"use client";

/**
 * Browser-side calls straight to Gooyal accounts (CORS is open there).
 * The client_id/secret are intentionally public here — see .env.local comment.
 */

import { toLatinDigits } from "@/lib/format/persian-digits";

const ACCOUNTS_BASE_URL = process.env.NEXT_PUBLIC_GOOYAL_ACCOUNTS_BASE_URL!;
const CLIENT_ID = process.env.NEXT_PUBLIC_GOOYAL_CLIENT_ID!;
const CLIENT_SECRET = process.env.NEXT_PUBLIC_GOOYAL_CLIENT_SECRET!;
const SCOPE = process.env.NEXT_PUBLIC_GOOYAL_OAUTH_SCOPE!;

function basicAuthHeader() {
  return "Basic " + btoa(`${CLIENT_ID}:${CLIENT_SECRET}`);
}

const ERROR_MESSAGES_FA: Record<string, string> = {
  invalid_grant: "کد تایید نامعتبر یا منقضی شده است.",
  invalid_client: "خطا در پیکربندی سرویس احراز هویت. لطفاً بعداً تلاش کنید.",
  invalid_request: "درخواست نامعتبر است.",
};

export class GooyalClientError extends Error {
  constructor(
    public status: number,
    public code: string,
    description?: string,
  ) {
    super(ERROR_MESSAGES_FA[code] ?? description ?? code);
  }
}

/**
 * Accepts local Iranian input (09..., 9..., 0098...) — including Persian-digit
 * keyboard input — and normalizes to Gooyal's required +989999999999.
 */
export function normalizeIranianPhone(input: string): string {
  const digits = toLatinDigits(input).replace(/\D/g, "");
  const local = digits.replace(/^0098/, "").replace(/^98/, "").replace(/^0/, "");
  return `+98${local}`;
}

function extractWrappedErrorMessage(data: unknown): string | undefined {
  const details = (data as { details?: { message?: string | Record<string, string[]> } })?.details;
  if (!details) return undefined;
  if (typeof details.message === "string") return details.message;
  if (details.message && typeof details.message === "object") {
    const first = Object.values(details.message)[0];
    return Array.isArray(first) ? first[0] : undefined;
  }
  return undefined;
}

export async function requestOtp(phoneNumber: string) {
  const res = await fetch(`${ACCOUNTS_BASE_URL}/users/api/request_otp/`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ phone_number: phoneNumber }),
  });
  const data = await res.json().catch(() => ({}));
  if (!res.ok) {
    throw new GooyalClientError(res.status, "request_otp_failed", extractWrappedErrorMessage(data));
  }
  return data as { phone_number: string; otp_expire: string; ttl: number };
}

export interface GooyalTokenResponse {
  access_token: string;
  refresh_token?: string;
  token_type: string;
  expires_in: number;
  scope: string;
}

export async function exchangeOtpForToken(phoneNumber: string, otp: string) {
  const body = new URLSearchParams({
    grant_type: "password",
    username: phoneNumber,
    password: otp,
    scope: SCOPE,
    auth_fields: "phone_number:otp",
  });
  const res = await fetch(`${ACCOUNTS_BASE_URL}/oauth2/token/`, {
    method: "POST",
    headers: {
      Authorization: basicAuthHeader(),
      "Content-Type": "application/x-www-form-urlencoded",
    },
    body: body.toString(),
  });
  const data = await res.json().catch(() => ({}));
  if (!res.ok) {
    throw new GooyalClientError(res.status, data.error ?? "token_exchange_failed", data.error_description);
  }
  return data as GooyalTokenResponse;
}