Add plain captcha and reverse captcha

lib/really_simple_captcha.rb

@@ -1,5 +1,10 @@
 require "really_simple_captcha/version"
 
+require "really_simple_captcha/util"
+require "really_simple_captcha/captcha/reverse_captcha"
+require "really_simple_captcha/captcha/plain_captcha"
+
 module ReallySimpleCaptcha
-  # Your code goes here...
 end
+
+require "really_simple_captcha/railtie" if defined?(Rails)

lib/really_simple_captcha/captcha/plain_captcha.rb

@@ -0,0 +1,79 @@
+require 'RMagick'
+require 'base64'
+
+module ReallySimpleCaptcha::Captcha
+  module PlainCaptcha
+    include ActiveSupport::Configurable
+    config_accessor :implode_amount
+    config_accessor :wave_amplitude
+    config_accessor :wave_length
+    config_accessor :pointsize
+    config_accessor :fill
+    config_accessor :background_color
+    config_accessor :text_length
+
+    config.text_length = 6
+
+    def self.configure(&block)
+      yield config
+    end
+
+    module ViewHelpers
+      def plain_captcha_tag
+        session[:plain_captcha] = ReallySimpleCaptcha::Util.random_string(PlainCaptcha.text_length)
+
+        image = PlainCaptcha.generate_image(session[:plain_captcha], {
+          implode_amount: PlainCaptcha.implode_amount,
+          wave_amplitude: PlainCaptcha.wave_amplitude,
+          wave_length: PlainCaptcha.wave_length,
+          pointsize: PlainCaptcha.pointsize,
+          fill: PlainCaptcha.fill,
+          background_color: PlainCaptcha.background_color,
+        })
+
+        content_tag :div, class: 'plain_captcha' do
+          html = image_tag "data:image/gif;base64,#{image}", alt: "Captcha"
+          html.concat text_field_tag 'plain_captcha', nil, required: 'required', autocomplete: 'off'
+
+          html
+        end
+      end
+    end
+
+    module ControllerHelpers
+      def plain_captcha_valid?
+        res = params[:plain_captcha] == session[:plain_captcha]
+        session[:plain_captcha] = nil
+
+        res
+      end
+    end
+
+    def self.generate_image(captcha_text, args={})
+      wave_amplitude = args[:wave_amplitude] || 4.0
+      wave_length = args[:wave_length] || 60.0
+      implode_amount = args[:implode_amount] || 0.2
+
+      pointsize = args[:pointsize] || 22
+      text_fill = args[:fill] || 'darkblue'
+
+      background_color = args[:background_color] || 'white'
+
+      image = ::Magick::Image.new(120, 40) do
+        self.background_color = background_color
+      end
+
+      text = ::Magick::Draw.new do
+        self.pointsize = pointsize
+        self.gravity = ::Magick::CenterGravity
+        self.fill = text_fill
+      end
+
+      text.annotate(image, 0, 0, 0, 0, captcha_text)
+
+      image = image.wave(wave_amplitude, wave_length).implode(implode_amount)
+
+      Base64.strict_encode64(image.to_blob { self.format = 'GIF' })
+    end
+  end
+end

lib/really_simple_captcha/captcha/reverse_captcha.rb

@@ -0,0 +1,24 @@
+module ReallySimpleCaptcha::Captcha
+  module ReverseCaptcha
+    include ActiveSupport::Configurable
+    config_accessor :field_name
+
+    config.field_name = :reverse_captcha
+
+    def self.configure(&block)
+      yield config
+    end
+
+    module ViewHelpers
+      def reverse_captcha_tag
+        content_tag :div, text_field_tag(ReverseCaptcha.field_name), class: 'reverse_captcha', style: 'display: none'
+      end
+    end
+
+    module ControllerHelpers
+      def reverse_captcha_valid?
+        params[ReverseCaptcha.field_name].blank?
+      end
+    end
+  end
+end

lib/really_simple_captcha/railtie.rb

@@ -0,0 +1,11 @@
+module ReallySimpleCaptcha
+  class Railtie < Rails::Railtie
+    initializer "really_simple_captcha.include_captcha_helpers" do
+      ActionView::Base.send :include, Captcha::PlainCaptcha::ViewHelpers
+      ActionController::Base.send :include, Captcha::PlainCaptcha::ControllerHelpers
+
+      ActionView::Base.send :include, Captcha::ReverseCaptcha::ViewHelpers
+      ActionController::Base.send :include, Captcha::ReverseCaptcha::ControllerHelpers
+    end
+  end
+end

lib/really_simple_captcha/util.rb

@@ -0,0 +1,8 @@
+module ReallySimpleCaptcha
+  module Util
+    def self.random_string(length=8)
+      (0...length).map{65.+(rand(26)).chr}.join
+    end
+  end
+end
+

really_simple_captcha.gemspec

@@ -16,4 +16,6 @@ Gem::Specification.new do |gem|
   gem.executables   = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
   gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
   gem.require_paths = ["lib"]
+
+  gem.add_runtime_dependency 'rmagick'
 end