···
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"Coves/internal/core/posts"
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type voteService struct {
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postRepo posts.Repository
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// NewVoteService creates a new vote service
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postRepo posts.Repository,
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// CreateVote creates a new vote or toggles an existing vote
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// - No vote -> Create vote
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// - Same direction -> Delete vote (toggle off)
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// - Different direction -> Delete old + Create new (toggle direction)
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func (s *voteService) CreateVote(ctx context.Context, voterDID string, userAccessToken string, req CreateVoteRequest) (*CreateVoteResponse, error) {
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return nil, NewValidationError("voterDid", "required")
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if userAccessToken == "" {
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return nil, NewValidationError("userAccessToken", "required")
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return nil, NewValidationError("subject", "required")
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if req.Direction != "up" && req.Direction != "down" {
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return nil, ErrInvalidDirection
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// 2. Validate subject URI format (should be at://...)
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if !strings.HasPrefix(req.Subject, "at://") {
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return nil, ErrInvalidSubject
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// 3. Get subject post/comment to verify it exists and get its CID (for strong reference)
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// For now, we assume the subject is a post. In the future, we'll support comments too.
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post, err := s.postRepo.GetByURI(ctx, req.Subject)
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if err == posts.ErrNotFound {
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return nil, ErrSubjectNotFound
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return nil, fmt.Errorf("failed to get subject post: %w", err)
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// 4. Check for existing vote on PDS (source of truth for toggle logic)
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// IMPORTANT: We query the user's PDS directly instead of AppView to avoid race conditions.
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// AppView is eventually consistent (updated via Jetstream), so querying it can cause
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// duplicate vote records if the user toggles before Jetstream catches up.
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existingVoteRecord, err := s.findVoteOnPDS(ctx, voterDID, userAccessToken, req.Subject)
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return nil, fmt.Errorf("failed to check existing vote on PDS: %w", err)
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// 5. Handle toggle logic
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var existingVoteURI *string
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if existingVoteRecord != nil {
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// Vote exists on PDS - implement toggle logic
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if existingVoteRecord.Direction == req.Direction {
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// Same direction -> Delete vote (toggle off)
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log.Printf("[VOTE-CREATE] Toggle off: deleting existing %s vote on %s", req.Direction, req.Subject)
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// Delete from user's PDS
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if err := s.deleteRecordOnPDSAs(ctx, voterDID, "social.coves.interaction.vote", existingVoteRecord.RKey, userAccessToken); err != nil {
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return nil, fmt.Errorf("failed to delete vote on PDS: %w", err)
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// Return empty response (vote was deleted, not created)
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return &CreateVoteResponse{
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// Different direction -> Delete old vote first, then create new one below
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log.Printf("[VOTE-CREATE] Toggle direction: %s -> %s on %s", existingVoteRecord.Direction, req.Direction, req.Subject)
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if err := s.deleteRecordOnPDSAs(ctx, voterDID, "social.coves.interaction.vote", existingVoteRecord.RKey, userAccessToken); err != nil {
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return nil, fmt.Errorf("failed to delete old vote on PDS: %w", err)
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existingVoteURI = &existingVoteRecord.URI
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// 6. Build vote record with strong reference
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voteRecord := map[string]interface{}{
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"$type": "social.coves.interaction.vote",
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"subject": map[string]interface{}{
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"direction": req.Direction,
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"createdAt": time.Now().Format(time.RFC3339),
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// 7. Write to user's PDS repository
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recordURI, recordCID, err := s.createRecordOnPDSAs(ctx, voterDID, "social.coves.interaction.vote", "", voteRecord, userAccessToken)
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return nil, fmt.Errorf("failed to create vote on PDS: %w", err)
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log.Printf("[VOTE-CREATE] Created %s vote: %s (CID: %s)", req.Direction, recordURI, recordCID)
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return &CreateVoteResponse{
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Existing: existingVoteURI,
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// DeleteVote removes a vote from a post/comment
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func (s *voteService) DeleteVote(ctx context.Context, voterDID string, userAccessToken string, req DeleteVoteRequest) error {
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return NewValidationError("voterDid", "required")
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if userAccessToken == "" {
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return NewValidationError("userAccessToken", "required")
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return NewValidationError("subject", "required")
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// 2. Find existing vote on PDS (source of truth)
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// IMPORTANT: Query PDS directly to avoid race conditions with AppView indexing
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existingVoteRecord, err := s.findVoteOnPDS(ctx, voterDID, userAccessToken, req.Subject)
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return fmt.Errorf("failed to check existing vote on PDS: %w", err)
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if existingVoteRecord == nil {
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// 3. Delete from user's PDS
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if err := s.deleteRecordOnPDSAs(ctx, voterDID, "social.coves.interaction.vote", existingVoteRecord.RKey, userAccessToken); err != nil {
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return fmt.Errorf("failed to delete vote on PDS: %w", err)
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log.Printf("[VOTE-DELETE] Deleted vote: %s", existingVoteRecord.URI)
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// GetVote retrieves a user's vote on a specific subject
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func (s *voteService) GetVote(ctx context.Context, voterDID string, subjectURI string) (*Vote, error) {
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return s.repo.GetByVoterAndSubject(ctx, voterDID, subjectURI)
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// Helper methods for PDS operations
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// createRecordOnPDSAs creates a record on the PDS using the user's access token
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func (s *voteService) createRecordOnPDSAs(ctx context.Context, repoDID, collection, rkey string, record map[string]interface{}, accessToken string) (string, string, error) {
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endpoint := fmt.Sprintf("%s/xrpc/com.atproto.repo.createRecord", strings.TrimSuffix(s.pdsURL, "/"))
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payload := map[string]interface{}{
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"collection": collection,
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return s.callPDSWithAuth(ctx, "POST", endpoint, payload, accessToken)
