#!/bin/bash
set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

# Get script directory
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$SCRIPT_DIR"

# Build directories
CPP_DIR="$PROJECT_ROOT/internal/cpp"
BUILD_DIR="$CPP_DIR/cmake-build-release"
RAGFLOW_SERVER_BINARY="$PROJECT_ROOT/bin/ragflow_server"
ADMIN_SERVER_BINARY="$PROJECT_ROOT/bin/admin_server"
INGESTOR_BINARY="$PROJECT_ROOT/bin/ingestor"
RAGFLOW_CLI_BINARY="$PROJECT_ROOT/bin/ragflow-cli"

# Strip symbols from Go binaries (set via --strip / -s)
STRIP_SYMBOLS=""

# office_oxide native library settings
OFFICE_OXIDE_PREFIX="${HOME}/.office_oxide"
OFFICE_OXIDE_VERSION="0.1.2"

# pdfium native library settings (from pypdfium2_raw PyPI wheel)
PDFIUM_PREFIX="${HOME}/.pdfium"
PDFIUM_VERSION="0.5.0"

# pdf_oxide native library settings (from GitHub Release)
PDF_OXIDE_PREFIX="${HOME}/.pdf_oxide"
PDF_OXIDE_VERSION="0.3.63"

echo -e "${GREEN}=== RAGFlow Go Server Build Script ===${NC}"

# Function to print section headers
print_section() {
    echo -e "\n${YELLOW}>>> $1${NC}"
}

# Detect the package-install command for pcre2 development files.
# Outputs the command on stdout; empty string if no supported manager is found.
detect_pcre2_install_cmd() {
    if [ "$(uname)" = "Darwin" ]; then
        echo "brew install pcre2"
    elif command -v apt-get >/dev/null 2>&1; then
        echo "sudo apt-get install -y libpcre2-dev"
    elif command -v zypper >/dev/null 2>&1; then
        echo "sudo zypper install -y pcre2-devel"
    elif command -v dnf >/dev/null 2>&1; then
        echo "sudo dnf install -y pcre2-devel"
    elif command -v pacman >/dev/null 2>&1; then
        echo "sudo pacman -S --noconfirm pcre2"
    else
        echo ""
    fi
}

# Check whether libpcre2-8 is available (static or shared).
check_pcre2() {
    # Prefer pkg-config when available — works across distros.
    if command -v pkg-config >/dev/null 2>&1 && pkg-config --exists libpcre2-8; then
        return 0
    fi
    # Fall back to known library paths:
    #   Debian/Ubuntu  -> /usr/lib/x86_64-linux-gnu
    #   openSUSE/RHEL  -> /usr/lib64
    #   generic Linux  -> /usr/lib, /usr/local/lib
    #   macOS Homebrew -> /opt/homebrew/lib (Apple Silicon), /usr/local/lib (Intel)
    for p in \
        /usr/lib/x86_64-linux-gnu/libpcre2-8.a \
        /usr/lib/x86_64-linux-gnu/libpcre2-8.so \
        /usr/lib64/libpcre2-8.a \
        /usr/lib64/libpcre2-8.so \
        /usr/lib/libpcre2-8.a \
        /usr/lib/libpcre2-8.so \
        /usr/local/lib/libpcre2-8.a \
        /usr/local/lib/libpcre2-8.so \
        /usr/local/lib/libpcre2-8.dylib \
        /opt/homebrew/lib/libpcre2-8.a \
        /opt/homebrew/lib/libpcre2-8.dylib; do
        [ -f "$p" ] && return 0
    done
    return 1
}

