wip(growth): improve data parsing

1. Fetch common data for all indicators
2. Remove headers during merge

Also, re-generate files.

lib/growth/indicators/download.ex

@@ -247,25 +247,47 @@ defmodule Growth.Indicators.Download do
     end
   end
 
+  @common_header ~w(source gender age_unit age l m s sd3neg sd2neg sd1neg sd0 sd1 sd2 sd3)
+
   def convert([header | rows], gender, url) do
-    age = header |> hd() |> String.downcase()
+    age_unit = header |> hd() |> String.downcase()
 
     fixed_header = header |> tl() |> Enum.map(&String.downcase/1) |> Enum.map(&String.trim/1)
 
     parsed_header = ["source" | ["gender" | ["age_unit" | ["age" | fixed_header]]]]
 
+    # NOTE: (jpd): parsing the rows consist in:
+    # 1. convert row values to decimal
+    # 2. prepend the values url source, gender, and age unit
+    # 3. convert row to keyword list using the parsed header
+    # 4. convert from keyword list to map
+    # 5. fetch common values based on common headers
+    # 6. sort row values based on common headers
     parsed_rows =
-      Enum.map(rows, fn row ->
-        parsed_row = Enum.map(row, &Decimal.new/1)
-
-        [url | [gender | [age | parsed_row]]]
+      rows
+      |> Stream.map(fn row -> Enum.map(row, &Decimal.new/1) end)
+      |> Stream.map(&[url | [gender | [age_unit | &1]]])
+      |> Stream.map(&Enum.zip(parsed_header, &1))
+      |> Stream.map(&Map.new/1)
+      |> Stream.map(&Map.take(&1, @common_header))
+      |> Enum.map(fn row ->
+        Enum.map(@common_header, fn key -> Map.get(row, key) end)
       end)
 
-    [parsed_header | parsed_rows]
+    [@common_header | parsed_rows]
   end
 
   def merge(datum) do
-    Enum.reduce(datum, [], fn data, accum ->
+    datum
+    |> Stream.with_index()
+    |> Stream.map(fn
+      {data, 0} ->
+        data
+
+      {[_ | data], _} ->
+        data
+    end)
+    |> Enum.reduce([], fn data, accum ->
       Enum.concat(accum, data)
     end)
   end