#!/bin/sh
#------------------------------------------------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     |
#   \\  /    A nd           | www.openfoam.com
#    \\/     M anipulation  |
#------------------------------------------------------------------------------
#     Copyright (C) 2011-2016 OpenFOAM Foundation
#     Copyright (C) 2017-2022 OpenCFD Ltd.
#------------------------------------------------------------------------------
# License
#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
#
# Script
#     foamCleanPath
#
# Description
#     Usage: foamCleanPath [OPTION] path [filter] .. [filter]
#            foamCleanPath [OPTION] -env=name [filter] .. [filter]
#
#     Prints its argument (which should be a ':' separated path)
#     without the following:
#         - duplicate elements
#         - elements matching the specified filter(s)
#         - inaccessible directories (with the -strip option)
#
# Note
#     - false matches possible when the filter contains '.' (sed regex) etc.
#     - a single composite filter can be passed in. This composite filter
#       is assumed to be delimited by whitespace, colons or semi-colons.
#     - will not filter out standard system paths (/usr/bin etc)
#
# Examples for cleaning the path:
#
#     - Using explicit arguments
#       cleaned=$(foamCleanPath "$PATH" dir1:dir2) && PATH=$cleaned
#
#     - Variable to clean passed as an option
#       cleaned=$(foamCleanPath -env=PATH dir1:dir2) && PATH=$cleaned
#
#     - Using shell evaluation for the output
#       eval "$(foamCleanPath -sh=PATH "$PATH" dir1:dir2)"
#       eval "$(foamCleanPath -sh=PATH -env=PATH dir1:dir2)"
#       eval "$(foamCleanPath -sh-env=PATH dir1:dir2)"
#       eval "$(foamCleanPath -sh-path dir1:dir2)"
#
#     - Similarly for c-shell
#       eval `foamCleanPath -csh-path dir1:dir2`
#
# For library paths, it is suggested to use -sh-lib, -env=-lib etc.
#
# On Darwin it uses FOAM_LD_LIBRARY_PATH instead of LD_LIBRARY_PATH.
# This should actually be DYLD_LIBRARY_PATH on Darwin, but setting that
# or LD_LIBRARY_PATH via a shell-script is disallowed when SIP is active.
#
#------------------------------------------------------------------------------
printHelp() {
    cat<<USAGE

Usage: foamCleanPath [OPTION] ENVNAME [filter] .. [filter]
       foamCleanPath [OPTION] -env=name [filter] .. [filter]
options:
  -env=NAME         Evaluate NAME to obtain initial content,
                    Accepts "-env=-path", "-env=-lib" shortcuts for PATH
                    and LD_LIBRARY_PATH (FOAM_LD_LIBRARY_PATH on Darwin)
  -sh=NAME          Produce 'NAME=...' output for sh eval
  -csh=NAME         Produce 'setenv NAME ...' output for csh eval
  -sh-env=NAME      Same as -sh=NAME -env=NAME
  -csh-env=NAME     Same as -csh=NAME -env=NAME
  -sh-path | -csh-path  Same as -[c]sh-env=PATH
  -sh-lib  | -csh-lib   Same as -[c]sh-env=LD_LIBRARY_PATH
                        (FOAM_LD_LIBRARY_PATH on Darwin)
  -debug            Print debug information to stderr
  -strip            Remove inaccessible directories
  -verbose          Report some progress (input, output, ...)
  -help             Print the usage

Prints its argument (which should be a ':' separated list) cleansed from
  * duplicate elements
  * elements whose start matches one of the filters
  * inaccessible directories (the -strip option)

Exit status
    0  on success
    1  general error
    2  initial value of ENVNAME is empty

USAGE
    exit 0  # A clean exit
}

# Report error and exit
die()
{
    exec 1>&2
    echo
    echo "Error encountered:"
    while [ "$#" -ge 1 ]; do echo "    $1"; shift; done
    echo
    echo "See '${0##*/} -help' for usage"
    echo
    exit 1
}

#-------------------------------------------------------------------------------

# Input and outputs
unset dirList shellFlavour shellOutput
unset optDebug optEnvName optStrip optVerbose

# Parse options
while [ "$#" -gt 0 ]
do
    case "$1" in
    (-h | -help*)
        printHelp
        ;;

    (-csh-lib | -csh-path | -sh-lib | -sh-path)
        shellFlavour="$1"
        case "$1" in
        (*-lib)
            name='LD_LIBRARY_PATH'
            if [ "$(uname -s 2>/dev/null)" = Darwin ]
            then
                name='FOAM_LD_LIBRARY_PATH' # Shadow DYLD_LIBRARY_PATH
            fi
            ;;
        (*-path)
            name='PATH'
            ;;
        esac
        optEnvName="$name"      # Use for input evaluation
        shellOutput="$name"     # Use for output
        ;;

