#!/bin/bash


### Define functions

function scriptHelp {
echo -e "\e[1;31mInvalid parameter(s) provided\e[0m\n"
echo -e "\e[1;39mUsage:"
echo -e "\e[1;36m$(basename ${0})" \
    "\e[1;35m-f /path/to/account/details.file" \
    "\e[1;33m-r record.to.update [-r another.record.to.update -r ...]"
echo -e "\t\e[0;92m[optional parameters]\e[0m\n"
echo -e "\e[1;39mNotes:\e[0m"
echo -e "-f and -r parameters are REQUIRED."
echo -e "Multiple A/AAAA records to update can be specified by supplying"
echo -e "\tmultiple -r parameters (see examples below)."
echo "This script can operate only in either IP4 OR IP6 mode. See below."
echo "This script will NOT verify the format or validity of supplied IP"
echo -e "\taddresses."
echo -e "\n\e[1;39mOptional parameters\e[0m"
echo -e "-i\tUse this IP address when updating DNS records"
echo -e "\tIf NOT supplied, the script will attempt to auto-detect this"
echo -e "\tmachine's IP address (depending on -4 or -6 parameters) and"
echo -e "\tuse that address for DNS updates.  The script does NOT check"
echo -e "\tthe validity of an address supplied using this parameter nor"
echo -e "\tthe protocol type (IP4 vs IP6)."
echo -e "-4\tOperate in IP4 mode and update A records (default)"
echo -e "\tThis is the default operating mode and does not need to be"
echo -e "\texplicitly specified.  Ensure you have supplied a valid IP4"
echo -e "\taddress using the -i parameter or that your machine's IP4"
echo -e "\taddress can be correctly detected externally."
echo -e "-6\tOperate in IP6 mode and update AAAA records"
echo -e "\tONLY AAAA records will be updated.  Ensure you have supplied"
echo -e "\ta valid IP6 address using the -i parameter or that your"
echo -e "\tmachine's IP6 address can be correctly detected externally."
echo -e "\n\e[1;39mExample: \e[0mUse details from myCloudFlareDetails.info"
echo -e "file in /home/janedoe directory. Update server.mydomain.com A record"
echo -e "with this machine's auto-detected IP4 address."
echo -e "\t\e[1;36m$(basename ${0})" \
    "\e[1;35m-f /home/janedoe/myCloudFlareDetails.info"
echo -e "\t\e[1;33m-r server.mydomain.com\e[0m"
echo -e "\n\e[1;39mExample: \e[0mUse details from myCloudFlareDetails.info"
echo -e "file in /home/janedoe directory. Update server.mydomain.com AND"
echo -e "server2.mydomain.com A records with this machine's auto-detected IP6"
echo -e "address."
echo -e "\t\e[1;36m$(basename ${0})" \
    "\e[1;35m-f /home/janedoe/myCloudFlareDetails.info"
echo -e "\t\e[1;33m-r server.mydomain.com" \
    "-r server2.mydomain.com \e[1;92m-6\e[0m"
echo -e "\n\e[1;39mExample: \e[0mUse details from myCloudFlareDetails.info"
echo -e "file in /home/janedoe directory. Update server.mydomain.com A record"
echo -e "using IP4 address 1.2.3.4."
echo -e "\t\e[1;36m$(basename ${0})" \
    "\e[1;35m-f /home/janedoe/myCloudFlareDetails.info"
echo -e "\t\e[1;33m-r server.mydomain.com \e[1;92m-i 1.2.3.4\e[0m"
echo -e "\n\e[1;39mExample: \e[0mUse details from myCloudFlareDetails.info"
echo -e "file in /home/janedoe directory. Update server3.mydomain.com AND"
echo -e "server7.mydomain.com AAAA records using IP6 address FE80::286A:FF91."
echo -e "\t\e[1;36m$(basename ${0})" \
    "\e[1;35m-f /home/janedoe/myCloudFlareDetails.info"
echo -e "\t\e[1;33m-r server.mydomain.com" \
    "\e[1;33m-r server2.mydomain.com \e[1;92m-i FE80::286A:FF91\e[0m"
exit 1
}

### end of functions


### unset environment variables used in this script and initialize arrays
unset PARAMS
unset accountFile
unset ipAddress
dnsRecords=()
cfDetails=()
ip4=1
ip6=0


### Process script parameters
if [ -z $1 ]; then
    scriptHelp
fi

while getopts ':f:r:i:46' PARAMS; do
    case "$PARAMS" in
        f)
            accountFile="${OPTARG}"
            ;;
        r)
            dnsRecords+=($OPTARG)
            ;;
        i)
            ipAddress="$OPTARG"
            ;;
        4)
            ip4=1
            ip6=0
            ;;
        6)
            ip4=0
            ip6=1
            ;;
        ?)
            scriptHelp            
            ;;
    esac
done

# Check validity of parameters
if [ -z "$accountFile" ] || [[ $accountFile == -* ]]; then
    echo -e "\e[1;31mNo file containing account details was specified."
    echo -e "\e[0;31m(-f parameter empty or missing)\e[0m"
    exit 101
elif [ ! -s "$accountFile" ]; then
    echo -e "\e[1;31mAccount details file is either empty or does not" \
        "exist.\e[0m"
    exit 102
elif [ -z ${dnsRecords} ]; then
    echo -e "\e[1;31mNo DNS records were specified."
    echo -e "\e[0;31m(-r parameter(s) empty or missing)\e[0m"
    exit 103
fi


## Extract needed information from accountDetails file
mapfile -t cfDetails < "$accountFile"

## Get current IP address, if not provided in parameters
if [ -z "$ipAddress" ]; then
    echo -e "\e[0;36mNo IP address for update provided.  Detecting" \
        "this machine's IP address..."
    if [ $ip4 -eq 1 ]; then
        echo -e "\e[1;36m(set to IP4 mode)\e[0m"
        ipAddress=$(curl -s http://ipv4.icanhazip.com)
    elif [ $ip6 -eq 1 ]; then
        echo -e "\e[1;36m(set to IP6 mode)\e[0m"
        ipAddress=$(curl -s http://ipv6.icanhazip.com)
    fi
    ipLookupResult=$(echo "$?")
    if [ "$ipLookupResult" -ne 0 ]; then
        echo -e "\e[1;31mIP address for update could not be detected."
        echo -e "\e[0;31mPlease re-run script and specify an IP address" \
            "to use via the -i flag.\e[0m"
        exit 201
    else
        echo -e "\e[0;36mUsing IP address: $ipAddress"
    fi
fi



### Echo results (testing)
echo -e "\nBased on parameters provided:"
echo -e "\e[0;35mLogin details at: ${accountFile}"
echo -e "\tAuthorized email: ${cfDetails[0]}"
echo -e "\tAuthorized key: ${cfDetails[1]}"
echo -e "\tZone identifier: ${cfDetails[2]}"
echo -e "\e[0;33mUpdating records: ${dnsRecords[*]}"
if [ $ip4 -eq 1 ]; then
    echo -e "\e[0;92mUpdating A records"
elif [ $ip6 -eq 1 ]; then
    echo -e "\e[0;92mUpdating AAAA records"
fi
echo -e "\e[0;92mPointing records to IP: $ipAddress\e[0m\n"
exit 0