Added Pagination

[ArhamSyed]

✅ Backend Pagination Added

Updated ChatMessageRepository.findFullChatHistory to accept Pageable instead of returning a full list.

Modified ChatService.getChatHistoryForAnonymous to:

Accept page and size

Use PageRequest.of(page, size, Sort.by("timestamp").descending())

Return a new ChatHistoryPageDto that includes:

paginated messages

page number

size

total pages

hasNextPage flag

✅ New DTO Added

Created PaginationDto.ChatHistoryPageDto containing:

List messages

int page

int size

int totalPages

boolean hasNextPage

✅ Controller Updated

[fred-maina]

LGTM. Will merge when change is effected on Frontend

[Copilot]

Pull request overview

This PR adds backend pagination support to the anonymous chat history endpoint (/api/chat/session_history), converting it from returning all messages at once to supporting page-based retrieval. The implementation follows Spring Data JPA pagination patterns using Page and Pageable.

Key Changes:

• Added pagination parameters (page and size) to the chat history endpoint with sensible defaults (page=0, size=50)
• Created a new PaginationDto to encapsulate paginated response metadata (page number, size, total pages, hasNextPage flag)
• Updated the repository query to accept Pageable and return Page<ChatMessage> instead of List<ChatMessage>

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 7 comments.

File	Description
PaginationDto.java	New DTO containing pagination metadata and message list; naming could be more specific
ChatMessageRepository.java	Updated findFullChatHistory to accept Pageable parameter; has conflicting ORDER BY clauses
ChatService.java	Modified to accept pagination params, create PageRequest, and return PaginationDto; lacks input validation
ChatController.java	Added pagination request parameters with defaults and expanded response to include pagination metadata

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review for a chance to win a $100 gift card. Take the survey.

[Copilot]

Missing input validation for page and size parameters. Negative values for page or non-positive values for size would cause issues when passed to PageRequest.of(). Consider adding validation to ensure page >= 0 and size > 0, or handle the IllegalArgumentException that PageRequest.of() throws for invalid values. You could also set reasonable upper bounds for size to prevent excessive memory usage.

Suggested change

	int page,int size) {
	int page,int size) {
	// Validate page and size parameters
	if (page < 0) {
	throw new IllegalArgumentException("Page index must not be negative: " + page);
	}
	int MAX_PAGE_SIZE = 100;
	if (size <= 0 || size > MAX_PAGE_SIZE) {
	throw new IllegalArgumentException("Page size must be between 1 and " + MAX_PAGE_SIZE + ": " + size);
	}

[Copilot]

Missing space after commas in method call. Should be findFullChatHistory(sessionId, recipient.getId(), pageable) instead of findFullChatHistory(sessionId,recipient.getId(),pageable) for consistency with Java formatting conventions.

Suggested change

	Page<ChatMessage> messages = chatMessageRepository.findFullChatHistory(sessionId,recipient.getId(),pageable);
	Page<ChatMessage> messages = chatMessageRepository.findFullChatHistory(sessionId, recipient.getId(), pageable);

[Copilot]

Inconsistent parameter formatting. The Pageable pageable parameter should be on the same line as the previous parameter or consistently indented. The comma-space before Pageable should follow the same pattern as line 30.

Suggested change

	Page<ChatMessage> findFullChatHistory(@Param("sessionId") String sessionId,
	@Param("recipientId") UUID recipientId
	, Pageable pageable);
	Page<ChatMessage> findFullChatHistory(
	@Param("sessionId") String sessionId,
	@Param("recipientId") UUID recipientId,
	Pageable pageable);

[Copilot]

Inconsistent indentation. The @RequestParam annotation on line 68 has extra leading spaces compared to the @RequestParam on line 69, making the parameter list formatting inconsistent.

Suggested change

	@RequestParam(defaultValue = "0") int page,
	@RequestParam(defaultValue = "50") int size
	@RequestParam(defaultValue = "0") int page,
	@RequestParam(defaultValue = "50") int size

[Copilot]

The class name PaginationDto is too generic for a DTO that is specifically designed for chat message pagination. Based on the PR description mentioning ChatHistoryPageDto and following the naming pattern of other DTOs in this package (like ChatMessageDto, ChatSessionDto), this should be named ChatHistoryPageDto instead. This would make the purpose clearer and avoid confusion if other paginated endpoints are added in the future.

Suggested change

	public class PaginationDto {
	public class ChatHistoryPageDto {

[Copilot]

The hardcoded ORDER BY m.timestamp in the @Query annotation conflicts with the Sort parameter passed through the Pageable. When Sort.by("timestamp").descending() is provided in the Pageable (as done in ChatService.java line 86), Spring Data JPA will append it to the query, resulting in duplicate ORDER BY clauses which could cause unexpected behavior or errors. Remove the ORDER BY m.timestamp from the query string and let the Pageable handle the sorting.

Suggested change

	"(m.toSessionId = :sessionId AND m.fromUser.id = :recipientId) " +
	"ORDER BY m.timestamp")
	"(m.toSessionId = :sessionId AND m.fromUser.id = :recipientId)")

[Copilot]

Missing space after comma in the parameter list. Should be int page, int size instead of int page,int size for consistency with Java formatting conventions.

Suggested change

	int page,int size) {
	int page, int size) {