File sharing in PHP

It is necessary to develop a similarity of a file sharing. The core is ready!!! It implements user registration, work with the database.
File-sharing


Administrator capabilities:
• Delete any files
User capabilities:
• Download files, download at maximum speed
• Comments on files
Guest capabilities:
• Registration
• Authorization
• Password recovery
• Ability to download a file at a reduced speed, after a minute of viewing advertising
• File search

Guest capabilities:
• Registration
• Authorization
• Password recovery
• Ability to download a file at a reduced speed, after a minute of viewing advertising
• File search



Downloading occurs via a cached link that exists for a certain time.

The application should be made by analogy with how the other functions are performed. The entire code should be commented on.