::string> update_dependency_urls;

  // Register services.
  for (auto& pair : config.TakeServices()) {
    if (std::find(update_dependencies.begin(), update_dependencies.end(),
                  pair.first) != std::end(update_dependencies)) {
      update_dependency_urls.insert(pair.second->url);
    }
    const bool optional =
        std::find(optional_services.begin(), optional_services.end(),
                  pair.first) != std::end(optional_services);
    RegisterSingleton(pair.first, std::move(pair.second), optional);
  }

  auto env_request = env_.NewRequest();
  fuchsia::sys::ServiceProviderPtr env_services;
  env_->GetLauncher(env_launcher_.NewRequest());
  env_->GetServices(env_services.NewRequest());

  if (auto_updates_enabled_) {
    const bool resolver_missing =
        std::find(update_dependencies.begin(), update_dependencies.end(),
                  fuchsia::pkg::PackageResolver::Name_) ==
        update_dependencies.end();
    // Check if any component urls that are excluded (dependencies of
    // PackageResolver/startup) were not registered from the above
    // configuration.
    bool missing_services = false;
    for (auto& dep : update_dependencies) {
      if (std::find(svc_names_->begin(), svc_names_->end(), dep) ==
          svc_names_->end()) {
        FXL_LOG(WARNING) << "missing service required for auto updates: "
                         << dep;
        missing_services = true;
      }
    }

    if (resolver_missing || missing_services) {
      FXL_LOG(WARNING) << "auto_update_packages = true but some update "
                          "dependencies are missing in the sys environment. "
                          "Disabling auto-updates.";
      auto_updates_enabled_ = false;
    }
  }

  // Configure loader.
  if (auto_updates_enabled_) {
    package_updating_loader_ = std::make_unique<PackageUpdatingLoader>(
        std::move(update_dependency_urls), std::move(env_services),
        async_get_default_dispatcher());
  }
  static const char* const kLoaderName = fuchsia::sys::Loader::Name_;
  auto child = std::make_unique<vfs::Service>(
      [this](zx::channel channel, async_dispatcher_t* dispatcher) {
        if (auto_updates_enabled_) {
          package_updating_loader_->Bind(
              fidl::InterfaceRequest<fuchsia::sys::Loader>(std::move(channel)));
        } else {
          component_context_->svc()->Connect(kLoaderName, std::move(channel));
        }
      });
  svc_names_.push_back(kLoaderName);
  svc_root_.AddEntry(kLoaderName, std::move(child));

  // Set up environment for the programs we will run.
  fuchsia::sys::ServiceListPtr service_list(new fuchsia::sys::ServiceList);
  service_list->names = std::move(svc_names_);
  service_list->host_directory = OpenAsDirectory();
  fuchsia::sys::EnvironmentPtr environment;
  component_context_->svc()->Connect(environment.NewRequest());
  environment->CreateNestedEnvironment(
      std::move(env_request), env_controller_.NewRequest(), kDefaultLabel,
      std::move(service_list), {});

  // Connect to startup services
  for (auto& startup_service : config.TakeStartupServices()) {
    FXL_VLOG(1) << "Connecting to startup service " << startup_service;
    zx::channel h1, h2;
    zx::channel::create(0, &h1, &h2);
    ConnectToService(startup_service, std::move(h1));
  }

  // Launch startup applications.
  for (auto& launch_info : config.TakeApps()) {
    LaunchApplication(std::move(*launch_info));
  }
}

App::~App() = default;

zx::channel App::OpenAsDirectory() {
  fidl::InterfaceHandle<fuchsia::io::Directory> dir;
  svc_root_.Serve(
      fuchsia::io::OPEN_RIGHT_READABLE | fuchsia::io::OPEN_RIGHT_WRITABLE,
      dir.NewRequest().TakeChannel());
  return dir.TakeChannel();
}

void App::ConnectToService(const std::string& service_name,
                           zx::channel channel) {
  vfs::Node* child;
  auto status = svc_root_.Lookup(service_name, &child);
  if (status == ZX_OK) {
    status = child->Serve(fuchsia::io::OPEN_RIGHT_READABLE, std::move(channel));
  }
  if (status != ZX_OK) {
    FXL_LOG(ERROR) << "Could not serve " << service_name << ": " << status;
  }
}

void App::RegisterSingleton(std::string service_name,
                            fuchsia::sys::LaunchInfoPtr launch_info,
                            bool optional) {
  auto child = std::make_unique<vfs::Service>(
      [this, optional, service_name, launch_info = std::move(launch_info),
       controller = fuchsia::sys::ComponentControllerPtr()](
          zx::channel client_handle, async_dispatcher_t* dispatcher) mutable {
        FXL_VLOG(2) << "Servicing singleton service request for "
                    << service_name;
        auto it = services_.find(launch_info->url);
        if (it == services_.end()) {
          FXL_VLOG(1) << "Starting singleton " << launch_info->url
                      << " for service " << service_name;
          fuchsia::sys::LaunchInfo dup_launch_info;
          dup_launch_info.url = launch_info->url;
          fidl::Clone(launch_info->arguments, &dup_launch_info.arguments);
          auto services = sys::ServiceDirectory::CreateWithRequest(
              &dup_launch_info.directory_request);
          controller.events().OnTerminated =
              [service_name, url = launch_info->url, optional](
                  int64_t return_code, fuchsia::sys::TerminationReason reason) {
                if (!optional &&
                    reason ==
                        fuchsia::sys::TerminationReason::PACKAGE_NOT_FOUND) {
                  FXL_LOG(ERROR) << "Could not load package for service "
                                 << service_name << " at " << url;
                }
              };
          controller.set_error_handler([this, optional, url = launch_info->url,
                                        &controller](zx_status_t error) {
            if (!optional) {
              FXL_LOG(ERROR) << "Singleton " << url << " died";
            }
            controller.Unbind();  // kills the singleton application
            services_.erase(url);
          });
          env_launcher_->CreateComponent(std::move(dup_launch_info),
                                         controller.NewRequest());

          std::tie(it, std::ignore) =
              services_.emplace(launch_info->url, std::move(services));
        }

        it->second->Connect(service_name, std::move(client_handle));
      });
  svc_names_.push_back(service_name);
  svc_root_.AddEntry(service_name, std::move(child));
}

void App::LaunchApplication(fuchsia::sys::LaunchInfo launch_info) {
  FXL_VLOG(1) << "Launching application " << launch_info.url;
  env_launcher_->CreateComponent(std::move(launch_info), nullptr);
}

}  // namespace sysmgr