#!/bin/bash
set -euo pipefail

# Builds shadowhook as a static library for Android arm64.
# Produces: libs/libshadowhook.a and libs/libshadowhook_nothing.so
#
# Skips the build entirely if both outputs already exist. Set FORCE_REBUILD=1
# to rebuild anyway (e.g. after changing CFLAGS, the toolchain, or the
# shadowhook sources themselves).

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
BUILD_DIR="$PROJECT_DIR/build/deps"

OUT_DIR="$SCRIPT_DIR"
SH="$SCRIPT_DIR/shadowhook/shadowhook/src/main/cpp"

if [ "${FORCE_REBUILD:-0}" != "1" ] \
    && [ -f "$OUT_DIR/libshadowhook.a" ] \
    && [ -f "$OUT_DIR/libshadowhook_nothing.so" ]; then
    echo "=== shadowhook already built, skipping (FORCE_REBUILD=1 to rebuild) ==="
    exit 0
fi

mkdir -p "$BUILD_DIR"

# --- Auto-detect Android NDK (same logic as build.sh) ---
find_ndk() {
    if [ -n "${ANDROID_NDK_HOME:-}" ] && [ -d "$ANDROID_NDK_HOME" ]; then
        echo "$ANDROID_NDK_HOME"; return
    fi
    local brew_ndk
    brew_ndk=$(find /opt/homebrew /usr/local -path "*/android-ndk/*/toolchains/llvm/prebuilt" -type d 2>/dev/null | head -1)
    if [ -n "$brew_ndk" ]; then
        echo "$(dirname "$(dirname "$(dirname "$brew_ndk")")")"; return
    fi
    local sdk_ndk
    sdk_ndk=$(find "$HOME/Library/Android/sdk/ndk" -maxdepth 1 -type d 2>/dev/null | sort -V | tail -1)
    if [ -n "$sdk_ndk" ] && [ -d "$sdk_ndk" ]; then
        echo "$sdk_ndk"; return
    fi
    for p in /opt/android-ndk /usr/local/android-ndk "$HOME/android-ndk"; do
        if [ -d "$p" ]; then echo "$p"; return; fi
    done
    echo ""
}

NDK_HOME="$(find_ndk)"
API_LEVEL="${ANDROID_API_LEVEL:-21}"
CC=""
if [ -n "$NDK_HOME" ]; then
    CC=$(find "$NDK_HOME/toolchains/llvm/prebuilt" -type f \
        -name "aarch64-linux-android${API_LEVEL}-clang" -print -quit 2>/dev/null)
fi
if [ -z "$CC" ]; then
    echo "ERROR: aarch64-linux-android clang not found."
    echo "  Set ANDROID_NDK_HOME to your NDK path."
    exit 1
fi

TOOLCHAIN_DIR="$(dirname "$CC")"
AR="$TOOLCHAIN_DIR/llvm-ar"
CFLAGS="-O2 -ffunction-sections -fdata-sections -fPIC -DANDROID -Wall -Wextra -Wno-unused-parameter -Wno-unused-function"

SH_SRCS=(
    "$SH/sh_elf.c"
    "$SH/sh_enter.c"
    "$SH/sh_hub.c"
    "$SH/sh_island.c"
    "$SH/sh_linker.c"
    "$SH/sh_recorder.c"
    "$SH/sh_safe.c"
    "$SH/sh_switch.c"
    "$SH/sh_task.c"
    "$SH/sh_xdl.c"
    "$SH/shadowhook.c"
    "$SH/arch/arm64/sh_a64.c"
    "$SH/arch/arm64/sh_inst.c"
    "$SH/arch/arm64/sh_glue.S"
    "$SH/common/bytesig.c"
    "$SH/common/sh_errno.c"
    "$SH/common/sh_log.c"
    "$SH/common/sh_ref.c"
    "$SH/common/sh_trampo.c"
    "$SH/common/sh_util.c"
    "$SH/third_party/xdl/xdl.c"
    "$SH/third_party/xdl/xdl_iterate.c"
    "$SH/third_party/xdl/xdl_linker.c"
    "$SH/third_party/xdl/xdl_lzma.c"
    "$SH/third_party/xdl/xdl_util.c"
)

SH_INCLUDES=(
    "-I$SH"
    "-I$SH/include"
    "-I$SH/arch/arm64"
    "-I$SH/common"
    "-I$SH/third_party/xdl"
    "-I$SH/third_party/bsd"
    "-I$SH/third_party/lss"
)

NOTHING_SRC="$SH/nothing/sh_nothing.c"

echo "=== Building shadowhook (arm64-v8a) ==="

SH_OBJS=()
for src in "${SH_SRCS[@]}"; do
    if [ ! -f "$src" ]; then
        echo "ERROR: shadowhook source not found: $src"
        exit 1
    fi

    rel="${src#"$SH"/}"
    flat="$(echo "$rel" | tr '/' '_')"
    obj="$BUILD_DIR/sh_${flat%.*}.o"

    "$CC" $CFLAGS "${SH_INCLUDES[@]}" -c "$src" -o "$obj"
    SH_OBJS+=("$obj")
done

"$AR" rcs "$OUT_DIR/libshadowhook.a" "${SH_OBJS[@]}"
SH_SIZE=$(wc -c < "$OUT_DIR/libshadowhook.a" 2>/dev/null || echo "unknown")
echo "  Built $OUT_DIR/libshadowhook.a ($SH_SIZE bytes)"

if [ ! -f "$NOTHING_SRC" ]; then
    echo "ERROR: ShadowHook companion source not found: $NOTHING_SRC"
    exit 1
fi

"$CC" -shared -Oz -fPIC -fno-ident -fno-unwind-tables -fno-asynchronous-unwind-tables \
    -nostdlib -nostartfiles -nodefaultlibs \
    -Wl,-z,max-page-size=16384 \
    -Wl,--strip-all -Wl,--as-needed -Wl,--hash-style=sysv \
    -Wl,--build-id=none \
    -o "$OUT_DIR/libshadowhook_nothing.so" "$NOTHING_SRC"
echo "  Built $OUT_DIR/libshadowhook_nothing.so"