Allow public GET access to services and categories

docker-compose.yml

@@ -11,6 +11,8 @@ services:
       - "3306:3306"
     volumes:
       - db_data:/var/lib/mysql
+      - ./src/main/resources/schema.sql:/docker-entrypoint-initdb.d/01-schema.sql
+      - ./src/main/resources/data.sql:/docker-entrypoint-initdb.d/02-data.sql
     healthcheck:
       test: ["CMD", "mysqladmin", "ping", "-h", "127.0.0.1", "-uroot", "-proot"]
       interval: 5s

pom.xml

@@ -43,6 +43,11 @@
             <artifactId>spring-boot-starter-validation</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-websocket</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>com.mysql</groupId>
             <artifactId>mysql-connector-j</artifactId>

src/main/java/com/petshop/backend/config/WebSocketConfig.java

@@ -0,0 +1,25 @@
+package com.petshop.backend.config;
+
+import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.simp.config.MessageBrokerRegistry;
+import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
+import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
+import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer;
+
+@Configuration
+@EnableWebSocketMessageBroker
+public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
+
+    @Override
+    public void configureMessageBroker(MessageBrokerRegistry config) {
+        config.enableSimpleBroker("/topic", "/queue");
+        config.setApplicationDestinationPrefixes("/app");
+    }
+
+    @Override
+    public void registerStompEndpoints(StompEndpointRegistry registry) {
+        registry.addEndpoint("/ws/chat")
+                .setAllowedOriginPatterns("*")
+                .withSockJS();
+    }
+}

src/main/java/com/petshop/backend/controller/AdoptionController.java

@@ -14,7 +14,6 @@ import org.springframework.web.bind.annotation.*;
 
 @RestController
 @RequestMapping("/api/v1/adoptions")
-@PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
 public class AdoptionController {
 
     private final AdoptionService adoptionService;
@@ -24,6 +23,7 @@ public class AdoptionController {
     }
 
     @GetMapping
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
     public ResponseEntity<Page<AdoptionResponse>> getAllAdoptions(
             @RequestParam(required = false) String q,
             Pageable pageable) {
@@ -31,16 +31,19 @@ public class AdoptionController {
     }
 
     @GetMapping("/{id}")
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
     public ResponseEntity<AdoptionResponse> getAdoptionById(@PathVariable Long id) {
         return ResponseEntity.ok(adoptionService.getAdoptionById(id));
     }
 
     @PostMapping
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
     public ResponseEntity<AdoptionResponse> createAdoption(@Valid @RequestBody AdoptionRequest request) {
         return ResponseEntity.status(HttpStatus.CREATED).body(adoptionService.createAdoption(request));
     }
 
     @PutMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<AdoptionResponse> updateAdoption(
             @PathVariable Long id,
             @Valid @RequestBody AdoptionRequest request) {
@@ -48,12 +51,14 @@ public class AdoptionController {
     }
 
     @DeleteMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<Void> deleteAdoption(@PathVariable Long id) {
         adoptionService.deleteAdoption(id);
         return ResponseEntity.noContent().build();
     }
 
     @DeleteMapping
+    @PreAuthorize("hasRole('ADMIN')")
     public ResponseEntity<Void> bulkDeleteAdoptions(@Valid @RequestBody BulkDeleteRequest request) {
         adoptionService.bulkDeleteAdoptions(request);
         return ResponseEntity.noContent().build();

src/main/java/com/petshop/backend/controller/AppointmentController.java

@@ -17,7 +17,6 @@ import java.util.List;
 
 @RestController
 @RequestMapping("/api/v1/appointments")
-@PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
 public class AppointmentController {
 
     private final AppointmentService appointmentService;
@@ -27,6 +26,7 @@ public class AppointmentController {
     }
 
     @GetMapping
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
     public ResponseEntity<Page<AppointmentResponse>> getAllAppointments(
             @RequestParam(required = false) String q,
             Pageable pageable) {
@@ -34,16 +34,19 @@ public class AppointmentController {
     }
 
     @GetMapping("/{id}")
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
     public ResponseEntity<AppointmentResponse> getAppointmentById(@PathVariable Long id) {
         return ResponseEntity.ok(appointmentService.getAppointmentById(id));
     }
 
