chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/ai/scripts/ai-gateway-pricing.ts

@@ -0,0 +1,67 @@
+import type { ModelCost, ModelCostRates, ModelCostTier } from "../src/types.ts";
+
+/** A prompt-length bracket. `min` is inclusive and `max` exclusive, both in prompt tokens. */
+export interface AiGatewayPriceTier {
+	cost?: string | number;
+	min?: number;
+	max?: number;
+}
+
+/** Vercel AI Gateway pricing in $/token. */
+export interface AiGatewayPricing {
+	input?: string | number;
+	output?: string | number;
+	input_cache_read?: string | number;
+	input_cache_write?: string | number;
+	input_tiers?: AiGatewayPriceTier[];
+	output_tiers?: AiGatewayPriceTier[];
+	input_cache_read_tiers?: AiGatewayPriceTier[];
+	input_cache_write_tiers?: AiGatewayPriceTier[];
+}
+
+const RATE_FIELDS = [
+	{ rate: "input", tiers: "input_tiers" },
+	{ rate: "output", tiers: "output_tiers" },
+	{ rate: "cacheRead", tiers: "input_cache_read_tiers" },
+	{ rate: "cacheWrite", tiers: "input_cache_write_tiers" },
+] as const;
+
+function perMillion(value: string | number | undefined): number {
+	const parsed = typeof value === "number" ? value : parseFloat(value ?? "0");
+	return Number.isFinite(parsed) ? Number((parsed * 1_000_000).toFixed(6)) : 0;
+}
+
+/**
+ * Convert AI Gateway pricing to $/million tokens. Each rate lists its own prompt-length brackets;
+ * every bracket start above zero becomes a request-wide tier with the rates in effect there.
+ */
+export function getAiGatewayCost(pricing: AiGatewayPricing | undefined): ModelCost {
+	const base: ModelCostRates = {
+		input: perMillion(pricing?.input),
+		output: perMillion(pricing?.output),
+		cacheRead: perMillion(pricing?.input_cache_read),
+		cacheWrite: perMillion(pricing?.input_cache_write),
+	};
+
+	const starts = new Set<number>();
+	for (const field of RATE_FIELDS) {
+		for (const bracket of pricing?.[field.tiers] ?? []) {
+			if (bracket.min !== undefined && bracket.min > 0) starts.add(bracket.min);
+		}
+	}
+
+	const tiers = [...starts]
+		.sort((a, b) => a - b)
+		.map((start): ModelCostTier => {
+			const tier: ModelCostTier = { inputTokensAbove: start - 1, ...base };
+			for (const field of RATE_FIELDS) {
+				const bracket = pricing?.[field.tiers]?.find(
+					(candidate) => (candidate.min ?? 0) <= start && (candidate.max === undefined || start < candidate.max),
+				);
+				if (bracket?.cost !== undefined) tier[field.rate] = perMillion(bracket.cost);
+			}
+			return tier;
+		});
+
+	return tiers.length > 0 ? { ...base, tiers } : base;
+}