What tenses can the 'If' clause followed by Present Indicative trigger?

There are essentially 3 different types of 'If' clauses that you will ever need in Spanish.The first one is when the 'Si' clause (Spanish 'If' clause) is used to describe a situation that may well be fulfilled and thus the consequence is seen as possible. Because it is still possible, the 'Si' clause will begin with a present indicative and the result clause will either be present indicative or future. In English, a possible 'If' clause could be: If I see Juan, I say hello. As you can see, in English both the 'If' clause and the result clause are in the present indicative and this is the SAME for Spanish.In Spanish the sentence "If I see Juan, I say hello" would be "Si veo a Juan, le digo hola" (both verbs in Present Indicative). So Present Indicative can trigger Present Indicative.The Present Indicative can also trigger the Future Indicative can also be used in the result clause i.e. If I see Juan, I will say hello = Si veo a Juan, le diré hola