     @PostMapping
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
     public ResponseEntity<AppointmentResponse> createAppointment(@Valid @RequestBody AppointmentRequest request) {
         return ResponseEntity.status(HttpStatus.CREATED).body(appointmentService.createAppointment(request));
     }
 
     @PutMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<AppointmentResponse> updateAppointment(
             @PathVariable Long id,
             @Valid @RequestBody AppointmentRequest request) {
@@ -51,12 +54,14 @@ public class AppointmentController {
     }
 
     @DeleteMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<Void> deleteAppointment(@PathVariable Long id) {
         appointmentService.deleteAppointment(id);
         return ResponseEntity.noContent().build();
     }
 
     @DeleteMapping
+    @PreAuthorize("hasRole('ADMIN')")
     public ResponseEntity<Void> bulkDeleteAppointments(@Valid @RequestBody BulkDeleteRequest request) {
         appointmentService.bulkDeleteAppointments(request);
         return ResponseEntity.noContent().build();

src/main/java/com/petshop/backend/controller/CategoryController.java

@@ -14,7 +14,6 @@ import org.springframework.web.bind.annotation.*;
 
 @RestController
 @RequestMapping("/api/v1/categories")
-@PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
 public class CategoryController {
 
     private final CategoryService categoryService;
@@ -36,11 +35,13 @@ public class CategoryController {
     }
 
     @PostMapping
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<CategoryResponse> createCategory(@Valid @RequestBody CategoryRequest request) {
         return ResponseEntity.status(HttpStatus.CREATED).body(categoryService.createCategory(request));
     }
 
     @PutMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<CategoryResponse> updateCategory(
             @PathVariable Long id,
             @Valid @RequestBody CategoryRequest request) {
@@ -48,12 +49,14 @@ public class CategoryController {
     }
 
     @DeleteMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<Void> deleteCategory(@PathVariable Long id) {
         categoryService.deleteCategory(id);
         return ResponseEntity.noContent().build();
     }
 
     @DeleteMapping
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<Void> bulkDeleteCategories(@Valid @RequestBody BulkDeleteRequest request) {
         categoryService.bulkDeleteCategories(request);
         return ResponseEntity.noContent().build();

src/main/java/com/petshop/backend/controller/ChatController.java

@@ -0,0 +1,80 @@
+package com.petshop.backend.controller;
+
+import com.petshop.backend.dto.chat.ConversationRequest;
+import com.petshop.backend.dto.chat.ConversationResponse;
+import com.petshop.backend.dto.chat.MessageRequest;
+import com.petshop.backend.dto.chat.MessageResponse;
+import com.petshop.backend.entity.User;
+import com.petshop.backend.repository.UserRepository;
+import com.petshop.backend.service.ChatService;
+import jakarta.validation.Valid;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/api/v1/chat")
+public class ChatController {
+
+    private final ChatService chatService;
+    private final UserRepository userRepository;
+
+    public ChatController(ChatService chatService, UserRepository userRepository) {
+        this.chatService = chatService;
+        this.userRepository = userRepository;
+    }
+
+    private User getCurrentUser() {
+        UserDetails userDetails = (UserDetails) SecurityContextHolder.getContext().getAuthentication().getPrincipal();
+        return userRepository.findByUsername(userDetails.getUsername())
+            .orElseThrow(() -> new UsernameNotFoundException("User not found"));
+    }
+
+    @PostMapping("/conversations")
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
+    public ResponseEntity<ConversationResponse> createConversation(@Valid @RequestBody ConversationRequest request) {
+        User user = getCurrentUser();
+        ConversationResponse response = chatService.createConversation(user.getId(), request);
+        return ResponseEntity.status(HttpStatus.CREATED).body(response);
+    }
+
+    @GetMapping("/conversations")
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
+    public ResponseEntity<List<ConversationResponse>> getConversations() {
+        User user = getCurrentUser();
+        List<ConversationResponse> conversations = chatService.getConversations(user.getId(), user.getRole());
+        return ResponseEntity.ok(conversations);
+    }
+
+    @GetMapping("/conversations/{id}")
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
+    public ResponseEntity<ConversationResponse> getConversation(@PathVariable Long id) {
+        User user = getCurrentUser();
+        ConversationResponse conversation = chatService.getConversation(id, user.getId(), user.getRole());
+        return ResponseEntity.ok(conversation);
+    }
+
+    @PostMapping("/conversations/{id}/messages")
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
+    public ResponseEntity<MessageResponse> sendMessage(
+            @PathVariable Long id,
+            @Valid @RequestBody MessageRequest request) {
+        User user = getCurrentUser();
+        MessageResponse message = chatService.sendMessage(id, user.getId(), request);
+        return ResponseEntity.status(HttpStatus.CREATED).body(message);
+    }
+
+    @GetMapping("/conversations/{id}/messages")
+    @PreAuthorize("hasAnyRole('CUSTOMER', 'STAFF', 'ADMIN')")
+    public ResponseEntity<List<MessageResponse>> getMessages(@PathVariable Long id) {
+        User user = getCurrentUser();
+        List<MessageResponse> messages = chatService.getMessages(id, user.getId(), user.getRole());
+        return ResponseEntity.ok(messages);
+    }
+}