# Check dependencies
check_cpp_deps() {
    print_section "Checking c++ dependencies"

    command -v cmake >/dev/null 2>&1 || { echo -e "${RED}Error: cmake is required but not installed.${NC}"; exit 1; }
    command -v g++ >/dev/null 2>&1 || { echo -e "${RED}Error: g++ is required but not installed.${NC}"; exit 1; }

    if check_pcre2; then
        echo "✓ pcre2 library found"
    else
        install_cmd="$(detect_pcre2_install_cmd)"
        echo -e "${YELLOW}Warning: libpcre2-8 not found. You may need to install it:${NC}"
        if [ -n "$install_cmd" ]; then
            echo "  $install_cmd"
        else
            echo "  (No supported package manager detected — install pcre2 development files manually)"
        fi
    fi

    echo "✓ Required tools are available"
}

check_go_deps() {
    print_section "Checking go dependencies"

    command -v go >/dev/null 2>&1 || { echo -e "${RED}Error: go is required but not installed.${NC}"; exit 1; }

    echo "✓ Required tools are available"
}

# Download and extract a tar.gz from a URL to a target directory
_download_and_extract() {
    local url="$1" target_dir="$2"
    echo "Downloading ${url} ..."
    local tmpfile
    tmpfile="$(mktemp)"
    if command -v curl >/dev/null 2>&1; then
        curl -fsSL "$url" -o "$tmpfile"
    elif command -v wget >/dev/null 2>&1; then
        wget -q "$url" -O "$tmpfile"
    else
        echo -e "${RED}Error: need curl or wget to download office_oxide${NC}"
        exit 1
    fi
    tar xzf "$tmpfile" -C "$target_dir"
    rm -f "$tmpfile"
}

# Check / install office_oxide native library (Rust → C FFI library)
check_office_oxide_deps() {
    print_section "Checking office_oxide native library"

    local lib_file header_path
    case "$(uname -s)" in
        Linux)  lib_file="liboffice_oxide.so" ;;
        Darwin) lib_file="liboffice_oxide.dylib" ;;
        *)      echo -e "${RED}Unsupported OS for office_oxide${NC}"; exit 1 ;;
    esac

    local lib_path="${OFFICE_OXIDE_PREFIX}/lib/${lib_file}"
    local header_path="${OFFICE_OXIDE_PREFIX}/include/office_oxide_c/office_oxide.h"

    if [ -f "$lib_path" ] && [ -f "$header_path" ]; then
        echo "✓ office_oxide native library found at ${OFFICE_OXIDE_PREFIX}"
        return 0
    fi

    echo "office_oxide native library not found. Installing..."

    # Map platform to the release asset name. Note: the GitHub release archives
    # omit the version number from the native-* asset filenames.
    local asset_name
    case "$(uname -s)" in
        Linux)
            case "$(uname -m)" in
                x86_64)  asset_name="native-linux-x86_64" ;;
                aarch64|arm64) asset_name="native-linux-aarch64" ;;
                *) echo -e "${RED}Unsupported arch: $(uname -m)${NC}"; exit 1 ;;
            esac
            ;;
        Darwin)
            case "$(uname -m)" in
                x86_64)  asset_name="native-macos-x86_64" ;;
                aarch64|arm64) asset_name="native-macos-aarch64" ;;
                *) echo -e "${RED}Unsupported arch: $(uname -m)${NC}"; exit 1 ;;
            esac
            ;;
    esac

    local release_url="https://github.com/yfedoseev/office_oxide/releases/download/v${OFFICE_OXIDE_VERSION}/${asset_name}.tar.gz"

    mkdir -p "${OFFICE_OXIDE_PREFIX}"
    _download_and_extract "$release_url" "${OFFICE_OXIDE_PREFIX}"

    if [ ! -f "$lib_path" ]; then
        echo -e "${RED}Error: Failed to install office_oxide native library (missing ${lib_path})${NC}"
        echo "  Try: curl -fsSL ${release_url} | tar xzf - -C ${OFFICE_OXIDE_PREFIX}"
        exit 1
    fi

    echo -e "${GREEN}✓ office_oxide native library installed${NC}"
}

# Check / install pdfium native library (libpdfium.so from pypdfium2_raw wheel).
check_pdfium_deps() {
    # 1. Check .venv (uv sync provides pypdfium2_raw).
    local venv_py="${PROJECT_ROOT}/.venv/bin/python3"
    if [ -x "$venv_py" ]; then
        local venv_so=$("$venv_py" -c "import pypdfium2_raw,os;print(os.path.join(os.path.dirname(pypdfium2_raw.__file__),'libpdfium.so'))" 2>/dev/null)
        if [ -n "$venv_so" ] && [ -f "$venv_so" ]; then
            echo "  pdfium          → ${venv_so} (.venv)"
            export CGO_LDFLAGS="$CGO_LDFLAGS -L$(dirname "$venv_so") -Wl,-rpath,$(dirname "$venv_so")"
            export LD_LIBRARY_PATH="$(dirname "$venv_so"):${LD_LIBRARY_PATH}"
            return 0
        fi
    fi

