#!/bin/bash
#*********************************************************************
#** prefix
#*********************************************************************
#** @(#)$Id: prefix 7988 2006-10-27 18:39:02Z spadkins $
#*********************************************************************

export OLD_PREFIX=$PREFIX
export PREFIX=${PREFIX:-/usr/local}

if [[ -f "$HOME/.prefixes" ]]      # check if multiple environments exist
then
   export PREFIXES_FILE=$HOME/.prefixes
else
   export PREFIXES_FILE=/etc/prefixes 
fi

print_usage ()
{
   echo
   echo "The prefix script allows you to manage multiple installations of"
   echo "a set of software installed on the same machine.  It helps in this"
   echo "by taking care of the reconfiguration of environment variables"
   echo "appropriate for each installation.  It is assumed that the"
   echo "software for each installation is all under a single directory"
   echo "whose name is assigned to an environment variable called PREFIX. "
   echo
   echo "This arrangement of enabling multiple installations of software"
   echo "on a single machine is useful at many times.  On a single server,"
   echo "it can provide for development, test, and production installations"
   echo "of software.  Alternatively, on development servers,"
   echo "it allows for multiple development \"sandboxes\", one for each"
   echo "developer.  On production servers, it allows for multiple versions"
   echo "of the production software to be installed.  One might be the currently"
   echo "running software, one the previous software kept online as a fall-back,"
   echo "and one a new release of software which is scheduled to be brought"
   echo "online soon."
   echo
   echo "There are three usages of the prefix script:"
   echo
   echo "  (1) The interactive usage should be placed as the last line"
   echo "      of a user's ".profile".  The user must be running the"
   echo "      Korn shell (ksh) or the Bourne Again shell (bash)."
   echo "      The user is prompted to enter one of the known PREFIX locations,"
   echo "      specified in the \$HOME/.prefixes file or the /etc/prefixes file."
   echo "      During configuration, the \$PREFIX/.prefixrc file is sourced"
   echo "      in order to accomplish environment-specific configurations."
   echo "  (2) The non-interactive user configuration does not consult"
   echo "      \$HOME/.prefixes or /etc/prefixes or prompt the user, but merely"
   echo "      configures the environment in accordance with the cmd line argument."
   echo "  (3) The batch command usage is mainly for running commands from"
   echo "      cron or running commands in another environment without changing"
   echo "      to that environment."
   echo
   echo "Usage (1): . prefix                     (sets up environment)"
   echo "      (2): . prefix <prefix>            (non-interactive setup)"
   echo "      (3): prefix <prefix> <cmd> <args> (runs cmd configured for PREFIX)"
   echo
}

if [[ "$1" = "-?" ]]
then
   print_usage
else
   export PREFIX_CMD=""
   if [[ "$1" != "" ]]
   then
      export NEW_PREFIX="$1"
      export PREFIX_ASK="no"
      shift
      if [[ $# -gt 0 ]]
      then
         export PREFIX_CMD="$*"
         set --                             # clear cmd line args
      fi
   fi

   if [[ "$PREFIX_ASK" != "no" ]]
   then
      if [[ -f "$PREFIXES_FILE" ]]     # check if multiple environments exist
      then
         export NUM_PREFIXES=$(wc -l < "$PREFIXES_FILE")
         if [[ "$NEW_PREFIX" = "" ]]      
         then
            export NEW_PREFIX=$(head -1 "$PREFIXES_FILE")
         fi
   
         if [[ "$PREFIX_ASK" != "no" && "$NUM_PREFIXES" -gt 1 ]]
         then
            echo "========================================================"
            echo "SET UP SOFTWARE PREFIX (ROOT DIRECTORY FOR THE SOFTWARE)"
            echo "========================================================"
            export PS3="Select a directory: "
            select NEW_PREFIX in $(sed 's/#.*//' "$PREFIXES_FILE")
            do
               break
            done
            if [[ "$NEW_PREFIX" = "" ]]
            then
               export NEW_PREFIX="$REPLY"
            fi
         fi
      fi
   fi

   if [[ "$NEW_PREFIX" = "" ]]
   then
      echo
      echo "ERROR: Please specify a PREFIX or create a ~/.prefixes file"
      echo "       to enable interactive usage."
      echo
      print_usage
   elif [[ ! -d $NEW_PREFIX/. ]]
   then
      echo
      echo "ERROR: Directory [$NEW_PREFIX] does not exist."
      echo
      print_usage
   else
      export PREFIX=$NEW_PREFIX
      if [[ -t 1 && "$PREFIX_CMD" = "" ]]
      then
         echo "Configuring Software Prefix [$NEW_PREFIX]."
      fi