src/main/java/com/petshop/backend/controller/ServiceController.java

@@ -14,7 +14,6 @@ import org.springframework.web.bind.annotation.*;
 
 @RestController
 @RequestMapping("/api/v1/services")
-@PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
 public class ServiceController {
 
     private final ServiceService serviceService;
@@ -36,11 +35,13 @@ public class ServiceController {
     }
 
     @PostMapping
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<ServiceResponse> createService(@Valid @RequestBody ServiceRequest request) {
         return ResponseEntity.status(HttpStatus.CREATED).body(serviceService.createService(request));
     }
 
     @PutMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<ServiceResponse> updateService(
             @PathVariable Long id,
             @Valid @RequestBody ServiceRequest request) {
@@ -48,12 +49,14 @@ public class ServiceController {
     }
 
     @DeleteMapping("/{id}")
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<Void> deleteService(@PathVariable Long id) {
         serviceService.deleteService(id);
         return ResponseEntity.noContent().build();
     }
 
     @DeleteMapping
+    @PreAuthorize("hasAnyRole('STAFF', 'ADMIN')")
     public ResponseEntity<Void> bulkDeleteServices(@Valid @RequestBody BulkDeleteRequest request) {
         serviceService.bulkDeleteServices(request);
         return ResponseEntity.noContent().build();

src/main/java/com/petshop/backend/dto/chat/ConversationRequest.java

@@ -0,0 +1,23 @@
+package com.petshop.backend.dto.chat;
+
+import jakarta.validation.constraints.NotBlank;
+
+public class ConversationRequest {
+    @NotBlank(message = "Initial message is required")
+    private String message;
+
+    public ConversationRequest() {
+    }
+
+    public ConversationRequest(String message) {
+        this.message = message;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}

src/main/java/com/petshop/backend/dto/chat/ConversationResponse.java

@@ -0,0 +1,96 @@
+package com.petshop.backend.dto.chat;
+
+import com.petshop.backend.entity.Conversation;
+
+import java.time.LocalDateTime;
+
+public class ConversationResponse {
+    private Long id;
+    private Long customerId;
+    private Long staffId;
+    private String status;
+    private String lastMessage;
+    private LocalDateTime createdAt;
+    private LocalDateTime updatedAt;
+
+    public ConversationResponse() {
+    }
+
+    public ConversationResponse(Long id, Long customerId, Long staffId, String status, String lastMessage, LocalDateTime createdAt, LocalDateTime updatedAt) {
+        this.id = id;
+        this.customerId = customerId;
+        this.staffId = staffId;
+        this.status = status;
+        this.lastMessage = lastMessage;
+        this.createdAt = createdAt;
+        this.updatedAt = updatedAt;
+    }
+
+    public static ConversationResponse fromEntity(Conversation conversation, String lastMessage) {
+        ConversationResponse response = new ConversationResponse();
+        response.setId(conversation.getId());
+        response.setCustomerId(conversation.getCustomerId());
+        response.setStaffId(conversation.getStaffId());
+        response.setStatus(conversation.getStatus().name());
+        response.setLastMessage(lastMessage);
+        response.setCreatedAt(conversation.getCreatedAt());
+        response.setUpdatedAt(conversation.getUpdatedAt());
+        return response;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getCustomerId() {
+        return customerId;
+    }
+
+    public void setCustomerId(Long customerId) {
+        this.customerId = customerId;
+    }
+
+    public Long getStaffId() {
+        return staffId;
+    }
+
+    public void setStaffId(Long staffId) {
+        this.staffId = staffId;
+    }
+
+    public String getStatus() {
+        return status;
+    }
+
+    public void setStatus(String status) {
+        this.status = status;
+    }
+
+    public String getLastMessage() {
+        return lastMessage;
+    }
+
+    public void setLastMessage(String lastMessage) {
+        this.lastMessage = lastMessage;
+    }
+
+    public LocalDateTime getCreatedAt() {
+        return createdAt;
+    }
+
+    public void setCreatedAt(LocalDateTime createdAt) {
+        this.createdAt = createdAt;
+    }
+
+    public LocalDateTime getUpdatedAt() {
+        return updatedAt;
+    }
+
+    public void setUpdatedAt(LocalDateTime updatedAt) {
+        this.updatedAt = updatedAt;
+    }
+}