    # 2. Check cache.
    local lib_path="${PDFIUM_PREFIX}/libpdfium.so"
    if [ -f "$lib_path" ]; then
        echo "  pdfium          → ${PDFIUM_PREFIX}"
        return 0
    fi

    echo "  pdfium not found, installing..."

    # 3. Map platform to PyPI wheel platform tag.
    local whl_platform
    case "$(uname -s)" in
        Linux)
            case "$(uname -m)" in
                x86_64)  whl_platform="manylinux_2_17_x86_64.manylinux2014_x86_64" ;;
                aarch64|arm64) whl_platform="manylinux_2_17_aarch64.manylinux2014_aarch64" ;;
                *) echo "  pdfium          → unsupported arch"; return 1 ;;
            esac
            ;;
        Darwin)
            case "$(uname -m)" in
                x86_64)  whl_platform="macosx_11_0_x86_64" ;;
                arm64)   whl_platform="macosx_11_0_arm64" ;;
                *) echo "  pdfium          → unsupported arch"; return 1 ;;
            esac
            ;;
        *) echo "  pdfium          → unsupported OS"; return 1 ;;
    esac

    # 4. Download .whl from PyPI and extract libpdfium.so (zero pip dependency).
    local whl_url
    whl_url=$(curl -fsSL "https://pypi.org/pypi/pypdfium2_raw/${PDFIUM_VERSION}/json" 2>/dev/null \
        | grep -o '"url":"[^"]*'${whl_platform}'[^"]*"' | head -1 | cut -d'"' -f4)

    if [ -n "$whl_url" ] && { command -v curl >/dev/null 2>&1 || command -v wget >/dev/null 2>&1; }; then
        local tmp_whl="$(mktemp)"
        if command -v curl >/dev/null 2>&1; then
            curl -fsSL "$whl_url" -o "$tmp_whl"
        else
            wget -q "$whl_url" -O "$tmp_whl"
        fi
        mkdir -p "${PDFIUM_PREFIX}"
        # Wheel is a zip; extract libpdfium.so via python3 or unzip.
        if command -v python3 >/dev/null 2>&1; then
            python3 -c "
import zipfile, os, shutil
with zipfile.ZipFile('$tmp_whl') as z:
    for n in z.namelist():
        if n.endswith('libpdfium.so'):
            z.extract(n, '${PDFIUM_PREFIX}')
            os.rename(os.path.join('${PDFIUM_PREFIX}', n), '$lib_path')
            # Remove empty pypdfium2_raw dir
            d = os.path.join('${PDFIUM_PREFIX}', 'pypdfium2_raw')
            if os.path.isdir(d): shutil.rmtree(d, ignore_errors=True)
            break
" 2>/dev/null
        elif command -v unzip >/dev/null 2>&1; then
            unzip -q -o "$tmp_whl" -d "${PDFIUM_PREFIX}" 'pypdfium2_raw/libpdfium.so' 2>/dev/null
            [ -f "${PDFIUM_PREFIX}/pypdfium2_raw/libpdfium.so" ] && mv "${PDFIUM_PREFIX}/pypdfium2_raw/libpdfium.so" "$lib_path"
            rm -rf "${PDFIUM_PREFIX}/pypdfium2_raw"
        fi
        rm -f "$tmp_whl"
    fi

    if [ -f "$lib_path" ]; then
        echo -e "${GREEN}✓ pdfium installed to ${PDFIUM_PREFIX}${NC}"
    else
        echo "  pdfium          → install failed (requires .venv, curl/wget + python3, or pre-cached ~/.pdfium)"
        return 1
    fi
}

