refactor: migrate project upload (#796)

* refactor: migrate project upload

apps/server/src/services/project-service/projectFileUtils.ts

@@ -0,0 +1,31 @@
+import { readFileSync } from 'fs';
+import { extname } from 'path';
+
+/**
+ * Given an array of file names, filters out any files that do not have a '.json' extension.
+ * We assume these are project files
+ * @param files
+ * @returns
+ */
+export function filterProjectFiles(files: Array<string>): Array<string> {
+  return files.filter((file) => {
+    const ext = extname(file).toLowerCase();
+    return ext === '.json';
+  });
+}
+
+export function parseProjectFile(filePath: string): object {
+  if (!filePath.endsWith('.json')) {
+    throw new Error('Invalid file type');
+  }
+
+  const rawdata = readFileSync(filePath, 'utf-8');
+  const uploadedJson = JSON.parse(rawdata);
+
+  // at this point, we think this is a DatabaseModel
+  // verify by looking for the required fields
+  if (uploadedJson?.settings?.app !== 'ontime') {
+    throw new Error('Not a ontime project file');
+  }
+  return uploadedJson;
+}