feat: add usage cost reporting

src/utils/usage-format.ts

@@ -0,0 +1,69 @@
+import type { NormalizedUsage } from "../agents/usage.js";
+import type { ClawdbotConfig } from "../config/config.js";
+
+export type ModelCostConfig = {
+  input: number;
+  output: number;
+  cacheRead: number;
+  cacheWrite: number;
+};
+
+export type UsageTotals = {
+  input?: number;
+  output?: number;
+  cacheRead?: number;
+  cacheWrite?: number;
+  total?: number;
+};
+
+export function formatTokenCount(value?: number): string {
+  if (value === undefined || !Number.isFinite(value)) return "0";
+  const safe = Math.max(0, value);
+  if (safe >= 1_000_000) return `${(safe / 1_000_000).toFixed(1)}m`;
+  if (safe >= 1_000)
+    return `${(safe / 1_000).toFixed(safe >= 10_000 ? 0 : 1)}k`;
+  return String(Math.round(safe));
+}
+
+export function formatUsd(value?: number): string | undefined {
+  if (value === undefined || !Number.isFinite(value)) return undefined;
+  if (value >= 1) return `$${value.toFixed(2)}`;
+  if (value >= 0.01) return `$${value.toFixed(2)}`;
+  return `$${value.toFixed(4)}`;
+}
+
+export function resolveModelCostConfig(params: {
+  provider?: string;
+  model?: string;
+  config?: ClawdbotConfig;
+}): ModelCostConfig | undefined {
+  const provider = params.provider?.trim();
+  const model = params.model?.trim();
+  if (!provider || !model) return undefined;
+  const providers = params.config?.models?.providers ?? {};
+  const entry = providers[provider]?.models?.find((item) => item.id === model);
+  return entry?.cost;
+}
+
+const toNumber = (value: number | undefined): number =>
+  typeof value === "number" && Number.isFinite(value) ? value : 0;
+
+export function estimateUsageCost(params: {
+  usage?: NormalizedUsage | UsageTotals | null;
+  cost?: ModelCostConfig;
+}): number | undefined {
+  const usage = params.usage;
+  const cost = params.cost;
+  if (!usage || !cost) return undefined;
+  const input = toNumber(usage.input);
+  const output = toNumber(usage.output);
+  const cacheRead = toNumber(usage.cacheRead);
+  const cacheWrite = toNumber(usage.cacheWrite);
+  const total =
+    input * cost.input +
+    output * cost.output +
+    cacheRead * cost.cacheRead +
+    cacheWrite * cost.cacheWrite;
+  if (!Number.isFinite(total)) return undefined;
+  return total / 1_000_000;
+}