#!/bin/bash

set -e

LIBRARY_NAME="Boost"
REPOSITORY_NAME="boost"

# Informational, for the usage message.
CURRENT_LIBRARY_VERSION=1.85.0

BUILD_SCRIPT_NAME="$(basename $BASH_SOURCE)"
BUILD_SCRIPT_DIR=`cd $(dirname "$BASH_SOURCE"); pwd`

UsageAndExit()
{
    echo "Build $LIBRARY_NAME for use with Unreal Engine on Mac"
    echo
    echo "Usage:"
    echo
    echo "    $BUILD_SCRIPT_NAME <$LIBRARY_NAME Version> [<library name> [<library name> ...]]"
    echo
    echo "Usage examples:"
    echo
    echo "    $BUILD_SCRIPT_NAME $CURRENT_LIBRARY_VERSION"
    echo "      -- Installs $LIBRARY_NAME version $CURRENT_LIBRARY_VERSION as header-only."
    echo
    echo "    $BUILD_SCRIPT_NAME $CURRENT_LIBRARY_VERSION iostreams system thread"
    echo "      -- Installs $LIBRARY_NAME version $CURRENT_LIBRARY_VERSION with iostreams, system, and thread libraries."
    echo
    echo "    $BUILD_SCRIPT_NAME $CURRENT_LIBRARY_VERSION all"
    echo "      -- Installs $LIBRARY_NAME version $CURRENT_LIBRARY_VERSION with all of its libraries."
    echo
    exit 1
}

# Get version from arguments.
LIBRARY_VERSION=$1
if [ -z "$LIBRARY_VERSION" ]
then
    UsageAndExit
fi

shift

# Get the requested libraries to build from arguments, if any.
ARG_LIBRARIES=()
BOOST_WITH_LIBRARIES=""

for arg in "$@"
do
    ARG_LIBRARIES+=("$arg")
    BOOST_WITH_LIBRARIES="$BOOST_WITH_LIBRARIES --with-$arg"
done

UE_MODULE_LOCATION=`cd $BUILD_SCRIPT_DIR/../..; pwd`
UE_ENGINE_LOCATION=`cd $UE_MODULE_LOCATION/../../..; pwd`

PYTHON_EXECUTABLE_LOCATION="$UE_ENGINE_LOCATION/Binaries/ThirdParty/Python3/Mac/bin/python3"
PYTHON_VERSION=3.11

echo [`date +"%r"`] Building $LIBRARY_NAME for Unreal Engine
echo "    Version  : $LIBRARY_VERSION"
if [ ${#ARG_LIBRARIES[@]} -eq 0 ]
then
    echo "    Libraries: <headers-only>"
else
    echo "    Libraries: ${ARG_LIBRARIES[*]}"
fi

BUILD_LOCATION="$UE_MODULE_LOCATION/Intermediate"

INSTALL_INCLUDEDIR=include

INSTALL_LOCATION="$UE_MODULE_LOCATION/Deploy/$REPOSITORY_NAME-$LIBRARY_VERSION"
INSTALL_INCLUDE_LOCATION="$INSTALL_LOCATION/$INSTALL_INCLUDEDIR"
INSTALL_MAC_LOCATION="$INSTALL_LOCATION/Mac"
INSTALL_LIB_LOCATION="$INSTALL_MAC_LOCATION/lib"

rm -rf $INSTALL_INCLUDE_LOCATION
rm -rf $INSTALL_MAC_LOCATION

# Set the following variable to 1 if you have already downloaded and extracted
# the Boost sources and you need to play around with the build configuration.
ALREADY_HAVE_SOURCES=0

LIBRARY_UNDERSCORE_VERSION="`echo $LIBRARY_VERSION | sed s/\\\./_/g`"
LIBRARY_VERSION_FILENAME="${REPOSITORY_NAME}_$LIBRARY_UNDERSCORE_VERSION"

if [ $ALREADY_HAVE_SOURCES -eq 0 ]
then
    rm -rf $BUILD_LOCATION
    mkdir $BUILD_LOCATION
else
    echo Expecting sources to already be available at $BUILD_LOCATION/$LIBRARY_VERSION_FILENAME
fi

pushd $BUILD_LOCATION > /dev/null

if [ $ALREADY_HAVE_SOURCES -eq 0 ]
then
    # Download Boost source file.
    BOOST_SOURCE_FILE="$LIBRARY_VERSION_FILENAME.tar.gz"
    BOOST_URL="https://archives.boost.io/release/$LIBRARY_VERSION/source/$BOOST_SOURCE_FILE"

    echo [`date +"%r"`] Downloading $BOOST_URL...
    curl -# -L -o $BOOST_SOURCE_FILE $BOOST_URL