    (-env=*)
        name="${1#*=}"
        [ -n "$name" ] || die "Option '$1' missing an ENVNAME"
        # Handle (-lib | -path) aliases
        case "$1" in
        (*=-lib)
            name='LD_LIBRARY_PATH'
            if [ "$(uname -s 2>/dev/null)" = Darwin ]
            then
                name='FOAM_LD_LIBRARY_PATH' # Shadow DYLD_LIBRARY_PATH
            fi
            ;;
        (*=-path)
            name='PATH'
            ;;
        esac
        optEnvName="$name"      # Use for input evaluation
        ;;

    (-csh=* | -csh-env=* | -sh=* | -sh-env=*)
        shellFlavour="$1"
        name="${1#*=}"
        [ -n "$name" ] || die "Option '$1' missing an ENVNAME"
        # Handle (-lib | -path) aliases
        case "$1" in
        (*=-lib)
            name='LD_LIBRARY_PATH'
            if [ "$(uname -s 2>/dev/null)" = Darwin ]
            then
                name='FOAM_LD_LIBRARY_PATH' # Shadow DYLD_LIBRARY_PATH
            fi
            ;;
        (*=-path)
            name='PATH'
            ;;
        esac
        shellOutput="$name"     # Use for output
        # Use for input evaluation
        case "$1" in (*-env=*) optEnvName="$name";; esac
        ;;

    (-debug)
        optDebug=true
        ;;
    (-strip)
        optStrip=true
        ;;
    (-verbose)
        optVerbose=true
        ;;
    (*)
        break
        ;;
    esac
    shift
done

# Set the output prefix
#    c-shell:  setenv ENVNAME ...
#    POSIX  :  ENVNAME=...
if [ -n "$shellOutput" ]
then
    case "$shellFlavour" in
    (-csh*) shellOutput="setenv ${shellOutput} " ;;
    (*)     shellOutput="${shellOutput}=" ;;
    esac
fi


# Basic checks
if [ -n "$optEnvName" ]
then
    eval "dirList=\$$optEnvName"
elif [ "$#" -ge 1 ]
then
    dirList="$1"
    shift
else
    die "Requires at least one argument, or use the -env option"
fi

[ -n "$dirList" ] || exit 2     # Quick exit on empty 'dirList'

#-------------------------------------------------------------------------------

# Debugging (optional)
if [ -n "$optDebug" ]
then
    printDebug() { while [ "$#" -ge 1 ]; do echo "$1" 1>&2; shift; done; }
else
    printDebug() { true; }      # No-op
fi

# Optional test for directory existence
if [ -n "$optStrip" ]
then
    isDir() { test -d "$1"; }   # Check for directory existence
else
    isDir() { test -n "$1"; }   # Only check for non-zero string
fi

# The "filter ... filterN" may have been passed as a single parameter
# or may contain ':' separators.
# Currently (OCT-2018) also accept split on whitespace too.

oldIFS="$IFS"       # Preserve initial IFS
IFS=':; '           # Split on colon, semicolon, whitespace
set -- $*

if [ -n "$optVerbose" ]
then
    echo "clean: $dirList" 1>&2
    echo "with:  $@" 1>&2
fi

printDebug "input>$dirList<"

# Apply filters via sed. Path and filter cannot contain '?'.
for filter
do
    case "$filter" in
    ( / | /bin | /sbin | /lib | /lib64 | /opt \
        | /usr | /usr/bin | /usr/sbin | /usr/lib | /usr/lib64 \
        | /usr/local | /usr/local/bin | /usr/local/lib | /usr/local/lib64 )
        # Do not filter out system directories
        printDebug "skip>$filter<"
        ;;

    (*)
        if [ -n "$filter" ]
        then
            printDebug "remove>$filter<"
            dirList=$(echo "$dirList:" | sed -e "s?${filter}[^:]*:??g")
        fi
        ;;
    esac
done
printDebug "intermediate>$dirList<"

IFS=':'             # Split on colon. No split on whitespace.
set -- $dirList

# Rebuild the list
unset dirList
for dir
do
    printDebug "check>$dir< in $dirList"
    if isDir "$dir"
    then
        # Detect duplicates (ie, dir already in the list)
        duplicate=$(echo ":$dirList:" | sed -ne '\?:'"$dir"':?p')

        if [ -n "$duplicate" ]
        then
            printDebug "duplicate>$dir<"
        else
            dirList="${dirList}${dirList:+:}$dir"
        fi
    fi
done

IFS="$oldIFS"       # Restore initial IFS

# Output:
#
# For eval mode, add quotes around the argument.
# - eg,  <. PATH="path1;path2;...">
#
# With regular output, any quoting would be done on the caller side.
# - eg,  <cleaned="($foamClean -env=PATH foo)

printDebug "output>$dirList<"
if [ -n "$optVerbose" ]
then
    echo "output: \"$dirList\"" 1>&2
fi

if [ -n "$shellOutput" ]
then
    echo "$shellOutput\"$dirList\""
else
    echo "$dirList"
fi

#------------------------------------------------------------------------------