#!/bin/bash
# Desc: Validates Input

yell() { echo "$0: $*" >&2; }      #o Yell, Die, Try Three-Fingered Claw technique
die() { yell "$*"; exit 111; }     #o Ref/Attrib: https://stackoverflow.com/a/25515370
try() { "$@" || die "cannot $*"; } #o
validateInput() {
    # Desc: Validates Input
    # Usage: validateInput [str input] [str input type]
    # Version: 0.1.0
    # Input: arg1: string to validate
    #        arg2: string specifying input type (ex:"ssh_pubkey")
    # Output: return code 0: if input string matched specified string type
    # Depends: bash 5, yell

    # Save function name
    local FN="${FUNCNAME[0]}";

    # Process arguments
    argInput="$1";
    argType="$2";
    if [[ $# -gt 2 ]]; then yell "ERROR:$0:$FN:Too many arguments."; exit 1; fi;

    # Check for blank
    if [[ -z "$argInput" ]]; then return 1; fi
    
    # Define input types
    ## ssh_pubkey
    ### Check for alnum/dash base64 (ex: "ssh-rsa AAAAB3NzaC1yc2EAAA")
    if [[ "$argType" = "ssh_pubkey" ]] && [[ "$argInput" =~ ^[[:alnum:]-]*[\ ]*[[:alnum:]+/=]*$ ]]; then
	return 0; fi;

    # Return error if no condition matched.
    return 1;
}

#==BEGIN sample code==
testKey1="ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCq8G0XWi8A+MXNu7MEaxDsZJUwtgPC4shGAAarXC4PQTRxLfUHtyWkNbzGh31U/bKI3Snp1O78yOVEZSjdmWkDvkwtWKJQcoZBStgqw9oIPE0oG8uh49XoX77nVabi0JCf8zO63Ai4/9EdwyqE9xsJ+soOYt2V5+UCj0zsv1xpt2YhfYyXrzBv9x6k9lCxy0NW3Ik1mSW+OzSOT3tgDf36ujV/CI2i8ERM9civWy8FtFOReZMV2kkbj7fXI4E1wKM1RFIn7er1MseCSvbvh3o2uCO46/euqHAstYs5cL+4yB2qM/xKfHT5aocDjq7GBLKtree9xdNF0EE9CNr/+J5R";
testKey2="blah-blah onetwothreeREEE";
testKey3="";
keyType="ssh_pubkey";
if validateInput "$testKey1" "$keyType"; then echo "$testKey1 looks like a valid $keyType."; else echo "$testKey1 doesn't look like a valid $keyType."; fi
if validateInput "$testKey2" "$keyType"; then echo "$testKey2 looks like a valid $keyType."; else echo "$testKey2 doesn't look like a valid $keyType."; fi
if validateInput "$testKey3" "$keyType"; then echo "$testKey3 looks like a valid $keyType."; else echo "$testKey3 doesn't look like a valid $keyType."; fi
#==END sample code==




# Author: Steven Baltakatei Sandoval (bktei.com)
# License: GPLv3+