feat: add tag filtering to modification queries and implement tag retrieval endpoint

src/main/java/com/onixbyte/deltaforceguide/controller/ModificationController.java

@@ -15,6 +15,8 @@ import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
+import java.util.List;
+
 @Validated
 @RestController
 @RequestMapping("/modifications")
@@ -32,9 +34,10 @@ public class ModificationController {
             @RequestParam(defaultValue = "20") @Min(1) @Max(100) int size,
             @RequestParam(required = false) @Positive Long firearmId,
             @RequestParam(defaultValue = "id") String sortBy,
-            @RequestParam(defaultValue = "DESC") Sort.Direction direction
+            @RequestParam(defaultValue = "DESC") Sort.Direction direction,
+            @RequestParam(required = false) List<String> tags
     ) {
-        return modificationService.pageQuery(firearmId, PageRequest.of(page, size, Sort.by(direction, sortBy)));
+        return modificationService.pageQuery(firearmId, tags, PageRequest.of(page, size, Sort.by(direction, sortBy)));
     }
 
     @GetMapping("/{id}")
@@ -42,4 +45,3 @@ public class ModificationController {
         return modificationService.queryById(id);
     }
 }
-

src/main/java/com/onixbyte/deltaforceguide/controller/TagController.java

@@ -0,0 +1,25 @@
+package com.onixbyte.deltaforceguide.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+import com.onixbyte.deltaforceguide.service.ModificationService;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/tags")
+public class TagController {
+
+    private final ModificationService modificationService;
+
+    public TagController(ModificationService modificationService) {
+        this.modificationService = modificationService;
+    }
+
+    @GetMapping
+    public List<String> getTags(@RequestParam(required = false) Long firearmId) {
+        return modificationService.findAllTags(firearmId);
+    }
+}

src/main/java/com/onixbyte/deltaforceguide/repository/ModificationRepository.java

@@ -5,8 +5,11 @@ import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.EntityGraph;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 
+import java.util.List;
 import java.util.Optional;
 
 @Repository
@@ -21,6 +24,20 @@ public interface ModificationRepository extends JpaRepository<Modification, Long
     @Override
     @EntityGraph(attributePaths = {"firearm"})
     Optional<Modification> findById(Long id);
+
+    @Query(value = """
+            SELECT * FROM modification m 
+            WHERE (:firearmId IS NULL OR m.firearm_id = :firearmId)
+              AND (CAST(:tagsJson AS text) IS NULL OR cast(m.tags as jsonb) @> cast(CAST(:tagsJson AS text) as jsonb))
+            """,
+            countQuery = """
+            SELECT count(*) FROM modification m 
+            WHERE (:firearmId IS NULL OR m.firearm_id = :firearmId)
+              AND (CAST(:tagsJson AS text) IS NULL OR cast(m.tags as jsonb) @> cast(CAST(:tagsJson AS text) as jsonb))
+            """,
+            nativeQuery = true)
+    Page<Modification> pageQueryByFirearmAndTags(@Param("firearmId") Long firearmId, @Param("tagsJson") String tagsJson, Pageable pageable);
+
+    @Query(value = "SELECT DISTINCT jsonb_array_elements_text(cast(tags as jsonb)) FROM modification WHERE (:firearmId IS NULL OR firearm_id = :firearmId)", nativeQuery = true)
+    List<String> findAllTags(@Param("firearmId") Long firearmId);
 }
-
-

src/main/java/com/onixbyte/deltaforceguide/service/ModificationService.java

@@ -4,6 +4,8 @@ import com.onixbyte.deltaforceguide.domain.dto.ModificationResponse;
 import com.onixbyte.deltaforceguide.domain.dto.PageResponse;
 import com.onixbyte.deltaforceguide.domain.entity.Modification;
 import com.onixbyte.deltaforceguide.repository.ModificationRepository;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
 import org.springframework.http.HttpStatus;
@@ -11,20 +13,36 @@ import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 import org.springframework.web.server.ResponseStatusException;
 
+import java.util.List;
+
 @Service
 public class ModificationService {
 
     private final ModificationRepository modificationRepository;
+    private final ObjectMapper objectMapper;
 
-    public ModificationService(ModificationRepository modificationRepository) {
+    public ModificationService(ModificationRepository modificationRepository, ObjectMapper objectMapper) {
         this.modificationRepository = modificationRepository;
+        this.objectMapper = objectMapper;
     }
 
     @Transactional(readOnly = true)
-    public PageResponse<ModificationResponse> pageQuery(Long firearmId, Pageable pageable) {
-        Page<Modification> page = firearmId == null
-                ? modificationRepository.findAllBy(pageable)
-                : modificationRepository.findAllByFirearm_Id(firearmId, pageable);
+    public PageResponse<ModificationResponse> pageQuery(Long firearmId, List<String> tags, Pageable pageable) {
+        String tagsJson = null;
+        if (tags != null && !tags.isEmpty()) {
+            try {
+                tagsJson = objectMapper.writeValueAsString(tags);
+            } catch (JsonProcessingException e) {
+                throw new RuntimeException("Failed to serialize tags", e);
+            }
+        }
+        
+        Page<Modification> page;
+        if (tagsJson != null || firearmId != null) {
+            page = modificationRepository.pageQueryByFirearmAndTags(firearmId, tagsJson, pageable);
+        } else {
+            page = modificationRepository.findAllBy(pageable);
+        }
 
         return PageResponse.from(page.map(ModificationResponse::from));
     }
@@ -35,5 +53,9 @@ public class ModificationService {
                 .map(ModificationResponse::from)
                 .orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND, "Modification not found: " + id));
     }
-}
 
+    @Transactional(readOnly = true)
+    public List<String> findAllTags(Long firearmId) {
+        return modificationRepository.findAllTags(firearmId);
+    }
+}