#!/usr/bin/env bash
# build_zstd_android.sh - 为 Android 交叉编译 libzstd.a
# 与 linux/lib/libzstd.a 版本对齐（1.5.6）
#
# 用法：
#   ./build_zstd_android.sh                          # 自动查找 NDK
#   ANDROID_NDK=/path/to/ndk ./build_zstd_android.sh
#
# 产出：
#   app/src/main/cpp/lib/arm64-v8a/libzstd.a
#   app/src/main/cpp/lib/armeabi-v7a/libzstd.a

set -euo pipefail
cd "$(dirname "$0")"

ZSTD_VERSION="1.5.6"
ZSTD_TAR="zstd-${ZSTD_VERSION}.tar.gz"
ZSTD_URL="https://github.com/facebook/zstd/releases/download/v${ZSTD_VERSION}/${ZSTD_TAR}"
ZSTD_DIR="zstd-${ZSTD_VERSION}"

# --- 定位 NDK ---
if [[ -z "${ANDROID_NDK:-}" ]]; then
    for candidate in \
        "$HOME/android-ndk-r27c" \
        "$HOME/Library/Android/sdk/ndk/$(ls "$HOME/Library/Android/sdk/ndk" 2>/dev/null | sort -V | tail -1)" \
        "$HOME/Android/Sdk/ndk/$(ls "$HOME/Android/Sdk/ndk" 2>/dev/null | sort -V | tail -1)"; do
        if [[ -f "${candidate}/build/cmake/android.toolchain.cmake" ]]; then
            ANDROID_NDK="$candidate"; break
        fi
    done
fi
[[ -z "${ANDROID_NDK:-}" ]] && { echo "Error: ANDROID_NDK not set"; exit 1; }
TOOLCHAIN="$ANDROID_NDK/build/cmake/android.toolchain.cmake"
echo "NDK: $ANDROID_NDK"

# --- 下载 zstd 源码 ---
if [[ ! -d "$ZSTD_DIR" ]]; then
    echo "Downloading zstd $ZSTD_VERSION..."
    wget -q "$ZSTD_URL" -O "$ZSTD_TAR"
    tar xf "$ZSTD_TAR"
    rm "$ZSTD_TAR"
fi

OUT_BASE="app/src/main/cpp/lib"
ABIS=("arm64-v8a" "armeabi-v7a")
for ABI in "${ABIS[@]}"; do
    BUILD_DIR="zstd_build/$ABI"
    OUT_DIR="$OUT_BASE/$ABI"
    rm -rf "$BUILD_DIR"
    echo
    echo "===== zstd $ABI ====="
    cmake \
        -B "$BUILD_DIR" -S "$ZSTD_DIR/build/cmake" \
        -DCMAKE_TOOLCHAIN_FILE="$TOOLCHAIN" \
        -DANDROID_ABI="$ABI" \
        -DANDROID_PLATFORM=android-21 \
        -DCMAKE_BUILD_TYPE=Release \
        -DCMAKE_C_FLAGS="-Os -g0" \
        -DZSTD_BUILD_STATIC=ON \
        -DZSTD_BUILD_SHARED=OFF \
        -DZSTD_BUILD_PROGRAMS=OFF \
        -DZSTD_BUILD_TESTS=OFF \
        -DZSTD_LEGACY_SUPPORT=0
    cmake --build "$BUILD_DIR" --config Release -j"$(nproc 2>/dev/null || sysctl -n hw.logicalcpu)"
    mkdir -p "$OUT_DIR"
    cp "$BUILD_DIR/lib/libzstd.a" "$OUT_DIR/libzstd.a"
    # strip residual debug symbols from the archive
    STRIP="$ANDROID_NDK/toolchains/llvm/prebuilt/linux-x86_64/bin/llvm-strip"
    [[ -f "$STRIP" ]] && "$STRIP" --strip-debug "$OUT_DIR/libzstd.a"
    ls -lh "$OUT_DIR/libzstd.a"
done

rm -rf zstd_build "$ZSTD_DIR"

echo
echo "===== Done ====="
echo "libzstd.a 已写入 app/src/main/cpp/lib/{arm64-v8a,armeabi-v7a}/"