# lib/moldb_web/live/search_live.ex
defmodule MoldbWeb.SearchLive do
  use MoldbWeb, :live_view
  alias Moldb.Search
  alias Moldb.RateLimiter

  @per_page 20
  @default_filters %{}

  @impl true
  def mount(_params, _session, socket) do
    {:ok,
     assign(socket,
       results: [],
       query: "",
       page: 1,
       per_page: @per_page,
       rate_limit_state: RateLimiter.init_state(),
       filters: @default_filters,
       loading: false
     )}
  end

  @impl true
  def handle_params(params, _url, socket) do
    {:noreply, apply_action(socket, socket.assigns.live_action, params)}
  end

  defp apply_action(socket, :index, _params) do
    assign(socket, :page_title, "Search Molecular Database")
  end

  @impl true
  def handle_event("load_more", _, socket) do
    %{query: query, page: page, per_page: per_page, filters: filters} = socket.assigns
    
    socket =
      case Search.execute_search(query, page + 1, per_page, filters) do
        {:ok, new_results} ->
          assign(socket,
            results: socket.assigns.results ++ new_results,
            page: page + 1,
            loading: false
          )

        {:error, :rate_limit_exceeded} ->
          put_flash(socket, :error, "Rate limit exceeded. Please wait before trying again.")

        {:error, _reason} ->
          put_flash(socket, :error, "Unable to load more results. Please try again later.")
      end

    {:noreply, socket}
  end

  @impl true
  def handle_event("apply_filter", %{"filter" => filter}, socket) do
    new_filters = Map.merge(socket.assigns.filters, filter)
    {:noreply, assign(socket, filters: new_filters)}
  end

  @impl true
  def handle_info({:search, query}, socket) do
    socket =
      case Search.execute_search(query, 1, socket.assigns.per_page, socket.assigns.filters) do
        {:ok, results} ->
          assign(socket, results: results, query: query, page: 1, loading: false)

        {:error, :rate_limit_exceeded} ->
          put_flash(socket, :error, "Rate limit exceeded. Please wait before trying again.")

        {:error, _reason} ->
          put_flash(socket, :error, "Search is temporarily unavailable. Please try again later.")
      end

    {:noreply, socket}
  end
end

# lib/moldb_web/live/components/search_component.ex
defmodule MoldbWeb.SearchComponent do
  use MoldbWeb, :live_component
  alias Moldb.Search

  @suggestion_limit 5
  @debounce_ms 300

  @impl true
  def render(assigns) do
    ~H"""
    <div>
      <form phx-submit="search" phx-target={@myself} class="relative">
        <div class="relative">
          <input type="text"
                 name="query"
                 value={@query}
                 placeholder="Search for compounds or substances..."
                 autocomplete="off"
                 phx-keyup="suggest"
                 phx-debounce={@debounce_ms}
                 phx-target={@myself}
                 class="w-full p-4 pr-12 text-sm border-gray-200 rounded-lg shadow-sm focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
          />
          <button type="submit" class="absolute inset-y-0 right-0 px-4 text-gray-600 hover:text-blue-600">
            <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke-width="1.5" stroke="currentColor" class="w-5 h-5">
              <path stroke-linecap="round" stroke-linejoin="round" d="M21 21l-5.197-5.197m0 0A7.5 7.5 0 105.196 5.196a7.5 7.5 0 0010.607 10.607z" />
            </svg>
          </button>
        </div>

        <%= if @suggestions != [] do %>
          <div class="absolute z-10 w-full mt-2 bg-white border border-gray-200 rounded-lg shadow-lg">
            <%= for suggestion <- @suggestions do %>
              <div class="px-4 py-2 cursor-pointer hover:bg-gray-100" phx-click="select_suggestion" phx-value-query={suggestion} phx-target={@myself}>
                <%= suggestion %>
              </div>
            <% end %>
          </div>
        <% end %>
      </form>
    </div>
    """
  end

  @impl true
  def update(assigns, socket) do
    {:ok, assign(socket, query: assigns[:query] || "", suggestions: [])}
  end

  @impl true
  def handle_event("suggest", %{"value" => query}, socket) when byte_size(query) >= 2 do
    suggestions = Search.suggest(query, @suggestion_limit)
    {:noreply, assign(socket, suggestions: suggestions, query: query)}
  end

  @impl true
  def handle_event("suggest", _params, socket), do: {:noreply, assign(socket, suggestions: [])}

  @impl true
  def handle_event("search", %{"query" => query}, socket) do
    send(self(), {:search, query})
    {:noreply, assign(socket, query: query, suggestions: [])}
  end

