Twitter autopost script

I need a script that i can upload to my server. The script must be php and be able to run with a cron job. My requirements- The script will log into my account and post a new tweet upon every cron job. So if i was to set the cron job to every 30minutes. It would post a new tweet every 30minutes. When the cron job is executed, it will access the php file, the php file will have a history of 1200+ tweets. It will RANDOMLY select one of these and post it. There must also be the option that if i add new tweets to this file, these new tweets will be posted first upon every new cron job, then if there are no more new tweets to post, it will harvest a tweet in the php file history and post a random one from there. These new tweets that have been posted will then go with the rest of the tweets. If you have any questions please fee free to ask before bidding. I will pay via escrow before the project starts. I require a 24hour testing period to ensure the script works fine before the payment is released.