1 files changed, 138 insertions, 0 deletions
diff --git a/src/main/java/design/model/course_search/CurrentSearchQuery.java b/src/main/java/design/model/course_search/CurrentSearchQuery.java
new file mode 100644
index 0000000..999dfcb
--- /dev/null
+++ b/src/main/java/design/model/course_search/CurrentSearchQuery.java
@@ -0,0 +1,138 @@
+package design.model.course_search;
+
+import design.persistence.MasterDatabase;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/*
+ * Represents the state of our current search.
+ */
+public class CurrentSearchQuery {
+    public static final CurrentSearchQuery INSTANCE = new CurrentSearchQuery();
+
+    // initialize our search with the master db data
+    MasterDatabase db = MasterDatabase.INSTANCE;
+    private CourseList query = db.getCourseList();
+    private final List<CourseSorter> filters = new ArrayList<CourseSorter>();
+
+    // reset the query
+    public void reset() {
+        query = db.getCourseList();
+    }
+
+    // add a new filter
+    public void addFilter(CourseSorter filter) {
+        filters.add(filter);
+    }
+
+    // clear the filters
+    public void clearFilters() {
+        filters.clear();
+    }
+
+    // print out the filters we're currently using and the order
+    public String printFilters() {
+        String filterResult = "";
+
+        // no filters? let the user know.
+        if (filters.size() == 0) {
+            return "nothing";
+        }
+
+        for (CourseSorter f : filters) {
+            filterResult += f.toString() + " --> ";
+        }
+
+        // remove last arrow and add padding
+        filterResult = filterResult.substring(0, filterResult.length() - 5);
+        filterResult += "\n";
+
+        return filterResult;
+    }
+
+    // get all the filters
+    public List<CourseSorter> getFilters() {
+        return filters;
+    }
+
+    // get our current query.
+    public CourseList getQueryResult() {
+        return query;
+    }
+
+    public void search(String searchQuery) {
+        // only grab courses which fit our search
+        List<ICourse> courses = db.getCourseList().getCourses().stream()
+                .filter(s -> s.toString().toLowerCase().contains(searchQuery.toLowerCase()))
+                .collect(Collectors.toList());
+
+        // and now, we filter it!
+        CourseList filtered = applyFilters(filters, courses);
+        query.setCourses(filtered.getCourses());
+    }
+
+    // to apply our filters we need to traverse the tree and make new grouping as we go. 
+    public CourseList applyFilters(List<CourseSorter> filters, List<ICourse> coursesToFilter) {
+        CourseList root = new CourseList();
+        root.setCourses(applyFiltersRecursive(coursesToFilter, filters, 0));
+        return root;
+    }
+
+    // the actual recursive part. Level is how many filters deep we are.
+    private List<ICourse> applyFiltersRecursive(List<ICourse> courses, List<CourseSorter> filters, int level) {
+        // base case. we have gone past all filters or theres only one course in this list. already sorted!
+        if (level >= filters.size() || courses.size() <= 1) {
+            return courses;
+        }
+
+        // grab out current sorting strategy for this level, and sort the courselist.
+        CourseSorter sorter = filters.get(level);
+        sorter.sortCourses(courses);
+
+        // the resulting sorted list, with new groupings
+        List<ICourse> result = new ArrayList<>();
+
+        // courses with an equal value.
+        List<ICourse> currentGroup = new ArrayList<>();
+
+        ICourse prev = null;
+
+        // run through the courses, if
+        for (ICourse c : courses) {
+            /* always add the first course to a new group. when iterating through courses, if we have to values that are equal, we need to add them into a group together.
+             * think about it this way. If we have [ 1, 2, 2, 2, 3, 4 ]. 1 is first, so its in it's own group. 2 /= 1, so 2 gets its own group.
+             * now do 2 again. we add it to the existing group 2. Same with the next 2. Now 3. 3 /= 2, so we put it in it's own group.
+             */
+            if (prev == null || !sorter.isEqual(prev, c)) {
+                // already a course in that group? we now have two equal values and so 
+                if (!currentGroup.isEmpty()) {
+                    result.add(makeGroup(currentGroup, filters, level));
+                    currentGroup = new ArrayList<>();
+                }
+            }
+
+            currentGroup.add(c);
+            prev = c;
+        }
+
+        // handle the last group.
+        if (!currentGroup.isEmpty()) {
+            result.add(makeGroup(currentGroup, filters, level));
+        }
+
+        return result;
+    }
+
+    // make a CourseList group, a sublist of a group, and filter it. 
+    private ICourse makeGroup(List<ICourse> group, List<CourseSorter> filters, int level) {
+        // base case, group only has one course in it (already sorted)
+        if (group.size() == 1) return group.get(0);
+
+        // group has more than 1 course in it, it needs to be sorted more if possible.
+        CourseList subList = new CourseList();
+        subList.setCourses(applyFiltersRecursive(group, filters, level + 1));
+        return subList;
+    }
+}