I am using Magento 2 and created 2 stores in site. By default store switcher is available only at bottom of page. I wish to have a pop up on first landing page which asks to select store.
You can use default modal js for popup.
Get all the stores of current website.
Disply them in popup.
Add some ajax logic in seperate controller so that when user clicks on one of your store, It redirects to cotroller and sets the default store session for that.
On ajax sucess redirect the user to current url.