      ######################################################
      # Remove all PATH references before adding them back
      ######################################################
      export SED_CLEAN_PATH=""
      export SED_CLEAN_LIBPATH=""
      export SED_CLEAN_MANPATH=""

      for AUX_DIR in $(echo "$OLD_PREFIX:$PRE_PREFIX:$POST_PREFIX" | sed -e 's/^/:/' -e 's!:\([^/~]\)!:'$PREFIX'/\1!' -e 's/:/ /g')
      do
         SED_CLEAN_PATH="$SED_CLEAN_PATH -e s!:$AUX_DIR/bin!!g"
         SED_CLEAN_LIBPATH="$SED_CLEAN_LIBPATH -e s!:$AUX_DIR/lib!!g"
         SED_CLEAN_MANPATH="$SED_CLEAN_MANPATH -e s!:$AUX_DIR/man!!g -e s!:$AUX_DIR/share/man!!g"
      done

      # Remove old references from the PATH
      export PATH=`echo $PATH | \
             sed -e "s/^:*/:/" \
                 -e "s/:*$/:/" \
                 -e "s/:::*/:/g" \
                 $SED_CLEAN_PATH \
                 -e "s/::*$//" \
                 -e "s/^::*//"`

      # Remove old references from the LD_LIBRARY_PATH
      OLD_LD_LIBRARY_PATH="$LD_LIBRARY_PATH"
      if [ "$OLD_LD_LIBRARY_PATH" = "" ]
      then
          OLD_LD_LIBRARY_PATH="/usr/local/lib:/usr/lib:/lib"
      fi
      export LD_LIBRARY_PATH=""
      export LD_LIBRARY_PATH=`echo $OLD_LD_LIBRARY_PATH | \
             sed -e "s/^:*/:/" \
                 -e "s/:*$/:/" \
                 -e "s/:::*/:/g" \
                 $SED_CLEAN_LIBPATH \
                 -e "s/::*$//" \
                 -e "s/^::*//"`
      unset OLD_LD_LIBRARY_PATH

      # Remove old references from the LIBPATH
      OLD_LIBPATH="$LIBPATH"
      if [ "$OLD_LIBPATH" = "" ]
      then
          OLD_LIBPATH="/usr/local/lib:/usr/lib:/lib"
      fi
      export LIBPATH=""
      export LIBPATH=`echo $OLD_LIBPATH | \
             sed -e "s/^:*/:/" \
                 -e "s/:*$/:/" \
                 -e "s/:::*/:/g" \
                 $SED_CLEAN_LIBPATH \
                 -e "s/::*$//" \
                 -e "s/^::*//"`
      unset OLD_LIBPATH

      # Remove old references from the MANPATH
      if [ "$MANPATH" = "" ]
      then
          MANPATH="/usr/local/man:/usr/share/man:/usr/man:/man"
      fi
      export MANPATH=`echo $MANPATH | \
             sed -e "s/^:*/:/" \
                 -e "s/:*$/:/" \
                 -e "s/:::*/:/g" \
                 $SED_CLEAN_MANPATH \
                 -e "s/::*$//" \
                 -e "s/^::*//"`

      ######################################################
      # source the environment's .rmsrc file if it exists
      ######################################################
      for AUX_DIR in $(echo $POST_PREFIX | sed -e 's/^/:/' -e 's!:\([^/~]\)!:'$PREFIX'/\1!' -e 's/:/ /g')
      do
         if [[ -f $AUX_DIR/.prefixrc ]]
         then
            . $AUX_DIR/.prefixrc
         fi
      done

      if [[ -f $PREFIX/.prefixrc ]]
      then
         . $PREFIX/.prefixrc
      fi

      for AUX_DIR in $(echo $PRE_PREFIX | sed -e 's/^/:/' -e 's!:\([^/~]\)!:'$PREFIX'/\1!' -e 's/:/ /g')
      do
         if [[ -f $AUX_DIR/.prefixrc ]]
         then
            . $AUX_DIR/.prefixrc
         fi
      done

