import { createOpenRouter } from "@openrouter/ai-sdk-provider";

type OpenRouterEnv = Readonly<Record<string, string | undefined>>;

function normalizeOptionalEnvValue(value: string | undefined): string | undefined {
  if (typeof value !== "string") {
    return undefined;
  }

  const trimmed = value.trim();
  return trimmed === "" ? undefined : trimmed;
}

export function createOpenRouterProvider(
  env: OpenRouterEnv = process.env,
): ReturnType<typeof createOpenRouter> {
  const apiKey = normalizeOptionalEnvValue(env.OPENROUTER_API_KEY);

  if (!apiKey) {
    throw new Error("OPENROUTER_API_KEY is required for OpenRouter provider.");
  }

  const appName = normalizeOptionalEnvValue(env.OPENROUTER_APP_NAME);
  const appUrl = normalizeOptionalEnvValue(env.OPENROUTER_APP_URL);

  return createOpenRouter({
    apiKey,
    appName,
    appUrl,
    compatibility: "strict",
    headers: {
      "Content-Type": "application/json",
    },
  });
}