#!/bin/bash
# Build script for uTun (supports both Linux and Windows/MSYS2)
# Usage: ./build.sh [options]
# Options:
#   -h, --help      Show this help
#   --clean         Clean before build
#   --full          Full rebuild (autoreconf + configure + make)
#   -j[N]           Build with N parallel jobs (default: 4)

set -e  # Exit on error

# Detect platform
if [[ "$OSTYPE" == "msys" ]] || [[ "$OSTYPE" == "cygwin" ]] || [[ -n "$MSYSTEM" ]]; then
    IS_WINDOWS=1
    echo "Detected Windows/MSYS2 environment"
else
    IS_WINDOWS=0
    echo "Detected Linux environment"
fi

# Parse arguments
CLEAN=0
FULL_REBUILD=0
JOBS="-j4"
MAKE_ARGS=""

while [[ $# -gt 0 ]]; do
    case $1 in
        -h|--help)
            echo "Usage: ./build.sh [options]"
            echo "Options:"
            echo "  -h, --help      Show this help"
            echo "  --clean         Clean before build"
            echo "  --full          Full rebuild (autoreconf + configure + make)"
            echo "  -j[N]           Build with N parallel jobs (default: 4)"
            exit 0
            ;;
        --clean)
            CLEAN=1
            shift
            ;;
        --full)
            FULL_REBUILD=1
            shift
            ;;
        -j*)
            JOBS="$1"
            shift
            ;;
        *)
            MAKE_ARGS="$MAKE_ARGS $1"
            shift
            ;;
    esac
done

# Check required tools
if ! command -v gcc &> /dev/null; then
    echo "Error: gcc not found."
    if [ "$IS_WINDOWS" -eq 1 ]; then
        echo "Please install: pacman -S mingw-w64-ucrt-x86_64-toolchain"
    else
        echo "Please install build-essential or gcc"
    fi
    exit 1
fi

# Clean if requested
if [ "$CLEAN" -eq 1 ]; then
    echo "Cleaning build..."
    make clean 2>/dev/null || true
    rm -f config.status config.h
fi

# Full rebuild: clean everything and regenerate
if [ "$FULL_REBUILD" -eq 1 ]; then
    echo ""
    echo "======================================"
    echo "FULL REBUILD: autoreconf + configure"
    echo "======================================"
    echo ""
    
    # Check for autotools
    if ! command -v autoreconf &> /dev/null; then
        echo "Error: autoreconf not found."
        if [ "$IS_WINDOWS" -eq 1 ]; then
            echo "Install autotools: pacman -S mingw-w64-ucrt-x86_64-autotools"
        else
            echo "Install autotools: apt-get install autoconf automake libtool"
        fi
        exit 1
    fi
    
    # Clean generated files
    echo "Cleaning generated files..."
    make distclean 2>/dev/null || true
    rm -f config.status config.h Makefile */Makefile
    
    # Regenerate build system
    echo ""
    echo "Running autoreconf -fi..."
    autoreconf -fi 2>&1 | tee autoreconf.log
    
    # Configure
    echo ""
    echo "Running configure..."
    ./configure --prefix=/usr/local 2>&1 | tee configure.log
    
    echo ""
    echo "======================================"
    echo "Build system regenerated successfully"
    echo "======================================"
    echo ""
else
    # Quick/incremental build: only configure if needed
    if [ ! -f ./configure ]; then
        echo "Configure script not found. Generating..."
        if ! command -v autoreconf &> /dev/null; then
            echo "Error: autoreconf not found."
            if [ "$IS_WINDOWS" -eq 1 ]; then
                echo "Install autotools: pacman -S mingw-w64-ucrt-x86_64-autotools"
            else
                echo "Install autotools: apt-get install autoconf automake libtool"
            fi
            exit 1
        fi
        autoreconf -fiv
    fi
    
    # Run configure if needed
    if [ ! -f config.status ] || [ config.status -ot configure ]; then
        echo "Configuring build..."
        ./configure --prefix=/usr/local 2>&1 | tee configure.log
    else
        echo "Using existing configuration."
    fi
fi

# Build
echo ""
echo "Compiling with $JOBS..."
BUILD_SUCCESS=0
make $JOBS $MAKE_ARGS 2>&1 | tee build_linux.log
if [ ${PIPESTATUS[0]} -eq 0 ]; then
    BUILD_SUCCESS=1
fi

if [ $BUILD_SUCCESS -eq 1 ]; then
    echo ""
    echo "Build completed successfully!"
    echo "Binary: src/utun"
else
    echo ""
    echo "ERROR: Build failed!"
    echo "Check build_linux.log for details"
    exit 1
fi