#!/usr/bin/env ruby
require 'twitter'
require 'tweetstream'
require 'rufus/scheduler'

module Ebooks
  class Bot
    attr_accessor :consumer_key, :consumer_secret, 
                  :oauth_token, :oauth_token_secret

    attr_accessor :username

    attr_reader :twitter, :stream

    @@all = [] # List of all defined bots
    def self.all; @@all; end

    def initialize(username, &b)
      # Set defaults
      @username = username

      # Override with callback
      b.call(self)

      Bot.all.push(self)
    end

    def log(*args)
      STDERR.puts "@#{@username}: " + args.map(&:to_s).join(' ')
      STDERR.flush
    end

    # Connects to tweetstream and opens event handlers for this bot
    def start
      TweetStream.configure do |config|
        config.consumer_key = @consumer_key
        config.consumer_secret = @consumer_secret
        config.oauth_token = @oauth_token
        config.oauth_token_secret = @oauth_token_secret
      end

      Twitter.configure do |config|
        config.consumer_key = @consumer_key
        config.consumer_secret = @consumer_secret
        config.oauth_token = @oauth_token
        config.oauth_token_secret = @oauth_token_secret
      end

      @twitter = Twitter::Client.new
      @stream = TweetStream::Client.new

      @stream.on_error do |msg|
        log "ERROR: #{msg}"
      end

      @stream.on_inited do
        log "Online!"
      end

      @stream.on_event(:follow) do |event|
        next if event[:source][:screen_name] == @username
        log "Followed by #{event[:source][:screen_name]}"
        @on_follow.call(event[:source])
      end

      @stream.on_direct_message do |dm|
        next if dm[:sender][:screen_name] == @username # Don't reply to self
        log "DM from @#{dm[:sender][:screen_name]}: #{dm[:text]}"
        @on_message.call(dm)
      end

      @stream.userstream do |ev|
        next unless ev[:text] # If it's not a text-containing tweet, ignore it
        next if ev[:user][:screen_name] == @username # Ignore our own tweets

        meta = {}
        mentions = ev.attrs[:entities][:user_mentions].map { |x| x[:screen_name] }

        reply_mentions = mentions.reject { |m| m.downcase == @username }
        reply_mentions << ev[:user][:screen_name]

        meta[:reply_prefix] = reply_mentions.uniq.map { |m| '@'+m }.join(' ') + ' '

        mless = ev[:text]
        ev.attrs[:entities][:user_mentions].reverse.each do |entity|
          mless = mless[0...entity[:indices][0]] + mless[entity[:indices][1]+1..-1]
        end
        meta[:mentionless] = mless

        # To check if this is a mention, ensure:
        # - The tweet mentions list contains our username
        # - The tweet is not being retweeted by somebody else
        # - Or soft-retweeted by somebody else
        if mentions.map(&:downcase).include?(@username) && !ev[:retweeted_status] && !ev[:text].start_with?('RT ')
          log "Mention from #{ev[:user][:screen_name]}: #{ev[:text]}"
          @on_mention.call(ev, meta)
        else
          @on_timeline.call(ev, meta)
        end
      end
    end

    # Wrapper for EM.add_timer
    # Delays add a greater sense of humanity to bot behaviour
    def delay(time, &b)
      time = time.to_a.sample unless time.is_a? Integer
      EM.add_timer(time, &b)
    end

    # Reply to a tweet or a DM.
    # Applies configurable @reply_delay range
    def reply(ev, text, opts={})
      opts = opts.clone
      delay = @reply_delay.to_a.sample

      if ev.is_a? Twitter::DirectMessage
        log "Sending DM to @#{ev[:sender][:screen_name]}: #{text}"
        @twitter.direct_message_create(ev[:sender][:screen_name], text, opts)
      elsif ev.is_a? Twitter::Tweet
        log "Replying to @#{ev[:user][:screen_name]}: #{text}"
        @twitter.update(text, in_reply_to_status_id: ev[:id]) 
      else
        raise Exception("Don't know how to reply to a #{ev.class}")
      end
    end

    def scheduler
      @scheduler ||= Rufus::Scheduler.new
    end

    def follow(*args)
      log "Following #{args}"
      @twitter.follow(*args)
    end

    def tweet(*args)
      log "Tweeting #{args.inspect}"
      @twitter.update(*args)
    end

    def on_follow(&b); @on_follow = b; end
    def on_mention(&b); @on_mention = b; end
    def on_timeline(&b); @on_timeline = b; end
    def on_message(&b); @on_message = b; end
  end
end