PowerShell scripts for SharePoint 2013 monitoring

Dear,

Can anyone provide automation PowerShell scripts for AppPool monitoring which Should trigger an email with statuses as well check all the site collection statuses whether all the sites are online or not if not online need to get an email  in SharePoint 2013. I have tried many scripts online but could not get it and some scripts are not generating email.

Versiton:SharePoint 2013, OS:Win2012 standard 

Thanks,