#!/bin/bash
#
# 2006-12: Written by Steven J. DeRose, sderose@acm.org.
# 2008-01-23 sjd: Add -A so we notice hidden files.
# 2010-03-16 sjd: Use $HOME env var.
# 2010-03-22 sjd: Make link to latest dir to make easier to find.
#

# Help
    if [ "$1" = "-h" ]; then
		echo "Usage: backup [options] [filenames]"
        echo "Copy file(s) to a time-stamped subdirectory in \$BACKUP_DIR."
		echo "   With -n name, append 'name' to the subdir name (or defaults)."
		echo "   Options for cp are ok, for example: backup -r foo."
		if [ "$BACKUP_DIR" = "" ]; then
			echo "   Currently, your back directory is '$BACKUP_DIR'."
		else
			echo "   You have not set \$BACKUP_DIR. Default is \$HOME/backups."
		fi
        exit
    fi

# Find/make a backups dir
    if [ "$BACKUP_DIR" = "" ]; then
        export BACKUP_DIR="$HOME/backups";
    fi

# Support option to append name to subdir timestamp
    if [ "$1" = "-n" ] || [ "$1" = "-name" ]; then
		shift
		suffix=$1
		shift
	else
		suffix=`echo "$*" | sed -e 's/ .*$/.../' -e 's/[^-_.a-zA-Z0-9]/_/g'`
		#echo "Suffix calculated from '$*' as '$suffix'."
	fi
    subdir="$BACKUP_DIR/"`date +%Y\-%m\-%dT%H.%M.%S`".$suffix";

# See if at least the first file listed exists
   if ! [ -e $1 ]; then
       echo "backup: Can't find file '$1'."
	   exit;
   fi
   
# Make sure they've named something to back up
    todo=`ls -A $* 2>/dev/null | wc -l`
	if [ "$todo" -lt "1" ]; then
		echo "backup: *** No files found ***"
		exit
	fi

# Make the target dir
    if ! [ -d $subdir ]; then
        mkdir -p $subdir;
        if ! [ -d $subdir ]; then
            echo "backup: Can't find or mkdir backup subdirectory '$subdir'.";
            exit
        fi
    fi

# Make a note, to preserve source info:
	notefile="$subdir/_backup_note.txt"
	echo "Backup command was:" >$notefile
	echo "   $0 $*" >>$notefile
	echo "PWD at the time was:" >>$notefile
	echo "   $PWD" >>$notefile

# Do the actual backup
    cp $* $subdir/
    found=`ls -A $subdir | wc -l`
	if [ -e $notefile ]; then
		let found="$found - 1"
	fi

    ln -s $subdir "$BACKUP_DIR/latest"

# Report results
	if [ $found = 0 ]; then
		echo "backup: *** No files backed up ***"
	else
		echo "backup: $found file(s) copied to $subdir (linked from 'latest')."
	fi

exit;