"use client";

import { useCallback, useEffect, useRef, useState } from "react";
import { useRouter } from "next/navigation";
import { Button, Container } from "@/components/ui";
import { getStoredToken, loginWithRedirect } from "@/lib/auth";
import { identityApi } from "@/lib/identity";
import {
  isValidMobile,
  normalizeOtpCode,
  normalizePhone,
  persianToEnglish,
} from "@/lib/phone";

export default function VerifyMobilePage() {
  const router = useRouter();
  const [mobile, setMobile] = useState("");
  const [code, setCode] = useState("");
  const [countdown, setCountdown] = useState(0);
  const [step, setStep] = useState<"mobile" | "code">("mobile");
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");
  const verifyingRef = useRef(false);

  useEffect(() => {
    if (!getStoredToken()) {
      void loginWithRedirect();
    }
  }, []);

  useEffect(() => {
    if (countdown <= 0) return;
    const timer = setTimeout(() => setCountdown((c) => c - 1), 1000);
    return () => clearTimeout(timer);
  }, [countdown]);

  const handleRequestOtp = async () => {
    const token = getStoredToken();
    if (!token) return;
    setError("");
    const normalized = normalizePhone(mobile);
    if (!isValidMobile(normalized)) {
      setError("شماره موبایل صحیح نیست");
      return;
    }
    setMobile(normalized);
    setLoading(true);
    try {
      const res = await identityApi.requestMobileVerify(normalized, token);
      setCountdown(res.expires_in);
      setStep("code");
    } catch (e) {
      setError(e instanceof Error ? e.message : "ارسال کد ناموفق بود");
    } finally {
      setLoading(false);
    }
  };

  const handleVerify = useCallback(async () => {
    const token = getStoredToken();
    if (!token || verifyingRef.current) return;
    const normalizedCode = normalizeOtpCode(code);
    if (normalizedCode.length !== 4) {
      setError("کد تأیید باید ۴ رقم باشد");
      return;
    }
    verifyingRef.current = true;
    setLoading(true);
    let keepLoading = false;
    try {
      await identityApi.verifyMobile(mobile, normalizedCode, token);
      keepLoading = true;
      router.replace("/dashboard");
    } catch (e) {
      setError(e instanceof Error ? e.message : "تأیید ناموفق بود");
    } finally {
      if (!keepLoading) {
        setLoading(false);
        verifyingRef.current = false;
      }
    }
  }, [code, mobile, router]);

  return (
    <Container className="py-16">
      <section className="mx-auto max-w-md rounded-2xl border border-gray-100 bg-white p-8 shadow-sm">
        <h1 className="text-2xl font-bold text-secondary">تأیید شماره موبایل</h1>
        <p className="mt-2 text-sm text-gray-600">
          برای استفاده از سامانه یکپارچه، تأیید شماره موبایل الزامی است.
        </p>

        {error && (
          <p className="mt-4 rounded-lg bg-red-50 px-3 py-2 text-sm text-red-600">{error}</p>
        )}

        {step === "mobile" ? (
          <div className="mt-6 space-y-4">
            <input
              type="tel"
              dir="ltr"
              placeholder="09123456789"
              value={mobile}
              onChange={(e) => setMobile(persianToEnglish(e.target.value))}
              className="w-full rounded-xl border border-gray-200 px-4 py-2.5"
            />
            <Button className="w-full" onClick={handleRequestOtp} loading={loading} loadingText="در حال ارسال...">
              دریافت کد تأیید
            </Button>
          </div>
        ) : (
          <div className="mt-6 space-y-4">
            <input
              type="text"
              dir="ltr"
              maxLength={4}
              value={code}
              onChange={(e) => setCode(normalizeOtpCode(e.target.value))}
              className="w-full rounded-xl border border-gray-200 px-4 py-2.5 text-center font-mono tracking-widest"
            />
            <Button
              className="w-full"
              onClick={handleVerify}
              loading={loading}
              loadingText="در حال تأیید..."
              disabled={code.length !== 4}
            >
              تأیید موبایل
            </Button>
          </div>
        )}
      </section>
    </Container>
  );
}