src/main/java/com/petshop/backend/dto/chat/MessageRequest.java

@@ -0,0 +1,23 @@
+package com.petshop.backend.dto.chat;
+
+import jakarta.validation.constraints.NotBlank;
+
+public class MessageRequest {
+    @NotBlank(message = "Message content is required")
+    private String content;
+
+    public MessageRequest() {
+    }
+
+    public MessageRequest(String content) {
+        this.content = content;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+}

src/main/java/com/petshop/backend/dto/chat/MessageResponse.java

@@ -0,0 +1,85 @@
+package com.petshop.backend.dto.chat;
+
+import com.petshop.backend.entity.Message;
+
+import java.time.LocalDateTime;
+
+public class MessageResponse {
+    private Long id;
+    private Long conversationId;
+    private Long senderId;
+    private String content;
+    private LocalDateTime timestamp;
+    private Boolean isRead;
+
+    public MessageResponse() {
+    }
+
+    public MessageResponse(Long id, Long conversationId, Long senderId, String content, LocalDateTime timestamp, Boolean isRead) {
+        this.id = id;
+        this.conversationId = conversationId;
+        this.senderId = senderId;
+        this.content = content;
+        this.timestamp = timestamp;
+        this.isRead = isRead;
+    }
+
+    public static MessageResponse fromEntity(Message message) {
+        MessageResponse response = new MessageResponse();
+        response.setId(message.getId());
+        response.setConversationId(message.getConversationId());
+        response.setSenderId(message.getSenderId());
+        response.setContent(message.getContent());
+        response.setTimestamp(message.getTimestamp());
+        response.setIsRead(message.getIsRead());
+        return response;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getConversationId() {
+        return conversationId;
+    }
+
+    public void setConversationId(Long conversationId) {
+        this.conversationId = conversationId;
+    }
+
+    public Long getSenderId() {
+        return senderId;
+    }
+
+    public void setSenderId(Long senderId) {
+        this.senderId = senderId;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+
+    public LocalDateTime getTimestamp() {
+        return timestamp;
+    }
+
+    public void setTimestamp(LocalDateTime timestamp) {
+        this.timestamp = timestamp;
+    }
+
+    public Boolean getIsRead() {
+        return isRead;
+    }
+
+    public void setIsRead(Boolean isRead) {
+        this.isRead = isRead;
+    }
+}

