cross-post/lib/cross-post/twitter.rb

require 'twitter'
require 'twitter-text'
require 'sanitize'
require 'cgi'
require 'ostruct'

::Twitter::Validation::MAX_LENGTH = 280

class CrossPost
	class Twitter
		def initialize(config)
			settings = config[:settings]
			@posts   = config[:posts]
			@users   = config[:users]

			config  = {
					consumer_key:        settings['twitter.consumer.key'],
					consumer_secret:     settings['twitter.consumer.secret'],
					access_token:        settings['twitter.access.token'],
					access_token_secret: settings['twitter.access.secret']
			}
			@client = ::Twitter::REST::Client.new config
			@stream = ::Twitter::Streaming::Client.new config
		end

		def post(content, media = [], id:, reply_to:)
			reply_to = OpenStruct.new id: reply_to unless reply_to.respond_to? :id

			media = media.collect { |f| @client.upload f }
			parts = split content
			unless media.empty?
				first, *parts = parts
				reply_to      = @client.update first, media_ids: media.join(','), in_reply_to_status: reply_to
			end
			parts.each { |p| reply_to = @client.update p, in_reply_to_status: reply_to }

			reply_to = reply_to.id if reply_to.respond_to? :id
			@posts[id] = reply_to
		end

		WHITESPACE_TAGS = {
				'br'  => { before: "\n", after: '' },
				'div' => { before: "\n", after: "\n" },
				'p'   => { before: "\n", after: "\n" }
		}.freeze

		def post_status(status)
			content = status.content
			content = Sanitize.clean(content, whitespace_elements: WHITESPACE_TAGS).strip
			content = CGI.unescape_html content

			@users.each do |mastodon, twitter|
				content = content.gsub /@\b#{mastodon}\b/, "@#{twitter}"
			end

			media   = status.media_attachments.collect { |f| open f.url }

			LOGGER.info { 'Sending to twitter' }
			LOGGER.debug { "  Content: #{content}" }
			LOGGER.debug { "  Attachments: #{media.size}" }

			reply   = status.in_reply_to_id
			reply_to = reply ? @posts[reply] : nil
			self.post content, media, id: status.id, reply_to: reply_to

			media.each do |f|
				f.close
				f.unlink
			end
		end

		private

		def split(text)
			parts = []
			part  = ''
			words = text.split /\ /
			words.each do |word|
				old_part = part
				part     += ' ' unless part == ''
				part     += word

				invalid = ::Twitter::Validation.tweet_invalid? part
				if invalid
					parts << old_part
					part = word
				end
			end
			parts << part unless part == ''
			parts
		end
	end
end