set -e
if test -n "$BASH_VERSION"; then set -o posix; fi


# See https://www.gnu.org/prep/standards/html_node/Directory-Variables.html
prefix=/usr/local
exec_prefix='$(PREFIX)'
bindir='$(EXEC_PREFIX)/bin'
verbose=0


main () {
    parseArgs "$@"
    printMakefile > Makefile
}


printHelp () {
    echo ''
    echo "Example usage:   $0 --prefix /usr/local"
    echo ''
    echo 'Options:'
    echo '    --prefix <path>      Default "/usr/local"'
    echo '    --bindir <path>      Default "$(EXEC_PREFIX)/bin"'
    echo ''
}


parseArgs () {
    # See: https://stackoverflow.com/a/14203146/4415884
    while test $# -gt 0 ; do
        case $1 in
            --help)        printHelp; exit 1; ;;
            --prefix)      prefix="$2"      shift; shift; ;;
            --exec_prefix) exec_prefix="$2" shift; shift; ;;
            --bindir)      bindir="$2"      shift; shift; ;;
            --verbose)     verbose="$2"     shift; shift; ;;
            *) echo "[ERROR] Unexpected argument: $1"; exit 1 ;;
        esac
    done
}


printMakefile () {
    printf '\n'
    printf '%s\n' 'CC=gcc'
    printf '%s\n' 'RIMRAF=rm -rf'
    printf '%s\n' 'MKDIRS=mkdir -p'
    printf '%s\n' 'COPYTO=cp -t'
    printf '%s\n' 'NDEBUG=1'

    printf '\n'
    printf '%s\n' "PREFIX=$prefix"
    printf '%s\n' "EXEC_PREFIX=$exec_prefix"
    printf '%s\n' "BINDIR=$bindir"

    printf '\n'
    printf '%s'   'PROJECT_VERSION=$(shell'
    printf '%s'   ' ret=$$(git describe --tags 2>/dev/null |sed -E "s;^v;;");'
    printf '%s'   ' if test -n "$$ret" -a -n "$$(git status --porcelain 2>/dev/null)"; then'
    printf '%s'       ' ret="$$ret+dirt";'
    printf '%s'   ' fi;'
    printf '%s'   ' if test -z "$$ret"; then ret=$$(date -u +0.0.0-%Y%m%d.%H%M%S); fi;'
    printf '%s\n' ' echo "$$ret")'

    if test "$verbose" = "0"; then printf '\n%s\n' '.SILENT:'; fi
    printf '%s\n' '.SUFFIXES:'

    printf '\n'
    printf '%s'   'CFLAGS=--std=c99 -fPIC -Wall -Wextra -Werror -fmax-errors=3'
    printf '%s'   ' -Wno-error=unused-function -Wno-error=unused-label -Wno-error=unused-variable'
    printf '%s'   ' -Wno-error=unused-parameter -Wno-error=unused-const-variable'
    printf '%s'   ' -Wno-error=unused-but-set-variable'
    printf '%s'   ' -Wno-error=discarded-qualifiers -Wno-error=sign-compare -Wno-error=pointer-sign'
    printf '%s'   ' -Wno-error=maybe-uninitialized -Werror=implicit-fallthrough=1'
    printf '%s'   ' -Wno-unused-function -Wno-unused-parameter -Wno-missing-field-initializers'
    printf '%s\n' ' -DPROJECT_VERSION=$(PROJECT_VERSION)'

    printf '\n'
    printf '%s\n' 'LDFLAGS=-Wl,--no-demangle,--fatal-warnings'

    # TODO replace gnumake by $(shell if ..)
    printf '\n'
    printf '%s\n' 'ifndef NDEBUG'
    printf '%s\n' '	CFLAGS := $(CFLAGS) -ggdb -O0 -g3'
    printf '%s\n' 'else'
    printf '%s\n' '	CFLAGS := $(CFLAGS) -ffunction-sections -fdata-sections -Os "-DNDEBUG=1"'
    printf '%s\n' '	LDFLAGS := $(LDFLAGS) -Wl,--gc-sections,--as-needed'
    printf '%s\n' 'endif'

    printf '\n'
    printf '%s\n' 'INCDIRS=-Isrc/main/c'
    printf '%s\n' 'LIBSDIR='

    printf '\n'
    printf '%s\n' '.PHONY: default'
    printf '%s\n' 'default: link dist'

    printf '\n'
    printf '%s\n' '.PHONY: link'
    printf '%s'   'link:'
    printf '%s'   ' build/bin/deflate$(BINEXT)'
    printf '%s\n' ' build/bin/inflate$(BINEXT)'

    printf '%s\n' '.PHONY: clean'
    printf '%s\n' 'clean:'
    printf '%s\n' '	echo "rm -rf build dist"'
    printf '%s\n' '	rm -rf build dist'

