PHP-based website parser

I would need a PHP 5-based script that prompts the user for the information required by [login to view URL] (it's a government-sponsored online legal database), then retrieves the list of results, downloads each document in that list and saves it locally. Depending on the parameters, the results list may extend over multiple pages. Documents should be organized by year and within each year by category (JUS Rechtssaetze vs. JUS Texte). If, for any reason, the download process is interrupted, the script should resume where it last stopped. I plan to initially download the last 10 years or so and then run a daily cron job to keep the database current. The fields on [login to view URL] have the following meanings: Suchworte = Query string (that should be left blank to make sure all documents are downloaded) Datum von = Start date bis = End date Gerichtstyp = Type of court (leave blank) Geschaeftszahl = File number (leave blank) Rechtssatz = Synposis (leave blank) Norm = Rule (leave blank) SUCHE STARTEN = Start search