  @impl true
  def handle_event("select_suggestion", %{"query" => query}, socket) do
    {:noreply, assign(socket, query: query, suggestions: [])}
  end
end

# lib/moldb/search.ex
defmodule Moldb.Search do
  @moduledoc """
  Handles all search-related functionality for the Moldb application.
  """

  import Ecto.Query
  alias Moldb.Repo
  alias Moldb.Compounds.{Compound, Substance}
  alias Moldb.RateLimiter

  @type search_result :: %{
    type: String.t(),
    id: integer(),
    name: String.t(),
    description: String.t()
  }

  @spec execute_search(String.t(), integer(), integer(), map()) :: {:ok, [search_result()]} | {:error, atom()}
  def execute_search(query, page, per_page, filters) when is_binary(query) and is_integer(page) and is_integer(per_page) do
    case RateLimiter.check_rate_limit() do
      :ok ->
        results = search(query, page, per_page, filters)
        {:ok, results}
      {:error, :rate_limit_exceeded} = error ->
        error
    end
  end

  @spec search(String.t(), integer(), integer(), map()) :: [search_result()]
  defp search(query, page, per_page, filters) do
    offset = (page - 1) * per_page

    [
      search_schema(Compound, :iupac_name, query, filters),
      search_schema(Substance, :substance_name, query, filters)
    ]
    |> Task.async_stream(&(&1), max_concurrency: 2, timeout: 15_000)
    |> Stream.flat_map(fn {:ok, results} -> results end)
    |> Enum.sort_by(&rank(&1, query), :desc)
    |> Enum.slice(offset, per_page)
  end

  @spec suggest(String.t(), integer()) :: [String.t()]
  def suggest(query, limit) when is_binary(query) and is_integer(limit) do
    [
      suggest_schema(Compound, :iupac_name, query),
      suggest_schema(Substance, :substance_name, query)
    ]
    |> Task.async_stream(&(&1), max_concurrency: 2, timeout: 5_000)
    |> Stream.flat_map(fn {:ok, suggestions} -> suggestions end)
    |> Enum.sort_by(&String.jaro_distance(&1, query), :desc)
    |> Enum.take(limit)
  end

  defp search_schema(schema, field, query, filters) do
    base_query(schema, field, query)
    |> apply_filters(filters)
    |> select_search_fields(schema, field)
    |> Repo.all()
  end

  defp suggest_schema(schema, field, query) do
    base_suggestion_query(schema, field, query)
    |> Repo.all()
  end

  defp base_query(schema, field, query) do
    from(s in schema,
      where: fragment("? %> ?", field(s, ^field), ^query),
      order_by: [desc: fragment("similarity(?, ?)", field(s, ^field), ^query)])
  end

  defp apply_filters(query, filters) do
    Enum.reduce(filters, query, fn {key, value}, acc ->
      where(acc, ^[{key, value}])
    end)
  end

  defp select_search_fields(query, schema, field) do
    type = schema |> Module.split() |> List.last() |> String.downcase()
    query
    |> select([s], %{
      type: ^type,
      id: s.id,
      name: field(s, ^field),
      description: fragment("LEFT(?, 100)", s.description)
    })
  end

  defp base_suggestion_query(schema, field, query) do
    from(s in schema,
      where: fragment("? %> ?", field(s, ^field), ^query),
      select: field(s, ^field),
      order_by: [desc: fragment("similarity(?, ?)", field(s, ^field), ^query)],
      limit: 100)
  end

  defp rank(%{type: type, name: name}, query) do
    base_score = if type == "compound", do: 1.0, else: 0.8
    String.jaro_distance(name, query) * base_score
  end
end

# lib/moldb/compounds.ex
defmodule Moldb.Compounds do
  @moduledoc """
  The Compounds context.
  """

  import Ecto.Query, warn: false
  alias Moldb.Repo
  alias Moldb.Compounds.{Compound, Substance}

  @doc """
  Returns the list of compounds.

  ## Examples

      iex> list_compounds()
      [%Compound{}, ...]

  """
  def list_compounds(opts \\ []) do
    Compound
    |> maybe_preload(opts[:preload])
    |> Repo.all()
  end

  @doc """
  Gets a single compound.

  Raises `Ecto.NoResultsError` if the Compound does not exist.

  ## Examples

      iex> get_compound!(123)
      %Compound{}

      iex> get_compound!(456)
      ** (Ecto.NoResultsError)

  """
  def get_compound!(id, opts \\ []) do
    Compound
    |> maybe_preload(opts[:preload])
    |> Repo.get!(id)
  end

  @doc """
  Gets a single compound with all associated data.

