#!/bin/sh

# TODO:
# add a --uploads option to specify the number of latest files to uploads. Good
# in case we missed some.
# add options to wait before starting, similar to mirror.tcl
# add option to sleep and restart automatically

#set -x

# All (good?) defaults
VERBOSE=0
KEEP=
PATHS=

# Dynamic vars
cmdname=$(basename $(readlink -f $0))
appname=${cmdname%.*}

# Print usage on stderr and exit
usage() {
  exitcode="$1"
  cat << USAGE >&2
  
Description:

  $cmdname will find the latest files matching a pattern and only keep a
  finite amount of the youngest files

Usage:
  $cmdname [-option arg --long-option(=)arg] ([--] command)

  where all dash-led options are as follows (long options can be followed by
  an equal sign):
    -v | --verbose       Be more verbose
    -k | --keep          Number of files to keep, defaults to empty,
                         meaning all
    -f | --files         List of files to select from for removal
USAGE
  exit "$exitcode"
}


# Parse options
while [ $# -gt 0 ]; do
    case "$1" in
        -k | --keep)
            KEEP=$2; shift 2;;
        --keep=*)
            KEEP="${1#*=}"; shift 1;;

        -f | --files)
            PATHS=$2; shift 2;;
        --files=*)
            PATHS="${1#*=}"; shift 1;;

        -v | --verbose)
            VERBOSE=1; shift;;

        -h | --help)
            usage 0;; 
        --)
            shift; break;;
        -*)
            echo "Unknown option: $1 !" >&2 ; usage 1;;
        *)
            break;;
    esac
done

if [ -z "$PATHS" ]; then
    echo "You need to specify files to select from for removal" >& 2
    usage 1
fi

# Conditional logging
log() {
    if [ "$VERBOSE" = "1" ]; then
        echo "$1"
    fi
}

if [ -n "${KEEP}" -a "${KEEP}" -gt "0" ]; then
    log "Keeping only ${KEEP} youngest file(s) of $PATHS"
    while [ "$(ls $PATHS -1 -t | wc -l)" -gt "$KEEP" ]; do
        DELETE=$(ls $PATHS -1 -t | sort -r | tail -n 1)
        log "Removing old copy $DELETE"
        rm -rf $DELETE
    done
fi

if [ $# -ne "0" ]; then
    log "Executing $*"
    exec "$@"
fi