#!/bin/bash
##
# THIS SOFTWARE IS DISTRIBUTED UNDER GPL LICENSE
#
# Copyright (C) 2009  Ankur Shah 
# http://ankurshah.net
# $comments > ashah (contact<a-t>ankurshah<d-o-t>net)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA or visit http://www.gnu.org/licenses/gpl.txt.
##

# ...system essentials
CURL=${CURL:-/usr/bin/curl}
TW_UID=${TW_UID:-"ankur_shah"}
TW_PWD=
TW_URL=http://twitter.com/statuses/update.xml
TW_MAX_LEN=140;
TW_MESSAGE="$@"
MSG_LENGTH=`echo ${#TW_MESSAGE}`

# ...routine to log messages to STDOUT
function log {
  echo "[$$ `date \"+%Y-%m-%d %H:%M:%S\"`] $@" >&1
}

# ...routine to log messages to STDERR. Exits system with $error_code
function error {
  error_code=$1
  shift
  echo "[$$ `date \"+%Y-%m-%d %H:%M:%S\"`] ERROR: $@" >&2
  log "==== EXIT with code $error_code ===="
  exit $error_code
}

# ...routine to display usage and exit
function usage {
    exit_code=$1
    echo "Usage: $0 <message>"
    exit $exit_code
}

# ...main routine
function main {
    if [ $MSG_LENGTH -eq 0 ]; then 
        usage 1
    elif [ $MSG_LENGTH -gt ${TW_MAX_LEN} ]; then 
        error 2 "Message length [${MSG_LENGTH}] longer than the allowed ${TW_MAX_LEN} characters limit"
    else
        log "Message length: ${MSG_LENGTH}"
    fi

    stty -echo 
    echo -n "Please enter your twitter password: "
    read TW_PWD
    stty echo

    log "Posting message"
    result=`${CURL} -u ${TW_UID}:${TW_PWD} -d status="${TW_MESSAGE}" ${TW_URL}`
    log "Got result [${result}]"
}

main