#!/bin/bash
# By default we enter from the latest block
# We can alter this by changing this value
entrance="$(cat $ZLATEST)"

# Start of tests
#entrance="QmW5WVXCJfhb4peHG6cbEdamC24vZzMX2Vz386vpENh38U"
#entrance="QmNjQq7GkuXGF8kFT1z2Mv3i4JhY7sBXVUmHDiR1zkQjoE"
#entrance="QmbFMke1KXqnYyBBWxB74N4c5SBnJMVAiMNRcGu6x1AwQH"
# End of tests

# We assign the IPFS CIDv0 of an empty file as this is used
# as our GENESIS block, hence the "seed" that the tree grows
# from.
seed="$(cat $ZGENESIS)"

# We assume that we found the entrance inside a block, hence
# ZBLOCK is labeled as previous
zblock="$entrance"

# The loop
# We break the loop from inside the loop
while true
do
	# Check if $zblock exists as variable
	if [ ! -v $zblock ]
	then
		# Check if it is not our seed cause if it is we skip this part
		if [ "$zblock" != "$seed" ]
		then
			# Announce to stdout which ZBLOCK is being read at the moment
			echo "Examining $zblock"

			# We create files named after each ZBLOCK IPFS CID for later
			# reference. Files are empty.
			touch $ZBLOCKDIR/$zblock

			# We concatenate the zblock's contents, pipe them through filter
			# json2bash and output them to tmp-file
			ipfs cat $zblock | json2bash > tmp-zblock

			# Supposingly you are on a safe environment and you only have
			# access to your chain, I would consider mild secure to source
			# the files into your bash.
			# File an issue/pull request if you think it can be done better!!
			source tmp-zblock

			# Same as above applies to BLOCK and DATA subparts of each ZBLOCK
			# BLOCKS
			ipfs cat $block | json2bash > tmp-block
			source tmp-block
			touch $BLOCKDIR/$block

			# DATA (but we don't source it's stuff)
			# Only print to stdout
			ipfs cat $data
			touch $DATADIR/$data

			# Now, since we sourced the BLOCK to our terminal, we can search
			# for $previous variable. In case we don't find one, we exit with
			# code 3
			if [ -v $previous ]
			then
				echo "Block $block has no previous zblock"
				exit 3

			# Otherwise, we inform of the sequence
			else
				echo "$zblock after $previous"
				zblock=$previous
			fi

		# Now check if it is equal to the seed
		# which apparently means we reached the seed.
		elif [ "$zblock" == "$seed" ]
		then
			echo "$zblock is GENESIS block"
			exit 0
		fi
	# And finally, if nothing is there exit with error
	else 
		echo "Check not passed... No previous IPFS CID"
		exit 1
	fi
done