# Tracks user activity to a given site.
class TrackableSession < TrackableBase

  # Mongoid Config =================================================================================

  include Mongoid::Document
  include Mongoid::Timestamps

  referenced_in :trackable_stat
  references_many :trackable_actions

  field :bounce, :type => Boolean
  field :clickthrough_destination
  field :duration, :type => Integer
  field :entrance_page
  field :exit_page
  field :has_clicks, :type => Boolean
  field :has_clickthroughs, :type => Boolean
  field :has_conversions, :type => Boolean
  field :has_mouseovers, :type => Boolean
  field :has_scrolls, :type => Boolean
  field :initial_request_url
  field :ip_address
  field :kind
  field :location
  field :new_visit, :type => Boolean
  field :referrer
  field :referring_keywords
  field :session_id
  field :site
  field :spider, :type => Boolean
  field :user_agent
  field :views_count, :type => Integer
  field :visit_kind

  index :bounce, :unique => false
  index :created_at, :unique => false
  index :has_clicks, :unique => false
  index :has_clickthroughs, :unique => false
  index :has_mouseovers, :unique => false
  index :has_scrolls, :unique => false
  index :ip_address, :unique => false
  index :kind, :unique => false
  index :new_visit, :unique => false
  index :referrer, :unique => false
  index :session_id, :unique => false
  index :site, :unique => false
  index :spider, :unique => false
  index :visit_kind, :unique => false

  # Callbacks ======================================================================================

  before_create :init

  # Constants ======================================================================================

  KINDS = ['direct', 'natural', 'paid', 'search']
  HUMAN_USER_AGENTS = ['Chrome', 'Firefox', 'Gecko', 'Mozilla', 'MSIE', 'Opera','Safari']

  # Scopes =========================================================================================

  scope :by_ip_address,       lambda { |ip| { :where => { :ip_address => ip } } }
  scope :of_kind,             lambda { |k| { :where => { :kind => k } } }
  scope :for_site,            lambda { |s| { :where => { :site => s } } }
  scope :for_month,           lambda { |d| { :where => { :created_at => { '$gte' => d.beginning_of_month,  '$lte' => d.end_of_month } } } }
  scope :for_week,            lambda { |d| { :where => { :created_at => { '$gte' => d.beginning_of_week,  '$lte' => d.end_of_week } } } }
  scope :for_date_range,      lambda { |start_date,end_date| { :where => { :created_at => { '$gte' => start_date.beginning_of_month,  '$lte' => end_date.end_of_month } } } }
  scope :bounces,             :where => {:bounce => true}
  scope :direct_visits,       :where => { :kind => 'direct' }, :order => 'created_at'
  scope :new_visits,          :where => { :new_visit => true }, :order => 'created_at'
  scope :organic_visits,      :where => { :kind => 'natural' }, :order => 'created_at'
  scope :ppc_visits,          :where => { :kind => 'paid' }, :order => 'created_at'
  scope :spider_visits,       :where => { :spider => true }, :order => 'created_at'
  scope :recent_visits,       :where => { :created_at => { '$gte' => Time.zone.now.beginning_of_month }}, :order => 'created_at DESC', :limit => 25
  scope :return_visits,       :where => { :new_visit => false }, :order => 'created_at'
  scope :search_visits,       :where => { :kind => 'search' }, :order => 'created_at'
  scope :with_any_actions
  scope :with_clicks,         :where => { :has_clicks => true }, :order => 'created_at'
  scope :with_clickthroughs,  :where => { :has_clickthroughs => true }
  scope :with_conversions,    :where => { :has_conversions => true }, :order => 'created_at'
  scope :with_leads,          :where => { :has_conversions => true }, :order => 'created_at'
  scope :with_mouseovers,     :where => { :has_mouseovers => true }, :order => 'created_at'
  scope :with_scrolls,        :where => { :has_scrolls => true }, :order => 'created_at'
  scope :with_views,          :where => { :views_count => { '$gte' => 1 } }, :order => 'created_at'