# Check / install pdf_oxide native library (Rust -> C FFI library).
check_pdf_oxide_deps() {
    local lib_path="${PDF_OXIDE_PREFIX}/libpdf_oxide.so"

    if [ -f "$lib_path" ]; then
        echo "  pdf_oxide       → ${PDF_OXIDE_PREFIX} (shared)"
        return 0
    fi

    # Also check for static library (user's local installation).
    local static_path="${PDF_OXIDE_PREFIX}/libpdf_oxide.a"
    if [ -f "$static_path" ]; then
        echo "  pdf_oxide       → ${PDF_OXIDE_PREFIX} (static)"
        return 0
    fi

    echo "  pdf_oxide not found, installing..."

    # Map platform to the release asset name.
    local asset_name
    case "$(uname -s)" in
        Linux)
            case "$(uname -m)" in
                x86_64)  asset_name="libpdf_oxide-v${PDF_OXIDE_VERSION}-linux-x86_64" ;;
                aarch64|arm64) asset_name="libpdf_oxide-v${PDF_OXIDE_VERSION}-linux-aarch64" ;;
                *) echo "  pdf_oxide       → unsupported arch"; return 1 ;;
            esac
            ;;
        Darwin)
            case "$(uname -m)" in
                x86_64)  asset_name="libpdf_oxide-v${PDF_OXIDE_VERSION}-darwin-x86_64" ;;
                arm64)   asset_name="libpdf_oxide-v${PDF_OXIDE_VERSION}-darwin-arm64" ;;
                *) echo "  pdf_oxide       → unsupported arch"; return 1 ;;
            esac
            ;;
        *) echo "  pdf_oxide       → unsupported OS"; return 1 ;;
    esac

    local release_url="https://github.com/yfedoseev/pdf_oxide/releases/download/v${PDF_OXIDE_VERSION}/${asset_name}.tar.gz"

    mkdir -p "${PDF_OXIDE_PREFIX}"
    _download_and_extract "$release_url" "${PDF_OXIDE_PREFIX}"

    if [ -f "$lib_path" ]; then
        echo -e "${GREEN}✓ pdf_oxide installed to ${PDF_OXIDE_PREFIX}${NC}"
    else
        echo "  pdf_oxide       → install failed"
        return 1
    fi
}

# Build C++ static library
build_cpp() {
    print_section "Building C++ static library"

    mkdir -p "$BUILD_DIR"
    cd "$BUILD_DIR"

    echo "Running cmake..."
    cmake .. -DCMAKE_BUILD_TYPE=Release

    echo "Building librag_tokenizer_c_api.a..."
    local jobs
    jobs="$(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 1)"
    make rag_tokenizer_c_api -j"$jobs"

    if [ ! -f "$BUILD_DIR/librag_tokenizer_c_api.a" ]; then
        echo -e "${RED}Error: Failed to build C++ static library${NC}"
        exit 1
    fi

    echo -e "${GREEN}✓ C++ static library built successfully${NC}"
}

# Build C++ test executable
build_cpp_test() {
    print_section "Building C++ test executable"

    if [ ! -d "$BUILD_DIR" ]; then
        echo "Build directory not found, running cmake first..."
        mkdir -p "$BUILD_DIR"
        cd "$BUILD_DIR"
        cmake .. -DCMAKE_BUILD_TYPE=Release
    else
        cd "$BUILD_DIR"
    fi

    echo "Building rag_analyzer_c_test..."
    local jobs
    jobs="$(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || echo 1)"
    make rag_analyzer_c_test -j"$jobs"

    if [ ! -f "$BUILD_DIR/rag_analyzer_c_test" ]; then
        echo -e "${RED}Error: Failed to build rag_analyzer_c_test${NC}"
        exit 1
    fi

    echo -e "${GREEN}✓ C++ test executable built successfully: $BUILD_DIR/rag_analyzer_c_test${NC}"
}

# Build Go server
build_go() {
    print_section "Building RAGFlow go"

    cd "$PROJECT_ROOT"

