/** API client — mock adapters when EXPO_PUBLIC_API_URL is unset. */

export const BASE_URLS = {
  core: process.env.EXPO_PUBLIC_API_URL ?? "https://api.gishen.example/v1",
} as const;

export const USE_MOCKS = !process.env.EXPO_PUBLIC_API_URL;

export type ApiError = { message: string; code?: string };

export type PaymentIntent = {
  id: string;
  provider: string;
  status: "requires_action" | "succeeded" | "pending";
  amountEtb: number;
  checkoutUrl?: string;
};

export async function initiatePayment(input: {
  provider: string;
  amountEtb: number;
  orderId: string;
}): Promise<PaymentIntent> {
  if (USE_MOCKS) {
    await delay(450);
    return {
      id: `pay_${Date.now()}`,
      provider: input.provider,
      status: input.provider === "bank" || input.provider === "cod" || input.provider === "pay_at_branch"
        ? "pending"
        : "succeeded",
      amountEtb: input.amountEtb,
      checkoutUrl:
        input.provider === "chapa" || input.provider === "arifpay"
          ? `https://checkout.mock.gishen/${input.provider}`
          : undefined,
    };
  }
  return callEndpoint<PaymentIntent>("/payments/intent", {
    method: "POST",
    body: JSON.stringify(input),
  });
}

export async function callEndpoint<T>(
  path: string,
  init?: RequestInit & { locale?: string }
): Promise<T> {
  const headers: Record<string, string> = {
    "Content-Type": "application/json",
    Accept: "application/json",
    ...(init?.locale ? { "Accept-Language": init.locale } : {}),
    ...(init?.headers as Record<string, string>),
  };

  if (USE_MOCKS) {
    throw new Error(`No mock for ${path} — pass EXPO_PUBLIC_API_URL or add an adapter`);
  }

  const res = await fetch(`${BASE_URLS.core}${path}`, {
    ...init,
    headers,
  });
  if (!res.ok) {
    const body = (await res.json().catch(() => ({}))) as ApiError;
    throw new Error(body.message || res.statusText);
  }
  return res.json() as Promise<T>;
}

function delay(ms: number) {
  return new Promise((r) => setTimeout(r, ms));
}