#!/usr/bin/env bash
# prunefiles, a script/function to remove all but the n latest versions of a file
#

prunefiles () {

    declare -ag PREFIXES
    declare -g KEEP_INT=1 # default # of files to keep

    printHelpAndExit () {

    cat <<-'EOF'
		USAGE:
		    pruneFiles -k 3 thisfileprefix [thatfileprefix]

		OPTIONS
		    -k, --keep NUMBER
		        Keep NUMBER of latest files that matches each file prefix (Default: 1)
		    -h, --help
		        Print this help dialog and exit
	EOF

    # Exit using passed exit code
    [[ -z $1 ]] && exit 0 || exit "$1"

    }

    parseInput () {

        if _input=$(getopt -o +hk: -l help,keep: -- "$@"); then
            eval set -- "$_input"
            while true; do
                case "$1" in
                    -k|--keep)
                        shift && KEEP_INT=$1
                        ;;
                    -h|--help)
                        printHelpAndExit 0
                        ;;
                    --)
                        shift; break
                        ;;
                esac
                shift
            done
        else
            echo "Incorrect option(s) provided"
            printHelpAndExit 1
        fi

        PREFIXES=( "$@" )
    }


    findAndRemove () {

        declare prefix file

        for prefix in "${PREFIXES[@]}"; do
            for file in $(find . -maxdepth 1 -type f -name "${prefix}*" -printf '%T@ %p\n' | sort -r -z -n | tail -n+$((KEEP_INT + 1)) | awk '{ print $2; }'); do
                rm "$file"
            done
        done
    }


    main () {
        parseInput "$@"
        findAndRemove
    }

    main "$@"
}

# Allow script to be safely sourced
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    prunefiles "$@"
    exit $?
fi