#!/bin/bash
#------------------------------------------------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     |
#   \\  /    A nd           | www.openfoam.com
#    \\/     M anipulation  |
#-------------------------------------------------------------------------------
#   Copyright (C) 2019-2021 OpenCFD Ltd.
#-------------------------------------------------------------------------------
# License
#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
#
# Script
#     wrap-lemon
#
# Usage
#     wrap-lemon [options] [lemon options/args]
#
# Description
#     A wrapper to use lemon compiled with OpenFOAM with the appropriate
#     parser template.
#
#     When called with m4 wrapping, it sets the m4 -I include to have
#     the following:
#     - the directory of the parser.
#     - include/ in the top-level source tree of the current target
#       (eg, src/finiteVolume/include/ when compiling libfiniteVolume)
#     - include/ from OpenFOAM
#
#------------------------------------------------------------------------------

binDir="${WMAKE_BIN:-$WM_PROJECT_DIR/platforms/tools/$WM_ARCH$WM_COMPILER}"
etcDir="${WM_DIR:-$WM_PROJECT_DIR/wmake}/etc"

# Executable and skeleton locations
lemon="${binDir}/lemon"
skel="-T${etcDir}/lempar.c"

printHelp() {
    cat<<USAGE

Usage: ${0##*/} [options] [lemon args/options]

options:
  -header           Generate header only, suppressing other output
  -dry-run          Process m4 only (output on stdout)
  -grammar          Output grammar tables (stdout)
  -no-tmp           Do not retain temporary m4 processed files
  -h, -help         Print the usage

A lemon wrapper using predefined executable and skeleton locations.
Files ending with 'm4' (eg, .lyym4, .lyy-m4) will be filtered through
the m4(1) macro processor and lemon will be called with 'm4' as a macro
definition, which can be used in conditions (%ifdef m4, %ifndef m4)

USAGE
    exit 0  # Clean exit
}

#------------------------------------------------------------------------------
# Parse arguments and options
#------------------------------------------------------------------------------

# Eg, wrap-lemon -header
unset optDryRun optHeader optGrammar optRemoveTmp m4Flags
while [ "$#" -gt 0 ]
do
    case "$1" in
    (-h | -help*)   printHelp ;;

    (-dry-run)      optDryRun=true ;;
    (-head*)        optHeader=true ;;
    (-gram*)        optGrammar=true ;;
    (-no-tmp)       optRemoveTmp=true ;;

    (*) break ;;
    esac
    shift
done


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

# Additional m4Flags (for includes etc)
#
# $1 : path-qualified name of the parser
#
# Set includes accordingly to
# - the directory containing the parser
# - include/ in the top-level source tree of the current target
# - include/ from OpenFOAM

defineM4Flags()
{
    # Always include the directory containing the parser file
    m4Flags="$m4Flags${m4Flags:+ }-I$(dirname ${1:-.})"

    local proj="$WM_PROJECT_DIR/src/${WM_PROJECT:-OpenFOAM}"
    local curr="$PWD"

    # Called from the Makefile (PWD contains the parser source)
    # or from elsewhere (eg, createCode)?
    if [ ! -f "$curr/Make/options" ]
    then
        # No Make/options (eg createCode) - discover with "wmake -pwd"
        curr="$(wmake -pwd 2>/dev/null)"
    fi

    # Avoid examining twice
    [ "$curr" != "$proj" ] || unset curr

    if [ -n "$curr" ] && [ -d "$curr/include" ]
    then
        m4Flags="$m4Flags -I$curr/include"
    fi

    if [ -n "$proj" ] && [ -d "$proj/include" ]
    then
        m4Flags="$m4Flags -I$proj/include"
    fi
}


