getPaper() {
  SERVER_TYPE="Paper Minecraft"

  if [[ -z "${MC_VERSION}" ]]; then
    die "MC_VERSION is required for Paper loader"
  fi

  if [[ -f server.jar ]]; then
    log "Paper server.jar already exists, skipping download."
    return
  fi

  local PAPERMC_URL

  if [[ -n "${PAPER_BUILD}" ]]; then
    log "Fetching Paper build ${PAPER_BUILD} for MC ${MC_VERSION}..."
    local BUILD_DATA
    BUILD_DATA=$(curl -sf --connect-timeout 10 --max-time 30 \
      -H "User-Agent: dockercraft/1.0" \
      "https://fill.papermc.io/v3/projects/paper/versions/${MC_VERSION}/builds") || true

    if [[ -n "$BUILD_DATA" ]]; then
      PAPERMC_URL=$(echo "$BUILD_DATA" | jq -r \
        "map(select(.id == ${PAPER_BUILD})) | .[0].downloads.\"server:default\".url // empty")
    fi

    if [[ -z "$PAPERMC_URL" ]]; then
      die "Paper build ${PAPER_BUILD} not found for MC ${MC_VERSION}"
    fi
  else
    log "Querying PaperMC API for latest stable build of ${MC_VERSION}..."
    local BUILDS_DATA
    BUILDS_DATA=$(curl -sf --connect-timeout 10 --max-time 30 \
      -H "User-Agent: dockercraft/1.0" \
      "https://fill.papermc.io/v3/projects/paper/versions/${MC_VERSION}/builds") || true

    if [[ -z "$BUILDS_DATA" ]]; then
      die "Could not fetch Paper builds for MC ${MC_VERSION}"
    fi

    # Check for API error
    if echo "$BUILDS_DATA" | jq -e '.ok == false' >/dev/null 2>&1; then
      local ERR_MSG
      ERR_MSG=$(echo "$BUILDS_DATA" | jq -r '.message // "Unknown error"')
      die "PaperMC API error: ${ERR_MSG}"
    fi

    PAPERMC_URL=$(echo "$BUILDS_DATA" | jq -r \
      'first(.[] | select(.channel == "STABLE") | .downloads."server:default".url) // empty')

    if [[ -z "$PAPERMC_URL" ]]; then
      die "No stable Paper build found for MC ${MC_VERSION}"
    fi
  fi

  log "Downloading Paper for MC ${MC_VERSION}..."
  curl -fL -o server.jar "$PAPERMC_URL"
  log "Paper for MC ${MC_VERSION} downloaded."
}