Implement bot that performs time-series metric analysis and suggests repo management improvements (#25945)

tools/gemini-cli-bot/metrics/history-helper.ts

@@ -0,0 +1,61 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { readFileSync, existsSync } from 'node:fs';
+import { join } from 'node:path';
+
+const TIMESERIES_FILE = join(
+  process.cwd(),
+  'tools',
+  'gemini-cli-bot',
+  'history',
+  'metrics-timeseries.csv',
+);
+
+/**
+ * Calculates the historical average of a metric over a given number of days.
+ */
+export function getHistoricalAverage(
+  metric: string,
+  days: number,
+): number | null {
+  if (!existsSync(TIMESERIES_FILE)) return null;
+
+  try {
+    const content = readFileSync(TIMESERIES_FILE, 'utf-8');
+    const lines = content.split('\n').slice(1); // skip header
+    const now = new Date();
+    const threshold = new Date(now.getTime() - days * 24 * 60 * 60 * 1000);
+
+    const values: number[] = [];
+    for (const line of lines) {
+      if (!line.trim()) continue;
+      const parts = line.split(',');
+      if (parts.length < 3) continue;
+
+      const timestamp = parts[0];
+      const m = parts[1];
+      const value = parts[2];
+
+      if (m === metric) {
+        const date = new Date(timestamp);
+        if (date >= threshold) {
+          const numValue = parseFloat(value);
+          if (!isNaN(numValue)) {
+            values.push(numValue);
+          }
+        }
+      }
+    }
+
+    if (values.length === 0) return null;
+    const sum = values.reduce((a, b) => a + b, 0);
+    return sum / values.length;
+  } catch (error) {
+    console.error(`Error reading historical average for ${metric}:`, error);
+    return null;
+  }
+}