Extract last year's interaction data

lib/mihainator/csv_parser.ex

@@ -1,37 +0,0 @@
-defmodule Mihainator.CSVParser do
-  @moduledoc false
-
-  def start(file) do
-    File.stream!(file)
-    |> CSV.decode!(separator: ?,, headers: true, escape_max_lines: 100)
-    |> Stream.chunk_every(2, 1, :discard)
-    |> Stream.filter(&next_day?/1)
-    |> Stream.map(&extract_data/1)
-    |> Enum.to_list()
-  end
-
-  defp next_day?([%{"posted_at" => current}, %{"posted_at" => next}]) do
-    current =
-      current
-      |> String.to_integer()
-      |> DateTime.from_unix!(:millisecond)
-
-    next =
-      next
-      |> String.to_integer()
-      |> DateTime.from_unix!(:millisecond)
-
-    Date.diff(next, current) == 1
-  end
-
-  defp extract_data([_, %{"isoutbox" => is_out, "posted_at" => posted_at}]) do
-    is_out = is_out == "1"
-
-    posted_at =
-      posted_at
-      |> String.to_integer()
-      |> DateTime.from_unix!(:millisecond)
-
-    [is_out, posted_at]
-  end
-end

lib/mihainator/extractor.ex

@@ -0,0 +1,70 @@
+defmodule Mihainator.Extractor do
+  @moduledoc """
+  This module will take Threema's CSV history file and parse dates / first interaction of day
+  """
+
+  def extract(file) do
+    raw_data = get_raw_data(file)
+
+    {last_date, _} = Enum.at(raw_data, -1)
+    first_date = Date.shift(last_date, year: -1)
+    date_range = Date.range(first_date, last_date)
+
+    interaction_data =
+      raw_data
+      |> Enum.filter(fn {date, _} -> Date.after?(date, first_date) end)
+      |> Map.new()
+      |> get_normalized_interaction_data(date_range)
+
+    %{
+      first_date: first_date,
+      last_date: last_date,
+      interaction_data: interaction_data
+    }
+  end
+
+  defp get_raw_data(file) do
+    File.stream!(file)
+    |> CSV.decode!(separator: ?,, headers: true, escape_max_lines: 100)
+    |> Stream.chunk_every(2, 1, :discard)
+    |> Stream.filter(&next_day?/1)
+    |> Stream.map(&extract_data/1)
+    |> Enum.to_list()
+  end
+
+  defp next_day?([%{"posted_at" => current}, %{"posted_at" => next}]) do
+    current =
+      current
+      |> String.to_integer()
+      |> DateTime.from_unix!(:millisecond)
+
+    next =
+      next
+      |> String.to_integer()
+      |> DateTime.from_unix!(:millisecond)
+
+    Date.diff(next, current) == 1
+  end
+
+  defp extract_data([_, %{"isoutbox" => is_out, "posted_at" => posted_at}]) do
+    is_out = is_out == "1"
+
+    posted_at =
+      posted_at
+      |> String.to_integer()
+      |> DateTime.from_unix!(:millisecond)
+      |> DateTime.to_date()
+
+    {posted_at, is_out}
+  end
+
+  defp get_normalized_interaction_data(date_to_postinfo, date_range) do
+    Enum.map(date_range, fn date ->
+      if Map.has_key?(date_to_postinfo, date) do
+        {date, Map.get(date_to_postinfo, date)}
+      else
+        {date, nil}
+      end
+    end)
+  end
+end

lib/mihainator_web/live/upload_live.ex

@@ -19,7 +19,7 @@ defmodule MihainatorWeb.UploadLive do
   @impl Phoenix.LiveView
   def handle_event("save", _params, socket) do
     consume_uploaded_entries(socket, :history, fn %{path: path}, _entry ->
-      Task.async(fn -> Mihainator.CSVParser.start(path) end)
+      Task.async(fn -> Mihainator.Extractor.extract(path) end)
 
       {:ok, nil}
     end)