#!/bin/sh

trap "rm -f conftest* core a.out; exit 1" 1 2 3 15

prefix="${prefix-/usr/local}"
exec_prefix="${exec_prefix-\$(prefix)}"
bindir="${bindir-\$(exec_prefix)/bin}"
mandir="${mandir-\$(prefix)/man}"
man1dir="${man1dir-\$(mandir)/man1}"

cc="${CC-gcc}"
#cc="${CC-clang}"
#cc="${CC-c99}"
cflags="$CFLAGS"

enable_debug=0

with_system_libpng=0
with_system_zlib=0

with_preconfigured_libpng=1
with_preconfigured_zlib=0

for arg in "$@"
do
    case "$arg" in
    -- )
        option="$arg"
        ;;
    --* )
        option=`expr "X$arg" : 'X-\(.*\)'`
        ;;
    * )
        option="$arg"
        ;;
    esac
    case "$arg" in
    *=* )
        optarg=`expr "X$arg" : 'X[^=]*=\(.*\)'`
        ;;
    * )
        optarg=""
        ;;
    esac
    case "$option" in
    -help | -hel | -he | -h )
        echo "Usage:"
        echo "    $0 [options]"
        echo "Options:"
        echo "    -h, -help               Show this help"
        echo "Installation directories:"
        echo "    -prefix=PREFIX          Install architecture-independent files in PREFIX"
        echo "                            [default: $prefix]"
        echo "    -exec-prefix=EPREFIX    Install architecture-dependent files in EPREFIX"
        echo "                            [default: PREFIX]"
        echo "    -bindir=DIR             Install executable in DIR [default: EPREFIX/bin]"
        echo "    -mandir=DIR             Install manual in DIR [default: PREFIX/man]"
        echo "Optional features:"
        echo "    -enable-debug           Enable debug build flags and run-time checks"
        echo "Optional packages:"
        echo "    -with-system-libpng     Use the system-supplied libpng"
        echo "                            [default: false]"
        echo "    -with-system-zlib       Use the system-supplied zlib"
        echo "                            [default: with-system-libpng]"
        echo "Environment variables:"
        echo "    CC                      C compiler command"
        echo "    LD                      Linker command"
        echo "    CFLAGS                  C compiler flags (e.g. -O3)"
        echo "    CPPFLAGS                C preprocessor flags (e.g. -I DIR)"
        echo "    LDFLAGS                 Linker flags (e.g. -L DIR)"
        echo "    LIBS                    Additional libraries (e.g. -lfoo)"
        exit 0
        ;;
    -prefix | -prefi | -pref | -pre | -pr | -p )
        prefix="$2"
        shift
        ;;
    -prefix=* | -prefi=* | -pref=* | -pre=* | -pr=* | -p=* )
        prefix="$optarg"
        ;;
    -exec-prefix | -exec_prefix | -exec-prefi | -exec_prefi \
    | -exec-pref |  -exec_pref | -exec-pre | -exec_pre \
    | -exec-pr | -exec_pr | -exec-p | -exec_p | exec- | -exec_ \
    | -exec | -exe | -ex | -e )
        exec_prefix="$2"
        shift
        ;;
    -exec-prefix=* | -exec_prefix=* | -exec-prefi=* | -exec_prefi=* \
    | -exec-pref=* |  -exec_pref=* | -exec-pre=* | -exec_pre=* \
    | -exec-pr=* | -exec_pr=* | -exec-p=* | -exec_p=* | exec-=* | -exec_=* \
    | -exec=* | -exe=* | -ex=* | -e=* )
        exec_prefix="$optarg"
        ;;
    -bindir | -bindi | -bind | -bin | -bi | -b )
        bindir="$2"
        shift
        ;;
    -bindir=* | -bindi=* | -bind=* | -bin=* | -bi=* | -b=* )
        bindir="$optarg"
        ;;
    -mandir | -mandi | -mand | -man | -ma | -m )
        mandir="$2"
        shift
        ;;
    -mandir=* | -mandi=* | -mand=* | -man=* | -ma=* | -m=* )
        mandir="$optarg"
        ;;
    -enable-debug )
        enable_debug=1
        ;;
    -disable-debug )
        enable_debug=0
        ;;
    -with-system-libpng )
        with_system_libpng=1
        # Must use the system-supplied zlib with the system-supplied libpng.
        with_system_zlib=1
        ;;
    -without-system-libpng )
        with_system_libpng=0
        ;;
    -with-system-zlib )
        with_system_zlib=1
        ;;
    -without-system-zlib )
        with_system_zlib=0
        # Can't use the system-supplied libpng without the system-supplied zlib.
        with_system_libpng=0
        ;;
    * )
        echo "error: unknown option: $arg"
        echo "Type \"$0 -help\" for help"
        exit 64  # EX_USAGE
        ;;
    esac
done

if test "$with_system_libpng" -ne 0
then
    sed_config_libpng="
        s:@USE_SYSTEM_LIBPNG_TRUE@::g
        s:@USE_SYSTEM_LIBPNG_FALSE@:#:g
    "
else
    sed_config_libpng="
        s:@USE_SYSTEM_LIBPNG_FALSE@::g
        s:@USE_SYSTEM_LIBPNG_TRUE@:#:g
    "
fi

