#!/bin/ksh
#
# Copyright (c) 2022 Nick Holland <nick@holland-consulting.net>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#
# Additional (non-license) usage notes:
# Really, using this code "as is" without carefully examining the assumptions
# made by me about your needs is highly discouraged.  
#
# I would love to hear if you are using this in your world in any way
# (even if as a counter example!).  Drop me an email and tell me about it
# at nick@holland-consulting.net

# Cheap and easy error checking.  Use if something shouldn't fail, but might
# and you don't feel like real error handling.
yell() { echo "$0: $*" >&2; }
die() { yell "$*"; rm -f $TMPDIR exit 111; }
try() { "$@" || die "cannot $*"; }

COMMANDLINE="$*"

# Strings to match the start and end of the RSYNC file list
RSYNCSTART="^receiving incremental file"
RSYNCEND="^$"

LINESMAX=20

TMPDIR=$(try mktemp -dt fart.XXXXXX)
CONFIG=/etc/ibs
TODAY=$(date "+%Y-%m-%d")

. $CONFIG/ibs.config
GLOBALFILTERS="/etc/ibs/GLOBAL.fart"

function help {
    cat <<-__ENDHELP
	usage:
	   $0 [options] [-f filter [ -f filter ...]] backuplog ...
	
	options
	   -a no limits on output
	   -d show diff commands for copy/paste
	   -D show actual diff between files
	   -f filter files.  Can be repeated.
	   -h this help screen
	   -l show "ls -l" for changed files
	   -n no cmp check (show touched but unaltered files)
	   -v verbose operation (diagnostic info)
	   -s Standard Run -- $LOGS/*-$TODAY
	   -t retain /tmp output

	Options have to come before filters, and filters before backuplogs
	__ENDHELP
    exit
    }

# no parameters?  just show help and exit.
if [[ -z $1 ]]; then
    help
fi

# If you want fart to look for "touched" but unchanged files,
# it has to be run as root...but that's the only reason.
if [[ $(whoami) != "root" ]]; then
    print "==>> not running as root, so -n (no cmp) is implied."
    print
    NOFILECMP="y"
fi

while [[ $1 = -* ]]; do
    case $1  in
	-a ) NOLIMITS="y"
		;;
	-d ) SHOWDIFFCMD="y"
		;;
	-D ) SHOWDIFF="y"
		;;
	-f ) break 
		;;
	-l ) SHOWLS="y"
		;;
	-h ) help
		;;
	-n ) NOFILECMP="y"
		;;
	-s ) STDRUN="y"
		;;
	-t ) RETAINTMP="y"
		;;
	-v ) DIAG="y"
		;;
	* ) print "Invalid option $1"
	    help
		;;
    esac
    shift
done

# IF any special options are given, print out the entire
# option list.  Probably can go away eventually.
if [[ -n "$NOLIMITS$SHOWDIFFCMD$SHOWDIFF$SHOWLS$NOFILECMP$RETAINTMP$DIAG" ]]; then
    print "NOLIMITS=$NOLIMITS " \
	"SHOWDIFCMD=$SHOWDIFFCMD " \
	"SHOWDIFF=$SHOWDIFF " \
	"SHOWLS=$SHOWLS" \
	"NOFILECMP=$NOFILECMP " \
	"RETAINTMP=$RETAINTMP " \
	"DIAG=$DIAG"
fi

# Build a list of the "this run" -f FART filters.
# They are applied to all reports in this run.
while [[ $1 = "-f" ]]; do
    if [[ -f $2 ]]; then
	GLOBALFILTERS="$GLOBALFILTERS $2"
    elif [[ -f $CONFIG/$2 ]]; then
	GLOBALFILTERS="$GLOBALFILTERS $CONFIG/$2"
    else
	print "Could not find filter $2"
	exit
    fi
    shift; shift
done

if [[ -z "$STDRUN" ]]; then
    RUNLIST="$*"
else
    RUNLIST="$(ls -1 $LOGS/*-$TODAY)"
fi
# Print headers.  Change as desired.
echo "GLOBALFILTERS="$GLOBALFILTERS
echo "Processing: "
for A in $RUNLIST; do
    print " * $(basename $A)"
done
#echo "TMPDIR=$TMPDIR"

