aprs.me/lib/aprsme/cached_queries.ex

defmodule Aprsme.CachedQueries do
  @moduledoc """
  Caching layer for database queries to improve performance
  """

  alias Aprsme.Packet
  alias Aprsme.Packets
  alias Aprsme.Repo

  # 1 minute for frequently changing data
  @cache_ttl_short to_timeout(minute: 1)
  # 1 minute for moderately changing data
  @cache_ttl_medium to_timeout(minute: 1)

  @doc """
  Get recent packets with caching
  """
  def get_recent_packets_cached(opts) do
    cache_key = generate_cache_key("recent_packets", opts)

    case Cachex.get(:query_cache, cache_key) do
      {:ok, result} when not is_nil(result) ->
        result

      _ ->
        result = Packets.get_recent_packets_optimized(opts)
        Cachex.put(:query_cache, cache_key, result, ttl: @cache_ttl_short)
        result
    end
  end

  @doc """
  Get weather packets with caching
  """
  def get_weather_packets_cached(callsign, start_time, end_time, opts) do
    cache_key = generate_cache_key("weather", {callsign, start_time, end_time, opts})

    case Cachex.get(:query_cache, cache_key) do
      {:ok, result} when not is_nil(result) ->
        result

      _ ->
        result = Packets.get_weather_packets(callsign, start_time, end_time, opts)
        Cachex.put(:query_cache, cache_key, result, ttl: @cache_ttl_medium)
        result
    end
  end

  @doc """
  Get packet count with caching
  """
  def get_total_packet_count_cached do
    cache_key = "total_packet_count"

    case Cachex.get(:query_cache, cache_key) do
      {:ok, result} when not is_nil(result) ->
        result

      _ ->
        result = Packets.get_total_packet_count()
        Cachex.put(:query_cache, cache_key, result, ttl: @cache_ttl_medium)
        result
    end
  end

  @doc """
  Get latest packet for callsign with caching
  """
  def get_latest_packet_for_callsign_cached(callsign) do
    cache_key = generate_cache_key("latest_packet", callsign)

    case Cachex.get(:query_cache, cache_key) do
      {:ok, result} when not is_nil(result) ->
        result

      _ ->
        result = Packets.get_latest_packet_for_callsign(callsign)
        # Shorter TTL for latest packets as they change frequently
        Cachex.put(:query_cache, cache_key, result, ttl: @cache_ttl_short)
        result
    end
  end

  @doc """
  Get latest weather packet for callsign with caching.
  Uses the optimized query that checks recent data first.
  """
  def get_latest_weather_packet_cached(callsign) do
    cache_key = generate_cache_key("latest_weather_packet", callsign)

    case Cachex.get(:query_cache, cache_key) do
      {:ok, result} when not is_nil(result) ->
        result

      _ ->
        result = Packets.get_latest_weather_packet(callsign)
        # Cache for 5 minutes since weather updates are less frequent
        Cachex.put(:query_cache, cache_key, result, ttl: @cache_ttl_short)
        result
    end
  end

  @doc """
  Check if a callsign has weather packets with caching.
  Uses exact match for performance.
  """
  def has_weather_packets_cached?(callsign) do
    cache_key = generate_cache_key("has_weather_packets", callsign)

    case Cachex.get(:query_cache, cache_key) do
      {:ok, result} when not is_nil(result) ->
        result

      _ ->
        # Use exact match with proper index instead of ilike
        import Ecto.Query

        query =
          from p in Packet,
            where: p.sender == ^callsign,
            where:
              not is_nil(p.temperature) or not is_nil(p.humidity) or not is_nil(p.pressure) or
                not is_nil(p.wind_speed) or not is_nil(p.wind_direction) or not is_nil(p.rain_1h),
            limit: 1,
            select: true

        result = Repo.exists?(query)
        # Cache for 15 minutes
        Cachex.put(:query_cache, cache_key, result, ttl: @cache_ttl_medium)
        result
    end
  end

  @doc """
  Invalidate cache entries for a specific callsign
  """
  def invalidate_callsign_cache(callsign) do
    # Pattern-based cache invalidation
    patterns = [
      "latest_packet:#{callsign}",
      "latest_weather_packet:#{callsign}",
      "has_weather_packets:#{callsign}",
      "weather:#{callsign}:*"
    ]

    Enum.each(patterns, fn pattern ->
      Cachex.del(:query_cache, pattern)
    end)
  end

  @doc """
  Invalidate all cached queries
  """
  def invalidate_all_cache do
    Cachex.clear(:query_cache)
  end

  @doc """
  Get cache statistics
  """
  def get_cache_stats do
    {:ok, stats} = Cachex.stats(:query_cache)
    stats
  end

  # Private helper functions

  defp generate_cache_key(prefix, data) do
    hash = :erlang.phash2(data)
    "#{prefix}:#{hash}"
  end
end