#----------------------------------*-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
#     have_petsc
#
# Description
#     Detection/setup of PETSC
#
# Requires
#     PETSC_ARCH_PATH
# or  config.sh/petsc
#
# Functions provided
#     have_petsc, no_petsc, echo_petsc, query_petsc, search_petsc
#     hint_petsc
#
# Variables set on success
#     HAVE_PETSC
#     PETSC_ARCH_PATH
#     PETSC_INC_DIR
#     PETSC_LIB_DIR
#
#------------------------------------------------------------------------------
. ${WM_PROJECT_DIR:?}/wmake/scripts/sysFunctions    # General system functions

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

# Reset
no_petsc()
{
    unset HAVE_PETSC PETSC_INC_DIR PETSC_LIB_DIR
}


# Report
echo_petsc()
{
    echo "petsc=${HAVE_PETSC:-false}"
    echo "root=$PETSC_ARCH_PATH"
    echo "include=$PETSC_INC_DIR"
    echo "library=$PETSC_LIB_DIR"
}


# Hint for enabling
hint_petsc()
{
    /bin/cat<<INFORMATION 1>&2
==> petsc not found?

Enable in the OpenFOAM etc/bashrc, define manually or try with the
following (POSIX shell):

    eval \$(foamEtcFile -sh -config petsc -- -force)

==
INFORMATION
}


# On success, return 0 and export variables
# -> HAVE_PETSC, PETSC_INC_DIR, PETSC_LIB_DIR
#
# $1 = prefix (eg, PETSC_ARCH_PATH)
search_petsc()
{
    local warn="==> skip petsc"
    local incName="petsc.h"
    local libName="libpetsc"
    local pkgName="PETSc"

    local prefix="${1:-system}"
    local header library

    # ----------------------------------
    if isNone "$prefix"
    then
        [ -n "$warn" ] && echo "$warn (disabled)"
        return 1
    elif hasAbsdir "$prefix"
    then
        header=$(findFirstFile "$prefix/include/$incName")
        library=$(findExtLib "$libName")
    elif isSystem "$prefix"
    then
        header=$(findSystemInclude -name="$incName")
        prefix=$(sysPrefix "$header")

        # No system header, attempt discovery with pkg-config
        if [ -z "$header" ] && pkg-config --exists "$pkgName" 2>/dev/null
        then
            header=$(pkg-config --cflags-only-I "$pkgName" | sed -e 's/^-[IL]//')
            library=$(pkg-config --libs-only-L "$pkgName" | sed -e 's/^-[IL]//')

            prefix="${header%/*}"     # Basename

            # Artifically adjust names (for later)
            [ -n "$header" ] && header="$header/$incName"
            [ -n "$library" ] && library="$library/$libName"
        fi
    else
        unset prefix
    fi
    # ----------------------------------

    # Header
    [ -n "$header" ] || {
        [ -n "$warn" ] && echo "$warn (no header)"
        return 2
    }

    # Library
    [ -n "$library" ] \
    || library=$(findLibrary -prefix="$prefix" -name="$libName") \
    || {
        [ -n "$warn" ] && echo "$warn (no library)"
        return 2
    }

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

    # TODO: check size of petsc integer vs label, real vs double?

    # OK
    export HAVE_PETSC=true
    export PETSC_ARCH_PATH="$prefix"
    export PETSC_INC_DIR="${header%/*}"     # Basename
    export PETSC_LIB_DIR="${library%/*}"    # Basename
}


# On success, return 0 and export variables
# -> HAVE_PETSC, PETSC_INC_DIR, PETSC_LIB_DIR
have_petsc()
{
    local warn="==> skip petsc"
    local config="config.sh/petsc"
    local file

    # Setup - prefer current environment value? (TDB)
    if [ ! -d "$PETSC_ARCH_PATH" ]
    then
        if file="$("$WM_PROJECT_DIR"/bin/foamEtcFile "$config")"
        then
            . "$file"
        else
            [ -n "$warn" ] && echo "$warn (no $config)"
            return 2
        fi
    fi

    search_petsc "$PETSC_ARCH_PATH"
}


# Query settings
query_petsc()
{
    local config="config.sh/petsc"
    local file

    if file="$("$WM_PROJECT_DIR"/bin/foamEtcFile -mode=o "$config")"
    then
        . "$file"
        _process_query petsc "$PETSC_ARCH_PATH"
    else
        echo "(no $config)" 1>&2
        echo "petsc=unknown"
    fi
}


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

# Reset
no_petsc

# Test/query
case "$1" in
-test)
    have_petsc
    echo_petsc
    ;;
-query)
    query_petsc
    ;;
esac

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