# The files on the command line can either be absolute
# paths or files in the default IBSLOG directory.
for IBSLOG in $RUNLIST; do
    test -n "$DIAG" && print "\nprocessing $IBSLOG"
    if [[ ! -f $IBSLOG ]]; then
	if [[  -f $LOGS/$IBSLOG ]]; then
	    IBSLOG="$LOGS/$IBSLOG"
	else
	    print "No log file: $IBSLOG"
	    continue
	fi
    fi
    # Parse out the host name and date from the file.
    IBSHOST=$(basename $(print $IBSLOG|sed 's/-2...-..-..$'//))
    CURRDATE=$(print $IBSLOG|sed "s/.*-\(2...-..-..$\)/\1/")
    IBSHOSTFILTER=$CONFIG/$IBSHOST.fart

    # CURRDIR, PREVDIR are the complete path to the backup and
    #  the previous for comparison.
    CURRDIR=$(ls -1d $IBSBASE/$IBSHOST/$CURRDATE*)
    PREVDIR=$IBSBASE/$IBSHOST/$(ls -1 $IBSBASE/$IBSHOST | grep -B1 $CURRDATE|head -1)
    if [[ ! -d "$CURRDIR" || ! -d "$PREVDIR" ]]; then
	# This is flawed in that once NOFILECMP is set, it stays set.
	print "$CURRDIR or $PREVDIR do not exist, so can't do file comparisons"
	NOFILECMP="y"
    fi
    FARTOUT="$TMPDIR/$(basename "$IBSLOG")"

    test -n "$DIAG" && echo "CURRDIR=$CURRDIR  PREVDIR=$PREVDIR"
    GREPFILE=$TMPDIR/$IBSHOST.grep


    # Make the actual grep RE file
    print "$RSYNCSTART" >$GREPFILE
    print "$RSYNCEND" >>$GREPFILE 
    print " [=-]> " >>$GREPFILE # rsync noise
    print '^.*/$' >>$GREPFILE  # ignore directories -- end with /
    cat $GLOBALFILTERS $IBSHOSTFILTER |\
	sed -e 's/#.*$//' -e 's/ *$//' -e 's/^\//^/' |\
	grep -v "^$" >>$GREPFILE


    LINESOUT=0
    # Parse through log file
    {
    sed -n "/$RSYNCSTART/,/^$/p" $IBSLOG|egrep -vf /$TMPDIR/$IBSHOST.grep |\
    while read F; do 
	if [[ ($LINESOUT -ge $LINESMAX) && (-z "$NOLIMITS") ]]; then
	    print -- "     ----> $LINESOUT line output limit reached, rerun."
	    print -- "     $0 -a $IBSLOG"
	    break
	fi
	if [[ -z $NOFILECMP ]]; then
	    if cmp -s "$CURRDIR/$F" "$PREVDIR/$F" ; then
		continue
	    fi
	fi	
	((LINESOUT=LINESOUT+1))
	DIFFCMD="  --> diff -u \"$CURRDIR/$F\" \"$PREVDIR/$F\""
	print "   $F"
	if [[ -n "$SHOWLS" ]]; then
	    ls -Tnl "$PREVDIR/$F" "$CURRDIR/$F" 2>/dev/null | sed "s/^/      /"
	fi
 	if [[ -n "$SHOWDIFFCMD" ]] ; then
	    print "  --> diff -u \"$PREVDIR/$F\" \"$CURRDIR/$F\""
	fi
	if [[ -n "$SHOWDIFF" ]] ; then
	    diff -u "$PREVDIR/$F" "$CURRDIR/$F" 2>&1 | sed "s/^/      /"
	fi

    done
    } >>$FARTOUT

    if [[ -s $FARTOUT ]]; then # if there was any output
	print
	print "======== $IBSLOG "
	cat $FARTOUT
    fi
done

if [[ -z $RETAINTMP ]]; then
    rm -r $TMPDIR
else
    print "TMPDIR=$TMPDIR left for you"
fi

print
print "EOT generated from $COMMANDLINE by $(whoami) on $(hostname)"