# Copyright (c) 2011 Roderick Monje
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
require 'rubygems'
require 'bundler/setup'
Bundler.require :default

class HitCounter
  include Mongoid::Document
  include Mongoid::Timestamps

  # Mongo Config ===================================================================================
  field :url
  field :hits, :type => Integer, :default => 0

  # Validates the <code>HitCounter</code>'s URL.
  #
  # If the URI library can parse the value and the scheme is valid, then we assume the url is valid.
  class UrlValidator < ActiveModel::EachValidator
    def validate_each record, attribute, value
      begin
        uri = Addressable::URI.parse value

        if !['http', 'https'].include? uri.scheme
          raise Addressable::URI::InvalidURIError
        end
      rescue Addressable::URI::InvalidURIError
        record.errors[attribute] << 'Invalid URL'
      end
    end
  end

  validates :url, :presence => true, :url => true, :uniqueness => true

  # Class methods ==================================================================================

  # Returns a <code>HitCounter</code> matching the specified URL. The HitCounter is created if no
  # matching one is found. In the latter case, the hits argument specifies the starting count.
  #
  # * *Args*
  #   - +url+ -> the URL for the site being counted
  #   - +hits+ -> the number of hits to start with
  # * *Returns*
  #   - the site's HitCounter
  def self.get url, hits = 0
    args = {:url => HitCounter.normalize_url(url)}
    args[:hits] = hits unless HitCounter.where(:conditions => args).exists?
    self.find_or_create_by args
  end

  # Instance methods: Overrides ====================================================================

  # Sets the number of hits.
  #
  # * *Args*
  #   - +value+ -> the number of hits
  # * *Returns*
  #   - the value
  def hits= value
    self[:hits] = value.to_i
  end

  # Sets the URL to be tracked. The http prefix is optional.
  #
  # * *Args*
  #   - +value+ -> the URL for the site being counted
  # * *Returns*
  #   - the value
  def url= value
    self[:url] = HitCounter.normalize_url value
  end

  # Instance methods ===============================================================================

  # Returns the hit count as a PNG image, using the specified style:
  #   1 odometer
  #   2 scout
  #   3 Celtic
  #
  # * *Args*
  #   - +style_number+ -> the image style
  # * *Returns*
  #   - the current hit count as a PNG image
  def image style_number
    image = HitCounter.cat_image self.hits.to_s, HitCounter.normalize_style_number(style_number)
    image.format = 'png'
    image
  end

  # Increments the hit count and saves the HitCounter.
  #
  # * *Returns*
  #   - true if the save was successful
  def increment
    self.hits += 1
    self.save
  end

  private

  STYLES = ['odometer', 'scout', 'celtic']

  def self.cat_image number, style_index, images = Magick::ImageList.new
    return images.append(false) if number.blank?
    HitCounter.cat_image number[1..-1], style_index, images << Magick::Image.read("#{Rails.root}/public/images/digits/#{STYLES[style_index]}/#{number[0..0]}.gif").first
  end

  def self.normalize_style_number value
    value = value.to_i
    value -= 1 if value > 0

    if value >= 0 && value < STYLES.size
      return value
    else
      value % 3
    end
  end

  def self.normalize_url value
    value !~ %r{^http://} ? "http://#{value}" : value
  end
end

if defined? Rails
  class Railtie < Rails::Railtie
    rake_tasks do
      namespace :hit_counter do
        desc 'Install HitCounter into your app.'
        task :install do
          puts 'Installing required image files...'
          system "rsync -ruv #{Gem.searcher.find('hit_counter').full_gem_path}/config ."
          system "rsync -ruv #{Gem.searcher.find('hit_counter').full_gem_path}/public ."
        end
      end
    end
  end
end