elixir-todo-list/lib/todo/list.ex

43 lines
1.1 KiB
Elixir

defmodule Todo.List do
defstruct entries: %{}, next_id: 1
def new(entries \\ []) do
Enum.reduce(entries, %__MODULE__{}, &add(&2, &1))
end
def add(
%__MODULE__{entries: entries, next_id: next_id} = todo_list,
%{date: _, title: _} = entry
) do
new_entry = Map.put(entry, :id, next_id)
new_entries = Map.put(entries, next_id, new_entry)
%__MODULE__{todo_list | entries: new_entries, next_id: next_id + 1}
end
def entries(%__MODULE__{} = todo_list, date) do
todo_list.entries
|> Map.filter(fn {_, entry} -> entry.date == date end)
|> Map.values()
end
def update(%__MODULE__{entries: entries} = todo_list, id, update_fun)
when is_function(update_fun, 1) do
case Map.fetch(entries, id) do
:error ->
todo_list
{:ok, entry} ->
new_entry = update_fun.(entry)
new_entries = Map.put(entries, id, new_entry)
%__MODULE__{todo_list | entries: new_entries}
end
end
def delete(%__MODULE__{entries: entries} = todo_list, id) when is_number(id) do
new_entries = Map.delete(entries, id)
%__MODULE__{todo_list | entries: new_entries}
end
end