#!/bin/bash
#
# jsoncerts2pem - Convert a JSON file containing a certificate and certificate chain to PEM format 
#
USAGE="jsoncerts2pem cert_file.json"
#
# Creates a file with a .pem suffix using the base name of the input file 
# (e.g., input file cert_file.json produces cert_file.pem)
#

if [ "$#" != 1 ]; then
    echo $USAGE
    exit 1
fi

json_file=$1
if [ ! -f "$json_file" ]; then
    echo "$json_file does not exist."
    exit 1
fi

tmpfile1=`basename $json_file .json`.tmp1
tmpfile2=`basename $json_file .json`.tmp2
outfile=`basename $json_file .json`.pem

# Append the chain cert to the cert after extracting both
jq '.["Certificate"]' $json_file > $tmpfile1
jq '.["CertificateChain"]' $json_file   >> $tmpfile1

# Convert newline chars to carriage returns
awk '{gsub(/\\n/,"\n")}1' $tmpfile1 > $tmpfile2
rm -f $tmpfile1

# Strip out the quotes
sed 's/\"//' $tmpfile2 > $outfile
rm -f $tmpfile2