if test "$with_system_zlib" -ne 0
then
    sed_config_zlib="
        s:@USE_SYSTEM_ZLIB_TRUE@::g
        s:@USE_SYSTEM_ZLIB_FALSE@:#:g
    "
else
    sed_config_zlib="
        s:@USE_SYSTEM_ZLIB_FALSE@::g
        s:@USE_SYSTEM_ZLIB_TRUE@:#:g
    "
    case `uname -s` in
    mingw* | MINGW* | windows* | WINDOWS* )
        with_preconfigured_zlib=1
        sed_config_zlib="
            $sed_config_zlib
            s:@ZLIB_MK@:win32/Makefile.gcc:g
            /MAKE.*ZLIB_MK/ s:distclean:clean:
        "
        ;;
    esac
fi

test=conftest$$
cat > $test.c <<EOM
int hello() { return 42; }
EOM

gccish=0
case "$cc" in
*gcc* | *clang* )
    echo "Checking for $cc..."
    if ($cc -c $cflags $test.c) 2>/dev/null
    then
        gccish=1
    fi
    ;;
esac

rm -f $test.c $test.o

if test $gccish -ne 0
then
    CC="${CC-$cc}"
    CFLAGS="${CFLAGS--O2 -Wall -Wextra}"
else
    CC="${CC-cc}"
    CFLAGS="${CFLAGS--O}"
fi

if test $enable_debug -ne 0
then
    CPPFLAGS="$CPPFLAGS -DDEBUG -D_DEBUG"
    CFLAGS="$CFLAGS -g"
    LDFLAGS="$LDFLAGS -g"
fi

if test $with_system_libpng -eq 0
then
    if test "$with_preconfigured_libpng" -ne 0
    then
        echo "Using pre-configured libpng..."
        if test $gccish -ne 0
        then
            sed_config_libpng="
                $sed_config_libpng
                s:@LIBPNG_MK@:scripts/makefile.gcc:g
            "
        else
            sed_config_libpng="
                $sed_config_libpng
                s:@LIBPNG_MK@:scripts/makefile.std:g
            "
        fi
    else
        echo "Configuring libpng..."
        (cd src/libpng && ./configure)
        if test $? -ne 0
        then
            echo "error: could not configure: libpng"
            exit 1
        fi
    fi
else
    echo "Checking for system libpng..."
    test=conftest$$
cat > $test.c <<EOM
#include <png.h>
#if PNG_LIBPNG_VER < 10209
#error This program requires libpng version 1.2.9 or higher
#endif
int dummy;
EOM
    ($CC -c $CPPFLAGS $CFLAGS $test.c) 2>/dev/null
    status=$?
    rm -f $test.c $test.o
    if test $status -ne 0
    then
        echo "error: missing libpng or incorrect libpng version"
        echo "note: libpng version 1.2.9 or higher is required"
        exit 1
    fi
fi

if test $with_system_zlib -eq 0
then
    if test "$with_preconfigured_zlib" -ne 0
    then
        echo "Using pre-configured zlib..."
    else
        echo "Configuring zlib..."
        (cd src/zlib && ./configure --static)
        if test $? -ne 0
        then
            echo "error: could not configure: zlib"
            exit 1
        fi
    fi
else
    echo "Checking for system zlib..."
    test=conftest$$
cat > $test.c <<EOM
#include <zlib.h>
#if ZLIB_VERNUM < 0x1210
#error This program requires zlib version 1.2.1 or higher.
#endif
int dummy;
EOM
    ($CC -c $CPPFLAGS $CFLAGS $test.c) 2>/dev/null
    status=$?
    rm -f $test.c $test.o
    if test $status -ne 0
    then
        echo "error: missing zlib or incorrect zlib version"
        echo "note: zlib version 1.2.1 or higher is required"
        exit 1
    fi
fi

sed_config="
    $sed_config_libpng
    $sed_config_zlib
    s#@prefix@#$prefix#g
    s#@exec_prefix@#$exec_prefix#g
    s#@bindir@#$bindir#g
    s#@mandir@#$mandir#g
    s#@man1dir@#$man1dir#g
    s#@CC@#${CC-cc}#g
    s#@CFLAGS@#${CFLAGS--O}#g
    s#@CPP@#${CPP-\$(CC) -E}#g
    s#@CPPFLAGS@#${CPPFLAGS-}#g
    s#@LD@#${LD-\$(CC)}#g
    s#@LDFLAGS@#${LDFLAGS--s}#g
    s#@AR@#${AR-ar}#g
    s#@ARFLAGS@#${ARFLAGS-cru}#g
    s#@RANLIB@#${RANLIB-ranlib}#g
    s#@LIBS@#${LIBS-}#g
    s#@LIBM@#${LIBM--lm}#g
    s#@LIBZ@#${LIBZ--lz}#g
    s#@LIBPNG@#${LIBPNG--lpng}#g
    s#@DIFF@#${DIFF-diff -b -u}#g
    s#@RM_F@#${RM_F-rm -f}#g
    s#@[A-Z]*_MK@#Makefile#g
    s# *\$##
"

for makefile in \
    ./Makefile \
    src/Makefile \
    src/gifread/Makefile \
    src/minitiff/Makefile \
    src/opngreduc/Makefile \
    src/optipng/Makefile \
    src/optipng/man/Makefile \
    src/pngxtern/Makefile \
    src/pnmio/Makefile
do
    sed "$sed_config" $makefile.in > $makefile
done