Determine emptier car location and crowding description #677
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lib/content/message/predictions.ex
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| 6 => [ | ||
| train_level: {1, 6} | ||
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Thinking out loud: This could be a place where pattern matching really shines. If we create a list that represents the status of each car, e.g. [:f, :e, :e, :f, :f, :f], we could pattern match against that, along with the number of empty cars, and create a series of cases like: {2, [_, _, _, :f, :f, :f]} -> :front. That gives a nice visual way to express the logic, and would also allow us to fold in the special cases from the code below.
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Hmm yeah that's an interesting idea. I sort of like how the current approach condenses the logic but I can also see that it's a bit more obscure than expressing everything as patterns. Will give it a try and see how it turns out
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| defp get_emptier_location(car_crowding_levels) do | ||
| case car_crowding_levels do |
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@panentheos Let me know what you think of this approach. With the number of cases laid out I find it a little hard to read, but I do like how it simplifies the code in the caller.
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I really like this. It's very dense, but everything is laid out so it's very traceable. Also the simplification of the caller is pretty huge.
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lib/content/message/predictions.ex
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| {2, [:f, :f, _, :f, :f, _]} -> :back | ||
| {2, [:f, :f, _, _, :f, :f]} -> :middle | ||
| {2, [:f, _, :f, _, :f, :f]} -> :middle | ||
| {2, [:f, :f, _, :f, _, :f]} -> :middle |
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Looks like 2 needs case(s) for :front_and_back. Check my logic, but I think we could collapse things a bit by relying on the fact that these are checked in order, so [_, _, :f, :f, _, _] would suffice as long as it came after :front and :back. Similarly, the :middle cases could be handled with just [:f, _, _, _, _, :f] as the last check (or just use a default).
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Ah good catch. I meant to add a default to catch the :front_and_back case but must've skipped it. I think you're right though about collapsing. Will check the logic on that and update the PR and merge if all looks good
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Summary of changes
Asana Ticket: 🟠🧑🤝🧑🔊 Crowding Message Selection Logic
This PR adds logic that calculates the emptier car locations and crowding description. These pieces will later be used to
create the full audio message that will get tagged onto either the Arrival or Approaching message.
The "crowding zone" logic is depicted in this diagram