#! /bin/bash

################################################################################
# Prepare
################################################################################

# Set up shell
#set -x                          # Output commands
set -e                          # Abort on errors


if [ -z "${LIBPNG_DIR}" ]; then
    echo "BEGIN MESSAGE"
    echo "LIBPNG selected, but LIBPNG_DIR not set.  Checking some places..."
    echo "END MESSAGE"
    
    FILES="include/png.h"
    DIRS="/usr /usr/local ${HOME}"
    for dir in $DIRS; do
        LIBPNG_DIR="$dir"
        for file in $FILES; do
            if [ ! -r "$dir/$file" ]; then
                unset LIBPNG_DIR
                break
            fi
        done
        if [ -n "$LIBPNG_DIR" ]; then
            break
        fi
    done
    
    if [ -z "$LIBPNG_DIR" ]; then
        echo "BEGIN MESSAGE"
        echo "LIBPNG not found"
        echo "END MESSAGE"
    else
        echo "BEGIN MESSAGE"
        echo "Found LIBPNG in ${LIBPNG_DIR}"
        echo "END MESSAGE"
    fi
fi

################################################################################
# Build
################################################################################

if [ -z "${LIBPNG_DIR}" -o "${LIBPNG_DIR}" = 'BUILD' ]; then
    echo "BEGIN MESSAGE"
    echo "Building libpng..."
    echo "END MESSAGE"

    # Set locations
    THORN=libpng
    NAME=libpng-1.5.8
    SRCDIR=$(dirname $0)
    BUILD_DIR=${SCRATCH_BUILD}/build/${THORN}
    INSTALL_DIR=${SCRATCH_BUILD}/external/${THORN}
    DONE_FILE=${SCRATCH_BUILD}/done/${THORN}
    LIBPNG_DIR=${INSTALL_DIR}

(
    exec >&2                    # Redirect stdout to stderr
    set -x                      # Output commands
    set -e                      # Abort on errors
    cd ${SCRATCH_BUILD}
    if [ -e ${DONE_FILE} -a ${DONE_FILE} -nt ${SRCDIR}/dist/${NAME}.tar.gz \
                         -a ${DONE_FILE} -nt ${SRCDIR}/libpng.sh ]
    then
        echo "libpng: The enclosed libpng library has already been built; doing nothing"
    else
        echo "libpng: Building enclosed libpng library"
        
        # Should we use gmake or make?
        MAKE=$(gmake --help > /dev/null 2>&1 && echo gmake || echo make)
        # Should we use gtar or tar?
        TAR=$(gtar --help > /dev/null 2> /dev/null && echo gtar || echo tar)
        
        # Set up environment
        unset LIBS

        echo "libpng: Preparing directory structure..."
        mkdir build external done 2> /dev/null || true
        rm -rf ${BUILD_DIR} ${INSTALL_DIR}
        mkdir ${BUILD_DIR} ${INSTALL_DIR}

        echo "libpng: Unpacking archive..."
        pushd ${BUILD_DIR}
        ${TAR} xzf ${SRCDIR}/dist/${NAME}.tar.gz

        echo "libpng: Configuring..."
        cd ${NAME}
        ./configure --prefix=${LIBPNG_DIR} --with-zlib=${ZLIB_DIR}
        
        echo "libpng: Building..."
        ${MAKE}
        
        echo "libpng: Installing..."
        ${MAKE} install
        popd
        
        echo "libpng: Cleaning up..."
        rm -rf ${BUILD_DIR}

        date > ${DONE_FILE}
        echo "libpng: Done."
    fi
)

    if (( $? )); then
        echo 'BEGIN ERROR'
        echo 'Error while building libpng.  Aborting.'
        echo 'END ERROR'
        exit 1
    fi
fi



################################################################################
# Configure Cactus
################################################################################

# Set options
LIBPNG_INC_DIRS="${LIBPNG_DIR}/include"
LIBPNG_LIB_DIRS="${LIBPNG_DIR}/lib"
LIBPNG_LIBS='png'

# Pass options to Cactus
echo "BEGIN MAKE_DEFINITION"
echo "HAVE_LIBPNG     = 1"
echo "LIBPNG_DIR      = ${LIBPNG_DIR}"
echo "LIBPNG_INC_DIRS = ${LIBPNG_INC_DIRS}"
echo "LIBPNG_LIB_DIRS = ${LIBPNG_LIB_DIRS}"
echo "LIBPNG_LIBS     = ${LIBPNG_LIBS}"
echo "END MAKE_DEFINITION"

echo 'INCLUDE_DIRECTORY $(LIBPNG_INC_DIRS)'
echo 'LIBRARY_DIRECTORY $(LIBPNG_LIB_DIRS)'
echo 'LIBRARY           $(LIBPNG_LIBS)'