// Copyright 2021 The Chromium OS 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 "rmad/rmad_interface_impl.h"

#include <base/values.h>

#include "rmad/proto_bindings/rmad.pb.h"

namespace rmad {

const base::FilePath kDefaultJsonStoreFilePath("/var/lib/rmad/state");
constexpr char kRmadCurrentState[] = "current_state";

namespace {

bool RoVerificationKeyPressed() {
  // TODO(b/181000999): Send a D-Bus query to tpm_managerd when API is ready.
  return false;
}

}  // namespace

RmadInterfaceImpl::RmadInterfaceImpl()
    : RmadInterface(),
      json_store_(kDefaultJsonStoreFilePath),
      state_handler_manager_(&json_store_) {
  Initialize();
}

RmadInterfaceImpl::RmadInterfaceImpl(const base::FilePath& json_store_file_path)
    : RmadInterface(),
      json_store_(json_store_file_path),
      state_handler_manager_(&json_store_) {
  Initialize();
}

void RmadInterfaceImpl::Initialize() {
  // Initialize state_.
  if (const base::Value * value;
      json_store_.GetValue(kRmadCurrentState, &value)) {
    if (!value->is_string() ||
        !RmadState_Parse(value->GetString(), &current_state_)) {
      // State string in json_store_ is invalid.
      current_state_ = RMAD_STATE_UNKNOWN;
    }
  } else if (RoVerificationKeyPressed()) {
    current_state_ = RMAD_STATE_WELCOME_SCREEN;
    if (!json_store_.SetValue(kRmadCurrentState,
                              base::Value(RmadState_Name(current_state_)))) {
      current_state_ = RMAD_STATE_UNKNOWN;
    }
  } else {
    current_state_ = RMAD_STATE_RMA_NOT_REQUIRED;
  }
  // Initialize state_handler_manager_.
  state_handler_manager_.InitializeStateHandlers();
}

void RmadInterfaceImpl::GetCurrentState(
    const GetCurrentStateRequest& request,
    const GetCurrentStateCallback& callback) {
  GetCurrentStateReply reply;
  reply.set_state(current_state_);
  callback.Run(reply);
}

void RmadInterfaceImpl::TransitionState(
    const TransitionStateRequest& request,
    const TransitionStateCallback& callback) {
  // TODO(chenghan): Add error replies when failed to get `state_handler`, or
  //                 failed to write `json_store_`.
  auto state_handler = state_handler_manager_.GetStateHandler(current_state_);
  if (state_handler) {
    current_state_ = state_handler->GetNextState();
    json_store_.SetValue(kRmadCurrentState,
                         base::Value(RmadState_Name(current_state_)));
  }

  TransitionStateReply reply;
  reply.set_state(current_state_);
  callback.Run(reply);
}

}  // namespace rmad