There is only one solution that will solve all problems in the long term.
It’s name is Buddhism.

Apply Buddhism to your constitution and religion and the following would happen:
-No more drunk girls, no more drinking and any meat consumption would be banned, with added health benefits. (Would make strong devotees of Islam to acknowledge that the principles there not only respect Islam, but surpass Islam).
-Any person in such a way would have the moral high ground against any Islamist, and thus, very likely, there would be a bigger aversion to stop bad sexual conducts from happening
-No guns would be needed. A person that is buddhist would more likely to be expert in some martial arts and thus, any confrontation between a strong buddhist and an Islamic, would lead into an obvious winner, on the Buddhist side.

Guns can make the problem worse and allow Islamists to actually use guns to do a very bad thing across Europe.
While knowledge of using guns would get some persons to have the stronger high ground, If you’re a buddhist, you would not only have the moral high ground, but also have defense methods learned from martial arts and tai chi(an islamist is more unlikely to learn such methods).

The answer to Islam problem, is not Christianity(It lacks solid spiritual knowledge and at the same time it is more likely than not, that it creates targets for Islamists to practice at), but Buddhism.

Increase the spread of Buddhism across Europe, and all problems will be solved.

Of course, there’s the scenario that some Buddhists have done great damage to Muslims:
http://www.dailymail.co.uk/news/article-2321278/Dalai-Lama-pleads-Buddhist-monks-end-deadly-attacks-Muslims-Burma-Sri-Lanka.html

It’s teaching don’t promote violence, though at the same time, it is seen that some members may take the initiative.
However, since it’s religion is the most peaceful and with a higher degree of awareness, it is more than likely to succeed in keeping things balanced.

Time will tell how things will go.