Add request cost to OutputStats (#12)

src/utils/calculateTokenCost.ts

@@ -0,0 +1,39 @@
+import { type SupportedModel, OpenAIChatModel } from "~/server/types";
+
+const openAIPromptTokensToDollars: { [key in OpenAIChatModel]: number } = {
+  "gpt-4": 0.00003,
+  "gpt-4-0613": 0.00003,
+  "gpt-4-32k": 0.00006,
+  "gpt-4-32k-0613": 0.00006,
+  "gpt-3.5-turbo": 0.0000015,
+  "gpt-3.5-turbo-0613": 0.0000015,
+  "gpt-3.5-turbo-16k": 0.000003,
+  "gpt-3.5-turbo-16k-0613": 0.000003,
+};
+
+const openAICompletionTokensToDollars: { [key in OpenAIChatModel]: number } = {
+  "gpt-4": 0.00006,
+  "gpt-4-0613": 0.00006,
+  "gpt-4-32k": 0.00012,
+  "gpt-4-32k-0613": 0.00012,
+  "gpt-3.5-turbo": 0.000002,
+  "gpt-3.5-turbo-0613": 0.000002,
+  "gpt-3.5-turbo-16k": 0.000004,
+  "gpt-3.5-turbo-16k-0613": 0.000004,
+};
+
+export const calculateTokenCost = (model: SupportedModel, numTokens: number, isCompletion = false) => {
+    if (model in OpenAIChatModel) {
+        return calculateOpenAIChatTokenCost(model as OpenAIChatModel, numTokens, isCompletion);
+    }
+    return 0;
+}
+
+const calculateOpenAIChatTokenCost = (
+  model: OpenAIChatModel,
+  numTokens: number,
+  isCompletion: boolean
+) => {
+    const tokensToDollars = isCompletion ? openAICompletionTokensToDollars[model] : openAIPromptTokensToDollars[model];
+    return tokensToDollars * numTokens;
+};