#!/bin/bash

# Variables
FBGL_BINARY="./fbgl_program"   # Path to your fbgl program binary
BUSYBOX_VERSION="1.36.1"       # BusyBox version to download
BUSYBOX_SRC="busybox-${BUSYBOX_VERSION}.tar.bz2"
BUSYBOX_DIR="busybox-${BUSYBOX_VERSION}"
BUSYBOX_IMAGE="busybox.img"    # Output image file
QEMU_ARCH="x86_64"             # Architecture for QEMU
MEMORY="512M"                  # Memory for QEMU

# Function to download and build BusyBox
build_busybox() {
    echo "Downloading BusyBox..."
    wget "https://busybox.net/downloads/${BUSYBOX_SRC}" || { echo "Failed to download BusyBox."; exit 1; }

    echo "Extracting BusyBox..."
    tar -xjf "${BUSYBOX_SRC}" || { echo "Failed to extract BusyBox."; exit 1; }

    echo "Configuring and building BusyBox..."
    cd "${BUSYBOX_DIR}" || exit
    make defconfig
    sed -i 's/.*CONFIG_STATIC is not set.*/CONFIG_STATIC=y/' .config # Enable static build
    make -j$(nproc) || { echo "Failed to build BusyBox."; exit 1; }

    echo "Creating root filesystem..."
    mkdir -p rootfs
    make install CONFIG_PREFIX=rootfs

    echo "Adding init script..."
    cat > rootfs/init <<EOF
#!/bin/sh
mount -t proc none /proc
mount -t sysfs none /sys
echo "Welcome to BusyBox!"
exec /bin/sh
EOF
    chmod +x rootfs/init

    echo "Packaging filesystem into an image..."
    cd rootfs || exit
    find . | cpio -o --format=newc > ../../"${BUSYBOX_IMAGE}" || { echo "Failed to create BusyBox image."; exit 1; }
    cd ../..
    echo "BusyBox image created successfully: ${BUSYBOX_IMAGE}"
}

# Ensure fbgl binary exists
if [[ ! -f $FBGL_BINARY ]]; then
    echo "FBGL binary not found at $FBGL_BINARY. Compile or provide the correct path."
    exit 1
fi

# Ensure BusyBox image exists or build it
if [[ ! -f $BUSYBOX_IMAGE ]]; then
    echo "BusyBox image not found. Building it now..."
    build_busybox
fi

# Run QEMU with fbgl and BusyBox
echo "Starting QEMU with BusyBox and FBGL..."
qemu-system-$QEMU_ARCH \
    -m $MEMORY \
    -kernel $BUSYBOX_IMAGE \
    -append "console=ttyS0" \
    -nographic \
    -initrd $FBGL_BINARY \
    -net nic -net user \
    -serial mon:stdio