module Remedy
  module Characters
    module_function

    def [] sequence_to_match
      all[sequence_to_match]
    end

    def all
      @all ||= printable.merge(nonprintable)
    end

    def printable
      @printable ||= whitespace.merge(
        alphabetical.merge(
          numeric.merge(
            punctuation)))
    end

    def whitespace
      {
        ' '  => :space,
        "\t" => :tab,
        "\r" => :carriage_return,
        "\n" => :line_feed
      }
    end

    def alphabetical
      @alphabetics ||= get_alphabetics
    end

    def numeric
      {
        '0' => :zero,
        '1' => :one,
        '2' => :two,
        '3' => :three,
        '4' => :four,
        '5' => :five,
        '6' => :six,
        '7' => :seven,
        '8' => :eight,
        '9' => :nine
      }
    end

    def punctuation
      {
        '.' => :period,
        ',' => :comma,
        ':' => :colon,
        ';' => :semicolon,

        '"' => :double_quote,
        "'" => :single_quote,
        '`' => :back_quote,

        '[' => :left_bracket,
        ']' => :right_bracked,
        '(' => :left_paren,
        ')' => :right_paren,

        '^' => :caret,
        '_' => :underscore,
        '-' => :dash,
        '~' => :tilde,

        '!' => :bang,
        '?' => :query,

        '|'       => :solid_pipe,
        "\u00A6"  => :broken_pipe,

        '/'  => :forward_slash,
        "\\" => :back_slash
      }
    end

    def nonprintable
      @nonprintable ||= special.merge(directional).merge(escape).merge(control)
    end

    def special
      {
        "\177"  => :backspace
      }
    end

    def directional
      {
        "\e[A" => :up,
        "\e[B" => :down,
        "\e[D" => :left,
        "\e[C" => :right
      }
    end

    def escape
      {
        "\e" => :escape,

        "\e[3~" => :delete
      }
    end

    def control
      {
        "\u0003" => :control_c,
        "\u0004" => :control_d,
        "\u0012" => :control_r
      }
    end

    def gremlins
      {
        space:           "\u2420",
        tab:             "\u21B9",
        carriage_return: "\u23CE",
        line_feed:       "\u240A",

        control_c: "\u2404",
        control_d: "\u2403",
        control_r: "\u2412",

        escape: "\u238B",

        backspace: "\u2408",
        delete:    "\u232B",

        up:    "\u2191",
        down:  "\u2193",
        left:  "\u2190",
        right: "\u2192"
      }
    end

    def alternate_names
      {
        control_c: :end_of_transmission,
        control_d: :end_of_text,

        control_r: :device_control_two
      }
    end

    def get_alphabetics
      letters = ('a'..'z').to_a + ('A'..'Z').to_a
      letters.inject(Hash.new) do |alphas, letter|
        alphas[letter] = letter.to_sym
        alphas
      end
    end
  end
end