feat: add usage command (#281)

src/cli/components/SessionStats.tsx

@@ -1,12 +1,6 @@
-import { Box, Text } from "ink";
 import type { SessionStatsSnapshot } from "../../agent/stats";
 
-interface SessionStatsProps {
-  stats: SessionStatsSnapshot;
-  agentId?: string;
-}
-
-function formatDuration(ms: number): string {
+export function formatDuration(ms: number): string {
   if (ms < 1000) {
     return `${Math.round(ms)}ms`;
   }
@@ -25,25 +19,43 @@ function formatDuration(ms: number): string {
   return `${(ms / 1000).toFixed(1)}s`;
 }
 
-function formatNumber(n: number): string {
+export function formatNumber(n: number): string {
   return n.toLocaleString();
 }
 
-export function SessionStats({ stats, agentId }: SessionStatsProps) {
-  const wallDuration = formatDuration(stats.totalWallMs);
-  const apiDuration = formatDuration(stats.totalApiMs);
-  const steps = stats.usage.stepCount;
-  const inputTokens = formatNumber(stats.usage.promptTokens);
-  const outputTokens = formatNumber(stats.usage.completionTokens);
-
-  return (
-    <Box flexDirection="column" paddingTop={1}>
-      <Text dimColor>Total duration (API): {apiDuration}</Text>
-      <Text dimColor>Total duration (wall): {wallDuration}</Text>
-      <Text dimColor>
-        Usage: {steps} steps · {inputTokens} input · {outputTokens} output
-      </Text>
-      {agentId && <Text dimColor>Agent ID: {agentId}</Text>}
-    </Box>
-  );
+interface BalanceInfo {
+  total_balance: number;
+  monthly_credit_balance: number;
+  purchased_credit_balance: number;
+  billing_tier: string;
+}
+
+interface FormatUsageStatsOptions {
+  stats: SessionStatsSnapshot;
+  balance?: BalanceInfo;
+}
+
+/**
+ * Format usage statistics as markdown text for display in CommandMessage
+ */
+export function formatUsageStats({
+  stats,
+  balance,
+}: FormatUsageStatsOptions): string {
+  const outputLines = [
+    `Total duration (API):  ${formatDuration(stats.totalApiMs)}`,
+    `Total duration (wall): ${formatDuration(stats.totalWallMs)}`,
+    `Session usage:         ${stats.usage.stepCount} steps, ${formatNumber(stats.usage.promptTokens)} input, ${formatNumber(stats.usage.completionTokens)} output`,
+    "",
+  ];
+
+  if (balance) {
+    outputLines.push(
+      `Available credits:     $${balance.total_balance.toFixed(2)}       Plan: [${balance.billing_tier}]`,
+      `  Monthly credits:     $${balance.monthly_credit_balance.toFixed(2)}`,
+      `  Purchased credits:   $${balance.purchased_credit_balance.toFixed(2)}`,
+    );
+  }
+
+  return outputLines.join("\n");
 }