[Added] Tests and some more functionality to the Services

backend/src/main/java/com/ninjaws/quiz/services/QuizService.java

@@ -0,0 +1,157 @@
+package com.ninjaws.quiz.services;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Optional;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Service;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.github.benmanes.caffeine.cache.Cache;
+import com.github.benmanes.caffeine.cache.Caffeine;
+import com.ninjaws.quiz.models.Answers;
+import com.ninjaws.quiz.models.ApiResponse;
+import com.ninjaws.quiz.models.Question;
+import com.ninjaws.quiz.models.QuizSettings;
+import com.ninjaws.quiz.models.Request;
+import com.ninjaws.quiz.models.Session;
+
+
+@Service
+public class QuizService {
+
+    @Autowired
+    private ApiService apiService;
+    @Autowired
+    private ObjectMapper objectMapper;
+
+    /**
+     * Stores all active sessions
+     * Gets added to when a user requests data
+     * Gets removed from when a user requests their score (by sending their answers)
+     */
+    // private final Map<String,Session> sessions = new ConcurrentHashMap<>();
+    private final Cache<String,Session> sessions;
+
+    /**
+     * Stores all user requests for data
+     * Executes them in order, one every 5 seconds (the limit of the external API)
+     * Removes them from the Queue when the request was succesful
+     */
+    private final BlockingQueue<Request> requests = new LinkedBlockingQueue<>();
+
+
+    public QuizService() {
+        sessions = (Caffeine.newBuilder()
+        .expireAfterWrite(1,TimeUnit.HOURS)
+        .build());
+    }
+
+    public QuizService(Cache<String, Session> cache) {
+        sessions = cache;
+    }
+
+    public QuizSettings jsonToQuizSettings(String json){
+        QuizSettings quizSettings = new QuizSettings();
+        return quizSettings;
+    }
+
+    /**
+     * Actions:
+     * - Creates a session with sessionId
+     * - Adds session to the cache
+     * - Creates a request and adds it to the queue
+     * @param quizSettings The values set by the user, determining the kind of quiz they want
+     * @return The sessionId
+     */
+    public String createSession(QuizSettings quizSettings) {
+        Session session = new Session();
+        try {
+            requests.put(new Request(session.getId(), quizSettings));
+        } catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+        }
+
+        return session.getId();
+    }
+
+    /**
+     * Actions:
+     * - Looks up the session in the cache
+     * - Checks if the data from the request is stored
+     * @param sessionId
+     * @return The data if it's available, Optional.empty() if not, and an Exception if the session is invalid
+     */
+    public Optional<Session> checkSession(String sessionId) throws IllegalArgumentException {
+        Session session = sessions.getIfPresent(sessionId);
+
+        if(session == null) {
+            throw new IllegalArgumentException("Invalid session ID: " + sessionId);
+        }
+
+        if (session.getQuestions() == null) {
+            return Optional.empty();
+        }
+        System.out.print(session.getQuestions().get(0).getIncorrectAnswers().get(0));
+        return Optional.of(session);
+    }
+
+    /**
+     * Every 5 seconds:
+     * - Take the top request from the queue (removes it)
+     * - Perform the request
+     * - Wait for the data
+     * - Find the matching session from the cache
+     * - Add the data to the session in the cache
+     */
+    @Scheduled(fixedDelay = 5000)
+    protected void processQueue() {
+        System.out.print("Schedule!");
+        Request request = requests.poll();
+        if (request != null) {
+            System.out.print("----------------An item!");
+            String json = apiService.requestQuestions(request.getQuizSettings());
+            System.out.print(json);
+            try {
+                List<Question> questions = extractQuestions(json);
+                Session session = sessions.getIfPresent(request.getSessionId());
+                session.setQuestions(questions);
+                sessions.put(request.getSessionId(), session);                
+            } catch (IOException e) {
+                //TODO: Log this
+            }
+        }
+    }
+
+    private List<Question> extractQuestions(String json) throws IOException {
+        return objectMapper.readValue(json, ApiResponse.class).getResults();
+    }
+
+    /**
+     * Receives: sessionId and answers
+     * 
+     * Actions: 
+     * - retrieves session from cache
+     * - Deletes session from cache
+     * - Matches answers answers to correctAnswers
+     * - Calculates score
+     * Returns: calculated score
+     *  */
+    public String getScore(Answers answers) {
+        Session session = sessions.getIfPresent(answers.getSessionId());
+        sessions.invalidate(session.getId());
+        return calculateScore(session, answers);
+    }
+
+    private String calculateScore(Session session, Answers answers) {
+        System.out.print(session);
+        System.out.print(answers);
+        return "You did great!";
+    }
+    
+}