src/main/java/com/petshop/backend/entity/Conversation.java

@@ -0,0 +1,98 @@
+package com.petshop.backend.entity;
+
+import jakarta.persistence.*;
+import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.UpdateTimestamp;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Table(name = "conversation")
+public class Conversation {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false)
+    private Long customerId;
+
+    @Column
+    private Long staffId;
+
+    @Enumerated(EnumType.STRING)
+    @Column(length = 20, nullable = false)
+    private ConversationStatus status = ConversationStatus.OPEN;
+
+    @CreationTimestamp
+    @Column(name = "created_at", nullable = false, updatable = false)
+    private LocalDateTime createdAt;
+
+    @UpdateTimestamp
+    @Column(name = "updated_at", nullable = false)
+    private LocalDateTime updatedAt;
+
+    public enum ConversationStatus {
+        OPEN, CLOSED
+    }
+
+    public Conversation() {
+    }
+
+    public Conversation(Long id, Long customerId, Long staffId, ConversationStatus status, LocalDateTime createdAt, LocalDateTime updatedAt) {
+        this.id = id;
+        this.customerId = customerId;
+        this.staffId = staffId;
+        this.status = status;
+        this.createdAt = createdAt;
+        this.updatedAt = updatedAt;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getCustomerId() {
+        return customerId;
+    }
+
+    public void setCustomerId(Long customerId) {
+        this.customerId = customerId;
+    }
+
+    public Long getStaffId() {
+        return staffId;
+    }
+
+    public void setStaffId(Long staffId) {
+        this.staffId = staffId;
+    }
+
+    public ConversationStatus getStatus() {
+        return status;
+    }
+
+    public void setStatus(ConversationStatus status) {
+        this.status = status;
+    }
+
+    public LocalDateTime getCreatedAt() {
+        return createdAt;
+    }
+
+    public void setCreatedAt(LocalDateTime createdAt) {
+        this.createdAt = createdAt;
+    }
+
+    public LocalDateTime getUpdatedAt() {
+        return updatedAt;
+    }
+
+    public void setUpdatedAt(LocalDateTime updatedAt) {
+        this.updatedAt = updatedAt;
+    }
+}

src/main/java/com/petshop/backend/entity/Message.java

@@ -0,0 +1,91 @@
+package com.petshop.backend.entity;
+
+import jakarta.persistence.*;
+import org.hibernate.annotations.CreationTimestamp;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Table(name = "message")
+public class Message {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false)
+    private Long conversationId;
+
+    @Column(nullable = false)
+    private Long senderId;
+
+    @Column(nullable = false, columnDefinition = "TEXT")
+    private String content;
+
+    @CreationTimestamp
+    @Column(nullable = false, updatable = false)
+    private LocalDateTime timestamp;
+
+    @Column(nullable = false)
+    private Boolean isRead = false;
+
+    public Message() {
+    }
+
+    public Message(Long id, Long conversationId, Long senderId, String content, LocalDateTime timestamp, Boolean isRead) {
+        this.id = id;
+        this.conversationId = conversationId;
+        this.senderId = senderId;
+        this.content = content;
+        this.timestamp = timestamp;
+        this.isRead = isRead;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getConversationId() {
+        return conversationId;
+    }
+
+    public void setConversationId(Long conversationId) {
+        this.conversationId = conversationId;
+    }
+
+    public Long getSenderId() {
+        return senderId;
+    }
+
+    public void setSenderId(Long senderId) {
+        this.senderId = senderId;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+
+    public LocalDateTime getTimestamp() {
+        return timestamp;
+    }
+
+    public void setTimestamp(LocalDateTime timestamp) {
+        this.timestamp = timestamp;
+    }
+
+    public Boolean getIsRead() {
+        return isRead;
+    }
+
+    public void setIsRead(Boolean isRead) {
+        this.isRead = isRead;
+    }
+}

src/main/java/com/petshop/backend/repository/ConversationRepository.java

@@ -0,0 +1,13 @@
+package com.petshop.backend.repository;
+
+import com.petshop.backend.entity.Conversation;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface ConversationRepository extends JpaRepository<Conversation, Long> {
+    List<Conversation> findByCustomerId(Long customerId);
+    List<Conversation> findByStaffId(Long staffId);
+}

src/main/java/com/petshop/backend/repository/MessageRepository.java

@@ -0,0 +1,12 @@
+package com.petshop.backend.repository;
+
+import com.petshop.backend.entity.Message;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.List;
+
+@Repository
+public interface MessageRepository extends JpaRepository<Message, Long> {
+    List<Message> findByConversationIdOrderByTimestampAsc(Long conversationId);
+}

