// Copyright 2021 Google LLC
//
// 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 <unistd.h>

#include <flasher/device.hpp>
#include <flasher/file.hpp>
#include <flasher/file/memory.hpp>
#include <flasher/mod.hpp>
#include <flasher/mutate.hpp>
#include <flasher/ops.hpp>
#include <flashupdate/args.hpp>
#include <flashupdate/info.hpp>
#include <flashupdate/logging.hpp>
#include <stdplus/exception.hpp>
#include <stdplus/raw.hpp>

#include <filesystem>
#include <memory>
#include <optional>
#include <stdexcept>
#include <vector>

namespace flashupdate
{
namespace ops
{

using flasher::ModArgs;
using stdplus::fd::OpenAccess;
using stdplus::fd::OpenFlag;
using stdplus::fd::OpenFlags;

info::UpdateInfo fetchInfo(const Args& args)
{
    // Get the filename only
    auto devMod = ModArgs(args.config.metadata.path);
    auto dev = flasher::openDevice(devMod);
    std::vector<std::byte> fileData(sizeof(info::UpdateInfo));
    dev->readAt(fileData, args.config.metadata.offset);

    // Convert bytes to struct and update the state
    return stdplus::raw::copyFrom<info::UpdateInfo>(fileData);
}

void writeInfo(const Args& args, info::UpdateInfo updateInfo)
{
    auto devMod = ModArgs(args.config.metadata.path);
    flasher::NestedMutate mutate{};
    auto dev = flasher::openDevice(devMod);

    // Convert struct into bytes
    // The UpdateInfo struct saves the staged/active version of the image and
    // the stage of the update process. It will also save information like
    // latest used stage flash index and the expected hash of the CR51
    // descriptor in the staging flash.
    auto file = flasher::file::Memory();
    file.writeAtExact(stdplus::raw::asSpan<std::byte>(updateInfo), 0);
    flasher::ops::automatic(*dev, args.config.metadata.offset, file, 0, mutate,
                            sizeof(info::UpdateInfo), std::nullopt, false);
}

} // namespace ops
} // namespace flashupdate