feat(growth): load csv indicators into ets tables

lib/growth/indicators/load.ex

@@ -0,0 +1,145 @@
+defmodule Growth.Indicators.Load do
+  @moduledoc """
+  Load local indicators csv files into ets.
+
+  For each measurement an ets table is created, so the system has the following tables:
+
+  * `:arm_circumference_for_age`
+  * `:bmi_for_age`
+  * `:head_circumference_for_age`
+  * `:height_for_age`
+  * `:subscapular_skinfold_for_age`
+  * `:telemetry_handler_table`
+  * `:triceps_skinfold_for_age`
+  * `:weight_for_age`
+  * `:weight_for_height`
+
+  The rows in the csv files are converted to two tuple, representing the a key and value, with the following format:
+
+  * **key**: `{gender, unit, t-value}`
+  * **value**: map with the keys:
+    * l
+    * m
+    * s
+    * sd3neg
+    * sd2neg
+    * sd1neg
+    * sd0
+    * sd1
+    * sd2
+    * sd3
+    * source
+    * category
+
+  """
+
+  @spec all :: [[boolean()]]
+  @doc """
+  Load indicators csv files into their own ets tables.
+  """
+  def all do
+    "priv/growth/indicators/*.csv"
+    |> Path.wildcard()
+    |> Enum.map(&create_ets/1)
+    |> Enum.map(&Task.async(__MODULE__, :load_measure, [&1]))
+    |> Task.await_many()
+  end
+
+  @spec create_ets(String.t()) :: {:atom, String.t()}
+  @doc """
+  Create a public ets table for the csv filename, using the file name as the table name.
+
+  Returns a tuple with table name as an atom and the filename.
+  """
+  def create_ets(filename) do
+    measure = filename |> Path.basename() |> Path.rootname() |> String.to_atom()
+
+    try do
+      :ets.new(measure, [:set, :public, :named_table])
+    rescue
+      _ ->
+        nil
+    end
+
+    {measure, filename}
+  end
+
+  @spec load_measure({:atom, String.t()}) :: [boolean()]
+  @doc """
+  Read, convert, and load a measure/filename into the proper ets table.
+  """
+  def load_measure({measure, filename}) do
+    filename
+    |> read()
+    |> convert()
+    |> load(measure)
+  end
+
+  @spec read(String.t()) :: Enumerable.t()
+  @doc false
+  def read(filename) do
+    filename
+    |> File.stream!()
+    |> IndicatorParser.parse_stream()
+  end
+
+  @spec convert(Enumerable.t()) :: Enumerable.t()
+  @doc false
+  def convert(data) do
+    Stream.map(data, fn [
+                          source,
+                          category,
+                          gender,
+                          unit,
+                          t,
+                          l,
+                          m,
+                          s,
+                          sd3neg,
+                          sd2neg,
+                          sd1neg,
+                          sd0,
+                          sd1,
+                          sd2,
+                          sd3
+                        ] ->
+      converted_t =
+        if unit in ~w(day week month) do
+          as_integer(t)
+        else
+          as_float(t)
+        end
+
+      key = {gender, unit, converted_t}
+
+      value = %{
+        l: as_float(l),
+        m: as_float(m),
+        s: as_float(s),
+        sd3neg: as_float(sd3neg),
+        sd2neg: as_float(sd2neg),
+        sd1neg: as_float(sd1neg),
+        sd0: as_float(sd0),
+        sd1: as_float(sd1),
+        sd2: as_float(sd2),
+        sd3: as_float(sd3),
+        source: source,
+        category: category
+      }
+
+      {key, value}
+    end)
+  end
+
+  @spec load(Enumerable.t(), atom()) :: [boolean()]
+  @doc false
+  def load(data, ets_table) do
+    Enum.map(data, fn {key, value} ->
+      :ets.insert_new(ets_table, {key, value})
+    end)
+  end
+
+  defp as_integer(value), do: value |> Integer.parse() |> elem(0)
+
+  defp as_float(value), do: value |> Float.parse() |> elem(0)
+end