javaVersionDetect() {
  if [[ -n "${JAVA_VERSION:-}" ]]; then
    return
  fi

  log "Auto-detecting Java version from Mojang manifest..."

  local MANIFEST
  MANIFEST=$(curl -sf --connect-timeout 10 --max-time 30 \
    "https://launchermeta.mojang.com/mc/game/version_manifest.json") || true
  if [[ -z "$MANIFEST" ]]; then
    warn "Could not fetch Mojang manifest, defaulting to temurin@21"
    JAVA_VERSION="temurin@21"
    return
  fi

  local VERSION_URL
  VERSION_URL=$(echo "$MANIFEST" | jq -r ".versions[] | select(.id == \"${MC_VERSION}\") | .url")
  if [[ -z "$VERSION_URL" || "$VERSION_URL" == "null" ]]; then
    warn "Version ${MC_VERSION} not found in manifest, defaulting to temurin@21"
    JAVA_VERSION="temurin@21"
    return
  fi

  local VERSION_DATA
  VERSION_DATA=$(curl -sf --connect-timeout 10 --max-time 30 "$VERSION_URL") || true
  if [[ -z "$VERSION_DATA" ]]; then
    warn "Could not fetch version data for ${MC_VERSION}, defaulting to temurin@21"
    JAVA_VERSION="temurin@21"
    return
  fi

  local JAVA_MAJOR
  JAVA_MAJOR=$(echo "$VERSION_DATA" | jq -r ".javaVersion.majorVersion // empty")
  if [[ -z "$JAVA_MAJOR" ]]; then
    JAVA_VERSION="temurin@8"
  else
    JAVA_VERSION="temurin@${JAVA_MAJOR}"
  fi
  log "Detected Java version: ${JAVA_VERSION}"
}

javaCheck() {
  javaVersionDetect

  JAVA_HOME="/data/java/${JAVA_VERSION}"
  if [[ -f "$HOME/.jabba/jabba.sh" ]]; then
    # shellcheck disable=SC1090
    source "$HOME/.jabba/jabba.sh"
  else
    die "Jabba not found at ~/.jabba/jabba.sh — installation may have failed"
  fi

  if [[ ! -f "/data/java/${JAVA_VERSION}/bin/java" ]]; then
    log "Installing Java ${JAVA_VERSION}..."
    rm -rf "/data/java/${JAVA_VERSION}"
    jabba install "${JAVA_VERSION}" -o "/data/java/${JAVA_VERSION}"
    log "Java ${JAVA_VERSION} installed."
  else
    log "Java ${JAVA_VERSION} already cached."
  fi
  PATH="${JAVA_HOME}/bin:$PATH"
  JAVA="java"
}