feat: implement developer collaboration hub with telegram/discord interactive UI

backend/src/main/java/com/rit/portal/controller/CollabController.java

@@ -0,0 +1,103 @@
+package com.rit.portal.controller;
+
+import com.rit.portal.entity.CollabApplication;
+import com.rit.portal.entity.CollabRequest;
+import com.rit.portal.repository.CollabApplicationRepository;
+import com.rit.portal.repository.CollabRequestRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.client.RestTemplate;
+
+import java.time.LocalDateTime;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+@RestController
+@RequestMapping("/api/collab")
+public class CollabController {
+
+    @Autowired
+    private CollabRequestRepository collabRequestRepository;
+
+    @Autowired
+    private CollabApplicationRepository collabApplicationRepository;
+
+    private final RestTemplate restTemplate = new RestTemplate();
+    private static final String BOT_COLLAB_APP_URL = "http://localhost:8082/send_collab_application";
+
+    @GetMapping
+    public List<CollabRequest> getAllCollabRequests() {
+        return collabRequestRepository.findAllByOrderByCreatedAtDesc();
+    }
+
+    @GetMapping("/{id}")
+    public ResponseEntity<CollabRequest> getCollabRequestById(@PathVariable Integer id) {
+        return collabRequestRepository.findById(id)
+                .map(ResponseEntity::ok)
+                .orElse(ResponseEntity.notFound().build());
+    }
+
+    @PostMapping
+    public CollabRequest createCollabRequest(@RequestBody CollabRequest request) {
+        if (request.getStatus() == null) request.setStatus("OPEN");
+        if (request.getApplicationsCount() == null) request.setApplicationsCount(0);
+        request.setCreatedAt(LocalDateTime.now());
+        return collabRequestRepository.save(request);
+    }
+
+    @PostMapping("/{id}/apply")
+    public ResponseEntity<CollabApplication> applyToCollabRequest(
+            @PathVariable Integer id,
+            @RequestBody CollabApplication application) {
+        return collabRequestRepository.findById(id).map(request -> {
+            application.setCollabRequest(request);
+            if (application.getStatus() == null) application.setStatus("PENDING");
+            application.setCreatedAt(LocalDateTime.now());
+
+            CollabApplication savedApp = collabApplicationRepository.save(application);
+
+            // Increment count on parent request
+            request.setApplicationsCount(request.getApplicationsCount() + 1);
+            collabRequestRepository.save(request);
+
+            // Notify Telegram/Discord intermediary bot asynchronously
+            new Thread(() -> {
+                try {
+                    Map<String, Object> payload = new HashMap<>();
+                    payload.put("collab_id", request.getId());
+                    payload.put("application_id", savedApp.getId());
+                    payload.put("project_idea", request.getProjectIdea());
+                    payload.put("tag", request.getTag());
+                    payload.put("author_name", request.getAuthorName());
+                    payload.put("contact_info", request.getContactInfo());
+                    payload.put("telegram_chat_id", request.getTelegramChatId());
+                    payload.put("discord_user_id", request.getDiscordUserId());
+                    payload.put("applicant_name", savedApp.getApplicantName());
+                    payload.put("applicant_dept", savedApp.getApplicantDept());
+                    payload.put("applicant_year", savedApp.getApplicantYear());
+                    payload.put("applicant_contact", savedApp.getApplicantContact());
+                    payload.put("message", savedApp.getMessage());
+
+                    restTemplate.postForEntity(BOT_COLLAB_APP_URL, payload, String.class);
+                } catch (Exception e) {
+                    System.err.println("Failed to send collab application notification to bot: " + e.getMessage());
+                }
+            }).start();
+
+            return ResponseEntity.ok(savedApp);
+        }).orElse(ResponseEntity.notFound().build());
+    }
+
+    @PutMapping("/applications/{applicationId}/status")
+    public ResponseEntity<CollabApplication> updateApplicationStatus(
+            @PathVariable Integer applicationId,
+            @RequestParam String status) {
+        return collabApplicationRepository.findById(applicationId).map(app -> {
+            app.setStatus(status.toUpperCase());
+            CollabApplication updated = collabApplicationRepository.save(app);
+            return ResponseEntity.ok(updated);
+        }).orElse(ResponseEntity.notFound().build());
+    }
+}