    # Create synthetic entrypoints
    printf '%s\n' 'build/link/%.c:'
    printf '%s\n' '	echo "  Gen   $@"'
    printf '%s\n' '	$(MKDIRS) "$(shell T=$@; echo $${T%/*})"'
    printf '%s\n' '	@echo "#include \"commonbase.h\"" >> $@'
    printf '%s\n' '	@echo "int main( int err, char**argv ){" >> $@'
    printf '%s\n' '	@echo "    err = $*(err, argv);" >> $@'
    printf '%s\n' '	@echo "    if( err < 0 ){ err = 0 - err; }" >> $@'
    printf '%s\n' '	@echo "    return (err > 127) ? 1 : err;" >> $@'
    printf '%s\n' '	@echo "}" >> $@'

    printf '%s\n' 'build/link/%.o: build/link/%.c'
    printf '%s\n' '	echo "  CC    $@"'
    printf '%s\n' '	$(MKDIRS) "$(shell T=$@; echo $${T%/*})"'
    printf '%s\n' '	$(CC) -c -o $@ $(CFLAGS) -Wno-implicit-function-declaration build/link/$*.c $(INCDIRS)'

    printf '\n'
    printf '%s\n' 'build/obj/main/%.o: src/main/c/%.c'
    printf '%s\n' '	echo "  CC    $@"'
    printf '%s\n' '	$(MKDIRS) "$(shell T=$@; echo $${T%/*})"'
    printf '%s\n' '	$(CC) -c -o $@ $^ $(CFLAGS) $(INCDIRS)'

    printf '%s'   'build/bin/deflate$(BINEXT):'
    printf '%s'   ' build/obj/main/deflate.o'
    printf '%s\n' ' build/link/deflate_main.o'
    printf '%s\n' '	@echo "  LN    $@"'
    printf '%s\n' '	$(MKDIRS) "$(shell T=$@; echo $${T%/*})"'
    printf '%s\n' '	$(CC) -o $@ $(LDFLAGS) $^ $(INCDIRS) $(LIBSDIR) -Wl,-Bdynamic -lz'

    printf '%s'   'build/bin/inflate$(BINEXT):'
    printf '%s'   ' build/obj/main/inflate.o'
    printf '%s\n' ' build/link/inflate_main.o'
    printf '%s\n' '	echo "  LN    $@"'
    printf '%s\n' '	$(MKDIRS) "$(shell T=$@; echo $${T%/*})"'
    printf '%s\n' '	$(CC) -o $@ $(LDFLAGS) $^ $(INCDIRS) $(LIBSDIR) -Wl,-Bdynamic -lz'

    printf '\n'
    printf '%s\n' '.PHONY: dist'
    printf '%s\n' 'dist: link'
    printf '%s\n' '	echo "  Package"'
    printf '%s\n' '	$(RIMRAF) build/dist-* dist'
    printf '%s\n' '	$(MKDIRS) dist'
                  # Create Executable bundle.
    printf '%s\n' '	$(MKDIRS) build/dist-bin'
    printf '%s\n' '	$(COPYTO) build/dist-bin  README* LICENCE*'
    printf '%s\n' '	$(MKDIRS) build/dist-bin/bin'
    printf '%s\n' '	$(COPYTO) build/dist-bin/bin  build/bin/*'
    printf '%s'   '	(cd build/dist-bin && find . -type f -not -name MD5SUM -exec md5sum -b {} +)'
    printf '%s\n'     ' > build/dist-bin/MD5SUM'
    printf '%s'   '	(cd build/dist-bin && tar --owner=0 --group=0'
    printf '%s\n'     ' -czf "../../dist/DeflateAndInflate-$(PROJECT_VERSION).tgz" *)'
    printf '%s\n' '	echo "" && echo "See '\''./dist/'\'' for result." && echo ""'
    printf '%s'   '	if test -n "$$(git status --porcelain 2>/dev/null)"; then'
    printf '%s'       ' echo "[WARN ] Worktree dirty!"; sleep 2;'
    printf '%s\n' ' fi'

    printf '\n'
    printf '%s\n' '.PHONY: install'
    printf '%s\n' 'install:'
    printf '%s\n' '	$(MKDIRS) "$(BINDIR)"'
    printf '%s\n' '	tar --strip-components=1 -C "$(BINDIR)" -xzf "$(shell ls dist/DeflateAndInflate-*.tgz)" -- bin'
}


main "$@"