Web and AI chat

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

@@ -0,0 +1,84 @@
+package com.petshop.backend.controller;
+
+import com.petshop.backend.dto.ai.AiChatRequest;
+import com.petshop.backend.dto.ai.AiChatResponse;
+import com.petshop.backend.entity.Pet;
+import com.petshop.backend.entity.User;
+import com.petshop.backend.repository.PetRepository;
+import com.petshop.backend.repository.UserRepository;
+import com.petshop.backend.service.OpenRouterService;
+import com.petshop.backend.util.AuthenticationHelper;
+import jakarta.validation.Valid;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.Collections;
+import java.util.List;
+
+@RestController
+@RequestMapping("/api/v1/ai-chat")
+public class AiChatController {
+
+    private final OpenRouterService openRouterService;
+    private final PetRepository petRepository;
+    private final UserRepository userRepository;
+
+    public AiChatController(OpenRouterService openRouterService,
+                            PetRepository petRepository,
+                            UserRepository userRepository) {
+        this.openRouterService = openRouterService;
+        this.petRepository = petRepository;
+        this.userRepository = userRepository;
+    }
+
+    private User getCurrentUser() {
+        try {
+            return AuthenticationHelper.getAuthenticatedUser(userRepository);
+        } 
+        
+        catch (RuntimeException ex) {
+            throw new UsernameNotFoundException(ex.getMessage(), ex);
+        }
+    }
+
+    @PostMapping("/message")
+    @PreAuthorize("isAuthenticated()")
+    public ResponseEntity<AiChatResponse> sendMessage(@Valid @RequestBody AiChatRequest request) {
+        if (request.getMessage() == null || request.getMessage().isBlank()) {
+            return ResponseEntity.badRequest().body(AiChatResponse.fail("Message cannot be empty"));
+        }
+
+        User user = getCurrentUser();
+
+        List<Pet> userPets;
+        try {
+            userPets = petRepository.findAllByOwner_IdOrderByPetNameAsc(user.getId());
+        } 
+        
+        catch (Exception e) {
+            userPets = Collections.emptyList();
+        }
+
+        try {
+            String aiReply = openRouterService.chat(
+                    request.getHistory(),
+                    request.getMessage(),
+                    userPets
+            );
+
+            return ResponseEntity.ok(AiChatResponse.ok(aiReply));
+        } 
+        
+        catch (IllegalStateException e) {
+            
+            return ResponseEntity.status(503).body(AiChatResponse.fail("AI service is not configured. Please contact support."));
+        } 
+        
+        catch (Exception e) {
+
+            return ResponseEntity.status(502).body(AiChatResponse.fail("AI service is temporarily unavailable. Please try again later."));
+        }
+    }
+}

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

@@ -55,7 +55,7 @@ public class ChatController {
     }
 
     @PostMapping("/conversations")
-    @PreAuthorize("hasRole('CUSTOMER')")
+    @PreAuthorize("isAuthenticated()")
     public ResponseEntity<ConversationResponse> createConversation(@Valid @RequestBody ConversationRequest request) {
         User user = getCurrentUser();
         ConversationResponse response = chatService.createConversation(user.getId(), request);
@@ -139,7 +139,7 @@ public class ChatController {
     }
 
     @PostMapping("/conversations/{id}/request-human")
-    @PreAuthorize("hasRole('CUSTOMER')")
+    @PreAuthorize("isAuthenticated()")
     public ResponseEntity<ConversationResponse> requestHumanTakeover(@PathVariable Long id) {
         User user = getCurrentUser();
         ConversationResponse conversation = chatService.requestHumanTakeover(id, user.getId(), user.getRole());