#------------------------------------------------------------------------------
# Get some information based on the lemon options
# * '-dXX' for the output directory
# * '-eXX' for the output extension
# The last argument is the input file

unset tmpDir tmpFile outputDir parser extCode
findLemonOptions()
{
    while [ "$#" -gt 1 ]
    do
        case "$1" in
        (-d*) outputDir="${1#-d}" ;;
        (-e*) extCode="${1#-e}" ;;
        esac
        shift
    done

    if [ "$#" -eq 1 ]
    then
        parser="$1"
    fi
}

findLemonOptions "$@"

unset parserFlags extParser usingM4

# Detect m4 use (defines parser macro too) and get extension without m4
case "$parser" in
(*.*m4)
    usingM4=true
    parserFlags="-Dm4"
    defineM4Flags "$parser"

    extParser=".${parser##*.}"      # The extension (with dot)
    extParser="${extParser%m4}"     # Without trailing m4
    extParser="${extParser/%[-_]/}" # Without - or _ separators
    ;;
esac

if [ -n "$optGrammar" ]
then
    parserFlags="${parserFlags}${parserFlags:+ }-g"
fi


exitCode=0  # No failures

#------------------------------------------------------------------------------
# Dry-run

if [ "$optDryRun" = true ]
then
    if [ "$usingM4" = true ]
    then
        echo "m4 flags: $m4Flags" 1>&2
        m4 $m4Flags "$parser"; exitCode=$?
    else
        echo "Nothing to do - not using m4" 2>/dev/null
    fi
    [ "$exitCode" -eq 0 ] || echo "m4 failed" 2>/dev/null
    exit "$exitCode"  # Done
fi


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

unset tmpFile tmpDir

if [ -n "$optHeader" ]
then
    ## echo "${0##*/} : generate header" 1>&2

    # Drop last argument (the parser input file)
    set -- "${@:1:${#}-1}"

    # Header only, which means we create a temp directory for the output
    tmpDir="lemonWrapper-$$"
    rm -rf "$tmpDir" 2>/dev/null
    mkdir "$tmpDir" 2>/dev/null

    trap 'rm -rf $tmpDir; exit $exitCode' EXIT TERM INT

    if [ "$usingM4" = true ]
    then
        # Using m4 - redirect to a temporary file
        tmpFile="$tmpDir/${parser##*/}"
        tmpFile="${tmpFile%.*}$extParser"   # Eg, from .lyy-m4 -> .lyy

        if m4 $m4Flags "$parser" > "$tmpFile" && [ -f "$tmpFile" ]
        then
            parser="$tmpFile"
        else
            echo "m4 stage failed on $parser" 2>/dev/null
            exitCode=1
        fi
    fi

    if [ "$exitCode" -eq 0 ]
    then
        "$lemon" "$skel" "-d$tmpDir" "$@" $parserFlags "$parser"
        exitCode=$?
    fi

    if [ "$exitCode" -eq 0 ]
    then
        for src in "$tmpDir"/*.h
        do
            dst="${src##*/}"
            if [ -f "$src" ]
            then
                if ! cmp "$src" "$dst" 2>/dev/null
                then
                    mv "$src" "$dst"
                    echo "Updating $dst" 1>&2
                fi
            fi
        done
    fi

elif [ "$usingM4" = true ]
then
    ## echo "${0##*/} : generate code (with m4 filtering)" 1>&2

    # Drop last argument (the parser input file)
    set -- "${@:1:${#}-1}"

    # Filter via m4
    if [ -n "$outputDir" ]
    then
        tmpFile="$outputDir/${parser##*/}"
    else
        tmpFile="${parser}"
    fi
    tmpFile="${tmpFile%.*}$extParser"   # Eg, from .lyy-m4 -> .lyy

    if [ -n "$optRemoveTmp" ]
    then
        trap 'rm -f $tmpFile; exit $exitCode' EXIT TERM INT
    fi

    if m4 $m4Flags "$parser" > "$tmpFile" && [ -f "$tmpFile" ]
    then
        "$lemon" "$skel" "$@" $parserFlags "$tmpFile"
        exitCode=$?
    else
        echo "m4 stage failed on $parser" 2>/dev/null
        exitCode=1
    fi

    if [ -z "$optRemoveTmp" ]
    then
        echo 2>/dev/null
        echo "Retaining intermediate: $tmpFile" 2>/dev/null
    fi

else

    # No special handling
    ## echo "${0##*/} : generate code" 1>&2

    "$lemon" "$skel" "$@"
    exitCode=$?
fi


exit "$exitCode"   # Exit with lemon return code

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