#!/bin/bash

# svndiff -- svn diff with vimdiff, support compare with different revision
#
# Written by Hean Kuan Ong (heankuanong@gmail.com)
# May 18, 2007
#
# Copyright (C) 2007 Hean Kuan Ong All rights reserved.
#
# This software is provided "as is" without express or implied warranties.
#
# Permission is granted to use, copy, modify and distribute this software,
# provided this disclaimer and copyright are preserved on all copies. This
# software may not, however, be sold or distributed for profit, or included
# with other software which is sold or distributed for profit, without the
# permission of the author.
# 

PROG=`basename $0`
N1=0
N2=0

helpme()
{
    echo ""
    echo "USAGE: svndiff [OPTION] [FILE]"
    echo ""
    echo "OPTION:"
    echo "-r <revision number>"
    echo ""
    echo "Examples:"
    echo "$PROG <file>                          - Compare working with current copy"
    echo "$PROG -r <rev no> <file>              - Compare specified rev copy with current copy"
    echo "$PROG -r <rev no> <rivision> <file>   - Compare 2 different copy" 
    exit 2
}

if [ $# -lt 1 ]
then
    helpme
elif [ -e $1 ]
then
    TEMP=/tmp/tmp.$$.`basename $1`
    svn cat $1 > $TEMP
    vimdiff $TEMP $1
    rm -f $TEMP
elif [[ "$1" = "-r"  ]]
then
    if [ $# -gt 2 ]
    then
        case "$2" in 
            *[!0-9]*) N1=0 ;;
            *) N1=1 ;;
        esac
        case "$3" in 
            *[!0-9]*) N2=0 ;;
            *) N2=1 ;;
        esac
    fi
    if [ -e $3 ]
    then
        if [ $N1 -ne 1 ]
        then
            helpme
        fi
        TEMP=/tmp/rev.$2.`basename $3`
        svn cat -r $2 $3 > $TEMP
        vimdiff $TEMP $3
        rm -f $TEMP
    elif [ -e $4 ]
    then
        if [ $N1 -ne 1 ] || [ $N2 -ne 1 ]
        then
            helpme
        fi
        TEMP=/tmp/rev.$2.`basename $4`
        TEMP2=/tmp/rev.$3.`basename $4`
        svn cat -r $2 $4 > $TEMP
        svn cat -r $3 $4 > $TEMP2
        vimdiff $TEMP $TEMP2
        rm -f $TEMP
        rm -f $TEMP2
    else
        helpme
    fi
else
    helpme
fi