  # Class Methods ==================================================================================

  # Returns the conversion rate for sessions matching the specified arguments, ie: percentage of the total number of visits that were conversions.
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.conversion_rate( :site => 'foo.com' )
  def self.conversion_rate(args)
    (TrackableSession.search(args).with_conversions.count.to_f / TrackableSession.search(args).count) * 100
  end

  # Returns a histogram for the number of clickthroughs to each referred site(s).
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.clickthroughs_histogram( :site => 'foo.com' )
  def self.clickthroughs_histogram(args)
    conditions = TrackableSession.search(args).selector
    TrackableSession.collection.group(:keyf => "function(x) { return { destination: x.clickthrough_destination }; }", :cond => conditions, :initial => { :count => 0}, :reduce => "function(x,y){y.count++}").inject({}){|h,k| h[k['destination']] = k['count'] unless k['destination'].blank?; h}
  end

  # Returns a histogram for the first page users visited for the specified site(s).
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.entrance_pages_histogram( :site => 'foo.com' )
  def self.entrance_pages_histogram(args)
    conditions = TrackableSession.search(args).selector
    TrackableSession.collection.group(:keyf => "function(x) { return { entrance_page: x.entrance_page }; }", :cond => conditions, :initial => { :count => 0}, :reduce => "function(x,y){y.count++}").inject({}){|h,k| h[k['entrance_page']] = k['count']; h}.sort{|a,b| a[1] <=> b[1]}.reverse
  end

  # Returns a histogram for the last page users visited for the specified site(s).
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.exit_pages_histogram( :site => 'foo.com' )
  def self.exit_pages_histogram(args)
    conditions = TrackableSession.search(args).selector
    TrackableSession.collection.group(:keyf => "function(x) { return { exit_page: x.exit_page }; }", :cond => conditions, :initial => { :count => 0}, :reduce => "function(x,y){y.count++}").inject({}){|h,k| h[k['exit_page']] = k['count']; h}.sort{|a,b| a[1] <=> b[1]}.reverse
  end

  # Returns a histogram for the search terms users used to find the specified site(s).
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.keywords_histogram( :site => 'foo.com' )
  def self.keywords_histogram(args)
    conditions = TrackableSession.search(args).selector
    TrackableSession.collection.group(:keyf => "function(x) { return { keyword: x.referring_keywords }; }", :cond => conditions, :initial => { :count => 0}, :reduce => "function(x,y){y.count++}").inject({}){|h,k| h[k['keyword']] = k['count'] unless k['keyword'].blank?; h}
  end

  def self.kinds_for_select
    [['All', 'all']] | TrackableSession::KINDS.sort.map{|k| [k.titleize, k]}
  end

  # Returns a histogram for the geocoded locations of visitors to the specified site(s).
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.locations_histogram( :site => 'foo.com' )
  def self.locations_histogram(args)
    conditions = TrackableSession.search(args).selector
    TrackableSession.collection.group(:keyf => "function(x) { return { location: x.location }; }", :cond => conditions, :initial => { :count => 0}, :reduce => "function(x,y){y.count++}").inject({}){|h,k| h[k['location']] = k['count'].to_i unless k['location'].blank? || k['location'] == 'Unknown'; h}
  end

  # Returns a human-readable user agent for the browser.
  def self.parsed_user_agent(user_agent)
    begin
      _ua = Agent.new(user_agent)
      _user_agent = "#{_ua.name} #{_ua.version} (#{_ua.os})"
    rescue
      _user_agent = "Unknown"
    end
    _user_agent
  end

  # Returns a histogram for the referrers for site(s) matching the specified arguments.
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.referrers_histogram( :site => 'foo.com' )
  def self.referrers_histogram(args)
    conditions = TrackableSession.search(args).selector
    TrackableSession.collection.group(:keyf => "function(x) { return { referrer: x.referrer }; }", :cond => conditions, :initial => { :count => 0}, :reduce => "function(x,y){y.count++}").inject({}){|h,k| h[k['referrer']] = k['count'] unless k['referrer'].blank?; h}
  end

