There are semantic and syntactic differences between the things we wish and the things we hope.
When we address wishes to another person we usually employ wish as a "ditransitive" verb: that is, the syntax requires that the person addressed (you) act as the Indirect Object, the Beneficiary, and the thing wished for that person be expressed as the Direct Object. This Direct Object is a noun phrase, not a clause:
I wish you (a) happy birthday!
I wish you many happy returns!
I wish you much joy!
When the complement of wish is a clause, there no Indirect Object, and wish expresses something which you desire for your own benefit.
If the clause employs a finite verb it is usually cast in the "subjunctive past" (a past form uninflected for person or number), often a past modal; in this case the sentence expresses either your longing for something you regard as impossible or only remotely possible.
I wish he would treat her better.
I wish she were here.
I wish I had a Mercedes instead of this damn 76 Dodge Dart.
If the clause employs a marked infinitive verb (to VERB), the sentence expresses a polite but firm command that the subject perform the action named; there is often an implied threat of your displeasure or worse if the action is not performed.
I wish him to treat her better (or I'll cut him out of my will.)
I wish her to come here (and stop wasting her time in the country.)
I wish to have a Mercedes (so take this damn Dart away and junk it.)
If you want to "wish" an event for somebody you usually express it with hope + a 'content' clause (that clause):
I hope (that) you have a happy birthday!
I hope (that) you never grow up!
But hope always implies some degree of uncertainty; your tone of voice, or further qualification, will usually indicate how much uncertainty is intended.
I hope you have a happy birthday, and I'm sure you will!
I hope you have a happy birthday, but it doesn't seem very likely.
You may also hope for an eventuality, with a noun, gerund or infinitive phrase as the object of for.