From 1ae55591f4e46bc82551e1eff4b3a1237b7f43f7 Mon Sep 17 00:00:00 2001
From: Experiments DB Dev <dev@experiments-db.local>
Date: Fri, 1 May 2026 07:47:17 -0400
Subject: [PATCH] feat(backend): add csv_analysis_config validator

---
 backend/src/lib/csvConfigValidation.js    | 51 +++++++++++++++++++
 backend/tests/csvConfigValidation.test.js | 61 +++++++++++++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 backend/src/lib/csvConfigValidation.js
 create mode 100644 backend/tests/csvConfigValidation.test.js

diff --git a/backend/src/lib/csvConfigValidation.js b/backend/src/lib/csvConfigValidation.js
new file mode 100644
index 0000000..23095dc
--- /dev/null
+++ b/backend/src/lib/csvConfigValidation.js
@@ -0,0 +1,51 @@
+const REQUIRED_DEFAULT_BUCKETS = ['Success', 'Failure', 'Other'];
+const ALLOWED_TYPES = new Set(['note', 'numerical']);
+
+/**
+ * Validate a csv_analysis_config payload.
+ * @param {unknown} body
+ * @returns {string|null} error message, or null if valid.
+ */
+function validateCsvConfig(body) {
+  if (body === null || typeof body !== 'object' || Array.isArray(body)) {
+    return 'Body must be an object';
+  }
+  const { buckets } = body;
+  if (!Array.isArray(buckets)) {
+    return 'buckets must be an array';
+  }
+
+  const seenNames = new Set();
+  for (const b of buckets) {
+    if (b === null || typeof b !== 'object' || Array.isArray(b)) {
+      return 'Each bucket must be an object';
+    }
+    if (typeof b.name !== 'string' || b.name.trim() === '') {
+      return 'Each bucket must have a non-empty name';
+    }
+    if (seenNames.has(b.name)) {
+      return `Duplicate bucket name: ${b.name}`;
+    }
+    seenNames.add(b.name);
+
+    if (!ALLOWED_TYPES.has(b.type)) {
+      return `Invalid type for bucket ${b.name}: ${b.type}`;
+    }
+    if (!Array.isArray(b.notes)) {
+      return `notes must be an array for bucket ${b.name}`;
+    }
+    if (!b.notes.every((n) => typeof n === 'string')) {
+      return `notes must be an array of strings for bucket ${b.name}`;
+    }
+  }
+
+  for (const required of REQUIRED_DEFAULT_BUCKETS) {
+    if (!seenNames.has(required)) {
+      return `Missing required default bucket: ${required}`;
+    }
+  }
+
+  return null;
+}
+
+module.exports = { validateCsvConfig, REQUIRED_DEFAULT_BUCKETS };
diff --git a/backend/tests/csvConfigValidation.test.js b/backend/tests/csvConfigValidation.test.js
new file mode 100644
index 0000000..9b94053
--- /dev/null
+++ b/backend/tests/csvConfigValidation.test.js
@@ -0,0 +1,61 @@
+const { validateCsvConfig } = require('../src/lib/csvConfigValidation');
+
+const okBuckets = [
+  { name: 'Success', type: 'note', notes: ['s'] },
+  { name: 'Failure', type: 'note', notes: ['f'] },
+  { name: 'Other',   type: 'note', notes: [] },
+];
+
+describe('validateCsvConfig', () => {
+  it('accepts a valid config with the three default buckets', () => {
+    expect(validateCsvConfig({ buckets: okBuckets })).toBeNull();
+  });
+
+  it('accepts a valid config with extra note + numerical buckets', () => {
+    const buckets = [
+      ...okBuckets,
+      { name: 'Lick latency', type: 'numerical', notes: ['L25'] },
+      { name: 'Bonus',        type: 'note',      notes: ['b'] },
+    ];
+    expect(validateCsvConfig({ buckets })).toBeNull();
+  });
+
+  it('rejects when body is not an object', () => {
+    expect(validateCsvConfig(null)).toMatch(/object/i);
+    expect(validateCsvConfig('x')).toMatch(/object/i);
+  });
+
+  it('rejects when buckets is not an array', () => {
+    expect(validateCsvConfig({ buckets: 'nope' })).toMatch(/array/i);
+  });
+
+  it('rejects an empty bucket name', () => {
+    const buckets = [...okBuckets, { name: '   ', type: 'note', notes: [] }];
+    expect(validateCsvConfig({ buckets })).toMatch(/name/i);
+  });
+
+  it('rejects duplicate bucket names', () => {
+    const buckets = [...okBuckets, { name: 'Success', type: 'note', notes: [] }];
+    expect(validateCsvConfig({ buckets })).toMatch(/duplicate/i);
+  });
+
+  it('rejects an invalid type value', () => {
+    const buckets = [...okBuckets, { name: 'X', type: 'weird', notes: [] }];
+    expect(validateCsvConfig({ buckets })).toMatch(/type/i);
+  });
+
+  it('rejects when notes is not an array', () => {
+    const buckets = [...okBuckets, { name: 'X', type: 'note', notes: 'oops' }];
+    expect(validateCsvConfig({ buckets })).toMatch(/notes/i);
+  });
+
+  it('rejects when notes contains non-strings', () => {
+    const buckets = [...okBuckets, { name: 'X', type: 'note', notes: [1, 2] }];
+    expect(validateCsvConfig({ buckets })).toMatch(/notes/i);
+  });
+
+  it('rejects when a default bucket is missing', () => {
+    const buckets = okBuckets.filter((b) => b.name !== 'Success');
+    expect(validateCsvConfig({ buckets })).toMatch(/Success/);
+  });
+});