  # Returns a scope based on time period, site, and visit kind. Null arguments returns all.
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.search( :site => 'foo.com' )
  def self.search(args)
    (args[:start_date], args[:end_date]) = dates_from_time_period(args[:time_period])
    sessions = args[:time_period] ? TrackableSession.for_date_range(args[:start_date], args[:end_date]) : TrackableSession.all
    sessions = sessions.send("with_#{args[:action_kind].pluralize.downcase}") if args[:action_kind]
    sessions = sessions.for_site(args[:site].downcase) unless args[:site].downcase == 'all sites'
    sessions = sessions.of_kind(args[:visit_kind].downcase) if args[:visit_kind] && args[:visit_kind].downcase != 'all'
    sessions.desc(:created_at)
  end

  # Returns a scope based on site and visit kind only.
  #
  # ==== Attributes
  #
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.search_without_date( :site => 'foo.com' )
  def self.search_without_date(args = {})
    args = args.clone
    args.delete(:time_period)
    self.search(args)
  end

  # Returns a histogram for the user agents for site(s) matching the specified arguments.
  #
  # ==== Attributes
  #
  # * +:time_period+ - date range as a string: 'past 3 months', 'past 6 months', 'past 12 months'
  # * +:site+ - name of a site
  # * +:visit_kind+ - kind of visit as a string: 'direct', 'natural', 'paid', 'search'
  #
  # ==== Examples
  #
  #    TrackableSession.user_agents_histogram( :site => 'foo.com' )
  def self.user_agents_histogram(args)
    conditions = TrackableSession.search(args).selector
    _histogram = TrackableSession.collection.group(:keyf => "function(x) { return { user_agent: x.user_agent }; }", :cond => conditions, :initial => { :count => 0}, :reduce => "function(x,y){y.count++}")
    _final = {}
    _histogram.each do |ua|
      _ua = parsed_user_agent(ua['user_agent'])
      _final[_ua] ||= 0
      _final[_ua] += ua['count'].to_i unless ua['user_agent'].blank? || ua['user_agent'] == 'Unknown'
    end
    _final
  end

  # Instance Methods ===============================================================================

  # Returns the number of non-view actions for this session.
  def actions
    self.trackable_actions.count - self.trackable_actions.views.count
  end

  # Returns true if this is a new visit.
  def detect_new_visit
    TrackableSession.where(:ip_address => self.ip_address) ? false : true
  end

  # Returns this session's duration in X minutes or Y seconds.
  def hr_duration
    return 0 unless self.duration
    self.duration > 60 ? sprintf("%.1f minutes", self.duration / 60.0) : sprintf("%.1f seconds", self.duration)
  end

  # Initializes a new session.
  def init
    self.bounce = true
    self.kind ||= self.kind_by_referrer
    self.new_visit ||= self.detect_new_visit
    self.referring_keywords = self.sanitize_referring_keywords
    self.spider ||= spider_visit?
    begin
      raise ArgumentError, "No IP address available" unless self.ip_address
      _location = Geokit::Geocoders::MultiGeocoder.geocode(self.ip_address)
      self.location ||= _location.success? ? "#{_location.city}, #{_location.state}" : "Unknown"
    rescue
      self.location = "Unknown"
    end
  end

  # Returns whether this session was initiated by a direct (bookmark or typed URL), search, paid (landing page), or natural (non-search link) referrer.
  def kind_by_referrer
    return "direct" unless self.referrer
    unless self.referrer.blank?
      return 'search' if ['google','bing','yahoo'].include?(self.referrer.split('.')[-2])
      return 'paid' if ppc_visit?(self.initial_request_url)
    end
    "natural"
  end

  # Returns the number of page views associated with this session.
  def pageviews
    self.trackable_actions.views.count
  end