    # Extract Boost source file.
    echo
    echo [`date +"%r"`] Extracting $BOOST_SOURCE_FILE...
    tar -xf $BOOST_SOURCE_FILE
fi

pushd $LIBRARY_VERSION_FILENAME > /dev/null

if [ ${#ARG_LIBRARIES[@]} -eq 0 ]
then
    # No libraries requested. Just copy header files.
    echo [`date +"%r"`] Copying header files...
    
    BOOST_HEADERS_DIRECTORY_NAME=boost

    mkdir -p $INSTALL_INCLUDE_LOCATION

    cp -rp $BOOST_HEADERS_DIRECTORY_NAME $INSTALL_INCLUDE_LOCATION
else
    # Build and install with libraries.
    echo [`date +"%r"`] Building $LIBRARY_NAME libraries...

    # Set tool set to current UE tool set.
    BOOST_TOOLSET=clang

    # Provide user config to specify Python configuration.
    BOOST_USER_CONFIG="$BUILD_SCRIPT_DIR/user-config.jam"

    MACOS_DEPLOYMENT_TARGET=13.0

    ARCH_FLAGS="-arch x86_64 -arch arm64"

    # Bootstrap before build.
    echo [`date +"%r"`] Bootstrapping $LIBRARY_NAME $LIBRARY_VERSION build...
    ./bootstrap.sh \
        --prefix=$INSTALL_LOCATION \
        --includedir=$INSTALL_INCLUDE_LOCATION \
        --libdir=$INSTALL_LIB_LOCATION \
        --with-toolset=$BOOST_TOOLSET \
        --with-python=$PYTHON_EXECUTABLE_LOCATION \
        --with-python-version=$PYTHON_VERSION \
        cflags="$ARCH_FLAGS" \
        cxxflags="$ARCH_FLAGS" \
        linkflags="$ARCH_FLAGS"

    echo [`date +"%r"`] Building $LIBRARY_NAME $LIBRARY_VERSION for architectures x86_64 and arm64...

    NUM_CPU=8

    # Depending on the system installation, the version of liblzma.dylib found
    # and used by iostreams may or may not be a universal binary, so disable
    # LZMA for now.
    ./b2 \
        --prefix=$INSTALL_LOCATION \
        --includedir=$INSTALL_INCLUDE_LOCATION \
        --libdir=$INSTALL_LIB_LOCATION \
        -j$NUM_CPU \
        address-model=64 \
        threading=multi \
        variant=release \
        $BOOST_WITH_LIBRARIES \
        --user-config=$BOOST_USER_CONFIG \
        --hash \
        --build-type=complete \
        --layout=tagged \
        --debug-configuration \
        toolset=$BOOST_TOOLSET \
        architecture=arm+x86 \
        -sNO_LZMA=1 \
        cflags="-mmacosx-version-min=$MACOS_DEPLOYMENT_TARGET $ARCH_FLAGS" \
        cxxflags="-mmacosx-version-min=$MACOS_DEPLOYMENT_TARGET $ARCH_FLAGS" \
        mflags="-mmacosx-version-min=$MACOS_DEPLOYMENT_TARGET $ARCH_FLAGS" \
        mmflags="-mmacosx-version-min=$MACOS_DEPLOYMENT_TARGET $ARCH_FLAGS" \
        linkflags="-mmacosx-version-min=$MACOS_DEPLOYMENT_TARGET $ARCH_FLAGS" \
        install
fi

popd > /dev/null

popd > /dev/null

echo [`date +"%r"`] $LIBRARY_NAME $LIBRARY_VERSION installed to $INSTALL_LOCATION
echo [`date +"%r"`] Done.