#----------------------------------*-sh-*--------------------------------------
# =========                 |
# \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
#  \\    /   O peration     |
#   \\  /    A nd           | www.openfoam.com
#    \\/     M anipulation  |
#------------------------------------------------------------------------------
#     Copyright (C) 2021 OpenCFD Ltd.
#------------------------------------------------------------------------------
# License
#     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
#
# Script
#     have_eigen
#
# Description
#     Detection/setup of EIGEN (Eigen3)
#
# Expects
#     config.sh/eigen
#
# Functions provided
#     have_eigen, no_eigen, echo_eigen, query_eigen, search_eigen
#
# Variables set on success
#     HAVE_EIGEN
#     EIGEN_INC_DIR
#
#------------------------------------------------------------------------------
. ${WM_PROJECT_DIR:?}/wmake/scripts/sysFunctions    # General system functions

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

# Reset
no_eigen()
{
    unset HAVE_EIGEN EIGEN_INC_DIR EIGEN_LIB_DIR
}


# Report
echo_eigen()
{
    echo "eigen=${HAVE_EIGEN:-false}"
    echo "include=\"$EIGEN_INC_DIR\""
}


# Search
# $1 : prefix (*_ARCH_PATH, system, ...)
#
# On success, return 0 and export variables
# -> HAVE_EIGEN, EIGEN_INC_DIR
search_eigen()
{
    local warn # warn="==> skip eigen"
    local incName="Eigen/Eigen"
    local pkgName="eigen3"
    local sentinel="signature_of_eigen3_matrix_library"

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

    # ----------------------------------
    if isNone "$prefix"
    then
        [ -n "$warn" ] && echo "$warn (disabled)"
        return 1
    elif hasAbsdir "$prefix"
    then
        header=$(findFirstFile "$prefix/include/$incName")
    elif isSystem "$prefix"
    then
        header=$(findSystemInclude -name="eigen3/$incName")

        # No system header, attempt discovery with pkg-config
        if [ -z "$header" ] && pkg-config --exists "$pkgName" 2>/dev/null
        then
            includeDirs=$(pkg-config --cflags-only-I "$pkgName" | sed -e 's/^-[IL]//; s/[ ]-[IL]/ /;')
            header="${includeDirs% *}/$incName"   # First entry (ie, split on space)
        fi
    else
        unset prefix
    fi
    # ----------------------------------

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

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

    header="${header%/*}"   # Strip one-level (include/Eigen/...)

    # OK
    export HAVE_EIGEN=true
    export EIGEN_INC_DIR="${header%/*}"     # Basename
}


# Output as per search_* function
have_eigen()
{
    local warn # warn="==> skip eigen"
    local config="config.sh/eigen"
    local path="$EIGEN_ARCH_PATH"
    local file

    # Setup - current environment if set
    if [ -z "$path" ]
    then
        if file="$("$WM_PROJECT_DIR"/bin/foamEtcFile "$config")"
        then
            . "$file"
            path="$EIGEN_ARCH_PATH"
        fi
    fi

    search_eigen "${path:-system}"
}


# Query settings
query_eigen()
{
    local config="config.sh/eigen"
    local file

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


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

# Reset
no_eigen

# Test/query
case "$1" in
-test)
    have_eigen
    echo_eigen
    ;;
-query)
    query_eigen
    ;;
esac

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