  Raises `Ecto.NoResultsError` if the Compound does not exist.

  ## Examples

      iex> get_compound_with_assocs!(123)
      %Compound{}

      iex> get_compound_with_assocs!(456)
      ** (Ecto.NoResultsError)

  """
  def get_compound_with_assocs!(id) do
    Compound
    |> Repo.get!(id)
    |> Repo.preload([:spectra, :properties, :external_identifiers, :predicted_properties])
  end

  @doc """
  Creates a compound.

  ## Examples

      iex> create_compound(%{field: value})
      {:ok, %Compound{}}

      iex> create_compound(%{field: bad_value})
      {:error, %Ecto.Changeset{}}

  """
  def create_compound(attrs \\ %{}) do
    %Compound{}
    |> Compound.changeset(attrs)
    |> Repo.insert()
  end

  @doc """
  Updates a compound.

  ## Examples

      iex> update_compound(compound, %{field: new_value})
      {:ok, %Compound{}}

      iex> update_compound(compound, %{field: bad_value})
      {:error, %Ecto.Changeset{}}

  """
  def update_compound(%Compound{} = compound, attrs) do
    compound
    |> Compound.changeset(attrs)
    |> Repo.update()
  end

  @doc """
  Deletes a compound.

  ## Examples

      iex> delete_compound(compound)
      {:ok, %Compound{}}

      iex> delete_compound(compound)
      {:error, %Ecto.Changeset{}}

  """
  def delete_compound(%Compound{} = compound) do
    Repo.delete(compound)
  end

  @doc """
  Returns an `%Ecto.Changeset{}` for tracking compound changes.

  ## Examples

      iex> change_compound(compound)
      %Ecto.Changeset{data: %Compound{}}

  """
  def change_compound(%Compound{} = compound, attrs \\ %{}) do
    Compound.changeset(compound, attrs)
  end

  @doc """
  Returns the list of substances.

  ## Examples

      iex> list_substances()
      [%Substance{}, ...]

  """
  def list_substances(opts \\ []) do
    Substance
    |> maybe_preload(opts[:preload])
    |> Repo.all()
  end

  @doc """
  Gets a single substance.

  Raises `Ecto.NoResultsError` if the Substance does not exist.

  ## Examples

      iex> get_substance!(123)
      %Substance{}

      iex> get_substance!(456)
      ** (Ecto.NoResultsError)

  """
  def get_substance!(id, opts \\ []) do
    Substance
    |> maybe_preload(opts[:preload])
    |> Repo.get!(id)
  end

  @doc """
  Creates a substance.

  ## Examples

      iex> create_substance(%{field: value})
      {:ok, %Substance{}}

      iex> create_substance(%{field: bad_value})
      {:error, %Ecto.Changeset{}}

  """
  def create_substance(attrs \\ %{}) do
    %Substance{}
    |> Substance.changeset(attrs)
    |> Repo.insert()
  end

  @doc """
  Updates a substance.

  ## Examples

      iex> update_substance(substance, %{field: new_value})
{:ok, %Substance{}}

      iex> update_substance(substance, %{field: bad_value})
      {:error, %Ecto.Changeset{}}

  """
  def update_substance(%Substance{} = substance, attrs) do
    substance
    |> Substance.changeset(attrs)
    |> Repo.update()
  end

  @doc """
  Deletes a substance.

  ## Examples

      iex> delete_substance(substance)
      {:ok, %Substance{}}

      iex> delete_substance(substance)
      {:error, %Ecto.Changeset{}}

  """
  def delete_substance(%Substance{} = substance) do
    Repo.delete(substance)
  end

  @doc """
  Returns an `%Ecto.Changeset{}` for tracking substance changes.

  ## Examples

      iex> change_substance(substance)
      %Ecto.Changeset{data: %Substance{}}

  """
  def change_substance(%Substance{} = substance, attrs \\ %{}) do
    Substance.changeset(substance, attrs)
  end

  @doc """
  Returns the name of a compound.
  """
  def compound_name(%Compound{} = compound), do: compound.iupac_name || "Unknown"

  @doc """
  Returns the name of a substance.
  """
  def substance_name(%Substance{} = substance), do: substance.substance_name || "Unknown"

  defp maybe_preload(query, nil), do: query
  defp maybe_preload(query, preloads), do: from(q in query, preload: ^preloads)
end

