creating_a_data_class.step

goals do
	goal "Write a class to get our data"
	goal "Display the topics on a web page"
	message "A class is a special piece of code for performing a given task"
end

steps do
	step do
		message "Create a new file called `TopicData.php` in the `public` directory"

		message "Type the following to create our empty class:"

		source_code :php, <<-PHP
			<?php
			class TopicData {
				// CLASS CONTENTS GO HERE
			}
			?>
		PHP
	end

	step do
		message "Now create a constructor that will assign a PDO instance to a class variable:"

		source_code :php, <<-PHP
			<?php
			class TopicData {
				protected $connection;
			
				public function __construct($pdo)
				{
					$this->connection = $pdo;
				}
			}
			?>
		PHP
	end

	step do
		message "Next lets make the class fetch all of our topics:"

		source_code :php, <<-PHP
			<?php
			class TopicData {

				protected $connection;

				public function __construct($pdo)
				{
					$this->connection = $pdo;
				}

				public function getAllTopics()
				{
					$query = $this->connection->prepare("SELECT * FROM topics");
					$query->execute();

					return $query;
				}
			}
			?>
		PHP

		tip "Notice how we use the same `SELECT` as in the previous section"
	end

	step do
		message "Now we can use the data class in `index.php`, to get our topics:"

		source_code :php, <<-PHP
			<?php
			require 'TopicData.php';
                        $pdo = new PDO("mysql:host=localhost;dbname=suggestotron", "root", "root");

			$data = new TopicData($pdo);
			$topics = $data->getAllTopics();
		PHP

		message "Now `$topics` is a database result object containing our topics."
	end

	step do
		message "Now we have our topics lets display them by using a `foreach` to iterate over them:"

		source_code :php, <<-PHP
			foreach ($topics as $topic) {
				echo "<h3>" .$topic['title']. " (ID: " .$topic['id']. ")</h3>";
				echo "<p>";
				echo nl2br($topic['description']);
				echo "</p>";
			}
		PHP
	end

	step do
		message "To see what this looks like, refresh the application in your browser!"
    	
    	img src: "img/List_of_topics.png", alt: "List of topics"
	end
end

explanation do
	message "With just these few lines of code we are able to connect to our database, fetch our data, and dynamically create an HTML page. *How neat is that?*"
end

next_step "adding_topics"