The worst could be over, but is that enough to justify buying it?With talk of marijuana policy reform brewing in the U.S. and elsewhere, could it be time to buy shares of Canopy Growth (CGC -4.29%) in hopes of the stock experiencing a glorious comeback from its recent years of turmoil and falling share prices? And what about current shareholders -- is it time to sell, or could there be relief in sight?Let's dive in and answer these questions by examining what the company has been up to during its difficult ...