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// deleteRecordOnPDSAs deletes a record from the PDS using the user's access token
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func (s *voteService) deleteRecordOnPDSAs(ctx context.Context, repoDID, collection, rkey, accessToken string) error {
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endpoint := fmt.Sprintf("%s/xrpc/com.atproto.repo.deleteRecord", strings.TrimSuffix(s.pdsURL, "/"))
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payload := map[string]interface{}{
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"collection": collection,
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_, _, err := s.callPDSWithAuth(ctx, "POST", endpoint, payload, accessToken)
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// callPDSWithAuth makes a PDS call with a specific access token
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func (s *voteService) callPDSWithAuth(ctx context.Context, method, endpoint string, payload map[string]interface{}, accessToken string) (string, string, error) {
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jsonData, err := json.Marshal(payload)
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return "", "", fmt.Errorf("failed to marshal payload: %w", err)
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req, err := http.NewRequestWithContext(ctx, method, endpoint, bytes.NewBuffer(jsonData))
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return "", "", fmt.Errorf("failed to create request: %w", err)
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req.Header.Set("Content-Type", "application/json")
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// Add authentication with provided access token
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req.Header.Set("Authorization", "Bearer "+accessToken)
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// Use 30 second timeout for write operations
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timeout := 30 * time.Second
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client := &http.Client{Timeout: timeout}
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resp, err := client.Do(req)
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return "", "", fmt.Errorf("failed to call PDS: %w", err)
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if closeErr := resp.Body.Close(); closeErr != nil {
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log.Printf("Failed to close response body: %v", closeErr)
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body, err := io.ReadAll(resp.Body)
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return "", "", fmt.Errorf("failed to read response: %w", err)
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if resp.StatusCode < 200 || resp.StatusCode >= 300 {
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return "", "", fmt.Errorf("PDS returned error %d: %s", resp.StatusCode, string(body))
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// Parse response to extract URI and CID
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URI string `json:"uri"`
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CID string `json:"cid"`
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if err := json.Unmarshal(body, &result); err != nil {
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return "", "", fmt.Errorf("failed to parse PDS response: %w", err)
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return result.URI, result.CID, nil
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// PDSVoteRecord represents a vote record returned from PDS listRecords
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type PDSVoteRecord struct {
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// findVoteOnPDS queries the user's PDS to find an existing vote on a specific subject
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// This is the source of truth for toggle logic (avoiding AppView race conditions)
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// IMPORTANT: This function paginates through ALL user votes with reverse=true (newest first)
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// to handle users with >100 votes. Without pagination, votes on older posts would not be found,
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// causing duplicate vote records and 404 errors on delete operations.
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func (s *voteService) findVoteOnPDS(ctx context.Context, voterDID, accessToken, subjectURI string) (*PDSVoteRecord, error) {
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const maxPages = 50 // Safety limit: prevent infinite loops (50 pages * 100 = 5000 votes max)
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client := &http.Client{Timeout: 10 * time.Second}
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if pageCount > maxPages {
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log.Printf("[VOTE-PDS] Reached max pagination limit (%d pages) searching for vote on %s", maxPages, subjectURI)
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// Build endpoint with pagination cursor and reverse=true (newest first)
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endpoint := fmt.Sprintf("%s/xrpc/com.atproto.repo.listRecords?repo=%s&collection=social.coves.interaction.vote&limit=100&reverse=true",
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strings.TrimSuffix(s.pdsURL, "/"), voterDID)
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endpoint += fmt.Sprintf("&cursor=%s", cursor)
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req, err := http.NewRequestWithContext(ctx, "GET", endpoint, nil)
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return nil, fmt.Errorf("failed to create request: %w", err)
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req.Header.Set("Authorization", "Bearer "+accessToken)
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resp, err := client.Do(req)
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return nil, fmt.Errorf("failed to query PDS: %w", err)
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if resp.StatusCode != http.StatusOK {
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body, _ := io.ReadAll(resp.Body)
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return nil, fmt.Errorf("PDS returned error %d: %s", resp.StatusCode, string(body))
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URI string `json:"uri"`
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URI string `json:"uri"`
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CID string `json:"cid"`
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Direction string `json:"direction"`
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Cursor string `json:"cursor,omitempty"` // Pagination cursor for next page
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if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
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return nil, fmt.Errorf("failed to decode PDS response: %w", err)
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// Find vote on this specific subject in current page
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for _, record := range result.Records {
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if record.Value.Subject.URI == subjectURI {
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rkey := extractRKeyFromURI(record.URI)
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log.Printf("[VOTE-PDS] Found existing vote on page %d: %s (direction: %s)", pageCount, record.URI, record.Value.Direction)
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Direction: record.Value.Direction,
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URI: record.Value.Subject.URI,
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CID: record.Value.Subject.CID,
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// No more pages to check
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if result.Cursor == "" {
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log.Printf("[VOTE-PDS] No existing vote found after checking %d page(s)", pageCount)
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// No vote found on this subject after paginating through all records
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// extractRKeyFromURI extracts the rkey from an AT-URI (at://did/collection/rkey)
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func extractRKeyFromURI(uri string) string {
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parts := strings.Split(uri, "/")
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return parts[len(parts)-1]
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// ValidationError represents a validation error
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type ValidationError struct {
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func (e *ValidationError) Error() string {
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return fmt.Sprintf("validation error for field '%s': %s", e.Field, e.Message)
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// NewValidationError creates a new validation error
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func NewValidationError(field, message string) error {
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return &ValidationError{
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