    # Check if C++ library exists
    if [ ! -f "$BUILD_DIR/librag_tokenizer_c_api.a" ]; then
        echo -e "${RED}Error: C++ static library not found. Run with --cpp first.${NC}"
        exit 1
    fi

    if check_pcre2; then
        echo "✓ pcre2 library found"
    else
        install_cmd="$(detect_pcre2_install_cmd)"
        if [ -z "$install_cmd" ]; then
            echo -e "${RED}Error: libpcre2-8 not found and no supported package manager detected.${NC}"
            echo "Please install pcre2 development files manually."
            exit 1
        fi
        if [ "$(uname)" = "Darwin" ]; then
            echo -e "${RED}Error: libpcre2-8 not found. Install with: $install_cmd${NC}"
            exit 1
        fi
        echo -e "${YELLOW}Warning: libpcre2-8 not found. Installing with: $install_cmd${NC}"
        eval "$install_cmd"
    fi

    setup_cgo_env

    local strip_flags=()
    [ -n "$STRIP_SYMBOLS" ] && strip_flags=(-ldflags="-s -w")

    echo "Building RAGFlow binary: $RAGFLOW_SERVER_BINARY, $ADMIN_SERVER_BINARY, $INGESTOR_BINARY, and $RAGFLOW_CLI_BINARY"
    GOPROXY=${GOPROXY:-https://goproxy.cn,https://proxy.golang.org,direct} CGO_ENABLED=1 \
        CGO_CFLAGS="$CGO_CFLAGS" CGO_LDFLAGS="$CGO_LDFLAGS" \
        go build "${strip_flags[@]}" -o "$RAGFLOW_SERVER_BINARY" cmd/server_main.go
    GOPROXY=${GOPROXY:-https://goproxy.cn,https://proxy.golang.org,direct} CGO_ENABLED=1 \
        CGO_CFLAGS="$CGO_CFLAGS" CGO_LDFLAGS="$CGO_LDFLAGS" \
        go build "${strip_flags[@]}" -o "$ADMIN_SERVER_BINARY" cmd/admin_server.go
    GOPROXY=${GOPROXY:-https://goproxy.cn,https://proxy.golang.org,direct} CGO_ENABLED=1 \
        CGO_CFLAGS="$CGO_CFLAGS" CGO_LDFLAGS="$CGO_LDFLAGS" \
        go build "${strip_flags[@]}" -o "$INGESTOR_BINARY" cmd/ingestor.go
    GOPROXY=${GOPROXY:-https://goproxy.cn,https://proxy.golang.org,direct} CGO_ENABLED=1 \
        CGO_CFLAGS="$CGO_CFLAGS" CGO_LDFLAGS="$CGO_LDFLAGS" \
        go build "${strip_flags[@]}" -o "$RAGFLOW_CLI_BINARY" cmd/ragflow-cli.go

    if [ ! -f "$RAGFLOW_SERVER_BINARY" ]; then
        echo -e "${RED}Error: Failed to build RAGFlow server binary${NC}"
        exit 1
    fi

    if [ ! -f "$ADMIN_SERVER_BINARY" ]; then
        echo -e "${RED}Error: Failed to build Admin server binary${NC}"
        exit 1
    fi

    if [ ! -f "$INGESTOR_BINARY" ]; then
        echo -e "${RED}Error: Failed to build Ingestor binary${NC}"
        exit 1
    fi

    echo -e "${GREEN}✓ Go ragflow_server built successfully: $RAGFLOW_SERVER_BINARY${NC}"
    echo -e "${GREEN}✓ Go admin_server built successfully: $ADMIN_SERVER_BINARY${NC}"
    echo -e "${GREEN}✓ Go ragflow-cli built successfully: $RAGFLOW_CLI_BINARY${NC}"
    echo -e "${GREEN}✓ Go ingestor built successfully: $INGESTOR_BINARY${NC}"
}

