import tweets from tweets.zip into Day One app. May or may not work with your dayone preference...

tweet_import.rb

#!/usr/bin/env ruby

require 'json'
require 'open3'
require 'date'

class Importer
  def initialize(*args)
    @js_files = *args
  end

  def import
    @js_files.each do |file|
      puts "Loading file #{file}\n"
      content = File.open(file).read
      content.sub! /^Grailbird.* = /, ''
      tweets = JSON.load(content).reverse
      tweets.each do |data|
        tweet = Tweet.new(data)
        handle_tweet tweet
      end
    end
  end

  def handle_tweet(tweet)
    unless tweet.reply? or tweet.retweet?
      unless imported?(tweet)
        import_tweet(tweet)
      end
    end
  end

  def imported?(tweet)
    load_cache! unless @tweets_cache
    @tweets_cache.key? tweet.url
  end

  def load_cache!
    @tweets_cache = {}
    Dir["#{ENV['HOME']}/Dropbox/Journal.dayone/entries/*.doentry"].each do |file|
      data = File.open(file).read
      if %r[(https?://twitter.com/\w+/status/\d+)</string>] === data
        @tweets_cache[$1] = 1
      end
    end
  end

  def import_tweet(tweet)
    Open3.popen3('dayone', "-d=#{tweet.localtime}", 'new') do |stdin, stdout, stderr|
      stdin.write(tweet.text + " " + tweet.url)
      stdin.close_write
      puts stdout.read
    end
  end
end

class Done < Exception; end

class Tweet
  def initialize(data)
    @data = data
  end

  def id
    @data['id']
  end

  def id_str
    @data['id_str']
  end

  def reply?
    /^@/.match @data['text']
  end

  def retweet?
    /^RT @/.match @data['text']
  end

  def url
    "http://twitter.com/#{@data['user']['screen_name']}/status/#{id_str}"
  end

  def text
    text = @data['text']
    if @data.key?('entities') and @data['entities'].key?('urls')
      @data['entities']['urls'].each do |entity|
        text.gsub! /#{entity['url']}/, entity['expanded_url']
      end
    end
    text
  end

  def localtime
    DateTime.parse(@data['created_at']).to_time.to_s
  end
end

Importer.new(*ARGV).import