#!/bin/bash
# vi:set ts=8 sw=4 et sta:
#
# Author : Clark J. Wang <dearvoid at gmail.com>
# License: GPLv2
# 
# $Date$
# $Author$
# $HeadURL$
# $Revision$
#
#--------------------------------------------------------------------#

{
    declare g_progName=$0
    declare g_sedExp
    declare g_all
    declare ESC=$'\033'
}

#--------------------------------------------------------------------------#

usage()
{
    cat << END
Usage: $g_progName [-a] [-h] sedExp file ...

    -a          Files and directories. Without this option, only files.
    -h          Help
    sedExp      Sed command

Report bugs to Clark J. Wang <dearvoid at gmail.com>
END

    exit $1
}

#--------------------------------------------------------------------------#

getargs()
{
    declare opt

    OPTIND=1
    OPTERR=0
    while getopts ":ah" opt "$@"; do
        case $opt in
            a)  g_all=yes ;;

            h|:|'?')
                [ $opt = h ] && usage 0 || usage 1 ;;
        esac
    done
    shift $((OPTIND - 1))

    if [ $# -lt 2 ]; then
        usage 1
    fi

    g_sedExp=$1
    shift
    if ! sed -e "$g_sedExp" < /dev/null 2> /dev/null; then
        echo "Invalid sed command: \`$g_sedExp'"
        exit 1
    fi

    g_files=( "$@" )
}

#--------------------------------------------------------------------------#

do_rename()
{
    declare file newFile

    for file in "${g_files[@]}"; do
        printf '%-20s -> ' "$file"
        if [ ! -e "$file" ]; then
            echo "[$ESC[0;31mNot found$ESC[0m]" 
            continue
        fi

        if [ -d "$file" -a "$g_all" != yes ]; then
            echo "[$ESC[0;31mDir skipped$ESC[0m]" 
            continue
        fi

        newFile=$(echo "$file" | sed -e "$g_sedExp")
        if [ "$file" = "$newFile" ]; then
            echo "[$ESC[0;31mNot changed$ESC[0m]" 
        elif [ -e "$newFile" ]; then
            echo "[$ESC[0;31mDst exists$ESC[0m]" 
        else
            echo "$newFile"
            mv "$file" "$newFile"
        fi
    done
}

#-- main() ----------------------------------------------------------------#

{
    getargs "$@"

    do_rename
}