hey_jude.exs

defmodule HeyJude do
    @lines [["make it bad", "be afraid", "let me down"], ["Take a sad song and make it better", "You were made to go out and get her", "You have found her, now go and get her"]]

    def lyrics do
        [intro]
        |> verse(0)
        |> verse(1)
        |> chorus(0)
        |> verse(2)
        |> chorus(1)
        |> verse(3)
        |> outro
        |> List.flatten
        |> Enum.join("\n")
    end

    def intro do
        "The Beatles: Hey Jude in Elixir (programming) Lyrics © SONY/ATV TUNES LLC; SONY BEATLES LTD"
    end

    def verse(current_lyrics, verse_number) do
        lines = (0..3)
        |> Enum.map(&(line(verse_number, &1)))
        [lines] ++ current_lyrics 
        |> Enum.reverse
    end

    def line(verse_number, 2) do
        case {verse_number, rem(verse_number + 1, 2)} do
            {1, 0} -> "The minute you let her under your skin"
            {1, _} -> "The minute you let her into your heart"
            {_, 0} -> "Remember to let her under your skin"
            {_, _} -> "Remember to let her into your heart"           
        end
    end

    def line(verse_number, 3) do
        case verse_number do  
            3 -> "Then you'll"
            _ -> "Then you"
        end
        <> case rem(verse_number, 2) do
            0 -> " can start "
            _ -> " begin "
        end
        <> "to make it "
        <> case verse_number do
            3 -> "\nBetter, " <> String.duplicate("better, ", 5) <> "oh"
            _ -> " better "    
        end
    end

    def line(verse_number, line_number) do
        temp_line = @lines
        |> Enum.at(rem(line_number, 3))        
        |> Enum.at(rem(verse_number, 3))
        case rem(line_number, 3) do 
            0 -> "Hey Jude, don't " <> temp_line
            _ -> temp_line
        end
    end

    def chorus(current_lyrics, 0) do
        ["And anytime you feel the pain, hey Jude, refrain",
        "Don't carry the world upon your shoulders",
        "For well you know that it's a fool who plays it cool",
        "By making his world a little colder"] ++ current_lyrics 
        |> Enum.reverse
    end

    def chorus(current_lyrics, 1) do
        ["So let it out and let it in, hey Jude, begin,",
        "You're waiting for someone to perform with.",
        "And don't you know that it's just you, hey Jude, you'll do,",
        "The movement you need is on your shoulder"] ++ current_lyrics
        |> Enum.reverse
    end

    def outro(current_lyrics) do
        [String.duplicate("Nah nah nah nah nah nah, nah nah nah, hey Jude \n", 10)] ++ current_lyrics
        |> Enum.reverse
    end
end

IO.puts HeyJude.lyrics

Hey Jude, don't make it bad
Take a sad song and make it better
Remember to let her into your heart
Then you can start to make it better
Hey Jude, don't be afraid
You were made to go out and get her
The minute you let her under your skin
Then you begin to make it better
And anytime you feel the pain, hey Jude, refrain
Don't carry the world upon your shoulders
For well you know that it's a fool who plays it cool
By making his world a little colder
Hey Jude, don't let me down
You have found her, now go and get her
Remember to let her into your heart
Then you can start to make it better
So let it out and let it in, hey Jude, begin,
You're waiting for someone to perform with.
And don't you know that it's just you, hey Jude, you'll do,
The movement you need is on your shoulder.
Hey Jude, don't make it bad
Take a sad song and make it better
Remember to let her under your skin
Then you'll begin to make it
Better, better, better, better, better, better, oh.
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude
Nah nah nah nah nah nah, nah nah nah, hey Jude