How should I handle a situation where I was approached and arrested for no reason while walking down the street?

Your question requires an attorney consultation. It is not a simple question that can be answered on this type of forum. There are many factors that would need to be considered and evaluated. I strongly suggest that you contact an experienced criminal law attorney for a face-to-face consultation and give him/her all of the facts surrounding your arrest. He/she would then be in a better position to analyze your case and advise you of your options.

Absolutely plead not guilty. They must prove you were so intoxicated that you could not care for your own safety or the safety of others. Certainly not what you describe. Either get a lawyer to handle this for you or if you cannot afford one, request a public defender.

Usually I would have expected you to be released after 7 or 8 hours and no charges filed. There must be something else or you are in Santa Clara County.

How should I handle? By defending the charges unless you're willing to simply plead guilty and go to jail. If you are charged with any crime, the proper questions are, can any evidence obtained in a test, search or statement be used against you, can you be convicted, and what can you do? Raise all appropriate defenses with whatever witnesses, evidence and sympathies are available for legal arguments, for evidence suppression or other motions, or for trial. No amount of free 'tips and hints' from here or elsewhere are going to effectively help in a legal defense. If you don't know how to represent yourself effectively against an experienced prosecutor intending to convict, then hire an attorney who does, who will try to get a dismissal, charge reduction, diversion, programs, or other decent outcome through motions, plea bargain, or take it to trial if appropriate.

Plead not guilty. Calif. Penal Code Section 647(f) is hard to prove. If the charge is a misdemeanor and you can not afford a lawyer ask the Judge for the Public Defender.