#!/bin/sh

set -e
GADGET_DIR=/sys/kernel/config/usb_gadget
GADGET_ID=g0

create() {
    if [ -s "$GADGET_DIR/$GADGET_ID/UDC" ]; then
        echo "HID devices already exists"
    
        exit 0
    fi
    mkdir -p $GADGET_DIR/$GADGET_ID && \
    cd $GADGET_DIR/$GADGET_ID

    echo 0x3346 > idVendor
    echo 0x1009 > idProduct
    echo 0x0200 > bcdUSB
    echo 0x0100 > bcdDevice
    mkdir strings/0x409
    cat /proc/device-tree/serial-number > strings/0x409/serialnumber
    echo 'rockchip' > strings/0x409/manufacturer
    echo 'rk3588' > strings/0x409/product

    mkdir configs/c.1
    #echo 0xE0 > configs/c.1/bmAttributes
    echo 0x80 > configs/c.1/bmAttributes # only self-powered, no remote-wakeup
    echo 120 > configs/c.1/MaxPower
    mkdir configs/c.1/strings/0x409
    echo "rk3588" >  configs/c.1/strings/0x409/configuration

    # keyboard
    mkdir functions/hid.GS0
    echo 1 > functions/hid.GS0/subclass
    echo 1 > functions/hid.GS0/protocol
    #echo 1 > functions/hid.GS0/no_out_endpoint
    echo 6 > functions/hid.GS0/report_length
    echo -ne \\x05\\x01\\x09\\x06\\xa1\\x01\\x05\\x07\\x19\\xe0\\x29\\xe7\\x15\\x00\\x25\\x01\\x75\\x01\\x95\\x08\\x81\\x02\\x95\\x01\\x75\\x08\\x81\\x03\\x95\\x05\\x75\\x01\\x05\\x08\\x19\\x01\\x29\\x05\\x91\\x02\\x95\\x01\\x75\\x03\\x91\\x03\\x95\\x06\\x75\\x08\\x15\\x00\\x25\\x65\\x05\\x07\\x19\\x00\\x29\\x65\\x81\\x00\\xc0 > functions/hid.GS0/report_desc
    
    # Logitech Apex keyboard
    #echo 8 > functions/hid.GS0/report_length
    #echo -ne "05010906a101050719e029e715002501750195088102750895018101050719002aff00150026ff00750895068100050819012903250175019503910295059101c0" | xxd -r -ps -c 1000 > functions/hid.GS0/report_desc

    # mouse
    mkdir functions/hid.GS1
    # echo 1 > functions/hid.GS1/subclass
    echo 2 > functions/hid.GS1/protocol
    #echo 1 > functions/hid.GS0/no_out_endpoint
    echo -ne \\x34 > functions/hid.GS1/report_length
    echo -ne \\x5\\x1\\x9\\x2\\xa1\\x1\\x9\\x1\\xa1\\x0\\x5\\x9\\x19\\x1\\x29\\x3\\x15\\x0\\x25\\x1\\x95\\x3\\x75\\x1\\x81\\x2\\x95\\x1\\x75\\x5\\x81\\x3\\x5\\x1\\x9\\x30\\x9\\x31\\x9\\x38\\x15\\x81\\x25\\x7f\\x75\\x8\\x95\\x3\\x81\\x6\\xc0\\xc0 > functions/hid.GS1/report_desc
    #ln -s functions/hid.GS1 configs/c.1

    # touchpad
    mkdir functions/hid.GS2
    # echo 1 > functions/hid.GS2/subclass
    echo 2 > functions/hid.GS2/protocol
    #echo 1 > functions/hid.GS0/no_out_endpoint
    echo 6 > functions/hid.GS2/report_length
    echo -ne \\x05\\x01\\x09\\x02\\xa1\\x01\\x09\\x01\\xa1\\x00\\x05\\x09\\x19\\x01\\x29\\x03\\x15\\x00\\x25\\x01\\x95\\x03\\x75\\x01\\x81\\x02\\x95\\x01\\x75\\x05\\x81\\x01\\x05\\x01\\x09\\x30\\x09\\x31\\x15\\x00\\x26\\xff\\x7f\\x35\\x00\\x46\\xff\\x7f\\x75\\x10\\x95\\x02\\x81\\x02\\x05\\x01\\x09\\x38\\x15\\x81\\x25\\x7f\\x35\\x00\\x45\\x00\\x75\\x08\\x95\\x01\\x81\\x06\\xc0\\xc0 > functions/hid.GS2/report_desc
    #ln -s functions/hid.GS2 configs/c.1

    mkdir functions/mass_storage.disk0
    echo 1 > functions/mass_storage.disk0/lun.0/removable
    echo 1 > functions/mass_storage.disk0/lun.0/ro
    #ln -s functions/mass_storage.disk0 configs/c.1/
}

