/*
 * libfud
 * Copyright 2024 Dominick Allen
 *
 * 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 "fud_c_file.hpp"

namespace fud {

CBinaryFile::CBinaryFile(const String& filename, CFileMode mode)
    : m_filename{filename},
      m_mode{CBinaryFileModeFromFlags(mode)},
      m_modeFlags{mode}
{
}

CBinaryFile::CBinaryFile(const String& filename, CFileMode mode, const String& extraFlags)
    : m_filename{filename},
      m_extraFlags{extraFlags},
      m_mode{String(CBinaryFileModeFromFlags(mode)).catenate(extraFlags)},
      m_modeFlags{mode}
{
}

CBinaryFile::~CBinaryFile() {
    close();
}

FudStatus CBinaryFile::open()
{
    if (!m_filename.valid()) {
        return FudStatus::ObjectInvalid;
    }
    m_file = fopen(m_filename.c_str(), m_mode.c_str());
    return m_file != nullptr ? FudStatus::Success : FudStatus::Failure;
}

void CBinaryFile::close()
{
    if (m_file != nullptr) {
        fclose(m_file);
        m_file = nullptr;
    }
}

const FILE* CBinaryFile::file() const
{
    return m_file;
}

FILE* CBinaryFile::file()
{
    return m_file;
}

bool CBinaryFile::isOpen() const
{
    return m_file != nullptr;
}

Result<size_t, FudStatus> CBinaryFile::size() const
{
    using RetType = Result<size_t, FudStatus>;
    if (!isOpen()) {
        return RetType::error(FudStatus::OperationInvalid);
    }

    auto seekStatus = fseek(m_file, 0, SEEK_END);
    if (seekStatus != 0) {
        return RetType::error(FudStatus::Failure);
    }

    auto fileSizeResult = ftell(m_file);
    if (fileSizeResult < 0) {
        return RetType::error(FudStatus::Failure);
    }

    auto fileSize = static_cast<size_t>(fileSizeResult);

    auto resetStatus = reset();
    if (resetStatus != FudStatus::Success) {
        return RetType::error(resetStatus);
    }

    return RetType::okay(fileSize);
}

ReadResult CBinaryFile::read(void* destination, size_t destinationSize, size_t length)
{
    return read(destination, destinationSize, length, 0);
}

ReadResult CBinaryFile::read(void* destination, size_t destinationSize, size_t length, size_t offset)
{
    ReadResult result{};
    if (length == 0) {
        return result;
    }

    if (destination == nullptr) {
        result.status = FudStatus::NullPointer;
        return result;
    }

    if (offset > LONG_MAX || SIZE_MAX - offset < length || destinationSize < length) {
        result.status = FudStatus::InvalidInput;
        return result;
    }

    auto fileSizeResult = size();
    if (fileSizeResult.isError()) {
        result.status = fileSizeResult.getError();
        return result;
    }

    auto fileSize = fileSizeResult.getOkay();
    if (offset + length > fileSize) {
        result.status = FudStatus::InvalidInput;
        return result;
    }

    auto seekResult = fseek(m_file, static_cast<long>(offset), SEEK_SET);
    if (seekResult != 0) {
        result.status = FudStatus::Failure;
        return result;
    }

    auto* destBytes = static_cast<char*>(destination);
    result.bytesRead = fread(destBytes, 1, length, m_file);
    static_cast<void>(reset());
    if (result.bytesRead != length) {
        result.status = FudStatus::Partial;
    } else {
        result.status = FudStatus::Success;
    }

    return result;
}

WriteResult CBinaryFile::write(const void* source, size_t sourceSize, size_t length)
{
    auto offsetResult = size();
    if (offsetResult.isError()) {
        return WriteResult{0, offsetResult.getError()};
    }

    return write(source, sourceSize, length, offsetResult.getOkay());
}

WriteResult CBinaryFile::write(const void* source, size_t sourceSize, size_t length, size_t offset)
{
    WriteResult result{};
    if (length == 0) {
        return result;
    }

    if (source == nullptr) {
        result.status = FudStatus::NullPointer;
        return result;
    }

    if (offset > LONG_MAX || SIZE_MAX - offset < length || sourceSize < length) {
        result.status = FudStatus::InvalidInput;
        return result;
    }

    auto fileSizeResult = size();
    if (fileSizeResult.isError()) {
        result.status = fileSizeResult.getError();
        return result;
    }

    // TODO: proper way of handling this
    auto fileSize = fileSizeResult.getOkay();
    int seekResult;
    if (offset > fileSize) {
        seekResult = fseek(m_file, 0, SEEK_END);
    } else {
        seekResult = fseek(m_file, static_cast<long>(offset), SEEK_SET);
    }

    if (seekResult != 0) {
        result.status = FudStatus::Failure;
        return result;
    }

    auto* sourceBytes = static_cast<const char*>(source);
    result.bytesWritten = fwrite(sourceBytes, 1, length, m_file);
    static_cast<void>(reset());
    if (result.bytesWritten != length) {
        result.status = FudStatus::Partial;
    } else {
        result.status = FudStatus::Success;
    }

    return result;
}

FudStatus CBinaryFile::reset() const {
    if (!isOpen()) {
        return FudStatus::OperationInvalid;
    }
    auto result = fseek(m_file, 0, SEEK_SET);
    return result == 0 ? FudStatus::Success : FudStatus::Failure;
}

} // namespace fud