#!/bin/bash

# makelinks: script for generating the links to run multiple versions
# of installed IDL, including the plain command line version, the
# development environment, and the online help, separately.  Run this
# script after installing/deleting a new version of idl.

# NOTE: WHEN INSTALLING A NEW VERISON OF IDL, DO NOT SAY "Y" TO THE
# "MAKE LINKS" OPTION OF THE INSTALL SCRIPT WHICH RUNS AT THE END OF
# INSTALLATION (YOU CAN OPT NOT TO RUN IT, AS THIS IS ALL IT DOES).
# INSTEAD, RUN THIS SCRIPT AFTER INSTALLATION COMPLETES.

# THIS SCRIPT MUST BE AT THE MAIN RSI INSTALL LEVEL, E.G. /usr/local/rsi

# J.D. Smith  2000-11-5

base=$(dirname $0)
# Edit this to make the links elsewhere, but this is usually good.
destdir="$base/../bin"

[ -x $destdir/idl ] || {
    echo "Generating $destdir/idl script"
    cat <<\EOF > $destdir/idl
#!/bin/bash
# idl: A script to run multiple versions of RSI's IDL, including
# separately the command line, the development environment, or the
# online help.  Each version is linked to this script (named idl),
# with names of type "prog_vers", where prog is one of:
# 	idl
# 	idlde
# 	idlhelp
# and vers is the version number, like 5.2.  An example is idlde_5.4.

# You can them simply say, e.g., idlhelp_5.1 to get version 5.1's
# help, or idl_5.4 to run the command-line idl version 5.4, etc.  If
# you find a version available which does not work, alert the
# sysadmin.

# The full set of links for all installed version of IDL are created
# by the script "makelinks" available in the RSI install directory.
# See that script for more info.  Run it after installing or deleting
# an installation of idl in the RSI install directory (often
# /usr/local/rsi, or /export/local/rsi for exported shares).  The
# installation directories are by default named idl_vers
# (e.g. /export/local/rsi/idl_5.4), and this naming convention must be
# retained.  If this script is run via one of its links which has no
# version number (idl, idlde, or idlhelp), the latest version will be
# run.  All IDL_PATH entries which reference a preset $IDL_DIR will be
# updated.  This will ensure the correct set of IDL libraries are
# being run.

# The user need no longer set IDL_DIR, it will be set by this script.
# It's not a problem if they do.  The can also use IDL_EXTRA to
# specify other paths they'd like to search, which will be appended
# beyond the distributed IDL library's path.  If they'd like to
# override the library, for instance, they can specify IDL_PATH
# directly, being sure to include $IDL_DIR/lib.  This is less portable
# and not always a good idea, unless you really need to specify the
# ordering of the paths.

# N.B.: This all means a new user need set up *nothing* in their
# .cshrc, .login, etc., to run any version of IDL immediately, and
# should simply specify a colon-separated lists of paths in
# "IDL_EXTRA" for their local programs (with a + prefix for recursion,
# if desired).

# N.B.: THIS FILE GOES IN THE DIRECTORY LABELED "destdir" IN THE
# SCRIPT makelinks (see the RSI install directory),

# J.D. Smith  2000-11-5

# Set this to the RSI install base, to run this script
rsi_base=/usr/local/rsi

base=$(dirname $0)

# Save the (possible) user-set idl dir
[ -n "$IDL_DIR" ] && old_dir=$IDL_DIR

# See how we were called.
vers=${0##*/}
case $vers in 
    *idlde*) 
	     vers=${vers#idlde_};
	     prog="idlde";
	     ;;
    *idlhelp*) 
	     vers=${vers#idlhelp_};
	     prog="idlhelp";
	     ;;
    *idl*)   
	     vers=${vers#idl_};
	     prog="idl";
	     ;;
    *)       
	     echo "Improperly formatted command name: $0";
	     exit 1;
	     ;;
esac

# Only dots and numbers
vers=$(echo $vers | tr -cd '[0-9].')

# No version?  No problem.  Find the latest version.
[ -z "$vers" ] && {
    latest="0.0"
    for scr in $base/idl_*; do
	[ -L $scr ] || continue # Only links please
	dvers=${scr##*/}
	dvers=${dvers#idl_}

	# Only dots and numbers, we need to compare
	dvers=$(echo $dvers | tr -cd '[0-9].')
	[ -z "$dvers" ] && continue

	major=${dvers%%.*}
	minor=${dvers#*.}
	minor=$(echo $minor | tr -d '.')
	fvers="$major.$minor"
	[ -n $(echo "if (${fvers}>${latest}) 1" | bc) ] && {
	    vers=$dvers;
	    latest=$fvers;
	}
    done
}

[ -z "$vers" ] && {
    echo "Cannot find any validly named version of idl in $base." 1>&2;
    exit 1;
}

export IDL_DIR="$rsi_base/idl_$vers"

# Update any relevant parts of the IDL_PATH to point to the new directory 
if [ -n "$old_dir" -a -n "$IDL_PATH" ]; then
	export IDL_PATH=$(echo $IDL_PATH | sed "s:$old_dir:$IDL_DIR:g")
fi

# If there wasn't one, make sure the lib directory is included
[ -z "$IDL_PATH" ] && export IDL_PATH="+$IDL_DIR/lib${IDL_EXTRA:+:$IDL_EXTRA}"
export IDL_DLM_PATH="+$IDL_DIR/bin${IDL_DLM_EXTRA:+:$IDL_DLM_EXTRA}"

# Run the correct version
exec $IDL_DIR/bin/$prog $@

EOF
chmod +x $destdir/idl
}

# Kill the old links, in case we removed a directory
rm -f $destdir/idl{,de,help}_*

# Go through the installed idl directories, making links
latest="0.0"
for dir in $base/idl_*; do
    [ -d $dir -a ! -L $dir -a -d $dir/bin ] || continue
    vers=${dir##*/}
    vers=${vers#idl_}

    # Only dots and numbers, we need to compare
    vers=$(echo $vers | tr -cd '[0-9].')
    [ -z "$vers" ] && continue

    echo VERSION $vers
    for end in "" de help; do
	echo "Making ${destdir}/idl${end}_${vers}";
	ln -s idl ${destdir}/idl${end}_${vers};
    done

    # Find the latest version
    major=${vers%%.*}
    minor=${vers#*.}
    minor=$(echo $minor | tr -d '.')
    fvers="$major.$minor"
    [ -n $(echo "if (${fvers}>${latest}) 1" | bc) ] && {
	latest_vers=$vers;
	latest=$fvers;
    }
done

# Set up links for running the latest version
[ -L $destdir/idlde ] || {
    echo "Making $destdir/idlde";
    ln -s idl $destdir/idlde;
}
[ -L $destdir/idlhelp ] || {
    echo "Making $destdir/idlhelp";
    ln -s idl $destdir/idlhelp;
}

[ -L $base/idl ] && {
    echo "LATEST VERSION";
    echo "Making idl->idl_${latest_vers}";
    rm -f idl;
    ln -s idl_${latest_vers} idl;
}