      ######################################################
      # source the user's .prefixrc file if it exists
      ######################################################
      if [[ -f ~/.prefixrc ]]
      then
         . ~/.prefixrc
      fi

      ##########################################################
      # Set appropriate defaults for common variables
      ##########################################################

      export AUX_PATH=""
      export AUX_LIBPATH=""
      export AUX_MANPATH=""
      export PREFIX_INCLUDES=""
      for AUX_DIR in $(echo $PRE_PREFIX | sed -e 's/^/:/' -e 's!:\([^/~]\)!:'$PREFIX'/\1!' -e 's/:/ /g')
      do
         AUX_PATH="$AUX_PATH$AUX_DIR/bin:"
         AUX_LIBPATH="$AUX_LIBPATH$AUX_DIR/lib:"
         AUX_MANPATH="$AUX_MANPATH$AUX_DIR/man:"
         PREFIX_INCLUDES="$PREFIX_INCLUDES -I$AUX_DIR/include"
      done

      PREFIX_INCLUDES="$PREFIX_INCLUDES -I$PREFIX/include"

      export AUX_PATHPOST=""
      export AUX_LIBPATHPOST=""
      export AUX_MANPATHPOST=""
      for AUX_DIR in $(echo $POST_PREFIX | sed -e 's/^/:/' -e 's!:\([^/~]\)!:'$PREFIX'/\1!' -e 's/:/ /g')
      do
         AUX_PATHPOST="$AUX_PATHPOST:$AUX_DIR/bin"
         AUX_LIBPATHPOST="$AUX_LIBPATHPOST:$AUX_DIR/lib"
         AUX_MANPATHPOST="$AUX_MANPATHPOST:$AUX_DIR/man"
         PREFIX_INCLUDES="$PREFIX_INCLUDES -I$AUX_DIR/include"
      done

      # Add new references into the PATH
      export PATH=$AUX_PATH$PREFIX/bin$AUX_PATHPOST:$PATH

      # Add new references into the LD_LIBRARY_PATH
      if [[ "$LD_LIBRARY_PATH" = "" ]]
      then
         export LD_LIBRARY_PATH=$AUX_LIBPATH$PREFIX/lib$AUX_LIBPATHPOST
      else
         export LD_LIBRARY_PATH=$AUX_LIBPATH$PREFIX/lib$AUX_LIBPATHPOST:$LD_LIBRARY_PATH
      fi

      # Add new references into the LIBPATH
      if [[ "$LIBPATH" = "" ]]
      then
         export LIBPATH=$AUX_LIBPATH$PREFIX/lib$AUX_LIBPATHPOST
      else
         export LIBPATH=$AUX_LIBPATH$PREFIX/lib$AUX_LIBPATHPOST:$LIBPATH
      fi

      # Add new references into the MANPATH
      if [[ "$MANPATH" = "" ]]
      then
         # guess at the base MANPATH
         MANPATH=$(ls -d /man /*/man /*/*/man 2> /dev/null | tr '\n' ':' | sed 's/:$//')
      fi
      # Add new references into the MANPATH
      if [[ "$MANPATH" = "" ]]
      then
         export MANPATH=$AUX_MANPATH$PREFIX/share/man:$PREFIX/man$AUX_MANPATHPOST
      else
         export MANPATH=$AUX_MANPATH$PREFIX/share/man:$PREFIX/man$AUX_MANPATHPOST:$MANPATH
      fi

   fi

   if [[ "$PREFIX_CMD" != "" ]]
   then
      exec $PREFIX_CMD
   fi
fi

set --   # clear cmd line args

unset PREFIXES_FILE
unset PREFIX_CMD
unset PREFIX_ASK
unset NUM_PREFIXES
unset NEW_PREFIX
unset OLD_PREFIX

unset SED_CLEAN_PATH
unset SED_CLEAN_LIBPATH
unset SED_CLEAN_MANPATH
unset AUX_PATH
unset AUX_LIBPATH
unset AUX_MANPATH
unset AUX_DIR
unset AUX_PATHPOST
unset AUX_LIBPATHPOST
unset AUX_MANPATHPOST