#119 create grants notification service

src/main/java/ru/ulstu/grant/service/GrantNotificationService.java

@@ -0,0 +1,66 @@
+package ru.ulstu.grant.service;
+
+import com.google.common.collect.ImmutableMap;
+import org.springframework.stereotype.Service;
+import ru.ulstu.core.util.DateUtils;
+import ru.ulstu.grant.model.Grant;
+import ru.ulstu.user.model.User;
+import ru.ulstu.user.service.MailService;
+
+import java.util.Date;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+@Service
+public class GrantNotificationService {
+    private final static int DAYS_TO_DEADLINE_NOTIFICATION = 7;
+    private final static String TEMPLATE_DEADLINE = "grantDeadlineNotification";
+    private final static String TEMPLATE_CREATE = "grantCreateNotification";
+    private final static String TEMPLATE_AUTHORS_CHANGED = "grantAuthorsChangeNotification";
+
+    private final static String TITLE_DEADLINE = "Приближается дедлайн гранта: %s";
+    private final static String TITLE_CREATE = "Создан грант: %s";
+    private final static String TITLE_AUTHORS_CHANGED = "Изменился состав рабочей группы гранта: %s";
+
+    private final MailService mailService;
+
+    public GrantNotificationService(MailService mailService) {
+        this.mailService = mailService;
+    }
+
+    public void sendDeadlineNotifications(List<Grant> grants, boolean isDeadlineBeforeWeek) {
+        Date now = DateUtils.addDays(new Date(), DAYS_TO_DEADLINE_NOTIFICATION);
+        grants.stream()
+                .filter(grant -> needToSendDeadlineNotification(grant, now, isDeadlineBeforeWeek))
+                .forEach(grant -> sendMessageDeadline(grant));
+    }
+
+    private boolean needToSendDeadlineNotification(Grant grant, Date compareDate, boolean isDeadlineBeforeWeek) {
+        return (grant.getNextDeadline().isPresent())
+                && (compareDate.before(grant.getNextDeadline().get().getDate()) && isDeadlineBeforeWeek
+                || compareDate.after(grant.getNextDeadline().get().getDate()) && !isDeadlineBeforeWeek)
+                && grant.getNextDeadline().get().getDate().after(new Date());
+    }
+
+    private void sendMessageDeadline(Grant grant) {
+        Map<String, Object> variables = ImmutableMap.of("grant", grant);
+        sendForAllAuthors(variables, grant, TEMPLATE_DEADLINE, String.format(TITLE_DEADLINE, grant.getTitle()));
+    }
+
+    public void sendCreateNotification(Grant grant) {
+        Map<String, Object> variables = ImmutableMap.of("grant", grant);
+        sendForAllAuthors(variables, grant, TEMPLATE_CREATE, String.format(TITLE_CREATE, grant.getTitle()));
+    }
+
+    public void authorsChangeNotification(Grant grant, List<User> oldAuthors) {
+        Map<String, Object> variables = ImmutableMap.of("grant", grant, "oldAuthors", oldAuthors);
+        sendForAllAuthors(variables, grant, TEMPLATE_AUTHORS_CHANGED, String.format(TITLE_AUTHORS_CHANGED, grant.getTitle()));
+    }
+
+    private void sendForAllAuthors(Map<String, Object> variables, Grant grant, String template, String title) {
+        Set<User> allAuthors = grant.getAuthors();
+        allAuthors.add(grant.getLeader());
+        allAuthors.forEach(author -> mailService.sendEmailFromTemplate(variables, author, template, title));
+    }
+}