#!/bin/bash -e

action="$1"
oldversion="$2"

if [ "$action" != configure ]; then
    exit 0
fi

target_checksum="c977d21306553913ae35b830f9711c03681c7d6c"
echo "Target checksum $target_checksum"

echo "Checking /data/system.img"

current_checksum="$(sha1sum /data/system.img | cut -d' ' -f1)"

echo "Checksum $current_checksum"

if [ "$target_checksum" == "$current_checksum" ];
then
  echo "Android system image upto date"
  exit 0
else
  tempfile="$(mktemp)"
  rm $tempfile
  echo "Downloading new Android system image"
  curl https://gemian.thinkglobally.org/system/system.$target_checksum.img.xz --output $tempfile.xz
  xz -d $tempfile.xz
  downloaded_checksum="$(sha1sum $tempfile | cut -d' ' -f1)"
  if [ "$target_checksum" == "$downloaded_checksum" ];
  then
    echo "Moving new system image into place, please reboot to activate"
    mv $tempfile /data/system.img
    exit 0
  else
    echo "Downloaded checksum fail - check your internet for random errors or man in the middle attacks and retry"
    exit 1
  fi
fi