# lib/moldb/rate_limiter.ex
defmodule Moldb.RateLimiter do
  @moduledoc """
  Implements a token bucket algorithm for rate limiting.
  """

  use GenServer

  @rate_limit_interval_ms 1000
  @rate_limit_max_requests 5

  def start_link(_opts) do
    GenServer.start_link(__MODULE__, %{}, name: __MODULE__)
  end

  def init_state do
    GenServer.call(__MODULE__, :init_state)
  end

  def check_rate_limit do
    GenServer.call(__MODULE__, :check_rate_limit)
  end

  @impl true
  def init(_) do
    {:ok, %{last_reset: System.monotonic_time(:millisecond), tokens: @rate_limit_max_requests}}
  end

  @impl true
  def handle_call(:init_state, _from, state) do
    {:reply, state, state}
  end

  @impl true
  def handle_call(:check_rate_limit, _from, state) do
    now = System.monotonic_time(:millisecond)
    {new_tokens, last_reset} = refill_tokens(state.tokens, state.last_reset, now)

    if new_tokens > 0 do
      new_state = %{tokens: new_tokens - 1, last_reset: last_reset}
      {:reply, :ok, new_state}
    else
      {:reply, {:error, :rate_limit_exceeded}, state}
    end
  end

  defp refill_tokens(tokens, last_reset, now) do
    elapsed = now - last_reset
    new_tokens = min(tokens + div(elapsed, @rate_limit_interval_ms), @rate_limit_max_requests)
    last_reset = if new_tokens > tokens, do: now, else: last_reset
    {new_tokens, last_reset}
  end
end

# lib/moldb_web/templates/search_live.html.heex
<div class="max-w-2xl mx-auto p-6">
  <h1 class="text-3xl font-bold mb-6 text-center text-gray-800">Molecular Database Search</h1>
  
  <.live_component module={MoldbWeb.SearchComponent} id="search" query={@query} />
  
  <div id="search-results" class="space-y-4 mt-8">
    <%= if Enum.empty?(@results) do %>
      <p class="text-center text-gray-600">No results found. Try a different search term.</p>
    <% else %>
      <%= for result <- @results do %>
        <div class="result bg-white p-4 rounded-lg shadow hover:shadow-md transition-shadow duration-200 ease-in-out cursor-pointer"
             phx-click="navigate"
             phx-value-id={result.id}
             phx-value-type={result.type}>
          <h3 class="text-lg font-semibold text-gray-800 mb-2"><%= result.name %></h3>
          <p class="text-sm text-gray-600"><%= result.description %></p>
          <span class="inline-block mt-2 px-2 py-1 text-xs font-semibold text-gray-700 bg-gray-200 rounded-full">
            <%= String.capitalize(result.type) %>
          </span>
        </div>
      <% end %>
    <% end %>
  </div>

  <%= if length(@results) >= @page * @per_page do %>
    <div class="mt-4 text-center">
      <button phx-click="load_more" class="px-4 py-2 bg-blue-500 text-white rounded hover:bg-blue-600 transition-colors" disabled={@loading}>
        Load More
      </button>
    </div>
  <% end %>
</div>

Refactor Elixir code from a Phoenix LiveView web app to meet enterprise standards, ensuring it is suitable for large-scale, high-traffic environments. Adhere strictly to Elixir, Phoenix, and Ecto documentation, while applying industry best practices for systems operating at a Google-scale level. Provide complete updated code.
1. Efficiency & Performance:
* Optimize for low latency, high throughput, and resource efficiency.
* Use the most performant data structures and algorithms.
* Refactor Ecto queries to eliminate N+1 issues and reduce database load, ensuring composability and efficient data retrieval.
2. Scalability & Robustness:
* Refactor for horizontal scalability and seamless concurrency, leveraging BEAM's strengths.
* Ensure fault tolerance and resilience, maintaining system stability without bottlenecks or downtime under high load.
3. SOLID & DRY Principles:
* Enforce SOLID principles to ensure modular, maintainable, and extensible code.
* Apply DRY principles to eliminate redundancy, simplifying codebase maintenance.
* Minimize state management complexity for clarity and maintainability.
4. Minimizing Overhead:
* Remove unnecessary abstractions and reduce CPU, memory, and I/O overhead.
* Ensure lightweight, efficient processes.
5. Integration & Consistency:
* Maintain consistent logic, structure, and style across the codebase.
* Enforce strict typing where applicable to enhance safety and integrity.
6. No Third-Party Dependencies:
* Refactor without introducing third-party tools or libraries.
* Avoid reliance on caching or indexes, ensuring performance gains come from efficient code, queries, and data structures.
7. Security & Maintainability:
* Follow security best practices to prevent vulnerabilities like injection attacks and race conditions.
* Ensure the codebase is easy to understand, test, and extend, prioritizing long-term maintainability.