#----------------------------------*-sh-*--------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     |
#   \\  /    A nd           | www.openfoam.com
#    \\/     M anipulation  |
#------------------------------------------------------------------------------
#     Copyright (C) 2018-2020 OpenCFD Ltd.
#------------------------------------------------------------------------------
# License
#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
#
# Script
#     sysFunctions
#
# Description
#     General system helper functions
#
# Functions provided
#     isNone, isSystem, isAbsdir, hasAbsdir
#     isDarwin, isWindows
#     findFirstFile
#     findLibrary
#     findExtLib
#     versionCompare
#
# Internal variables used
#     extLibraries
#
#------------------------------------------------------------------------------

if [ -z "$WMAKE_SCRIPTS_SYSFUNCTIONS" ]
then
    # Load once, but do not rely on this variable elsewhere
    WMAKE_SCRIPTS_SYSFUNCTIONS=loaded

    # True if OS is Darwin.
    isDarwin()
    {
        test Darwin = "$(uname -s 2>/dev/null)"
    }

    # True if target OS is Windows
    # Uses cached value from libso extension
    isWindows()
    {
        test MSwindows = "$WM_OSTYPE"
    }

    # Static, dynamic library extensions
    extLibraries=".a .so"

    if isDarwin
    then
        extLibraries=".a .dylib"
    elif isWindows
    then
        extLibraries=".a .dll .dll.a"  # including cross-compiling
    fi


    # True if '$1' begins with '/'
    isAbsdir()
    {
        test "$1" = "/${1#/}"
    }


    # True if '$1' begins with '/' and also exists as a directory
    hasAbsdir()
    {
        test "$1" = "/${1#/}" -a -d "$1"
    }


    # True if '$1' is an empty string, "none" or ends in "-none"
    # Eg,
    #    if isNone "$BOOST_ARCH_PATH" ...
    isNone()
    {
        test -z "$1" -o "${1##*-}" = none
    }


    # True if '$1' is "system" or ends in "-system"
    # Eg,
    #    if isSystem "$BOOST_ARCH_PATH"
    isSystem()
    {
        test "${1##*-}" = system
    }


    # Return system prefix (/usr, /usr/local, ...) based on hint provided
    # Eg,
    #    sysPrefix "/usr/local/include/fftw3.h"  -> "/usr/local"
    #
    # Without a hint, echoes "/usr"
    sysPrefix()
    {
        case "$1" in
        /usr/local/*)
            echo "/usr/local"
            ;;
        *)
            echo "/usr"
            ;;
        esac
    }


    # Check existence of any of the files
    # On success, echoes the file found and returns 0, otherwise returns 2
    findFirstFile()
    {
        local file

        for file
        do
            if [ -f "$file" ] && [ -r "$file" ]
            then
                echo "$file"  # Found
                return 0
            fi
        done
        return 2
    }


    # Check existence of library with ending '.a', '.so' ...
    #
    # On success, echoes the resolved file and returns 0, otherwise returns 2
    findLibrary()
    {
        local file ext

        for file
        do
            [ -n "$file" ] || continue
            for ext in '' $extLibraries
            do
                if [ -f "$file$ext" ] && [ -r "$file$ext" ]
                then
                    echo "$file$ext"  # Found
                    return 0
                fi
            done
        done

        return 2
    }


    # Check existence of library in FOAM_EXT_LIBBIN, but conditional
    # on FOAM_EXT_LIBBIN being located in the ThirdParty directory
    #
    # On success, echoes the resolved file and returns 0, otherwise returns 2
    findExtLib()
    {
        local file

        if [ -n "$FOAM_EXT_LIBBIN" ] && \
           [ -n "$WM_THIRD_PARTY_DIR" ] && \
           [ "${FOAM_EXT_LIBBIN#$WM_THIRD_PARTY_DIR}" != "$FOAM_EXT_LIBBIN" ]
        then
            for file
            do
                if file="$(findLibrary "$FOAM_EXT_LIBBIN/$file")"
                then
                    echo "$file"
                    return 0
                fi
            done
        fi

        return 2
    }


    # Compare version tuples with syntax similar to POSIX shell,
    # but respecting dot separators.
    #
    # arg1 OP arg2
    #   OP is one of -eq, -ne, -lt, -le, -gt, or -ge.
    #   Returns true for a successful comparison.
    #   Arg1 and arg2 normally comprise positive integers, but leading content
    #   before a '-' is stripped.
    #   Missing digits are treated as '0'.
    #
    # Eg,
    #    versionCompare "software-1.2.3" -gt 1.1 && echo True
    #
    # Ad hoc handling of "git" version as always newest.
    #    "git" -gt "1.2.3" : True
    #    "1.2.3" -lt "git" : True
    versionCompare()
    {
        [ "$#" -eq 3 ] || {
            echo "Compare needs 3 arguments (was given $#)" 1>&2
            return 2
        }

        local arg1="${1#*-}"    # Strip leading prefix-
        local op="${2}"
        local arg2="${3#*-}"    # Strip leading prefix-
        local result=''         # Empty represents 'equal'

        arg1="${arg1:-0}."
        arg2="${arg2:-0}."

        if   [ "$arg1" = "$arg2" ];        then unset arg1 arg2 # Identical
        elif [ "${arg1#git}" != "$arg1" ]; then result='more'   # (git > arg2)
        elif [ "${arg2#git}" != "$arg2" ]; then result='less'   # (arg1 < git)
        fi

        while [ -z "$result" ] && [ -n "${arg1}${arg2}" ]
        do
            local digits1="${arg1%%.*}"
            local digits2="${arg2%%.*}"

            arg1="${arg1#*.}"
            arg2="${arg2#*.}"

            : "${digits1:=0}"
            : "${digits2:=0}"

            # Other handling of non-integer values?
            if   [ "$digits1" -lt "$digits2" ]; then result='less'
            elif [ "$digits1" -gt "$digits2" ]; then result='more'
            fi
        done

        case "$op" in
        (-eq | eq)  [ -z "$result" ] ;;
        (-ne | ne)  [ -n "$result" ] ;;
        (-lt | lt)  [ 'less' = "$result" ] ;;
        (-gt | gt)  [ 'more' = "$result" ] ;;
        (-le | le)  [ 'less' = "${result:-less}" ] ;;
        (-ge | ge)  [ 'more' = "${result:-more}" ] ;;
        (*)
            echo "Unknown operator: '$op'" 1>&2
            return 2
            ;;
        esac
    }
fi


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