47 lines
1.3 KiB
Elixir
47 lines
1.3 KiB
Elixir
defmodule TodoList do
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defstruct auto_id: 1, entries: %{}
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def new(), do: %TodoList{}
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def add_entry(todo_list, entry) do
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entry = Map.put(entry, :id, todo_list.auto_id)
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new_entries =
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Map.put(
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todo_list.entries,
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todo_list.auto_id,
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entry
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)
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%TodoList{todo_list | entries: new_entries, auto_id: todo_list.auto_id + 1}
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end
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def entries(todo_list, date) do
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todo_list.entries
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|> Stream.filter(fn {_, entry} -> entry.date == date end)
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|> Enum.map(fn {_, entry} -> entry end)
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end
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def update_entry(todo_list, %{} = new_entry) do
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update_entry(todo_list, new_entry.id, fn _ -> new_entry end)
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end
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def update_entry(todo_list, entry_id, updater_fun) do
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case Map.fetch(todo_list.entries, entry_id) do
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:error ->
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todo_list
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{:ok, old_entry} ->
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old_entry_id = old_entry.id
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# Make sure that the result of the updater is a map and the
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# id remains unchanged.
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new_entry = %{id: ^old_entry_id} = updater_fun.(old_entry)
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new_entries = Map.put(todo_list.entries, new_entry.id, new_entry)
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%TodoList{todo_list | entries: new_entries}
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end
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end
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def delete_entry(todo_list, entry_id) do
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%TodoList{todo_list | entries: Map.delete(todo_list.entries, entry_id)}
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end
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end
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