# Configure CGO flags for native libraries (office_oxide, pdfium, pdf_oxide).
# Call before any `go build` / `go test` step that links against these libraries.
setup_cgo_env() {
    # ── office_oxide ──────────────────────────────────────────────────
    check_office_oxide_deps
    export CGO_CFLAGS="-I${OFFICE_OXIDE_PREFIX}/include/office_oxide_c${CGO_CFLAGS:+ $CGO_CFLAGS}"
    export CGO_LDFLAGS="-L${OFFICE_OXIDE_PREFIX}/lib -loffice_oxide -Wl,-rpath,${OFFICE_OXIDE_PREFIX}/lib"
    export LD_LIBRARY_PATH="${OFFICE_OXIDE_PREFIX}/lib${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"

    # ── pdfium ────────────────────────────────────────────────────────
    check_pdfium_deps || return 1
    if [ -f "${PDFIUM_PREFIX}/libpdfium.so" ]; then
        export CGO_LDFLAGS="$CGO_LDFLAGS -L${PDFIUM_PREFIX} -Wl,-rpath,${PDFIUM_PREFIX}"
        export LD_LIBRARY_PATH="${PDFIUM_PREFIX}:${LD_LIBRARY_PATH}"
    fi

    # ── pdf_oxide ─────────────────────────────────────────────────────
    check_pdf_oxide_deps || return 1
    if [ -f "${PDF_OXIDE_PREFIX}/libpdf_oxide.so" ]; then
        export CGO_LDFLAGS="$CGO_LDFLAGS -L${PDF_OXIDE_PREFIX} -lpdf_oxide -Wl,-rpath,${PDF_OXIDE_PREFIX}"
        export LD_LIBRARY_PATH="${PDF_OXIDE_PREFIX}:${LD_LIBRARY_PATH}"
    elif [ -f "${PDF_OXIDE_PREFIX}/libpdf_oxide.a" ]; then
        export CGO_LDFLAGS="$CGO_LDFLAGS ${PDF_OXIDE_PREFIX}/libpdf_oxide.a"
    fi

    echo "CGO_CFLAGS:   $CGO_CFLAGS"
    echo "Exporting CGO_CFLAGS: $CGO_CFLAGS"
    echo "CGO_LDFLAGS:  $CGO_LDFLAGS"
    echo "Exporting CGO_LDFLAGS: $CGO_LDFLAGS"
}

# Run Go unit tests with the same CGO env as `build_go`. Pass any extra args
# to `go test`, e.g. `./build.sh --test -run TestFoo ./internal/admin/...`.
run_go_tests() {
    print_section "Running Go tests"

    cd "$PROJECT_ROOT"
    setup_cgo_env

    if [ "$#" -eq 0 ]; then
        set -- ./...
    fi
    GOPROXY=${GOPROXY:-https://goproxy.cn,https://proxy.golang.org,direct} CGO_ENABLED=1 \
        CGO_CFLAGS="$CGO_CFLAGS" CGO_LDFLAGS="$CGO_LDFLAGS" \
        go test -count=1 "$@"
}

# Clean build artifacts
clean() {
    print_section "Cleaning build artifacts"

    rm -rf "$BUILD_DIR"
    rm -f "$RAGFLOW_SERVER_BINARY"
    rm -f "$ADMIN_SERVER_BINARY"
    rm -f "$INGESTOR_BINARY"
    rm -f "$RAGFLOW_CLI_BINARY"

    echo -e "${GREEN}✓ Build artifacts cleaned${NC}"
}

# Run the server
run() {
    if [ ! -f "$ADMIN_SERVER_BINARY" ]; then
        echo -e "${RED}Error: $ADMIN_SERVER_BINARY not found. Build first with --all or --go${NC}"
        exit 1
    fi
    if [ ! -f "$RAGFLOW_SERVER_BINARY" ]; then
        echo -e "${RED}Error: $RAGFLOW_SERVER_BINARY not found. Build first with --all or --go${NC}"
        exit 1
    fi
    if [ ! -f "$INGESTOR_BINARY" ]; then
        echo -e "${RED}Error: $INGESTOR_BINARY not found. Build first with --all or --go${NC}"
        exit 1
    fi

    cd "$PROJECT_ROOT"

