#pragma once
#include "call_camera_protocol.h"
#include "debug_config.h"
#include <QUuid>
#ifdef Q_OS_WIN
#include <qt_windows.h>
#else
#include <QTemporaryFile>
#include <memory>
#endif

// Владение пикселями задаётся FRAME/ACK. Закрытие mapping никогда не ждёт другой процесс.
class CallCameraBuffer {
    QString m_name, m_error;
    uchar* m_data = nullptr;
#ifdef Q_OS_WIN
    HANDLE m_mapping = nullptr;
#else
    std::unique_ptr<QFile> m_file;
#endif
    bool fail(const QString& error) { m_error = error; close(); return false; }
    bool map() {
#ifdef Q_OS_WIN
        m_data = static_cast<uchar*>(MapViewOfFile(m_mapping, FILE_MAP_WRITE, 0, 0, CallCameraProtocol::FrameBytes));
        if (!m_data) return fail(QStringLiteral("MapViewOfFile error=%1").arg(GetLastError()));
#else
        m_data = m_file->map(0, CallCameraProtocol::FrameBytes);
        if (!m_data) return fail(m_file->errorString());
#endif
        return true;
    }
public:
    CallCameraBuffer() = default;
    CallCameraBuffer(const CallCameraBuffer&) = delete;
    CallCameraBuffer& operator=(const CallCameraBuffer&) = delete;
    ~CallCameraBuffer() { close(); }
    bool create() {
        close();
#ifdef Q_OS_WIN
        m_name = QStringLiteral("Local\\vibechat-camera-") + QUuid::createUuid().toString(QUuid::Id128);
        m_mapping = CreateFileMappingW(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0, CallCameraProtocol::FrameBytes,
            reinterpret_cast<const wchar_t*>(m_name.utf16()));
        const DWORD error = GetLastError();
        if (!m_mapping || error == ERROR_ALREADY_EXISTS) return fail(QStringLiteral("CreateFileMapping error=%1").arg(error));
#else
        auto file = std::make_unique<QTemporaryFile>();
        if (!file->open() || !file->resize(CallCameraProtocol::FrameBytes)) return fail(file->errorString());
        m_name = file->fileName(); m_file = std::move(file);
#endif
        return map();
    }
    bool attach(const QString& name) {
        close(); m_name = name;
#ifdef Q_OS_WIN
        m_mapping = OpenFileMappingW(FILE_MAP_WRITE, FALSE, reinterpret_cast<const wchar_t*>(name.utf16()));
        if (!m_mapping) return fail(QStringLiteral("OpenFileMapping error=%1").arg(GetLastError()));
#else
        m_file = std::make_unique<QFile>(name);
        if (!m_file->open(QIODevice::ReadWrite | QIODevice::ExistingOnly)) return fail(m_file->errorString());
        if (m_file->size() != CallCameraProtocol::FrameBytes) return fail(QStringLiteral("Invalid camera buffer size"));
#endif
        return map();
    }
    void close() {
#ifdef Q_OS_WIN
        if (m_data && !UnmapViewOfFile(m_data))
            DEBUG_WARN(DEBUG_CATEGORY_CALL, "camera buffer unmap error=%lu", (unsigned long)GetLastError());
        if (m_mapping && !CloseHandle(m_mapping))
            DEBUG_WARN(DEBUG_CATEGORY_CALL, "camera buffer close error=%lu", (unsigned long)GetLastError());
        m_mapping = nullptr;
#else
        m_file.reset();
#endif
        m_data = nullptr;
    }
    uchar* data() const { return m_data; }
    QString name() const { return m_name; }
    QString errorString() const { return m_error; }
};