#!/bin/bash
PROGRAM=$(basename $0) 
usage(){
	echo "$PROGRAM - Zchain rebase"
	echo ""
	echo "Description:"
	echo "Backs up your latest block into IPFS filesystem, replaces it with an empty file (GENESIS hardcode) and pushes its IPFS link as your chain's latest block."
	echo ""
	echo "Disclaimer:"
	echo "This program, does NOT delete anything from your IPFS repository, neither denies access to previously created blocks."
	echo ""
	echo "Usage:"
	echo "	$PROGRAM rebase <zblock>"
	exit 0
}
rebase (){
    ZTARGET="$1"
	echo "Reseting ZLATEST to ZTARGET"
	echo $ZTARGET > $ZLATEST
	if [ $? != 0 ]; then exit 1; fi

	echo "Make sure /zarchive folder exists within IPFS FS"
	ipfs files mkdir /zarchive
	if [ $? != 0 ]; then echo "Folder already there"; fi

	echo "Archive the previous ZLATEST"
	ipfs files cp /zlatest /zarchive/$(date -u +%s)-$(ipfs files stat /zlatest | head -n 1)
	if [ $? != 0 ]; then exit 1; fi

	echo "Removing previous /zlatest entry"
	ipfs files rm /zlatest
	if [ $? != 0 ]; then exit 1; fi

	echo "Copying rebased ZLATEST"
	CZLATEST="$(cat $ZLATEST)"
	ipfs files cp /ipfs/$CZLATEST /zlatest
	if [ $? != 0 ]; then exit 1; fi

	echo "Publishing new (rebased) ZLATEST"
	ipfs name publish --key=zchain /ipfs/$(cat $ZLATEST)
	if [ $? != 0 ]; then exit 1; fi
	
	echo "Rebase was successful"
	exit 0
}
if [ ! -z $1 ] && [ ! -z $2 ]; then
	case $1 in
		rebase) rebase $2; exit;;
		* ) usage;;
	esac
else usage
fi