TodoList in Elixir using GenServer.

todoList.ex

defmodule TodoList do
  use GenServer

  @moduledoc """
    A TodoList add, list, find, update & remove.
  """
  def start do
    {:ok, state} = GenServer.start_link(__MODULE__, [])
    state
  end

  def add(pid, value) do
    GenServer.cast(pid, {:add, value})
  end

  def list(pid) do
    GenServer.call(pid, :list)
  end

  def find(pid, value) do
    GenServer.call(pid, {:find, value})
  end

  def remove(pid, index) do
    GenServer.call(pid, {:remove, index})
  end

  def complete(pid, value) do
    GenServer.call(pid, {:complete, value})
  end

  # GenServer functions.
  def init(state) do
    {:ok, state}
  end

  def handle_cast({:add, value}, state) do
    obj = %{task: value, status: 0}
    {:noreply, [obj | state]}
  end
  
  def handle_call(:list, _from, state) do
    {:reply, state, state}
  end

  @doc """
  Find task details by name
  """
  def handle_call({:find, value}, _from, state) do
    val = Enum.find(state, fn x -> x.task == value end)
    {:reply, val, state}
  end

  @doc """
  Remove and return the requested task.
  """
  def handle_call({:remove, index}, _from, state) do
    {first, rest} = List.pop_at(state, index)
    {:reply, first, rest}
  end

  @doc """
    Update the specfic task by name to update.
  """
  def handle_call({:complete, value}, _from, state) do
    update = Enum.map(state, &update(&1, value))
    {:reply, update, update}
  end

  defp update(map, val) do
    if(map.task == val) do
      %{map | status: 1}
    else
      map
    end
  end
end