register route on application.py Pset7

@app.route("/register", methods=["GET", "POST"])
def register():
    """Register user."""

    #forget any user_id
    session.clear()

    # if user reached route via POST (as by submitting a form via POST)
    if request.method == "POST":

        # ensure username was submitted
        if not request.form.get("username"):
            return apology("must provide username")

        #ensure password was submitted
        elif not request.form.get("password"):
            return apology("must provide password")

        # ensure same password was entered twice
        if request.form.get("password") != request.form.get("password confirmation"):
            return apology("passwords much match! (password field and password confirmation field)")

        # secure user's password: hash password with pwd_context.encrypt()
        # "username" is a UNIQUE field in the database, as is the "user_id" field.
        # check for db.execute failure
        # try to add user to database with:
        # db.execute("INSERT INTO users (username, hash) VALUES(:username, :hash)", username=request.form.get("username"), hash=hash)
        # if not result:
        #    return apology("...") to print error message that the username already exists
        # once they register successfully, log them in automatically
        # store their id in session
        #     session["user_id"]
        hash = pwd_context.encrypt(request.form.get("password"))
        result = db.execute("INSERT INTO users (username, hash) VALUES(:username, :hash)", username=request.form.get("username"), hash=hash)
        if not result:
            return apology("username already exists!")

        rows = db.execute("SELECT * FROM users WHERE username = :username", username=request.form.get("username"))
        if not rows:
            apology("something went wrong")
        session["user_id"] = rows[0]["id"]
        return render_template("register.html")