// Copyright (C) 2023 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
\page android-openssl-support.html
\ingroup android-platform-extra-topics
\title Adding OpenSSL Support for Android
\brief How to package OpenSSL libraries with a Qt for Android application.
\previouspage deployment-android.html
\nextpage android-manifest-file-configuration.html

The Qt installation package comes with OpenSSL support, but the OpenSSL libraries
are not part of the package due to legal restrictions in some countries. If your
application depends on OpenSSL, consider packaging the SSL libraries with your
Application Package (\c APK or \c AAB) as the target device may or may not have them.

You can use the \l {QSslSocket::supportsSsl()} static function to check for SSL
support on the target device. First, include the header:
\code
#include <QSslSocket>
\endcode

Then use the following line to check if SSL is supported:
\code
qDebug() << "Device supports OpenSSL: " << QSslSocket::supportsSsl();
\endcode

Check \QC's \c {Application Output} section or the Android \c logcat for
that log message.

\section1 Adding OpenSSL Libraries

Using the convenience \l {OpenSSL for Android} repository,
you can directly include OpenSSL libraries in your own project.

With CMake, add the following to your \c {CMakeLists.txt}:

\badcode
if (ANDROID)
    include(FetchContent)
    FetchContent_Declare(
        android_openssl
        DOWNLOAD_EXTRACT_TIMESTAMP true
        URL https://github.com/KDAB/android_openssl/archive/refs/heads/master.zip
    )
    FetchContent_MakeAvailable(android_openssl)
    include(${android_openssl_SOURCE_DIR}/android_openssl.cmake)
endif()
\endcode

\b{Or} if you cloned the repository into a subdirectory:

\badcode
include(<path/to/android_openssl>/android_openssl.cmake)
\endcode

Then, add the libraries to your targets:

\badcode
qt_add_executable(your_target_name ..)
qt_add_executable(your_second_target_name ..)

if (ANDROID)
    add_android_openssl_libraries(your_target_name your_second_target_name)
endif()
\endcode

For \c qmake, add the following to your \c {.pro} file:

\badcode
android: include(<path/to/android_openssl/openssl.pri)
\endcode

Alternatively, to add extra libraries, such as \c libcrypto and \c libssl.
For CMake, use:

\badcode
set_target_properties(<target_name> PROPERTIES
    QT_ANDROID_EXTRA_LIBS "<path_to_libs_dir>/libcrypto_3.so" "<path_to_libs_dir>/libssl_3.so"
)
\endcode

Or for \c qmake use:

\badcode
ANDROID_EXTRA_LIBS += \
    <path_to_libs_dir>/libcrypto_3.so \
    <path_to_libs_dir>/libssl_3.so
\endcode

\note When targeting multiple architectures, include OpenSSL libraries
for all the targeted architectures.

Using \QC, it is possible to add extra libraries. For more
information, see \l {\QC: Add libraries to CMake projects} and
\l{\QC: Add libraries to qmake projects}.

\section1 Building OpenSSL for Android

The following instructions guide you to build the OpenSSL libraries manually:

\list 1
    \li Download \l{OpenSSL Source}{OpenSSL} sources.

    \li Extract the sources to a folder and navigate to that folder using
        the CLI.
        \note If your development platform is Windows, you need \c msys with
        \c perl 5.14 or later to build OpenSSL.

    \li Add the Android LLVM toolchain to your path, for example, for Linux use:

        \badcode \NdkFullVer
        export PATH=~/Android/Sdk/ndk/\1/toolchains/llvm/prebuilt/<host>/bin:$PATH
        \endcode

        \include src/platforms/android/android-prerequisites.qdoc Android SDK Paths

    \li Configure the OpenSSL sources to build for Android using
        the following command, where <arch> can take a value of:
        \c arm, \c arm64, \c x86 or \c x86_64:

        \badcode \AndroidMinApiVer
        ./Configure shared android-<arch> -D__ANDROID_API__=\1
        \endcode

        \note You must consider enabling or disabling the SSL features based on
        the legal restrictions in the region where your application is available.
        For more information about the configurable features, see
        \l{OpenSSL Configure Options}.

    \li Without a suffix, Android loads the system libraries \c libcrypto.so and
        \c libssl.so. These may be different versions from your libraries or from what
        Qt expects. To ensure that Qt apps can load the manually built OpenSSL libraries,
        run the following commands:

        \badcode
        make -j$(nproc) SHLIB_VERSION_NUMBER= build_libs

        mkdir -p ${out_path}
        cp libcrypto.so ${out_path}/libcrypto_3.so
        cp libssl.so ${out_path}/libssl_3.so

        cd ${out_path}
        patchelf --set-soname libcrypto_3.so libcrypto_3.so
        patchelf --set-soname libssl_3.so libssl_3.so
        patchelf --replace-needed libcrypto.so libcrypto_3.so libssl_3.so
        \endcode

        \note Though the \c libcrypto and \c libssl shared libraries that are not versioned,
        they will have a \e _3 suffix.

        Then set the environment variable in your main.cpp file:

        \code
        qputenv("ANDROID_OPENSSL_SUFFIX", "<custom_suffix>");
        \endcode

        \note Android does not load versioned libraries.
\endlist

*/