delete() {
    if [ ! -d "$GADGET_DIR/$GADGET_ID" ]; then
        echo "No HID devices to delete."
        exit 0
    fi

    if grep -q '[^[:space:]]' "$GADGET_DIR/$GADGET_ID/UDC"; then
        echo "HID devices are still attached. Please detach them before deleting."
        exit 1
    fi

    cd "$GADGET_DIR" || exit 1

    #rm -f $GADGET_ID/configs/c.1/hid.GS0
    #rm -f $GADGET_ID/configs/c.1/hid.GS1
    #rm -f $GADGET_ID/configs/c.1/hid.GS2
    #rm -f $GADGET_ID/configs/c.1/mass_storage.disk0

    rmdir $GADGET_ID/functions/hid.GS0
    rmdir $GADGET_ID/functions/hid.GS1
    rmdir $GADGET_ID/functions/hid.GS2
    rmdir $GADGET_ID/functions/mass_storage.disk0
    

    rmdir $GADGET_ID/configs/c.1/strings/0x409
    rmdir $GADGET_ID/configs/c.1
    rmdir $GADGET_ID/strings/0x409
    rmdir "$GADGET_ID"

    echo "HID devices have been deleted."
}

attach() {
    if grep -q '[^[:space:]]' "$GADGET_DIR/$GADGET_ID/UDC"; then
        echo "Error: Device is already attached."
        exit 1
    fi

    ln -s $GADGET_DIR/$GADGET_ID/functions/hid.GS0 $GADGET_DIR/$GADGET_ID/configs/c.1
    ln -s $GADGET_DIR/$GADGET_ID/functions/hid.GS1 $GADGET_DIR/$GADGET_ID/configs/c.1
    ln -s $GADGET_DIR/$GADGET_ID/functions/hid.GS2 $GADGET_DIR/$GADGET_ID/configs/c.1
    ln -s $GADGET_DIR/$GADGET_ID/functions/mass_storage.disk0 $GADGET_DIR/$GADGET_ID/configs/c.1

    ls /sys/class/udc/ | cat > "$GADGET_DIR/$GADGET_ID/UDC"
    
    echo "Device has been attached."
}

detach() {
    # we can't just detach UDC and attach it later
    # for some reason configuration on host reports about incorrect bytes in report_desc
    # unlinking/linking configuration helps, but in this case every time then iso mounted
    # UDC and all other devices configuration should be disconnected.
    echo '' > "$GADGET_DIR/$GADGET_ID/UDC"

    rm -f $GADGET_DIR/$GADGET_ID/configs/c.1/hid.GS0
    rm -f $GADGET_DIR/$GADGET_ID/configs/c.1/hid.GS1
    rm -f $GADGET_DIR/$GADGET_ID/configs/c.1/hid.GS2
    rm -f $GADGET_DIR/$GADGET_ID/configs/c.1/mass_storage.disk0
    
    echo "Device has been detached."
}

mount_iso() {
    iso_file="$1"
    
    if [[ ! -f "$iso_file" ]]; then
        echo "Error: ISO file '$iso_file' does not exist."
        exit 1
    fi

    if grep -q '[^[:space:]]' "$GADGET_DIR/$GADGET_ID/UDC"; then
        echo "Error: Device is still attached. Please detach it before mounting the ISO."
        exit 1
    fi

    echo "$iso_file" > "$GADGET_DIR/$GADGET_ID/functions/mass_storage.disk0/lun.0/file"
    echo "ISO file: $iso_file inserted."
}

mounted_iso() {
    cat "$GADGET_DIR/$GADGET_ID/functions/mass_storage.disk0/lun.0/file"
}

unmount_iso() {
    if grep -q '[^[:space:]]' "$GADGET_DIR/$GADGET_ID/UDC"; then
        echo "Error: Device is still attached. Please detach it before unmounting the ISO."
        exit 1
    fi

    echo > "$GADGET_DIR/$GADGET_ID/functions/mass_storage.disk0/lun.0/file"
}

if [ ! -d "$GADGET_DIR" ]; then
    echo "$DIRECTORY does not exist. Load modules or recompile the kernel to support usb_gadget"
    exit 0
fi


case "$1" in
    create)
        create
        ;;
    delete)
        delete
        ;;
    attach)
        attach
        ;;
    detach)
        detach
        ;;
    mount_iso)
        mount_iso "$2"
        ;;
    unmount_iso)
        unmount_iso
        ;;
    mounted_iso)
        mounted_iso
        ;;
    *)
        echo "Usage: $0 {create|delete|attach|detach|mount_iso|unmount_iso|mounted_iso}"
        ;;
esac