#!/bin/sh

# Default value for the RMGDIFF_GUI environment variable.
: ${RMGDIFF_GUI:=/usr/bin/mgdiff}

#
# You shouldn't need to edit beneath here.
#

SHOW_FILE_TYPES="TRUE"
USE_CVS=""
DEBUG=""
USE_GUI="TRUE"
RMGDIFF_VERSION=""



Usage() {
cat <<-EOF

Usage: `basename "$0"` [-b] [-c] [-d] [-g <gui>] [-n] [-v] <dir1> <dir2>

    -b: basic reporting (no file type info will be printed)
    -c: bzr, cvs, fossil, git, hg, and svn files will be included in diff
    -d: print debugging information
    -g: which gui to use
    -n: no gui will pop up
    -v: version

EOF
}

verify_exec () {
    type "$1" 1>/dev/null 2>&1
    if [ $? -ne 0 ] ; then
        echo "$progname: Error: Unable to find executable for \"$1\"." >&2
        exit 1
    fi
}

# Some machines don't have a "readlink" command.
read_link_via_ls() {
    if [ $# -ne 1 ] ; then
        echo "$progname: Internal Error: Invalid args for" \
             "readlink_via_ls: $@" >&2
        exit 1
    fi

    \ls -l "$1" | sed -e 's|.*-> ||'
}


# Some machines don't have a "realpath" command.  follow_link_via_ls
# does not pretend to be "realpath" because it will leave all sorts of
# cruft in the path string, but it should eventuall reach a regular
# file.
follow_link_via_ls() {

    if [ $# -ne 1 ] ; then
        echo "$progname: Internal Error: Invalid args for" \
             "follow_link_via_ls: $@" >&2
        exit 1
    fi

    local_iteration_count=0
    local_iteration_max=1024

    # Prime the pump.
    local_tmp=
    local_rv="$1"

    while [ $local_iteration_count -lt $local_iteration_max ] ; do

        if [ ! -h "$local_rv" ] ; then
            break
        fi

        local_tmp=`read_link_via_ls "$local_rv"`

        # The "read_link_via_ls" above could result in an absolute
        # path or a relative one.  The Solaris /bin/sh does not
        # support "${PSTREE_AWK_SCRIPT#/}".  So, use grep instead.
        echo "$local_tmp" | grep '^/' >/dev/null 2>&1
        if [ $? -ne 0 ] ; then
            # The path given by readlink was relative.  So, we have a
            # little more work to do because we need to prepend the
            # same path used to reach the original symlink.
            local_tmp=`dirname "$local_rv"`/"$local_tmp"
        fi

        local_rv="$local_tmp"

        local_iteration_count=`expr $local_iteration_count + 1`

    done

    if [ $local_iteration_count -ge $local_iteration_max ] ; then
        echo "$progname: Error: Symbolic link nesting is too deep when" \
             "following \"$1\"." >&2
        exit 1
    fi 

    echo "$local_rv"

}


#
# Script starts here.
#

progname="rmgdiff"
verify_exec "basename"
progname=`basename "$0"`

# Use GNU diff if possible.
type "gdiff" 1>/dev/null 2>&1
if [ $? -eq 0 ] ; then
    DIFF="gdiff"
else
    DIFF="diff"
fi

# Use GNU awk if possible.
for NAWK in gawk nawk awk ; do
    type "$NAWK" 1>/dev/null 2>&1
    if [ $? -eq 0 ] ; then
        break
    fi
done

verify_exec "$DIFF"
verify_exec "dirname"
verify_exec "expr"
verify_exec "file"
verify_exec "grep"
verify_exec "ls"
verify_exec "$NAWK"
verify_exec "$RMGDIFF_GUI"
verify_exec "sed"

while getopts "bcdg:nv" OPT ; do
    case "$OPT" in
        b)  SHOW_FILE_TYPES=""
            ;;
        c)  USE_CVS="TRUE"
            ;;
        d)  DEBUG="TRUE"
            ;;
        g)  RMGDIFF_GUI="$OPTARG"
            ;;
        n)  USE_GUI=""
            ;;
        v)  RMGDIFF_VERSION="TRUE"
            ;;
        \?) Usage
            exit 1
            ;;
    esac
done
shift `expr $OPTIND - 1`

#
# Find the rmgdiff awk script.  It is located in the same directory as
# this shell script after following all the symlinks.
#
lib_dir=`follow_link_via_ls "$0"`
RMGDIFF_AWK=`dirname "$lib_dir"`/rmgdiff.awk


# If the user just wants the version ...
if [ -n "$RMGDIFF_VERSION" ] ; then
    exec "$NAWK" -v version="$RMGDIFF_VERSION" -f "$RMGDIFF_AWK"
fi

if [ $# -lt 2 ] || [ $# -gt 2 ] ; then
    Usage
    exit 1
fi

if [ ! -d "$1" ] ; then
    echo "$progname: dir1=\"$1\" is not a directory." 1>&2
    exit 1
fi

if [ ! -d "$2" ] ; then
    echo "$progname: dir2=\"$2\" is not a directory." 1>&2
    exit 1
fi

exec "$DIFF" -rq "$1" "$2" | "$NAWK" -v debug="$DEBUG" \
                                     -v dir1="$1" \
                                     -v dir2="$2" \
                                     -v rmgdiff_gui="$RMGDIFF_GUI" \
                                     -v show_file_types="$SHOW_FILE_TYPES" \
                                     -v use_cvs="$USE_CVS" \
                                     -v use_gui="$USE_GUI" \
                                     -v version="$RMGDIFF_VERSION" \
                                     -f "$RMGDIFF_AWK"