#!/usr/bin/env bash
# Builds the mod jar into build/libs/.
#
# Gradle 8.12 cannot run on a JDK newer than 23, and a distro's default java is
# often newer than that, so this picks a JDK Gradle can run on rather than
# leaving you to read the "Type T not present" failure that comes of not doing
# so. The build itself still compiles against Java 21 either way - that is the
# toolchain in build.gradle, and Gradle provisions it if it is missing.
set -euo pipefail

cd "$(dirname "$0")"

# Major version of the java at $1/bin/java, or nothing if it will not run.
java_major() {
    local out
    out=$("$1/bin/java" -version 2>&1) || return 0
    sed -n 's/^[^"]*"\([0-9]*\).*/\1/p' <<<"$out" | head -1
}

usable() {
    local major
    [ -x "$1/bin/java" ] || return 1
    major=$(java_major "$1")
    [ -n "$major" ] && [ "$major" -ge 17 ] && [ "$major" -le 23 ]
}

if [ -z "${JAVA_HOME:-}" ] || ! usable "$JAVA_HOME"; then
    for candidate in /usr/lib/jvm/java-{21,17}-openjdk /usr/lib/jvm/java-{21,17}-openjdk-amd64; do
        if usable "$candidate"; then
            export JAVA_HOME="$candidate"
            break
        fi
    done
fi

if [ -z "${JAVA_HOME:-}" ] || ! usable "$JAVA_HOME"; then
    echo "build.sh: no JDK between 17 and 23 found - Gradle 8.12 cannot run on anything newer." >&2
    echo "Install one (e.g. pacman -S jdk17-openjdk) or point JAVA_HOME at it." >&2
    exit 1
fi

echo "build.sh: using JDK $(java_major "$JAVA_HOME") at $JAVA_HOME"
./gradlew build "$@"

# Name the jar this run produced. Old versions linger in build/libs/, so listing
# the whole directory would be ambiguous about which one is current.
prop() { sed -n "s/^$1=//p" gradle.properties; }
jar="build/libs/$(prop mod_id)-$(prop mod_version).jar"

echo
if [ -f "$jar" ]; then
    echo "Built: $jar"
else
    echo "build.sh: expected $jar, but it is not there." >&2
    exit 1
fi