elixir-todo-list/todo_list.ex

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Elixir
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2024-08-03 08:51:48 +02:00
defmodule TodoServer do
def start(entries \\ []) do
spawn(fn -> loop(TodoList.new(entries)) end)
end
def from_list(todo_list) do
spawn(fn -> loop(todo_list) end)
end
defp loop(todo_list) do
new_todo_list =
receive do
message ->
process_message(todo_list, message)
after
1000 -> todo_list
end
loop(new_todo_list)
end
defp process_message(todo_list, {:add, entry}) do
TodoList.add(todo_list, entry)
end
defp process_message(todo_list, {:entries, sender, date}) do
entries = TodoList.entries(todo_list, date)
send(sender, {:entries, entries})
todo_list
end
defp process_message(todo_list, {:update, id, update_fun}) do
TodoList.update(todo_list, id, update_fun)
end
defp process_message(todo_list, {:delete, id}) do
TodoList.delete(todo_list, id)
end
defp process_message(todo_list, invalid_message) do
IO.puts("Invalid message: #{IO.inspect(invalid_message)}")
todo_list
end
def add(pid, entry) do
send(pid, {:add, entry})
nil
end
def entries(pid, date) do
send(pid, {:entries, self(), date})
receive do
{:entries, value} ->
{:ok, value}
after
1000 -> {:error}
end
end
def update(pid, id, update_fun) do
send(pid, {:update, id, update_fun})
nil
end
def delete(pid, id) do
send(pid, {:delete, id})
nil
end
end
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defmodule TodoList 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
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def entries(%__MODULE__{} = todo_list, date) do
todo_list.entries
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|> 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
defmodule TodoList.CSVImporter do
def import(path) do
path
|> File.stream!()
|> Stream.map(&parse_line/1)
|> TodoList.new()
end
defp parse_line(line) do
line
|> String.trim()
|> String.split(",")
|> create_entry()
end
defp create_entry([date, title]) do
final_date = parse_date(date)
%{date: final_date, title: title}
end
defp parse_date(string) do
[year, month, day] = string |> String.split("-") |> Enum.map(&String.to_integer/1)
Date.new!(year, month, day)
end
end