import { useRef, useState, type RefObject } from 'react';
import { Link, useNavigate } from 'react-router-dom';
import {
  getLastPhone,
  getPartnerProfile,
  request,
  saveRememberedSession,
  type PartnerSessionPayload,
} from '../lib/api';
import { usePartnerSession } from '../contexts/PartnerSessionContext';
import { partnerHomePath } from '../lib/partnerAccess';

const REMEMBER_PHONE_KEY = 'partner_remember_phone';
const REMEMBER_FLAG_KEY = 'partner_remember_account';

function AgreementCheckbox({
  agreed,
  onChange,
  inputRef,
}: {
  agreed: boolean;
  onChange: (next: boolean) => void;
  inputRef?: RefObject<HTMLLabelElement>;
}) {
  return (
    <label className="partner-checkbox-row partner-checkbox-row--agreement" ref={inputRef}>
      <input type="checkbox" checked={agreed} onChange={(e) => onChange(e.target.checked)} />
      <span>
        我已阅读并同意{' '}
        <Link to="/legal/user-agreement" className="text-primary" style={{ fontWeight: 600 }} onClick={(e) => e.stopPropagation()}>
          《用户协议》
        </Link>{' '}
        与{' '}
        <Link to="/legal/privacy-policy" className="text-primary" style={{ fontWeight: 600 }} onClick={(e) => e.stopPropagation()}>
          《隐私政策》
        </Link>
      </span>
    </label>
  );
}

function loadRememberedPhone(): { phone: string; remember: boolean } {
  try {
    const remember = localStorage.getItem(REMEMBER_FLAG_KEY) === '1';
    const phone = remember ? localStorage.getItem(REMEMBER_PHONE_KEY) || '' : '';
    return { phone, remember };
  } catch {
    return { phone: '', remember: false };
  }
}

function formatPartnerError(e: unknown): string {
  const text = e instanceof Error ? e.message : '操作失败';
  if (text.includes('合伙人账号不存在') || text.includes('未找到合伙人账号')) {
    return '未找到合伙人账号';
  }
  if (text.includes('合伙人账号已停用')) {
    return '合伙人账号已停用';
  }
  return text;
}

export default function LoginPage() {
  const navigate = useNavigate();
  const { applySession, refresh, account } = usePartnerSession();
  const savedProfile = getPartnerProfile();
  const remembered = loadRememberedPhone();
  const [phone, setPhone] = useState(remembered.phone || getLastPhone());
  const [code, setCode] = useState('');
  const [rememberAccount, setRememberAccount] = useState(remembered.remember);
  const [agreed, setAgreed] = useState(false);
  const [loading, setLoading] = useState(false);
  const [msg, setMsg] = useState('');
  const [codeCooldown, setCodeCooldown] = useState(0);
  const agreementRef = useRef<HTMLLabelElement>(null);

  function ensureAgreed() {
    if (!agreed) {
      setMsg('请先勾选并同意用户协议');
      agreementRef.current?.scrollIntoView({ behavior: 'smooth', block: 'center' });
      return false;
    }
    return true;
  }

  function persistRememberAccount(nextPhone: string) {
    try {
      if (rememberAccount) {
        localStorage.setItem(REMEMBER_FLAG_KEY, '1');
        localStorage.setItem(REMEMBER_PHONE_KEY, nextPhone);
      } else {
        localStorage.removeItem(REMEMBER_FLAG_KEY);
        localStorage.removeItem(REMEMBER_PHONE_KEY);
      }
    } catch {
      /* ignore */
    }
  }

  async function sendCode() {
    if (!ensureAgreed()) return;
    setMsg('');
    try {
      await request('PARTNER_H5', '/partner/auth/sms/send', {
        method: 'POST',
        body: JSON.stringify({ phone, scene: 'PARTNER_LOGIN' }),
        silent: true,
      });
      setMsg('验证码已发送');
      setCodeCooldown(60);
      const timer = setInterval(() => {
        setCodeCooldown((s) => {
          if (s <= 1) {
            clearInterval(timer);
            return 0;
          }
          return s - 1;
        });
      }, 1000);
    } catch (e) {
      setMsg(formatPartnerError(e));
    }
  }

  async function finishLoginNavigate() {
    const me = await refresh();
    navigate(partnerHomePath(me ?? account ?? savedProfile));
  }

  async function login() {
    if (!ensureAgreed()) return;
    setLoading(true);
    setMsg('');
    try {
      const data = await request<PartnerSessionPayload>('PARTNER_H5', '/partner/auth/login/sms', {
        method: 'POST',
        body: JSON.stringify({ phone, code }),
        silent: true,
      });
      saveRememberedSession(data);
      applySession(data);
      persistRememberAccount(phone);
      await finishLoginNavigate();
    } catch (e) {
      setMsg(formatPartnerError(e));
    } finally {
      setLoading(false);
    }
  }

  return (
    <div className="partner-auth-page">
      <div className="partner-auth-brand">
        <div className="partner-auth-logo-circle">
          <span className="material-symbols-outlined">wine_bar</span>
        </div>
        <h1 className="partner-auth-title">杜康好客</h1>
        <p className="partner-auth-subtitle">城市合伙人端</p>
      </div>

      <main className="partner-auth-card">
        <h2 className="partner-auth-card-title">城市合伙人登录</h2>
        <div style={{ display: 'flex', flexDirection: 'column', gap: 16 }}>
          <div className="partner-input-wrap">
            <span className="material-symbols-outlined partner-input-icon">smartphone</span>
            <input
              className="partner-input"
              type="tel"
              maxLength={11}
              placeholder="请输入手机号"
              value={phone}
              onChange={(e) => {
                setPhone(e.target.value);
                setMsg('');
              }}
            />
          </div>

          <div className="partner-input-row">
            <div className="partner-input-wrap">
              <span className="material-symbols-outlined partner-input-icon">shield</span>
              <input
                className="partner-input"
                type="text"
                maxLength={6}
                placeholder="验证码"
                value={code}
                onChange={(e) => setCode(e.target.value)}
              />
            </div>
            <button type="button" className="partner-code-btn" onClick={sendCode} disabled={codeCooldown > 0}>
              {codeCooldown > 0 ? `${codeCooldown}s` : '获取验证码'}
            </button>
          </div>

          <label className="partner-remember-row">
            <input
              type="checkbox"
              checked={rememberAccount}
              onChange={(e) => setRememberAccount(e.target.checked)}
            />
            <span>记住账号</span>
          </label>

          <AgreementCheckbox
            agreed={agreed}
            onChange={setAgreed}
            inputRef={agreementRef}
          />

          {msg && <p className="partner-auth-msg" style={{ color: 'var(--color-error, #d33)', fontSize: 13, textAlign: 'center' }}>{msg}</p>}

          <button type="button" className="partner-btn-primary" onClick={() => void login()} disabled={loading}>
            <span>{loading ? '登录中...' : '登录'}</span>
            {!loading && <span className="material-symbols-outlined">arrow_forward</span>}
          </button>
          <p className="partner-auth-msg" style={{ textAlign: 'center' }}>
            手机号验证成功后，7 天内无需再次输入验证码
          </p>
        </div>
      </main>

      <footer className="partner-auth-footer">
        <div style={{ display: 'flex', alignItems: 'center', gap: 6 }}>
          <span className="material-symbols-outlined">verified_user</span>
          <span className="label-md" style={{ fontSize: 10, letterSpacing: '0.15em', textTransform: 'uppercase' }}>SECURED BY DUKANG HERITAGE</span>
        </div>
      </footer>
    </div>
  );
}