#!/bin/bash

# Script that executes wget using a socks proxy if the environment variable
# socks_proxy is set.
#
# The socks_proxy variable shall have one of the forms:
#   socks://username:password@host:port
#   socks4://username:password@host:port
#   socks5://username:password@host:port
# with username, password and port fields being optional
#
# As socksification applies to the whole process, domains defined in the
# no_proxy setting are *not* excluded.
#

# Requisites: bash (version 3.2.3 or later), tsocks and wget

####################################
#  Copyright (C) 2014 Ángel González
#  Permission is hereby granted, free of charge, to any person obtaining a copy
#  of this software and associated documentation files (the "Software"), to deal
#  in the Software without restriction, including without limitation the rights
#  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#  copies of the Software, and to permit persons to whom the Software is
#  furnished to do so, subject to the following conditions:
#
#  The above copyright notice and this permission notice shall be included in
#  all copies or substantial portions of the Software.
#
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
#  THE SOFTWARE.
#

set -eu

# Binary to be executed. Use an absolute path if installing this script as 'wget'
WGET=wget

if [ -z "${socks_proxy:-}" ]; then
exec "$WGET" "$@"
fi

CONFIG=""

if [[ "${socks_proxy}" =~ ^socks[45]?:// ]]; then
 if [[ "${socks_proxy:5:1}" != ":" ]]; then
  CONFIG+="server_type = ${socks_proxy:5:1}"
  socks_proxy="${socks_proxy:9}"
 else
  socks_proxy="${socks_proxy:8}"
 fi
elif [[ "${socks_proxy}" =~ ^[[:alnum:]]*:// ]]; then
 echo "Bad value specified for socks_proxy: $socks_proxy" >&2
 exit 2
fi

if [[ "${socks_proxy}" =~ ^([^@:]*)(:([^@]*))?@ ]]; then
 unset TSOCKS_USERNAME
 CONFIG+="
   default_user = ${BASH_REMATCH[1]}"

 if [ ! -z "${BASH_REMATCH[3]}" ]; then
  unset TSOCKS_PASSWORD
  CONFIG+="
   default_pass = ${BASH_REMATCH[3]}"
 fi
 socks_proxy="${socks_proxy:${#BASH_REMATCH[0]}}"
fi


# Get rid of trailing slashes
if [[ "${socks_proxy}" =~ ^([^/]*)/ ]]; then
 socks_proxy="${socks_proxy:0:${#BASH_REMATCH[1]}}"
fi

if [[ "${socks_proxy}" =~ :([0-9]+)$ ]]; then
  CONFIG+="
   server_port = ${BASH_REMATCH[1]}"
  socks_proxy=${socks_proxy:0:${#socks_proxy} - ${#BASH_REMATCH[0]}}
fi

CONFIG+="
   server = ${socks_proxy}"

TSOCKS_CONF_FILE=<(echo "$CONFIG") exec tsocks "$WGET" --no-proxy "$@"