#!/bin/bash

# Copyright (C) 2013 Ole Tange and Free Software Foundation, Inc.
#
# 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 3 of the License, or
# (at your option) any later version.
#
# This script downloads the latest version of GNU Parallel, checks
# the signature and installs it.
#
# It first tries to install it globally.
# If that fails, it does a personal installation.
# If that fails, it copies to $HOME/bin

# Download and run the script directly by:
#   (wget -O - pi.dk/3 || curl pi.dk/3/ || fetch -o - http://pi.dk/3) | bash

# tail on openindiana must be /usr/xpg4/bin/tail
TAIL=$(echo | tail -n 1 2>/dev/null && echo tail || (echo | /usr/xpg4/bin/tail -n 1 && echo /usr/xpg4/bin/tail))
# grep on openindiana must be /usr/xpg4/bin/grep
GREP=$(echo | grep -vE . 2>/dev/null && echo grep || (echo | /usr/xpg4/bin/grep -vE . && echo /usr/xpg4/bin/grep))
# FreeBSD prefers 'fetch', MacOS prefers 'curl', Linux prefers 'wget'
GET=$(
    (fetch -o /dev/null file:///bin/sh && echo fetch -o -) ||
    (curl -h >/dev/null && echo curl -L) || 
    (wget -h >/dev/null && echo wget -qO -) ||
    echo 'No wget, curl, fetch: Please inform parallel@gnu.org what you use for downloading URLs' >&2
)
if test "$GET" = ""; then
  exit 1
fi

LATEST=$($GET http://ftpmirror.gnu.org/parallel | perl -ne '/(parallel-\d{8})/ and print $1."\n"' | sort | $TAIL -n1)
if test \! -e $LATEST.tar.bz2; then
  # Source tar does not exist
  rm -f $LATEST.tar.bz2 $LATEST.tar.bz2.sig
  $GET http://ftpmirror.gnu.org/parallel/$LATEST.tar.bz2 > $LATEST.tar.bz2
  $GET http://ftpmirror.gnu.org/parallel/$LATEST.tar.bz2.sig > $LATEST.tar.bz2.sig
fi

# Check signature - in case ftpmirror.gnu.org is compromised
if gpg -h 2>/dev/null >/dev/null; then
  # GnuPG installed
  # Setup .gnupg/gpg.conf if not already done
  echo | gpg 2>/dev/null >/dev/null
  gpg --keyserver keys.gnupg.net --recv-key FFFFFFF1
  gpg --keyserver keys.gnupg.net --recv-key 88888888
  if gpg --with-fingerprint $LATEST.tar.bz2.sig 2>&1 | $GREP -E '^Primary key fingerprint: BE9C B493 81DE 3166 A3BC  66C1 2C62 29E2 FFFF FFF1|^Primary key fingerprint: CDA0 1A42 08C4 F745 0610  7E7B D1AB 4516 8888 8888' ; then
    # Source code signed by Ole Tange <ole@tange.dk> KeyID FFFFFFF1/88888888
    true
  else
    # GnuPG signature failed
    echo 
    echo "The signature on $LATEST.tar.bz2 is wrong. This may indicate that a criminal has changed the code."
    echo "THIS IS BAD AND THE CODE WILL NOT BE INSTALLED."
    echo
    echo "See http://git.savannah.gnu.org/cgit/parallel.git/tree/README for other installation methods."
    exit 1
  fi
else
  # GnuPG not installed
  echo "GnuPG (gpg) is not installed so the signature cannot be checked."
  echo "This means that if the code has been changed by criminals, you will not discover that!"
  echo 
  echo "Continue anyway? (y/n)"
  read YN </dev/tty
  if test "$YN" = "n"; then
	# Stop
	exit 2
  else
	# Continue
	true
  fi
fi

bzip2 -dc $LATEST.tar.bz2 | tar xf -
cd $LATEST || exit 2
if ./configure && make && make install; then
  echo
  echo GNU $LATEST installed globally
else
  if ./configure --prefix=$HOME && make && make install; then
    echo
    echo GNU $LATEST installed in $HOME/bin
  else
    mkdir -p $HOME/bin/;
    chmod 755 src/*;
    cp src/parallel src/sem src/sql src/niceload $HOME/bin;
    echo
    echo GNU $LATEST copied to $HOME/bin
  fi

  # Is $HOME/bin already in $PATH?
  if echo $PATH | grep $HOME/bin >/dev/null; then
    # $HOME/bin is already in $PATH
    true
  else
    # Add $HOME/bin to $PATH for both bash and csh
    echo 'PATH=$PATH:$HOME/bin' >> $HOME/.bashrc
    echo 'setenv PATH ${PATH}:${HOME}/bin' >> $HOME/.cshrc
  fi

  # Is $HOME/share/man already in $MANPATH?
  if echo $MANPATH | grep $HOME/share/man >/dev/null; then
    # $HOME/share/man is already in $MANPATH
    true
  else
    # Add $HOME/share/man to $MANPATH for both bash and csh
    echo 'MANPATH=$MANPATH:$HOME/share/man' >> $HOME/.bashrc
    echo 'setenv MANPATH ${MANPATH}:${HOME}/share/man' >> $HOME/.cshrc
  fi
fi