Add store rates robustness (#34)

This removes the window and always uses the closest price but emails
when the gap is over five days.

It closes #31.

Author: backspace

lib/mix/tasks/store_rates.ex

@@ -6,8 +6,7 @@ defmodule Mix.Tasks.StoreRates do
   alias PrisonRideshare.Repo
   alias PrisonRideshareWeb.{GasPrice, Ride}
   alias PrisonRideshare.CalculateRatesFromGasPrice
-
-  alias Timex.Duration
+  alias PrisonRideshare.Email
 
   import Ecto.Query
 
@@ -28,17 +27,30 @@ defmodule Mix.Tasks.StoreRates do
     gas_prices = Repo.all(GasPrice, order_by: :inserted_at)
 
     Enum.each(rides, fn ride ->
-      window_before_ride_start = Timex.subtract(ride.start, Duration.from_days(1))
-
-      window_after_ride_start = Timex.add(ride.start, Duration.from_days(1))
+      # Choose the nearest gas price by proximity to start time
 
       closest_gas_price =
-        Enum.find(gas_prices, fn gas_price ->
-          Timex.after?(gas_price.inserted_at, window_before_ride_start) &&
-            Timex.before?(gas_price.inserted_at, window_after_ride_start)
-        end)
+        case gas_prices do
+          [] ->
+            nil
+
+          _ ->
+            Enum.min_by(gas_prices, fn gp ->
+              abs(Timex.diff(gp.inserted_at, ride.start, :seconds))
+            end)
+        end
 
       if closest_gas_price do
+        # send a warning if the assigned gas price is 5 days or more from the ride start
+        diff_seconds =
+          Timex.diff(closest_gas_price.inserted_at, ride.start, :seconds)
+          |> abs()
+
+        if diff_seconds >= 5 * 24 * 60 * 60 do
+          Email.store_rates_gap_warning_report(ride, closest_gas_price)
+          |> PrisonRideshare.Mailer.deliver_now()
+        end
+
         rate =
           if ride.institution.far,
             do: CalculateRatesFromGasPrice.far_rate(closest_gas_price),

lib/prison_rideshare_web/email.ex

@@ -69,6 +69,34 @@ defmodule PrisonRideshare.Email do
     )
   end
 
+  def store_rates_gap_warning_report(ride, gas_price) do
+    diff_seconds =
+      Timex.diff(gas_price.inserted_at, ride.start, :seconds)
+      |> abs()
+
+    gap_days = div(diff_seconds, 86_400)
+
+    body =
+      [
+        "Gas price assignment gap warning: the gas price assigned to a ride is #{gap_days} days apart from the ride start, is archival broken?",
+        "",
+        "Ride ID: #{ride.id}",
+        "Visitor: #{ride.name}",
+        "Ride start: #{ride.start}",
+        "Assigned gas price timestamp: #{gas_price.inserted_at}",
+        "Gap: #{gap_days} days"
+      ]
+      |> Enum.join("\n")
+
+    new_email(
+      to: ["barnone.coordinator+gap+warning@gmail.com", "bot@barnonewpg.org"],
+      from: {"Bar None Bot", "bot@barnonewpg.org"},
+      subject: "Gas price assignment gap warning",
+      html_body: body,
+      text_body: body
+    )
+  end
+
   defp format_gas_price_failure_reason(:missing_value), do: "missing pageFunctionResult"
   defp format_gas_price_failure_reason(:invalid_number), do: "invalid number format"
   defp format_gas_price_failure_reason(:invalid_format), do: "invalid response format"

test/mix/tasks/store_rates_test.exs

@@ -1,6 +1,7 @@
 defmodule Mix.Tasks.StoreRatesTest do
   use ExUnit.Case
   use PrisonRideshareWeb.ConnCase
+  use Bamboo.Test
 
   alias PrisonRideshare.Repo
 
@@ -22,7 +23,7 @@ defmodule Mix.Tasks.StoreRatesTest do
         inserted_at: NaiveDateTime.from_erl!({{2018, 6, 24}, {16, 37, 0}})
       })
 
-    other_price =
+    ancient_price =
       Repo.insert!(%GasPrice{
         price: 5,
         inserted_at: NaiveDateTime.from_erl!({{2017, 1, 1}, {0, 0, 0}})
@@ -40,6 +41,16 @@ defmodule Mix.Tasks.StoreRatesTest do
         far: true
       })
 
+    _ancient_ride =
+      Repo.insert!(%Ride{
+        start: NaiveDateTime.from_erl!({{2017, 2, 2}, {11, 0, 0}}),
+        institution: close_institution,
+        end: NaiveDateTime.from_erl!({{2017, 2, 2}, {12, 0, 0}}),
+        address: "address",
+        contact: "contact",
+        name: "name"
+      })
+
     _old_ride =
       Repo.insert!(%Ride{
         start: NaiveDateTime.from_erl!({{2018, 5, 23}, {11, 0, 0}}),
@@ -95,7 +106,7 @@ defmodule Mix.Tasks.StoreRatesTest do
       Repo.insert!(%Ride{
         start: NaiveDateTime.from_erl!({{2018, 6, 28}, {11, 0, 0}}),
         institution: far_institution,
-        gas_price: other_price,
+        gas_price: ancient_price,
         end: NaiveDateTime.from_erl!({{2018, 6, 28}, {12, 0, 0}}),
         address: "address",
         contact: "contact",
@@ -116,6 +127,7 @@ defmodule Mix.Tasks.StoreRatesTest do
     Mix.Tasks.StoreRates.run([])
 
     [
+      ancient,
       old,
       yesterday,
       zero_rate_ride,
@@ -129,7 +141,10 @@ defmodule Mix.Tasks.StoreRatesTest do
       |> preload(:gas_price)
       |> Repo.all()
 
-    refute old.gas_price
+    assert ancient.gas_price.id == ancient_price.id
+
+    assert old.gas_price.id == yesterday_price.id
+    assert old.rate == ~M[23]
 
     assert yesterday.gas_price.id == yesterday_price.id
     assert yesterday.rate == ~M[23]
@@ -140,14 +155,24 @@ defmodule Mix.Tasks.StoreRatesTest do
     assert today.gas_price.id == today_price.id
     assert today.rate == ~M[20]
 
-    refute tomorrow.gas_price
+    assert tomorrow.gas_price.id == today_price.id
+    assert tomorrow.rate == ~M[20]
 
-    assert already_set_gas_price.gas_price.id == other_price.id
+    assert already_set_gas_price.gas_price.id == ancient_price.id
     refute already_set_rate.gas_price
 
-    [yesterday_version, _zero_version, _today_version] = Repo.all(PaperTrail.Version)
-    assert yesterday_version.event == "update"
-    assert yesterday_version.origin == "StoreRates"
-    assert yesterday_version.item_id == yesterday.id
+    ancient_version = hd(Repo.all(PaperTrail.Version))
+
+    assert ancient_version.event == "update"
+    assert ancient_version.origin == "StoreRates"
+    assert ancient_version.item_id == ancient.id
+
+    assert_delivered_email(
+      PrisonRideshare.Email.store_rates_gap_warning_report(ancient, ancient_price)
+    )
+
+    assert_delivered_email(
+      PrisonRideshare.Email.store_rates_gap_warning_report(old, yesterday_price)
+    )
   end
 end