1 files changed, 158 insertions, 0 deletions

diff --git a/src/client/sync/pull.ts b/src/client/sync/pull.ts
index 8b55a9b..4771757 100644
--- a/src/client/sync/pull.ts
+++ b/src/client/sync/pull.ts
@@ -10,6 +10,16 @@ import type {
 	LocalReviewLog,
 	RatingType,
 } from "../db/index";
+import {
+	base64ToBinary,
+	CrdtEntityType,
+	type CrdtEntityTypeValue,
+	type CrdtSyncPayload,
+	crdtSyncStateManager,
+	getCrdtRepository,
+	mergeAndConvert,
+	parseDocumentId,
+} from "./crdt";
 import type { SyncQueue } from "./queue";
 
 /**
@@ -136,6 +146,8 @@ export interface SyncPullResult {
 	noteFieldTypes: ServerNoteFieldType[];
 	notes: ServerNote[];
 	noteFieldValues: ServerNoteFieldValue[];
+	/** CRDT document changes for conflict-free sync */
+	crdtChanges?: CrdtSyncPayload[];
 	currentSyncVersion: number;
 }
 
@@ -309,6 +321,147 @@ export function pullResultToLocalData(result: SyncPullResult): {
 }
 
 /**
+ * Result of applying CRDT changes
+ */
+export interface ApplyCrdtChangesResult {
+	/** Number of documents that were merged */
+	merged: number;
+	/** Number of documents that were new (no local version) */
+	created: number;
+	/** Merged entities grouped by type */
+	entities: {
+		decks: Omit<LocalDeck, "_synced">[];
+		noteTypes: Omit<LocalNoteType, "_synced">[];
+		noteFieldTypes: Omit<LocalNoteFieldType, "_synced">[];
+		notes: Omit<LocalNote, "_synced">[];
+		noteFieldValues: Omit<LocalNoteFieldValue, "_synced">[];
+		cards: Omit<LocalCard, "_synced">[];
+		reviewLogs: Omit<LocalReviewLog, "_synced">[];
+	};
+}
+
+/**
+ * Apply CRDT changes from pull response
+ *
+ * This function:
+ * 1. Parses each CRDT payload from the server
+ * 2. Loads existing local CRDT document if present
+ * 3. Merges remote and local documents using Automerge
+ * 4. Stores the merged binary in sync state
+ * 5. Converts merged document to local entity format
+ *
+ * @param crdtChanges Array of CRDT payloads from server
+ * @param syncVersion The sync version to associate with merged documents
+ * @returns Result containing merged entities ready for database storage
+ */
+export async function applyCrdtChanges(
+	crdtChanges: CrdtSyncPayload[],
+	syncVersion: number,
+): Promise<ApplyCrdtChangesResult> {
+	const result: ApplyCrdtChangesResult = {
+		merged: 0,
+		created: 0,
+		entities: {
+			decks: [],
+			noteTypes: [],
+			noteFieldTypes: [],
+			notes: [],
+			noteFieldValues: [],
+			cards: [],
+			reviewLogs: [],
+		},
+	};
+
+	// Process each CRDT payload
+	for (const payload of crdtChanges) {
+		const parsed = parseDocumentId(payload.documentId);
+		if (!parsed) {
+			console.warn(`Invalid document ID: ${payload.documentId}`);
+			continue;
+		}
+
+		const { entityType, entityId } = parsed;
+
+		// Load existing local CRDT binary if present
+		const localBinary = await crdtSyncStateManager.getDocumentBinary(
+			entityType,
+			entityId,
+		);
+
+		// Convert remote payload binary from base64
+		const remoteBinary = base64ToBinary(payload.binary);
+
+		// Get the repository and merge based on entity type
+		// We use type assertions here because getCrdtRepository returns a union type
+		// but we know the specific type based on entityType
+		const repository = getCrdtRepository(entityType);
+		const mergeResult = mergeAndConvert(
+			localBinary,
+			remoteBinary,
+			// biome-ignore lint/suspicious/noExplicitAny: Repository type is determined by entityType at runtime
+			repository as any,
+		);
+
+		// Store the merged binary in sync state
+		await crdtSyncStateManager.setDocumentBinary(
+			entityType,
+			entityId,
+			mergeResult.binary,
+			syncVersion,
+		);
+
+		// Track statistics
+		if (localBinary === null) {
+			result.created++;
+		} else {
+			result.merged++;
+		}
+
+		// Add entity to the appropriate array based on type
+		addEntityToResult(result.entities, entityType, mergeResult.entity);
+	}
+
+	return result;
+}
+
+/**
+ * Helper to add an entity to the result based on its type
+ */
+function addEntityToResult(
+	entities: ApplyCrdtChangesResult["entities"],
+	entityType: CrdtEntityTypeValue,
+	entity: unknown,
+): void {
+	switch (entityType) {
+		case CrdtEntityType.Deck:
+			entities.decks.push(entity as Omit<LocalDeck, "_synced">);
+			break;
+		case CrdtEntityType.NoteType:
+			entities.noteTypes.push(entity as Omit<LocalNoteType, "_synced">);
+			break;
+		case CrdtEntityType.NoteFieldType:
+			entities.noteFieldTypes.push(
+				entity as Omit<LocalNoteFieldType, "_synced">,
+			);
+			break;
+		case CrdtEntityType.Note:
+			entities.notes.push(entity as Omit<LocalNote, "_synced">);
+			break;
+		case CrdtEntityType.NoteFieldValue:
+			entities.noteFieldValues.push(
+				entity as Omit<LocalNoteFieldValue, "_synced">,
+			);
+			break;
+		case CrdtEntityType.Card:
+			entities.cards.push(entity as Omit<LocalCard, "_synced">);
+			break;
+		case CrdtEntityType.ReviewLog:
+			entities.reviewLogs.push(entity as Omit<LocalReviewLog, "_synced">);
+			break;
+	}
+}
+
+/**
  * Pull sync service
  *
  * Handles pulling changes from the server:
@@ -339,6 +492,11 @@ export class PullService {
 		// Pull changes from server
 		const result = await this.pullFromServer(lastSyncVersion);
 
+		// Process CRDT changes if present
+		if (result.crdtChanges && result.crdtChanges.length > 0) {
+			await applyCrdtChanges(result.crdtChanges, result.currentSyncVersion);
+		}
+
 		// If there are changes, apply them to local database
 		if (
 			result.decks.length > 0 ||