#! /bin/sh

# This is a simple form of make, called as a post_hook from rebar,
# but depending on make for rebar support seemed ... wrong somehow

is_up_to_date () {
    target="$1"
    shift
    test ! -f "$target" && return 1
    for f in "$@"
    do
        test "$f" -nt "$target" && return 1
    done
    return 0
}

# The || exit $? is needed, if sh is a bash, then with some
# versions of bash with -e, execution does not terminte if a
# subshell exits with non-zero exit code

set -e

if [ -d "$REBAR_DEPS_DIR/gpb" ]; then
    # rebar3
    EBIN="$REBAR_DEPS_DIR/gpb/ebin"
    TEST="$REBAR_DEPS_DIR/gpb/test"
    mkdir -p "$EBIN"
else
    # rebar2
    EBIN="./ebin"
    TEST="./test"
fi

is_up_to_date descr_src/gpb_descriptor.erl \
          priv/proto3/google/protobuf/descriptor.proto || \
    ( echo "Compiling descriptor.proto..."
    erl +B -noinput -pa "$EBIN" \
        -I priv/proto3/google/protobuf -o descr_src \
    -modprefix gpb_ \
        -s gpb_compile c descriptor.proto ) || exit $?
is_up_to_date "$EBIN/gpb_descriptor.beam descr_src/gpb_descriptor.erl" || \
    ( echo "Compiling gpb_descriptor.erl..."
    erlc -Idescr_src -Iinclude -o "$EBIN" +debug_info \
        descr_src/gpb_descriptor.erl ) || exit $?
is_up_to_date "$EBIN/gpb_compile_descr.beam" \
    descr_src/gpb_compile_descr.erl \
    descr_src/gpb_descriptor.hrl || \
    ( echo "Compiling gpb_compile_descr.erl..."
    erlc -Idescr_src -Iinclude -o "$EBIN" +debug_info \
    descr_src/gpb_compile_descr.erl ) || exit $?
if [ -d "$TEST" ]; then
    # eg: "rebar3 eunit" or "rebar2 eunit"
    # but not "rebar3 compile"
    # and not when compiling gpb as a dependency, since
    # the test directory does not exist in the hex package.
    is_up_to_date "$TEST/gpb_compile_descr_tests.beam" \
        descr_src/gpb_compile_descr_tests.erl \
        descr_src/gpb_descriptor.hrl || \
        ( echo "Compiling gpb_compile_descr_tests.erl..."
        erlc -Idescr_src -Iinclude -o "$TEST" +debug_info \
        descr_src/gpb_compile_descr_tests.erl ) || exit $?
fi