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All right.
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So this just one last thing left to do.
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If we were baking a cake, we wouldn't need to tidy up and wash everything and make sure that we're leaving
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the place as brand spanking clean as we found it.
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And in our case, we need to tidy up our code so that if we come back to it in a month or in a year or
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if somebody else were to collaborate with us on this project that they actually understand what's going
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on and it's not a whole jumble of mess.
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So the first thing that we should try to eliminate are places where we have a lot of hard coding.
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So one of the most obvious ones is this
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count number here, because why would it be?
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Because safe in the future, we decided to upgrade our Twitter API membership to their premier or enterprise
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versions and we stopped paying them so that we can get more tweets back in the same query, say, a thousand tweets
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or 10,000 tweets.
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Then we don't want to be digging through this count
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and also here in the for loop changing it or forgetting to change it which is even worse because we'll
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end up with bug that we don't know the reason for.
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So let's make sure that we change this into a constant up here so that when we decide to update that,
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we can easily find it.
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So let's call it something like tweetCount and let's set it to 100, and we can replace it
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now over here, and also inside our for loop.
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All right.
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So that's one thing checked off, removing some hardcoding.
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Now, the next thing that we need to do is to make some methods and split up the functionality of our code
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so that it's not all inside our IBAction because having this large a chunk of code, and especially if
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we're going to add to it, is not great when it comes to debugging.
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So let's go ahead and move some of this code into some distinct functions.
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So a function that we might have is something like fetchTweets, and another one that we might have is
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makePrediction.
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And finally, we might have one that simply updates the UI,
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so that in the future if we were to have any problems with fetchingTweets, for example, we weren't getting
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any tweets back from Twitter, then we would know to look inside here and look for the method that fetches
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our tweets.
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And if we had problems with making the prediction, then equally, we can navigate to this method.
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And this just makes our code so much more manageable
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and a lot more modular. So let's move the part that fetches our tweets which currently it's kind of all
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entangled with the predictions.
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So I'm going to take everything inside our IBAction here and I'm just going to cut it and I'm going
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to paste it into our function fetchTweets.
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Now, be sure to remember to actually call fetchTweets, so that when the user presses the predict button,
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it actually goes to this function.
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Now, inside this function, the parts that make the prediction,
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I'm going to take away and put it into the makePrediction function.
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So I'm going to take this entire "do catch" block, so everything that's involved in making the prediction
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and place it inside the function, that is our makePrediction function.
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So, now our fetchTweets function only has enough functionality to search Twitter and make the request
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to fetchTweets from the Twitter API. And in our makePrediction function, we're able to do all of the
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rest which needs further splitting up.
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But before we do that, we have one problem where it says, "Use of unresolved identifier 'tweets.'"
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And that's because when that code was over here, we had our tweets right up here which we appended to
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inside our for loop.
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But now what we have to do is we need to call our makePrediction here,
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and so that it triggers this method, and we're going to pass in this tweet array. So this makePrediction
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is going to take a single parameter and I'm going to call it with tweets.
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So this is going to be of type TweetSentimentClassifierInput array.
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And when we call the method, we're going to use the external parameter. And inside the function, we're
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still going to use the same parameter called tweets,
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so that gets put over here.
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Now, when we call this method, we, of course, now have to use "with."
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And the thing that it is expecting is of type TweetSentimentClassifierInput array which is, of course,
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our tweets
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All right.
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So that's fixed, that part.
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Now, the next thing we need to do is once we've gotten our sentimentScore, we need to update the UI, and
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all of that is inside this section here.
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And so let's go ahead and cut that and paste it into our updateUI method, so that we know the part, so
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that it's separated from the functionality of making predictions.
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Now, we have another problem here,
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namely that the sentimentScore doesn't exist outside of the scope of makePrediction because we created
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it in here.
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Now, one of the ways of solving this, that we've done previously when we had less experience with Swift,
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is to simply make this a global variable
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and while that's very, very easy to do. Having a global variable comes with some of its own problems.
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For example, if you have a global variable inside your class ViewController,
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If I create a new object of ViewController, I can affect the value of that global variable.
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Now, if I have it as a local variable that's only available inside this method,
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I won't be able to accidentally mess with this value from other classes,
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and this is an important distinction between global and local variables.
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Now,if you want to read more about when you should use global and when you should use local variables,
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in the resources list for this lesson, I've included a link so that you can do some further background
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reading on this topic.
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Now, over here, we have to solve the short-term problem of how do we use this local variable 
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sentimentScore.
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Well, at the point when we need to call our update UI function which is hereafter the for loop, we're
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going to call updateUI and we're going to pass in our sentiment score.
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And that means, of course, we need to update this method,
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so that it takes a sentimentScore as an integer, and our errors should now go away, because we are calling
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the method update UI passing in the latest sentimentScore that's tallied up from all 100 tweets, and
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then that gets passed into this method and gets used in the "if" statement.
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Now, we just have one error left which is that makePrediction is a method call that we're making inside
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a closure.
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So we have to change this to have the "self" marker in front, so that we know explicitly that it's a method
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in the current class. And now, there you have it.
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Here's our refactored code eliminating global variables, eliminating any hardcoding, and splitting
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off our functionality into distinct modules making our code much easier to maintain and to understand
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when we come back to it or when we collaborate with other people.
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So, of course, there are further ways of simplifying or shortening the code, but there's always a sweet
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spot between clarity of code and the length of code.
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So, personally, I feel like this is acceptable. But if you wish to do further refactoring, then feel free
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to keep going. Or if you want to add more features to this app and make it even more interesting using
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your imagination, then I really look forward to all of your creation and seeing them in the Q & A section.
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Be sure to show off anything fantastic that you've come up with.
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So that's all from me for this module.
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I hope to see you in the next module where I'll be back with more project and more challenges.
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So see you there.