#!/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)
#   --asan          Build with AddressSanitizer (debug)
#   --hardened      Build with compiler security hardening flags
#   -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
USE_ASAN=0
USE_HARDENED=0
JOBS="-j4"
MAKE_ARGS=""
HARDEN_FLAGS=""

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 "  --asan          Build with AddressSanitizer"
            echo "  --hardened      Build with compiler security hardening flags"
            echo "  -j[N]           Build with N parallel jobs (default: 4)"
            exit 0
            ;;
        --clean)
            CLEAN=1
            shift
            ;;
        --full)
            FULL_REBUILD=1
            shift
            ;;
        --asan)
            USE_ASAN=1
            shift
            ;;
        --hardened)
            USE_HARDENED=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
fi

# Full rebuild: regenerate build system
if [ "$FULL_REBUILD" -eq 1 ]; then
    echo ""
    echo "======================================"
    echo "FULL REBUILD: autoreconf"
    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 -rf build/

    # Regenerate build system (root Makefile is hand-written, not generated)
    echo ""
    echo "Running autoreconf -fi..."
    autoreconf -fi 2>&1 | tee autoreconf.log

    echo ""
    echo "======================================"
    echo "Build system regenerated successfully"
    echo "======================================"
    echo ""
else
    # Quick/incremental build: generate 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
fi

# Auto-detect FFmpeg (optional video transcoding). If libav libraries are
# available, build with --with-ffmpeg; configure gracefully skips it otherwise.
FFMPEG_OPT=""
if command -v pkg-config >/dev/null 2>&1 && \
   pkg-config --exists libavformat libavcodec libavutil libswscale libswresample 2>/dev/null; then
    FFMPEG_OPT="--with-ffmpeg"
    echo "FFmpeg detected — building with video transcoding"
else
    echo "FFmpeg not found — building without video transcoding"
fi

# Generate Makefiles if needed
if [ ! -f Makefile ]; then
    echo ""
    echo "Running ./configure..."
    if [ "$USE_ASAN" -eq 1 ]; then
        ./configure CFLAGS="-g -Og -fsanitize=address -fno-omit-frame-pointer -fno-pie" LDFLAGS="-no-pie" $FFMPEG_OPT
    elif [ "$USE_HARDENED" -eq 1 ]; then
        ./configure --enable-hardening $FFMPEG_OPT
    else
        ./configure $FFMPEG_OPT
    fi
fi

# Build (all .o files go to build/ directory, binary copied to project root)
echo ""
echo "Compiling with $JOBS..."
BUILD_SUCCESS=0
if [ "$USE_ASAN" -eq 1 ]; then
    echo "(AddressSanitizer enabled — lib/ and src/ only, skipping tests)"
    AF="-fsanitize=address -fno-omit-frame-pointer -g -Og"
    AL="-fsanitize=address"
    (cd lib && make clean $JOBS $MAKE_ARGS 2>&1 && make "CFLAGS+=$AF" "LDFLAGS+=$AL" $JOBS $MAKE_ARGS 2>&1) || { echo "lib build failed"; exit 1; }
    (cd src && make clean $JOBS $MAKE_ARGS 2>&1 && make "CFLAGS+=$AF" "LDFLAGS+=$AL" $JOBS $MAKE_ARGS 2>&1) || { echo "src build failed"; exit 1; }
    BUILD_SUCCESS=1
elif [ "$USE_HARDENED" -eq 1 ]; then
    echo "(Hardening flags enabled)"
    HF="-D_FORTIFY_SOURCE=2 -fstack-protector-strong -fstack-clash-protection -Wformat=2 -Wformat-overflow=2 -fPIE"
    HL="-Wl,-z,relro -Wl,-z,now -pie"
    (cd lib && make clean $JOBS $MAKE_ARGS 2>&1 && make "CFLAGS+=$HF" "LDFLAGS+=$HL" $JOBS $MAKE_ARGS 2>&1) || { echo "lib build failed"; exit 1; }
    (cd src && make clean $JOBS $MAKE_ARGS 2>&1 && make "CFLAGS+=$HF" "LDFLAGS+=$HL" $JOBS $MAKE_ARGS 2>&1) || { echo "src build failed"; exit 1; }
    (cd tests && make clean $JOBS $MAKE_ARGS 2>&1 && make "CFLAGS+=$HF" "LDFLAGS+=$HL" $JOBS $MAKE_ARGS 2>&1) || { echo "tests build failed"; exit 1; }
    BUILD_SUCCESS=1
else
    make $JOBS $MAKE_ARGS 2>&1 | tee build.log
    if [ ${PIPESTATUS[0]} -eq 0 ]; then
        BUILD_SUCCESS=1
    fi
fi

if [ $BUILD_SUCCESS -eq 1 ]; then
    echo ""
    echo "Build completed successfully!"
    echo "Binary: utun"

    # Rebuild chatgui (CMake project) if transport sources changed
    if [ -f tools/chatgui/build/CMakeCache.txt ] && command -v cmake &> /dev/null; then
        echo ""
        echo "======================================"
        echo "Rebuilding chatgui (CMake)"
        echo "======================================"
        (cd tools/chatgui/build && cmake --build . -j4 2>&1) || echo "WARNING: chatgui build failed"
    fi
else
    echo ""
    echo "ERROR: Build failed!"
    echo "Check build.log for details"
    exit 1
fi