Use server prices for text billing estimates

src/utils/modelPricing.ts

@@ -0,0 +1,104 @@
+import type { PublicModelPrice } from "../api/publicPricingClient";
+import type { TextTokenCreditRate } from "./taskLifecycle";
+
+const TOKENS_PER_MILLION = 1_000_000;
+const BACKEND_TOKEN_PRICE_UNIT = 1_000;
+const CREDITS_PER_CNY = 100;
+const MILLS_PER_CNY = 1_000;
+const CREDITS_PER_MILL = CREDITS_PER_CNY / MILLS_PER_CNY;
+
+function isUsablePrice(value: number | null | undefined): value is number {
+  return typeof value === "number" && Number.isFinite(value) && value >= 0;
+}
+
+function normalizeModelKey(value: string): string {
+  return value.trim().toLowerCase();
+}
+
+function compactModelKey(value: string): string {
+  return normalizeModelKey(value).replace(/[^a-z0-9]+/g, "");
+}
+
+function addCandidate(
+  candidates: PublicModelPrice[],
+  seen: Set<string>,
+  price: PublicModelPrice,
+): void {
+  const key = normalizeModelKey(price.modelKey);
+  if (seen.has(key)) return;
+  seen.add(key);
+  candidates.push(price);
+}
+
+export function millsPerThousandTokensToCreditsPerMillion(
+  priceMills: number,
+): number {
+  if (!isUsablePrice(priceMills)) return 0;
+  return (
+    priceMills *
+    (TOKENS_PER_MILLION / BACKEND_TOKEN_PRICE_UNIT) *
+    CREDITS_PER_MILL
+  );
+}
+
+export function modelPriceToTextTokenCreditRate(
+  price: PublicModelPrice,
+): TextTokenCreditRate | null {
+  if (
+    !isUsablePrice(price.inputPriceMills) ||
+    !isUsablePrice(price.outputPriceMills)
+  )
+    return null;
+
+  return {
+    inputCreditsPerMillion: millsPerThousandTokensToCreditsPerMillion(
+      price.inputPriceMills,
+    ),
+    outputCreditsPerMillion: millsPerThousandTokensToCreditsPerMillion(
+      price.outputPriceMills,
+    ),
+    source: "server",
+    modelKey: price.modelKey,
+  };
+}
+
+export function resolveTextTokenCreditRate(
+  prices: PublicModelPrice[],
+  modelKey: string | null | undefined,
+): TextTokenCreditRate | null {
+  const normalizedTarget = normalizeModelKey(modelKey || "");
+  if (!normalizedTarget) return null;
+
+  const compactTarget = compactModelKey(normalizedTarget);
+  const candidates: PublicModelPrice[] = [];
+  const seen = new Set<string>();
+
+  for (const price of prices) {
+    if (normalizeModelKey(price.modelKey) === normalizedTarget) {
+      addCandidate(candidates, seen, price);
+    }
+  }
+
+  for (const price of prices) {
+    if (compactModelKey(price.modelKey) === compactTarget) {
+      addCandidate(candidates, seen, price);
+    }
+  }
+
+  for (const price of prices) {
+    const compactPriceKey = compactModelKey(price.modelKey);
+    if (
+      compactPriceKey.includes(compactTarget) ||
+      compactTarget.includes(compactPriceKey)
+    ) {
+      addCandidate(candidates, seen, price);
+    }
+  }
+
+  for (const price of candidates) {
+    const rate = modelPriceToTextTokenCreditRate(price);
+    if (rate) return rate;
+  }
+
+  return null;
+}