#!/bin/sh
# Build rsync for each Android ABI from pinned source via the NDK. Output is a
# stripped PIE executable named lib*.so, packaged inside the APK and exec'd from
# nativeLibraryDir. Optional dependencies are disabled so the binary needs
# nothing outside Bionic; zlib and popt come from rsync's bundled copies.
set -eu

root=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
. "$root/versions"

# Locate the NDK toolchain.
ndk=${ANDROID_NDK_HOME:-${ANDROID_NDK_ROOT:-}}
if [ -z "$ndk" ] && [ -n "${ANDROID_HOME:-}" ]; then
	ndk="$ANDROID_HOME/ndk/$ANDROID_NDK"
fi
if [ -z "$ndk" ] || [ ! -d "$ndk" ]; then
	echo "rsync: Android NDK not found; set ANDROID_NDK_HOME" >&2
	exit 1
fi
# NDK prebuilt toolchains are named by build host, not target. Pick the tag
# matching this machine (macOS ships an x86_64 clang that runs under Rosetta on
# Apple Silicon); the target ABI is selected separately below.
case "$(uname -s)" in
Linux)  host_tag=linux-x86_64 ;;
Darwin) host_tag=darwin-x86_64 ;;
*)      echo "rsync: unsupported build host $(uname -s)" >&2; exit 1 ;;
esac
tc="$ndk/toolchains/llvm/prebuilt/$host_tag/bin"
if [ ! -d "$tc" ]; then
	echo "rsync: NDK toolchain not found at $tc" >&2
	exit 1
fi

work="$root/rsync/work"
tarball="$root/rsync/rsync-${RSYNC_VERSION}.tar.gz"
src="$work/rsync-${RSYNC_VERSION}"

# Fetch and verify the pinned source tarball.
mkdir -p "$work"
if [ ! -f "$tarball" ]; then
	echo "rsync: fetching $RSYNC_URL"
	curl -fsSL "$RSYNC_URL" -o "$tarball"
fi
echo "rsync: verifying sha256"
( cd "$root/rsync" && sha256sum -c "rsync-${RSYNC_VERSION}.tar.gz.sha256" )

# No system libraries, no docs (md2man needs python3), no iconv.
flags="--disable-md2man --disable-openssl --disable-xxhash --disable-zstd \
--disable-lz4 --disable-iconv --disable-acl-support --disable-xattr-support \
--with-included-popt --with-included-zlib"

for abi in $ABIS; do
	case "$abi" in
	arm64-v8a)   host=aarch64-linux-android  cc="aarch64-linux-android${ANDROID_MIN_SDK}-clang" ;;
	armeabi-v7a) host=arm-linux-androideabi  cc="armv7a-linux-androideabi${ANDROID_MIN_SDK}-clang" ;;
	x86_64)      host=x86_64-linux-android   cc="x86_64-linux-android${ANDROID_MIN_SDK}-clang" ;;
	x86)         host=i686-linux-android     cc="i686-linux-android${ANDROID_MIN_SDK}-clang" ;;
	*) echo "rsync: unknown ABI $abi" >&2; exit 1 ;;
	esac

	# Fresh build tree per ABI.
	rm -rf "$src"
	tar xzf "$tarball" -C "$work"

	echo "rsync: configuring $abi"
	( cd "$src" && \
		CC="$tc/$cc" AR="$tc/llvm-ar" RANLIB="$tc/llvm-ranlib" \
		CFLAGS="-O2 -fPIE -ffile-prefix-map=$src=." LDFLAGS="-pie" \
		./configure --host="$host" $flags >/dev/null )

	echo "rsync: building $abi"
	( cd "$src" && make -s rsync )

	dest="$root/app/src/main/jniLibs/$abi"
	mkdir -p "$dest"
	cp "$src/rsync" "$dest/libxrsync.so"
	"$tc/llvm-strip" "$dest/libxrsync.so"
	echo "rsync: $abi -> jniLibs/$abi/libxrsync.so"
done