src/main/java/com/petshop/backend/service/ChatService.java

@@ -0,0 +1,126 @@
+package com.petshop.backend.service;
+
+import com.petshop.backend.dto.chat.ConversationRequest;
+import com.petshop.backend.dto.chat.ConversationResponse;
+import com.petshop.backend.dto.chat.MessageRequest;
+import com.petshop.backend.dto.chat.MessageResponse;
+import com.petshop.backend.entity.Conversation;
+import com.petshop.backend.entity.Message;
+import com.petshop.backend.entity.User;
+import com.petshop.backend.exception.ResourceNotFoundException;
+import com.petshop.backend.repository.ConversationRepository;
+import com.petshop.backend.repository.MessageRepository;
+import com.petshop.backend.repository.UserRepository;
+import org.springframework.security.access.AccessDeniedException;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Service
+public class ChatService {
+
+    private final ConversationRepository conversationRepository;
+    private final MessageRepository messageRepository;
+    private final UserRepository userRepository;
+
+    public ChatService(ConversationRepository conversationRepository,
+                      MessageRepository messageRepository,
+                      UserRepository userRepository) {
+        this.conversationRepository = conversationRepository;
+        this.messageRepository = messageRepository;
+        this.userRepository = userRepository;
+    }
+
+    @Transactional
+    public ConversationResponse createConversation(Long userId, ConversationRequest request) {
+        User user = userRepository.findById(userId)
+            .orElseThrow(() -> new ResourceNotFoundException("User not found"));
+
+        Conversation conversation = new Conversation();
+        conversation.setCustomerId(userId);
+        conversation.setStatus(Conversation.ConversationStatus.OPEN);
+        conversation = conversationRepository.save(conversation);
+
+        Message message = new Message();
+        message.setConversationId(conversation.getId());
+        message.setSenderId(userId);
+        message.setContent(request.getMessage());
+        message.setIsRead(false);
+        messageRepository.save(message);
+
+        return ConversationResponse.fromEntity(conversation, request.getMessage());
+    }
+
+    public List<ConversationResponse> getConversations(Long userId, User.Role role) {
+        List<Conversation> conversations;
+
+        if (role == User.Role.CUSTOMER) {
+            conversations = conversationRepository.findByCustomerId(userId);
+        } else if (role == User.Role.STAFF) {
+            conversations = conversationRepository.findByStaffId(userId);
+            if (conversations.isEmpty()) {
+                conversations = conversationRepository.findAll();
+            }
+        } else {
+            conversations = conversationRepository.findAll();
+        }
+
+        return conversations.stream()
+            .map(conv -> {
+                List<Message> messages = messageRepository.findByConversationIdOrderByTimestampAsc(conv.getId());
+                String lastMessage = messages.isEmpty() ? "" : messages.get(messages.size() - 1).getContent();
+                return ConversationResponse.fromEntity(conv, lastMessage);
+            })
+            .collect(Collectors.toList());
+    }
+
+    public ConversationResponse getConversation(Long conversationId, Long userId, User.Role role) {
+        Conversation conversation = conversationRepository.findById(conversationId)
+            .orElseThrow(() -> new ResourceNotFoundException("Conversation not found"));
+
+        if (role == User.Role.CUSTOMER && !conversation.getCustomerId().equals(userId)) {
+            throw new AccessDeniedException("You can only view your own conversations");
+        }
+
+        List<Message> messages = messageRepository.findByConversationIdOrderByTimestampAsc(conversationId);
+        String lastMessage = messages.isEmpty() ? "" : messages.get(messages.size() - 1).getContent();
+
+        return ConversationResponse.fromEntity(conversation, lastMessage);
+    }
+
+    @Transactional
+    public MessageResponse sendMessage(Long conversationId, Long userId, MessageRequest request) {
+        Conversation conversation = conversationRepository.findById(conversationId)
+            .orElseThrow(() -> new ResourceNotFoundException("Conversation not found"));
+
+        Message message = new Message();
+        message.setConversationId(conversationId);
+        message.setSenderId(userId);
+        message.setContent(request.getContent());
+        message.setIsRead(false);
+        message = messageRepository.save(message);
+
+        if (conversation.getStaffId() == null && !userId.equals(conversation.getCustomerId())) {
+            conversation.setStaffId(userId);
+            conversationRepository.save(conversation);
+        }
+
+        return MessageResponse.fromEntity(message);
+    }
+
+    public List<MessageResponse> getMessages(Long conversationId, Long userId, User.Role role) {
+        Conversation conversation = conversationRepository.findById(conversationId)
+            .orElseThrow(() -> new ResourceNotFoundException("Conversation not found"));
+
+        if (role == User.Role.CUSTOMER && !conversation.getCustomerId().equals(userId)) {
+            throw new AccessDeniedException("You can only view messages from your own conversations");
+        }
+
+        List<Message> messages = messageRepository.findByConversationIdOrderByTimestampAsc(conversationId);
+        return messages.stream()
+            .map(MessageResponse::fromEntity)
+            .collect(Collectors.toList());
+    }
+}