  # Returns this session's human-readable user agent.
  def parsed_user_agent
    TrackableSession.parsed_user_agent(self.user_agent)
  end

  # Returns the date of the last visit if this user visited before.
  def last_visit_date
    return nil if previous_visits_count.zero?
    TrackableSession.by_ip_address(self.ip_address).asc(:created_at).only(:created_at).map{|s| s.created_at}.sort[-2]
  end

  # Returns the number of times this user has been here before.
  def previous_visits_count
    TrackableSession.by_ip_address(self.ip_address).count - 1
  end

  # Unescapes referring keywords for display.
  def sanitize_referring_keywords
    self.referring_keywords.to_s.gsub('+',' ')
  end

  # Updates this session with whatever the user just did.
  #
  # ==== Attributes
  #
  # * +:action_kind+ - action as a string: 'click', 'clickthrough', 'conversion', 'mouseover', 'scroll', 'view'
  # * +:destination+ - clickthrough destination
  # * +:last_url+ - the referring URL
  #
  # ==== Examples
  #
  #    trackable_session.touch( 'click', 'cnn.com', 'foo.com/cnn' )
  def touch(action_kind = nil, destination = nil, last_url = nil)
    if action_kind && action_kind == 'scroll'
      self.update_attributes(
        :has_scrolls => true,
        :bounce => self.trackable_actions.count <= 1,
        :duration => Time.zone.now - self.created_at
      )
    elsif action_kind && action_kind == 'click'
      self.update_attributes(
        :has_clicks => true,
        :bounce => self.trackable_actions.count <= 1,
        :duration => Time.zone.now - self.created_at
      )
    elsif action_kind && action_kind == 'clickthrough'
      self.update_attributes(
        :has_clickthroughs => true,
        :clickthrough_destination => destination,
        :bounce => false,
        :duration => Time.zone.now - self.created_at
      )
    elsif action_kind && action_kind == 'conversion'
      self.update_attributes(
        :has_conversions => true,
        :bounce => self.trackable_actions.count <= 1,
        :duration => Time.zone.now - self.created_at
      )
    elsif action_kind && action_kind == 'mouseover'
      self.update_attributes(
        :has_mouseovers => true,
        :bounce => self.trackable_actions.count <= 1,
        :duration => Time.zone.now - self.created_at
      )
    else
      # View
      self.update_attributes(:updated_at => Time.zone.now, :duration => Time.zone.now - self.created_at, :views_count => self.views_count.to_i + 1, :exit_page => last_url, :bounce => self.trackable_actions.count > 1 ? false : true)
    end
    touch_stat
  end

  # Returns whether this session is new or existing.
  def visit_type
    self.new_visit? ? "New" : "Returning"
  end

  # Upserts stats associated with this session. Called every time this session is touched.
  def touch_stat
    # Upsert associated stat
    if trackable_stat = TrackableStat.by_site(self.site).by_date(self.created_at).first
      trackable_stat.touch(self, self.trackable_actions[-1], self.trackable_actions[-2])
    else
      trackable_stat = TrackableStat.create(:site => self.site, :created_at => self.created_at)
      trackable_stat.touch(self, self.trackable_actions.last)
    end
  end

  private

  def ppc_visit?(url)
    begin
      _params = URI.parse(url).query.to_s.downcase
    rescue
      false
    end
    return false if _params.blank?
    return true if _params.include?('gclid')      # Google AdWords
    return true if _params.include?('keyword')    # AdCenter
    return true if _params.include?('adid')       # AdCenter?
    return true if _params.include?('matchtype')  # Generic
    return true if _params.include?('ppc')        # Generic
    return true if _params.include?('cpc')        # Generic
    return false
  end

  def spider_visit?
    _spider = true
    return false if self.user_agent == "Unknown" || self.user_agent.nil?
    unless self.user_agent.to_s.include?('bot')
      HUMAN_USER_AGENTS.each{ |ua| _spider = false if self.user_agent.to_s.include?(ua) }
    end
    _spider
  end

end