#!/bin/bash -e
#use this script with sudo and image link as argument.
#Ensure that destination address of DD points to your SD card
if [ -z "$2" ] ; then
  echo Usage: $0 URL DEVICE
  echo
  echo Example:
  echo "  $0 https://aws1-vgateway-images.s3.amazonaws.com/raspberrypi-ubuntu-18.04.3-arm64.s.kcH5u5bc7841GJHsGG095vMN.img.zip  /dev/sdb"
  exit 1
fi

url="$1"
device="$2"

if [[ !  $url =~ ^https://s3\..*\.amazonaws.com/.* ]] && [[ ! -f $url ]] ; then
    echo ERROR: URL $url is invalid
    exit 2
fi

if [ ! -b $device ] ; then
    echo ERROR: $device is not a block device
    exit 3
fi


# ensure nothing is mounted
mounts=`grep $device /proc/mounts |cut -f1 -d' '`
if [ -n "$mounts" ] ; then
    echo ERROR: $device in use: $mounts are mounted, aborting.
    exit 4
fi

# Support local files
downloadCmd="curl --fail $url"

if [[ -f "$url" ]] ; then
  downloadCmd="pv $url"
fi

# Ensure user doesn't need to enter the password when running 'sudo dd'
sudo -v

time {
  $downloadCmd | funzip  | sudo dd of=$device bs=32M
  sync
}

sudo eject $device