// Copyright 2021 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 "src/graphics/bin/vulkan_loader/icd_component.h"

#include <dirent.h>
#include <lib/async/cpp/task.h>
#include <lib/fdio/directory.h>
#include <lib/fdio/io.h>
#include <lib/fit/defer.h>
#include <lib/syslog/cpp/macros.h>

#include <fbl/unique_fd.h>

#include "rapidjson/prettywriter.h"
#include "rapidjson/schema.h"
#include "src/graphics/bin/vulkan_loader/app.h"
#include "src/lib/json_parser/json_parser.h"

namespace {

const char* kSchema = R"(
{
 "$schema": "http://json-schema.org/schema#",
 "type": "object",
 "properties": {
   "version": {"type":"number", "maximum": 1, "minimum": 1},
   "library_path": {"type":"string"},
   "file_path": {"type":"string"}
 },
 "required": ["version", "library_path", "file_path"]
}
)";

const char* kCollectionName = "icd-loaders";

}  // namespace

IcdComponent::~IcdComponent() {
  if (realm_ && !child_instance_name_.empty()) {
    fuchsia::sys2::ChildRef child_ref;

    child_ref.name = child_instance_name_;
    child_ref.collection = kCollectionName;
    realm_->DestroyChild(std::move(child_ref),
                         [](fit::result<void, fuchsia::component::Error> result) {});
  }
}

void IcdComponent::Initialize(sys::ComponentContext* context, inspect::Node* parent_node) {
  realm_ = context->svc()->Connect<fuchsia::sys2::Realm>();
  static uint64_t name_id;
  auto pending_action_token = app_->GetPendingActionToken();

  child_instance_name_ = std::to_string(name_id++);
  node_ = parent_node->CreateChild(child_instance_name_);
  initialization_status_ = node_.CreateString("status", "uninitialized");
  node_.CreateString("component_url", component_url_, &value_list_);
  fuchsia::sys2::CollectionRef collection;
  collection.name = kCollectionName;
  fuchsia::sys2::ChildDecl decl;
  decl.set_name(child_instance_name_);
  decl.set_url(component_url_);
  decl.set_startup(fuchsia::sys2::StartupMode::LAZY);
  auto failure_callback =
      fit::defer_callback([this, pending_action_token = std::move(pending_action_token)]() {
        std::lock_guard lock(vmo_lock_);
        stage_ = LookupStages::kFailed;
        app_->NotifyIcdsChanged();
      });
  realm_->CreateChild(
      collection, std::move(decl),
      [this, failure_callback = std::move(failure_callback)](
          fit::result<void, fuchsia::component::Error> response) mutable {
        if (response.is_error()) {
          FX_LOGS(INFO) << component_url_ << " CreateChild err "
                        << static_cast<uint32_t>(response.error());
          node_.CreateUint("create_response", static_cast<uint32_t>(response.error()),
                           &value_list_);
          child_instance_name_ = "";
          return;
        }
        initialization_status_.Set("created");

        fuchsia::sys2::ChildRef child_ref;

        child_ref.name = child_instance_name_;
        child_ref.collection = kCollectionName;

        fidl::InterfaceHandle<fuchsia::io::Directory> directory;
        auto directory_request = directory.NewRequest();
        realm_->BindChild(
            child_ref, std::move(directory_request),
            [this, directory = std::move(directory),
             failure_callback = std::move(failure_callback)](
                fit::result<void, fuchsia::component::Error> response) mutable {
              if (response.is_error()) {
                FX_LOGS(INFO) << component_url_ << " BindChild failed with error "
                              << static_cast<uint32_t>(response.error());
                node_.CreateUint("bind_response", static_cast<uint32_t>(response.error()),
                                 &value_list_);
                return;
              }
              initialization_status_.Set("bound");
              async::PostTask(
                  app_->fdio_loop_dispatcher(), [this, shared_this = this->shared_from_this(),
                                                 failure_callback = std::move(failure_callback),
                                                 directory = std::move(directory)]() mutable {
                    ReadFromComponent(std::move(failure_callback), std::move(directory));
                  });
            });
      });
}

// static
bool IcdComponent::ValidateMetadataJson(const std::string& component_url,
                                        const rapidjson::GenericDocument<rapidjson::UTF8<>>& doc) {
  rapidjson::Document schema_doc;
  schema_doc.Parse(kSchema);
  FX_CHECK(!schema_doc.HasParseError()) << schema_doc.GetParseError();

  rapidjson::SchemaDocument schema(schema_doc);
  rapidjson::SchemaValidator validator(schema);
  if (!doc.Accept(validator)) {
    rapidjson::StringBuffer sb;
    rapidjson::PrettyWriter<rapidjson::StringBuffer> w(sb);
    validator.GetError().Accept(w);
    FX_LOGS(ERROR) << component_url << " metadata.json failed validation " << sb.GetString();
    return false;
  }
  return true;
}

