62 lines
1.8 KiB
Elixir
62 lines
1.8 KiB
Elixir
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defmodule DancingDots.DotGroup do
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# This module is an example of how behaviours can be used in practice.
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# You don't need to read it to solve this exercise.
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# It's here for the curious :)
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@moduledoc """
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Allows applying a list of one or more animations to a group of one or more dots.
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"""
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defstruct [:dots, :animations_with_opts]
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@type t :: %__MODULE__{}
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@doc """
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Creates a new dot group with given dots and an empty list of animations.
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"""
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@spec new([DancingDots.Dot.t()]) :: t()
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def new(dots) do
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%__MODULE__{
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dots: dots,
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animations_with_opts: []
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}
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end
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@doc """
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Validates the given animation module with its given options and adds it to the group.
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"""
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@spec add_animation(t(), module, DancingDots.Animation.opts()) ::
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{:ok, t()} | {:error, DancingDots.Animation.error()}
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def add_animation(dot_group, animation_module, opts) do
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# using Animation's init/1 callback
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init_result = animation_module.init(opts)
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case init_result do
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{:ok, opts} ->
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animations_with_opts = [{animation_module, opts} | dot_group.animations_with_opts]
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dot_group = %{dot_group | animations_with_opts: animations_with_opts}
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{:ok, dot_group}
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{:error, error} ->
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{:error, error}
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end
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end
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@doc """
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Applies the list of animations to all the dots.
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"""
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@spec render_dots(t(), DancingDots.Animation.frame_number()) :: [DancingDots.Dot.t()]
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def render_dots(dot_group, frame_number) do
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%{
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dots: dots,
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animations_with_opts: animations_with_opts
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} = dot_group
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Enum.map(dots, fn dot ->
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Enum.reduce(animations_with_opts, dot, fn {animation_module, opts}, acc ->
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# using Animation's handle_frame/3 callback
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animation_module.handle_frame(acc, frame_number, opts)
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end)
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end)
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end
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end
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