Added pagination to the shop results

src/main/java/com/example/clientproject/web/restControllers/ShopSearch.java

@@ -2,13 +2,14 @@ package com.example.clientproject.web.restControllers;
 
 import com.example.clientproject.data.shops.Shops;
 import com.example.clientproject.data.shops.ShopsRepo;
+import com.example.clientproject.data.tags.Tags;
+import com.example.clientproject.data.tags.TagsRepo;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
-import java.util.List;
-import java.util.Locale;
+import java.util.*;
 import java.util.stream.Collectors;
 
 @RestController
@@ -16,11 +17,14 @@ public class ShopSearch {
     @Autowired
     ShopsRepo shopsRepo;
 
+    @Autowired
+    TagsRepo tagsRepo;
+
     @GetMapping("/shop/search")
     public String searchShops(@RequestParam(value = "q", required = false) String query,
                               @RequestParam(value = "p", required = false) Integer page,
                               @RequestParam(value = "t", required = false) List<String> tags){
-        final Integer itemsPerPage = 6;
+        final Integer ITEMS_PER_PAGE = 6;
 
         //Get all the active shops
         List<Shops> allShops = shopsRepo.findActiveShops();
@@ -34,12 +38,70 @@ public class ShopSearch {
         }
 
         //Filter using the tags provided
+        if(tags!=null){
+            List<Long> validTagIds = new ArrayList<>();
+            for (String t : tags){
+                Optional<Tags> tagsOptional = tagsRepo.findByTagNameIgnoreCase(t);
+                if(tagsOptional.isPresent()){
+                    Long tagId = tagsOptional.get().getTagId();
+                    if (!validTagIds.contains(tagId)){
+                        validTagIds.add(tagId);
+                    }
+                }
+            }
+            List<Shops> validShops = new ArrayList<>();
+            for (Shops s : allShops){
+                boolean match = false;
+                for (Tags t : s.getShopTags()){
+                    if (validTagIds.contains(t.getTagId())){
+                        match = true;
+                        break;
+                    }
+                }
+                if (match){
+                    validShops.add(s);
+                }
+            }
+            allShops = validShops;
+        }
 
         //Paginate
+        boolean hasNextPage = false;
+        if (allShops.size() > ITEMS_PER_PAGE){
+            if(page==null){
+                page = 1;
+            }
+            List<List<Shops>> pages = getPages(allShops, ITEMS_PER_PAGE);
+            if(page > pages.size()){
+                page = 1;
+            }
+            if (pages.size() >= page){
+                allShops = pages.get(page-1);
+            }
+            if (pages.size() >= page + 1){
+                hasNextPage = true;
+            }
+        }
 
         //Convert to required format
 
+
+        //Add details such as the amount of rewards
+
         return allShops.toString();
 
     }
+
+    public <T> List<List<T>> getPages(Collection<T> c, Integer pageSize) {
+        if (c == null)
+            return Collections.emptyList();
+        List<T> list = new ArrayList<T>(c);
+        if (pageSize == null || pageSize <= 0 || pageSize > list.size())
+            pageSize = list.size();
+        int numPages = (int) Math.ceil((double)list.size() / (double)pageSize);
+        List<List<T>> pages = new ArrayList<List<T>>(numPages);
+        for (int pageNum = 0; pageNum < numPages;)
+            pages.add(list.subList(pageNum * pageSize, Math.min(++pageNum * pageSize, list.size())));
+        return pages;
+    }
 }