backend/src/main/java/com/petshop/backend/dto/ai/AiChatRequest.java

@@ -0,0 +1,61 @@
+package com.petshop.backend.dto.ai;
+
+import java.util.List;
+
+public class AiChatRequest {
+
+    private String message;
+    private List<ChatHistoryItem> history;
+
+    public AiChatRequest() {
+    }
+
+    public String getMessage() {
+
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+
+    public List<ChatHistoryItem> getHistory() {
+
+        return history;
+    }
+
+    public void setHistory(List<ChatHistoryItem> history) {
+        this.history = history;
+    }
+
+    public static class ChatHistoryItem {
+        private String role;
+        private String content;
+
+        public ChatHistoryItem() {
+        }
+
+        public ChatHistoryItem(String role, String content) {
+            this.role = role;
+            this.content = content;
+        }
+
+        public String getRole() {
+
+            return role;
+        }
+
+        public void setRole(String role) {
+            this.role = role;
+        }
+
+        public String getContent() {
+            
+            return content;
+        }
+
+        public void setContent(String content) {
+            this.content = content;
+        }
+    }
+}

backend/src/main/java/com/petshop/backend/dto/ai/AiChatResponse.java

@@ -0,0 +1,54 @@
+package com.petshop.backend.dto.ai;
+
+public class AiChatResponse {
+
+    private String message;
+    private boolean success;
+    private String error;
+
+    public AiChatResponse() {
+    }
+
+    public static AiChatResponse ok(String message) {
+        AiChatResponse r = new AiChatResponse();
+        r.message = message;
+        r.success = true;
+
+        return r;
+    }
+
+    public static AiChatResponse fail(String error) {
+        AiChatResponse r = new AiChatResponse();
+        r.success = false;
+        r.error = error;
+
+        return r;
+    }
+
+    public String getMessage() {
+
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+
+    public boolean isSuccess() {
+
+        return success;
+    }
+
+    public void setSuccess(boolean success) {
+        this.success = success;
+    }
+
+    public String getError() {
+        
+        return error;
+    }
+
+    public void setError(String error) {
+        this.error = error;
+    }
+}

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

@@ -48,10 +48,6 @@ public class ChatService {
         User user = userRepository.findById(userId)
             .orElseThrow(() -> new ResourceNotFoundException("User not found"));
 
-        if (user.getRole() != User.Role.CUSTOMER) {
-            throw new AccessDeniedException("Only customers can start new conversations");
-        }
-
         Conversation conversation = new Conversation();
         conversation.setCustomerId(userId);
         conversation.setStatus(Conversation.ConversationStatus.OPEN);
@@ -210,7 +206,7 @@ public class ChatService {
             throw new AccessDeniedException("Conversation is closed");
         }
 
-        if (role != User.Role.CUSTOMER || !hasConversationAccess(conversation, userId, role)) {
+        if (!hasConversationAccess(conversation, userId, role)) {
             throw new AccessDeniedException("You can only request human takeover for your own conversations");
         }
 

