require 'digest/md5'
require "animal/identicon/version"

module Animal
  class Identicon
    class TypeError < StandardError; end

    def initialize(identifier)
      @identifier = identifier
    end

    def to_svg(size = 128, type: "square")
      digits = generate_digits
      icon   = generate_icon(digits)
      color  = generate_color(digits)

      case type
      when "circle"
        radius = 50
      when "square"
        radius = 0
      else
        raise TypeError.new("Please pass type 'circle' or 'square'")
      end

      "<svg style='background-color: ##{color}; height: #{size}px; width: #{size}px; border-radius: #{radius}%;'>
        <image xlink:href='https://ssl.gstatic.com/docs/common/profile/#{icon}_lg.png' style='height: #{size}px; width: #{size}px'></image>
       </svg>"
    end

    private

    def generate_digits
      Digest::MD5.hexdigest(@identifier)[-3..-1].to_i(16)
    end

    def generate_icon(digits)
      animal_number = digits % 64
      animals = [
        'alligator', 'anteater', 'armadillo', 'auroch', 'badger', 'bat', 'beaver', 'buffalo', 'camel', 'capybara',
        'chameleon', 'cheetah', 'chinchilla', 'chipmunk', 'chupacabra', 'cormorant', 'coyote', 'crow', 'dingo', 'dolphin',
        'duck', 'elephant', 'ferret', 'fox', 'giraffe', 'gopher', 'grizzly', 'hippo', 'hyena', 'ibex',
        'iguana', 'jackal', 'kangaroo', 'koala', 'kraken', 'lemur', 'leopard', 'liger', 'llama', 'manatee',
        'mink', 'monkey', 'moose', 'narwhal', 'orangutan', 'otter', 'panda', 'penguin', 'platypus', 'python',
        'quagga', 'rabbit', 'raccoon', 'rhino', 'sheep', 'shrew', 'skunk', 'squirrel', 'tiger', 'turtle',
        'walrus', 'wolf', 'wolverine', 'wombat'
      ]

      animals[animal_number]
    end

    def generate_color(digits)
      color_number = (digits / 64).floor
      colors = [
        '721acb', '841acb', '931acb', 'a51acb', 'b41acb', 'c51acb', 'cb1abf', 'cb1ab1', 'cb1a9f', 'cb1a8d',
        'cb1a7e', 'cb1a6c', 'cb1a5e', 'cb1a4c', 'cb1a3a', 'cb1a2b', 'cb1a1a', 'cb2b1a', 'cb3a1a', 'cb4c1a',
        'cb5e1a', 'cb6c1a', 'cb7e1a', 'cb8d1a', 'cb9f1a', 'cbb11a', 'cbbf1a', 'c5cb1a', 'b4cb1a', 'a5cb1a',
        '93cb1a', '84cb1a', '72cb1a', '61cb1a', '52cb1a', '40cb1a', '31cb1a', '1fcb1a', '1acb25', '1acb34',
        '1acb46', '1acb58', '1acb67', '1acb78', '1acb87', '1acb99', '1acbab', '1acbb9', '1acbcb', '1ab9cb',
        '1aabcb', '1a99cb', '1a87cb', '1a78cb', '1a67cb', '1a58cb', '1a46cb', '1a34cb', '1a25cb', '1f1acb',
        '311acb', '401acb', '521acb', '611acb'
      ]

      colors[color_number]
    end
  end
end