    # admin_server must be running before ragflow_server, otherwise ragflow_server's
    # heartbeats to admin will error out (see internal/development.md).
    print_section "Starting admin server (background)"
    "$ADMIN_SERVER_BINARY" &
    ADMIN_PID=$!
    trap 'kill "$ADMIN_PID" 2>/dev/null || true' EXIT INT TERM

    # Give admin_server a moment to bind its listening port (9383) before
    # ragflow_server starts sending heartbeats to it.
    sleep 1

    print_section "Starting ingestor (background)"
    "$INGESTOR_BINARY" &
    INGESTOR_PID=$!
    trap 'kill "$INGESTOR_PID" 2>/dev/null || true' EXIT INT TERM
    sleep 1

    print_section "Starting RAGFlow server (foreground)"
    "$RAGFLOW_SERVER_BINARY"
}

# Show help
show_help() {
    # Quoted delimiter so backticks, `$var`, and `\$` in the help text are
    # printed literally instead of being interpreted as command substitution.
    cat << 'EOF'
Usage: $0 [OPTIONS]

Build script for RAGFlow Go server with C++ bindings.

OPTIONS:
    --all, -a       Build everything (C++ library + Go server) [default]
    --cpp, -c       Build only C++ static library
    --cpp-test      Build C++ test executable (requires --cpp first)
    --go, -g        Build only Go server (requires C++ library to be built)
    --test, -t      Run Go unit tests (sets up CGO env for office_oxide).
                    Pass extra args after `--` to forward to `go test`, e.g.
                    `$0 --test -- -run TestFoo ./internal/admin/...`
    --clean, -C     Clean all build artifacts
    --run, -r       Build and run the server
    --strip, -s     Strip debug symbols from Go binaries (-ldflags="-s -w")
                    (disabled by default, useful for smaller production binaries)
    --help, -h      Show this help message

EXAMPLES:
    $0              # Build everything
    $0 --cpp        # Build only C++ library
    $0 --go         # Build only Go server
    $0 --cpp-test   # Build C++ test executable
    $0 --test       # Run all Go tests
    $0 --test -- -run TestFoo ./internal/admin/...   # Targeted Go tests
    $0 --run        # Build and run
    $0 --clean      # Clean build artifacts

DEPENDENCIES:
    - cmake >= 4.0
    - go >= 1.24
    - g++ with C++17/23 support
    - office_oxide native library (auto-downloaded on first build)
    - pcre2 development files
        - Debian/Ubuntu: libpcre2-dev
        - openSUSE/RHEL/Fedora: pcre2-devel
        - macOS (Homebrew): pcre2
EOF
}

# Main function
main() {
    # Parse --strip / -s before other arguments
    local args=()
    for arg in "$@"; do
        case "$arg" in
            --strip|-s) STRIP_SYMBOLS="1" ;;
            *) args+=("$arg") ;;
        esac
    done

    case "${args[0]:-}" in
        --cpp|-c)
            check_cpp_deps
            build_cpp
            ;;
        --cpp-test)
            check_cpp_deps
            build_cpp_test
            ;;
        --go|-g)
            check_go_deps
            build_go
            ;;
        --test|-t)
            check_go_deps
            # Forward any args after `--` to `go test`.
            if [ "${2:-}" = "--" ]; then
                shift 2
                run_go_tests "$@"
            else
                run_go_tests
            fi
            ;;
        --clean|-C)
            clean
            ;;
        --run|-r)
            check_cpp_deps
            check_go_deps
            build_cpp
            build_go
            run
            ;;
        --help|-h)
            show_help
            ;;
        --all|-a|"")
            check_cpp_deps
            check_go_deps
            build_cpp
            build_go
            echo -e "\n${GREEN}=== Build completed successfully! ===${NC}"
            echo "Binary: $RAGFLOW_SERVER_BINARY, $ADMIN_SERVER_BINARY, $INGESTOR_BINARY, $RAGFLOW_CLI_BINARY"
            ;;
        *)
            echo -e "${RED}Unknown option: $1${NC}"
            show_help
            exit 1
            ;;
    esac
}

main "$@"