File System Todo

Mix.install([
  {:jason, "~> 1.4"},
  {:kino, "~> 0.8.0", override: true},
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"}
])

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Overview

You’re going to create a TodoList application with persistence using a file system.

Example Solution

defmodule TodoList do
  @storage "todolist"

  def list do
    case File.read(@storage) do
      {:ok, list} -> :erlang.binary_to_term(list)
      # other operations will create the storage if it does not yet exist.
      _ -> []
    end
  end

  def add(item) do
    new_list = [item | list()]
    File.write(@storage, :erlang.term_to_binary(new_list))
  end

  def complete(item) do
    new_list = list() -- [item]
    File.write(@storage, :erlang.term_to_binary(new_list))
  end
end

Implement the TodoList module as documented. You may choose any file for your persistence mechanism.

defmodule TodoList do
  @moduledoc """
  Documentation for `TodoList`
  """
  @doc """
  Retrieve the persistent todo list.

  ## Examples

      iex> TodoList.list()
      []
  """
  def list do
  end

  @doc """
  Add an item to our persistent todo list.

  ## Examples

      iex> TodoList.add("finish homework")
      iex> TodoList.list()
      ["finish homework"]
      
      iex> TodoList.add("task 1")
      iex> TodoList.add("task 2")
      iex> TodoList.list()
      ["task 2", "task 1"]
  """
  def add(item) do
  end

  @doc """
  Complete (remove) and item from the persistent todo list.

  ## Examples

      iex> TodoList.add("finish homework")
      iex> TodoList.complete("finish homework")
      iex> TodoList.list()
      []
  """
  def complete(item) do
  end
end

Mark As Completed

file_name = Path.basename(Regex.replace(~r/#.+/, __ENV__.file, ""), ".livemd")

save_name =
  case Path.basename(__DIR__) do
    "reading" -> "file_system_todo_app_reading"
    "exercises" -> "file_system_todo_app_exercise"
  end

progress_path = __DIR__ <> "/../progress.json"
existing_progress = File.read!(progress_path) |> Jason.decode!()

default = Map.get(existing_progress, save_name, false)

form =
  Kino.Control.form(
    [
      completed: input = Kino.Input.checkbox("Mark As Completed", default: default)
    ],
    report_changes: true
  )

Task.async(fn ->
  for %{data: %{completed: completed}} <- Kino.Control.stream(form) do
    File.write!(
      progress_path,
      Jason.encode!(Map.put(existing_progress, save_name, completed), pretty: true)
    )
  end
end)

form

Commit Your Progress

Run the following in your command line from the curriculum folder to track and save your progress in a Git commit. Ensure that you do not already have undesired or unrelated changes by running git status or by checking the source control tab in Visual Studio Code.

$ git checkout -b file-system-todo-app-exercise
$ git add .
$ git commit -m "finish file system todo app exercise"
$ git push origin file-system-todo-app-exercise

Create a pull request from your file-system-todo-app-exercise branch to your solutions branch. Please do not create a pull request to the DockYard Academy repository as this will spam our PR tracker.

DockYard Academy Students Only:

Notify your teacher by including @BrooklinJazz in your PR description to get feedback. You (or your teacher) may merge your PR into your solutions branch after review.

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