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

@@ -0,0 +1,144 @@
+package com.petshop.backend.service;
+
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.petshop.backend.dto.ai.AiChatRequest;
+import com.petshop.backend.entity.Pet;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+import java.util.List;
+
+@Service
+public class OpenRouterService {
+
+    private static final String OPENROUTER_URL = "https://openrouter.ai/api/v1/chat/completions";
+
+    @Value("${openrouter.api-key:}")
+    private String apiKey;
+
+    @Value("${openrouter.model:meta-llama/llama-3.3-70b-instruct:free}")
+    private String model;
+
+    private final ObjectMapper objectMapper = new ObjectMapper();
+    private final HttpClient httpClient = HttpClient.newBuilder()
+            .connectTimeout(Duration.ofSeconds(30))
+            .build();
+
+    public String chat(List<AiChatRequest.ChatHistoryItem> history, String userMessage, List<Pet> userPets) {
+        if (apiKey == null || apiKey.isBlank()) {
+            throw new IllegalStateException("OpenRouter API key is not configured");
+        }
+
+        try {
+            String systemPrompt = buildSystemPrompt(userPets);
+            String requestBody = buildRequestBody(systemPrompt, history, userMessage);
+
+            HttpRequest request = HttpRequest.newBuilder()
+                    .uri(URI.create(OPENROUTER_URL))
+                    .header("Content-Type", "application/json")
+                    .header("Authorization", "Bearer " + apiKey)
+                    .header("HTTP-Referer", "https://petshop.local")
+                    .header("X-Title", "Leon's Pet Store AI Assistant")
+                    .POST(HttpRequest.BodyPublishers.ofString(requestBody))
+                    .timeout(Duration.ofSeconds(60))
+                    .build();
+
+            HttpResponse<String> response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+
+            if (response.statusCode() != 200) {
+                throw new RuntimeException("OpenRouter API returned status " + response.statusCode() + ": " + response.body());
+            }
+
+            return extractContent(response.body());
+        } 
+        
+        catch (InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new RuntimeException("AI request was interrupted", e);
+        } 
+        
+        catch (RuntimeException e) {
+            throw e;
+        } 
+        
+        catch (Exception e) {
+            throw new RuntimeException("Failed to call OpenRouter API: " + e.getMessage(), e);
+        }
+    }
+
+    private String buildSystemPrompt(List<Pet> userPets) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("You are a helpful AI assistant for Leon's Pet Store, specializing in pet ownership and adoption advice. ");
+        sb.append("You help customers with pet care requirements, supplies (food, habitat, grooming, etc.), ");
+        sb.append("veterinary and grooming appointments, and general pet-related questions. ");
+        sb.append("You can recommend pets based on the user's experience level (beginner, intermediate, expert). ");
+        sb.append("Always be friendly, informative, and focused on pet-related topics.\n\n");
+
+        if (userPets != null && !userPets.isEmpty()) {
+            sb.append("The user currently owns the following pets:\n");
+            for (Pet pet : userPets) {
+                sb.append("- ").append(pet.getPetName());
+                sb.append(" (").append(pet.getPetSpecies());
+
+                if (pet.getPetBreed() != null && !pet.getPetBreed().isBlank()) {
+                    sb.append(", ").append(pet.getPetBreed());
+                }
+
+                if (pet.getPetAge() != null) {
+                    sb.append(", ").append(pet.getPetAge()).append(" year(s) old");
+                }
+                sb.append(")\n");
+            }
+            sb.append("Use this information to personalize your responses when relevant.\n");
+        } 
+        
+        else {
+            sb.append("The user does not currently own any pets registered in the system.\n");
+        }
+
+        return sb.toString();
+    }
+
+    private String buildRequestBody(String systemPrompt, List<AiChatRequest.ChatHistoryItem> history, String userMessage) throws Exception {
+        ObjectNode root = objectMapper.createObjectNode();
+        root.put("model", model);
+
+        ArrayNode messages = root.putArray("messages");
+
+        ObjectNode systemMsg = messages.addObject();
+        systemMsg.put("role", "system");
+        systemMsg.put("content", systemPrompt);
+
+        if (history != null) {
+            for (AiChatRequest.ChatHistoryItem item : history) {
+                ObjectNode msg = messages.addObject();
+                msg.put("role", item.getRole());
+                msg.put("content", item.getContent());
+            }
+        }
+
+        ObjectNode userMsg = messages.addObject();
+        userMsg.put("role", "user");
+        userMsg.put("content", userMessage);
+
+        return objectMapper.writeValueAsString(root);
+    }
+
+    private String extractContent(String responseBody) throws Exception {
+        JsonNode root = objectMapper.readTree(responseBody);
+        JsonNode choices = root.path("choices");
+        if (choices.isArray() && choices.size() > 0) {
+            return choices.get(0).path("message").path("content").asText();
+        }
+        
+        throw new RuntimeException("No content in OpenRouter response: " + responseBody);
+    }
+}

backend/src/main/resources/application.yml

@@ -2,6 +2,9 @@ spring:
   application:
     name: petshop-backend
 
+  config:
+    import: optional:file:.env[.properties]
+
   servlet:
     multipart:
       enabled: true
@@ -53,6 +56,10 @@ jwt:
 stripe:
   secret-key: ${STRIPE_SECRET_KEY:}
 
+openrouter:
+  api-key: ${OPENROUTER_API_KEY:}
+  model: ${OPENROUTER_MODEL:openai/gpt-oss-120b:free}
+
 logging:
   level:
     com.petshop: ${LOG_LEVEL:INFO}