move helpers to techdocs-react

Signed-off-by: Chris Suich <csuich2@gmail.com>

plugins/techdocs-react/src/helpers.ts

@@ -15,7 +15,23 @@
  */
 
 import { Config } from '@backstage/config';
-import { CompoundEntityRef } from '@backstage/catalog-model';
+import {
+  CompoundEntityRef,
+  DEFAULT_NAMESPACE,
+  Entity,
+  parseEntityRef,
+} from '@backstage/catalog-model';
+import {
+  TECHDOCS_EXTERNAL_ANNOTATION,
+  TECHDOCS_EXTERNAL_PATH_ANNOTATION,
+} from '@backstage/plugin-techdocs-common';
+import { RouteFunc } from '@backstage/core-plugin-api';
+
+export type TechDocsRouteFunc = RouteFunc<{
+  namespace: string;
+  kind: string;
+  name: string;
+}>;
 
 /**
  * Lower-case entity triplets by default, but allow override.
@@ -35,3 +51,52 @@ export function toLowercaseEntityRefMaybe(
 
   return entityRef;
 }
+
+export function getEntityRootTechDocsPath(entity: Entity): string {
+  let path = entity.metadata.annotations?.[TECHDOCS_EXTERNAL_PATH_ANNOTATION];
+  if (!path) {
+    return '';
+  }
+  if (!path.startsWith('/')) {
+    path = `/${path}`;
+  }
+  return path;
+}
+
+export const buildTechDocsURL = (
+  entity: Entity,
+  routeFunc: TechDocsRouteFunc | undefined,
+) => {
+  if (!routeFunc) {
+    return undefined;
+  }
+
+  let namespace = entity.metadata.namespace || DEFAULT_NAMESPACE;
+  let kind = entity.kind;
+  let name = entity.metadata.name;
+
+  if (entity.metadata.annotations?.[TECHDOCS_EXTERNAL_ANNOTATION]) {
+    try {
+      const techdocsRef = parseEntityRef(
+        entity.metadata.annotations?.[TECHDOCS_EXTERNAL_ANNOTATION],
+      );
+      namespace = techdocsRef.namespace;
+      kind = techdocsRef.kind;
+      name = techdocsRef.name;
+    } catch {
+      // not a fan of this but we don't care if the parseEntityRef fails
+    }
+  }
+
+  const url = routeFunc({
+    namespace,
+    kind,
+    name,
+  });
+
+  // Add on the external entity path to the url if one exists. This allows deep linking into another
+  // entities TechDocs.
+  const path = getEntityRootTechDocsPath(entity);
+
+  return `${url}${path}`;
+};

plugins/techdocs-react/src/index.ts

@@ -52,4 +52,9 @@ export {
   useShadowRootElements,
   useShadowRootSelection,
 } from './hooks';
-export { toLowercaseEntityRefMaybe } from './helpers';
+export {
+  toLowercaseEntityRefMaybe,
+  getEntityRootTechDocsPath,
+  buildTechDocsURL,
+} from './helpers';
+export type { TechDocsRouteFunc } from './helpers';