module Agents
  class TwitterStreamAgent < Agent
    include TwitterConcern
    cannot_receive_events!

    description <<-MD
      The TwitterStreamAgent follows the Twitter stream in real time, watching for certain keywords, or filters, that you provide.

      You must provide an oAuth `consumer_key`, `consumer_secret`, `oauth_token`, and `oauth_token_secret`, as well as an array of `filters`.  Multiple words in a filter
      must all show up in a tweet, but are independent of order.

      If you provide an array instead of a filter, the first entry will be considered primary and any additional values will be treated as aliases.

      To get oAuth credentials for Twitter, [follow these instructions](https://github.com/cantino/huginn/wiki/Getting-a-twitter-oauth-token).

      Set `expected_update_period_in_days` to the maximum amount of time that you'd expect to pass between Events being created by this Agent.

      `generate` should be either `events` or `counts`.  If set to `counts`, it will output event summaries whenever the Agent is scheduled.
    MD

    event_description <<-MD
      When in `counts` mode, TwitterStreamAgent events look like:

          {
            "filter": "hello world",
            "count": 25,
            "time": 3456785456
          }

      When in `events` mode, TwitterStreamAgent events look like:

          {
            "filter": "selectorgadget",
             ... every Tweet field, including ...
            "text": "something",
            "user": {
              "name": "Mr. Someone",
              "screen_name": "Someone",
              "location": "Vancouver BC Canada",
              "description":  "...",
              "followers_count": 486,
              "friends_count": 1983,
              "created_at": "Mon Aug 29 23:38:14 +0000 2011",
              "time_zone": "Pacific Time (US & Canada)",
              "statuses_count": 3807,
              "lang": "en"
            },
            "retweet_count": 0,
            "entities": ...
            "lang": "en"
          }
    MD

    default_schedule "11pm"

    def validate_options
      unless options[:filters].present? &&
             options[:expected_update_period_in_days].present? &&
             options[:generate].present?
        errors.add(:base, "expected_update_period_in_days, generate, and filters are required fields")
      end
    end

    def working?
      event_created_within(options[:expected_update_period_in_days]) && !recent_error_logs?
    end

    def default_options
      {
          :consumer_key => "---",
          :consumer_secret => "---",
          :oauth_token => "---",
          :oauth_token_secret => "---",
          :filters => %w[keyword1 keyword2],
          :expected_update_period_in_days => "2",
          :generate => "events"
      }
    end

    def process_tweet(filter, status)
      filter = lookup_filter(filter)

      if filter
        if options[:generate] == "counts"
          # Avoid memory pollution by reloading the Agent.
          agent = Agent.find(id)
          agent.memory[:filter_counts] ||= {}
          agent.memory[:filter_counts][filter] ||= 0
          agent.memory[:filter_counts][filter] += 1
          remove_unused_keys!(agent, :filter_counts)
          agent.save!
        else
          create_event :payload => status.merge(:filter => filter)
        end
      end
    end

    def check
      if options[:generate] == "counts" && memory[:filter_counts] && memory[:filter_counts].length > 0
        memory[:filter_counts].each do |filter, count|
          create_event :payload => { :filter => filter, :count => count, :time => Time.now.to_i }
        end
      end
      memory[:filter_counts] = {}
    end

    protected

    def lookup_filter(filter)
      options[:filters].each do |known_filter|
        if known_filter == filter
          return filter
        elsif known_filter.is_a?(Array)
          if known_filter.include?(filter)
            return known_filter.first
          end
        end
      end
    end

    def remove_unused_keys!(agent, base)
      if agent.memory[base]
        (agent.memory[base].keys - agent.options[:filters].map {|f| f.is_a?(Array) ? f.first.to_s : f.to_s }).each do |removed_key|
          agent.memory[base].delete(removed_key)
        end
      end
    end
  end
end