From 2cde89432ff3a8348d8968f339bdc7e09527ca15 Mon Sep 17 00:00:00 2001
From: Jon Eubank <joneubank@gmail.com>
Date: Wed, 21 May 2025 15:31:11 -0400
Subject: [PATCH] Add getDiff to client rest module

---
 packages/client/src/rest/getDiff.ts | 67 +++++++++++++++++++++++++++++
 packages/client/src/rest/index.ts   |  1 +
 2 files changed, 68 insertions(+)
 create mode 100644 packages/client/src/rest/getDiff.ts

diff --git a/packages/client/src/rest/getDiff.ts b/packages/client/src/rest/getDiff.ts
new file mode 100644
index 00000000..cff48dc9
--- /dev/null
+++ b/packages/client/src/rest/getDiff.ts
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2025 The Ontario Institute for Cancer Research. All rights reserved
+ *
+ * This program and the accompanying materials are made available under the terms of
+ * the GNU Affero General Public License v3.0. You should have received a copy of the
+ * GNU Affero General Public License along with this program.
+ *  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+ * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+import { DictionaryDiffArray, failure, success, type Result } from '@overture-stack/lectern-dictionary';
+import axios, { AxiosError } from 'axios';
+import formatAxiosError from './formatAxiosError';
+
+const getDiffResponseSchema = DictionaryDiffArray;
+
+/**
+ * Fetches from a Lectern server the diff array between two versions of the same dictionary.
+ *
+ * This function requires a left (current) and right (previous) version of the dictionary to compare.
+ * If the server has both versions, then an array of all fields that have differences will be returned.
+ */
+export const getDiff = async (
+	lecternHost: string,
+	dictionary: { name: string; leftVersion: string; rightVersion: string },
+	options?: {
+		showReferences?: boolean;
+	},
+): Promise<Result<DictionaryDiffArray>> => {
+	try {
+		const diffResponse = await axios.request({
+			method: 'GET',
+			baseURL: lecternHost,
+			url: `/diff`,
+			params: {
+				name: dictionary.name,
+				left: dictionary.leftVersion,
+				right: dictionary.rightVersion,
+
+				references: options?.showReferences,
+			},
+		});
+
+		const parseResult = getDiffResponseSchema.safeParse(diffResponse.data);
+		if (!parseResult.success) {
+			console.log(parseResult.error.flatten);
+			return failure(
+				'Unable to parse response from server. Ensure that the Lectern client and server are using compatible versions.',
+			);
+		}
+		return success(parseResult.data);
+	} catch (error: unknown) {
+		if (error instanceof AxiosError) {
+			return failure(formatAxiosError(error));
+		}
+		return failure(`Unexpected error: ${error}`);
+	}
+};
diff --git a/packages/client/src/rest/index.ts b/packages/client/src/rest/index.ts
index d8b91e20..7e3c4141 100644
--- a/packages/client/src/rest/index.ts
+++ b/packages/client/src/rest/index.ts
@@ -18,4 +18,5 @@
  */
 
 export * from './getDictionary';
+export * from './getDiff';
 export * from './listDictionaries';