zx::status<zx::vmo> IcdComponent::CloneVmo() const {
  std::lock_guard lock(vmo_lock_);
  if (!vmo_info_)
    return zx::error(ZX_ERR_BAD_STATE);

  uint64_t size;
  zx_status_t status = vmo_info_->vmo.get_size(&size);
  if (status != ZX_OK)
    return zx::error(status);
  zx::vmo vmo;
  // Snapshot is ok because we never modify our VMO, and blobfs should never modify it either. We
  // use ZX_VMO_CHILD_NO_WRITE because otherwise ZX_RIGHT_EXECUTE is removed.
  status = vmo_info_->vmo.create_child(
      ZX_VMO_CHILD_SNAPSHOT_AT_LEAST_ON_WRITE | ZX_VMO_CHILD_NO_WRITE, 0, size, &vmo);
  if (status != ZX_OK)
    return zx::error(status);
  return zx::ok(std::move(vmo));
}

// See the accompanying README.md for a description of what a Vulkan component needs to have.
void IcdComponent::ReadFromComponent(fit::deferred_callback failure_callback,
                                     fidl::InterfaceHandle<fuchsia::io::Directory> out_dir) {
  initialization_status_.Set("reading from package");
  fidl::InterfaceHandle<fuchsia::io::Directory> metadata_loader;
  zx_status_t status =
      fdio_open_at(out_dir.channel().get(), "metadata", fuchsia::io::OPEN_RIGHT_READABLE,
                   metadata_loader.NewRequest().TakeChannel().release());
  if (status != ZX_OK) {
    FX_PLOGS(ERROR, status) << component_url_ << " Failed opening metadata dir";
    return;
  }
  fidl::InterfaceHandle<fuchsia::io::Directory> contents_loader;
  status = fdio_open_at(out_dir.channel().get(), "contents",
                        fuchsia::io::OPEN_RIGHT_READABLE | fuchsia::io::OPEN_RIGHT_EXECUTABLE,
                        contents_loader.NewRequest().TakeChannel().release());
  if (status != ZX_OK) {
    FX_PLOGS(ERROR, status) << component_url_ << " Failed opening pkg dir";
    return;
  }
  fbl::unique_fd metadata_dir_fd;
  zx_handle_t metadata_channel = metadata_loader.TakeChannel().release();
  status = fdio_fd_create(metadata_channel, metadata_dir_fd.reset_and_get_address());
  if (status != ZX_OK) {
    FX_PLOGS(ERROR, status) << component_url_ << " Failed creating FD for metadata";
    return;
  }

  json_parser::JSONParser parser;
  auto doc = parser.ParseFromFileAt(metadata_dir_fd.get(), "metadata.json");
  if (parser.HasError()) {
    FX_LOGS(ERROR) << component_url_ << " JSON parser had error " << parser.error_str();
    return;
  }

  fbl::unique_fd contents_dir_fd;
  status = fdio_fd_create(contents_loader.TakeChannel().release(),
                          contents_dir_fd.reset_and_get_address());
  if (status != ZX_OK) {
    FX_PLOGS(ERROR, status) << component_url_ << " Failed creating FD";
    return;
  }
  if (!ValidateMetadataJson(component_url_, doc)) {
    return;
  }
  node_.CreateUint("version", doc["version"].GetInt(), &value_list_);
  std::string file_path = doc["file_path"].GetString();
  std::string library_path = doc["library_path"].GetString();
  node_.CreateString("file_path", file_path, &value_list_);
  node_.CreateString("library_path", library_path, &value_list_);
  fbl::unique_fd fd;

  initialization_status_.Set("opening VMO");
  status = fdio_open_fd_at(contents_dir_fd.get(), file_path.c_str(),
                           fuchsia::io::OPEN_RIGHT_READABLE | fuchsia::io::OPEN_RIGHT_EXECUTABLE,
                           fd.reset_and_get_address());
  if (status != ZX_OK) {
    FX_LOGS(ERROR) << component_url_ << " Could not open path " << library_path << ":" << status;
    return;
  }
  zx::vmo vmo;
  status = fdio_get_vmo_exec(fd.get(), vmo.reset_and_get_address());
  fd.reset();
  if (status != ZX_OK) {
    FX_LOGS(ERROR) << component_url_ << " Could not clone vmo exec: " << status;
    return;
  }
  // Create another pending action token to keep everything alive until we're done initializing
  // the data.
  auto pending_action_token = app_->GetPendingActionToken();
  VmoInfo info;
  info.library_path = library_path;
  info.vmo = std::move(vmo);
  {
    std::lock_guard lock(vmo_lock_);
    vmo_info_ = std::move(info);
    failure_callback.cancel();
    stage_ = LookupStages::kFinished;
  }
  app_->NotifyIcdsChanged();
  initialization_status_.Set("initialized");
}