/** Shared UI primitives (docs/07 §4). */
import { useEffect, useRef, useState, type ReactNode } from 'react';
import type { PublicUser } from '@bg/shared/lite';
import { formatRoomCode, isBotId } from '@bg/shared/lite';
import { useToasts, toast } from '../store/toast';
import { useRoom } from '../net/socket';
import { haptic } from '../lib/feedback';
import { useOnline } from '../lib/pwa';

const AVATAR_COLORS = ['#2563eb', '#db2777', '#16a34a', '#ea580c', '#7c3aed', '#0891b2', '#ca8a04', '#dc2626'];

export function Avatar({ user, size = 40 }: { user: Pick<PublicUser, 'id' | 'nickname' | 'avatar'>; size?: number }) {
  let h = 0;
  for (const ch of user.id) h = (h * 31 + ch.charCodeAt(0)) >>> 0;
  const bg = AVATAR_COLORS[h % AVATAR_COLORS.length];
  return (
    <span className="avatar" style={{ width: size, height: size, background: bg, fontSize: size * 0.45 }} aria-hidden>
      {user.avatar ? <img src={user.avatar} alt="" loading="lazy" referrerPolicy="no-referrer" /> : isBotId(user.id) ? '🤖' : [...user.nickname][0]}
    </span>
  );
}

export function CopyButton({ text, label, done = '복사했어요 ✓', className = 'btn btn-secondary' }: { text: string; label: ReactNode; done?: ReactNode; className?: string }) {
  const [copied, setCopied] = useState(false);
  const onClick = async () => {
    try {
      await navigator.clipboard.writeText(text);
    } catch {
      // Fallback for old browsers / insecure contexts.
      const ta = document.createElement('textarea');
      ta.value = text;
      document.body.appendChild(ta);
      ta.select();
      const ok = document.execCommand('copy');
      ta.remove();
      if (!ok) {
        toast(`복사가 안 돼요. 직접 적어 주세요: ${text}`, 'error', 6000);
        return;
      }
    }
    haptic(30);
    setCopied(true);
    setTimeout(() => setCopied(false), 1500);
  };
  return (
    <button type="button" className={className} onClick={onClick} aria-live="polite">
      {copied ? done : label}
    </button>
  );
}

export function ShareButton({ title, text, url, className = 'btn btn-secondary' }: { title: string; text: string; url: string; className?: string }) {
  const canShare = typeof navigator !== 'undefined' && 'share' in navigator;
  if (!canShare) return <CopyButton text={`${text}\n${url}`} label="💬 초대글 복사" className={className} />;
  return (
    <button
      type="button"
      className={className}
      onClick={() => navigator.share({ title, text, url }).catch(() => {})}
    >
      📤 공유하기
    </button>
  );
}

export function Sheet({ onClose, children, label }: { onClose: () => void; children: ReactNode; label: string }) {
  const ref = useRef<HTMLDivElement>(null);
  useEffect(() => {
    const prev = document.activeElement as HTMLElement | null;
    ref.current?.focus();
    const onKey = (e: KeyboardEvent) => e.key === 'Escape' && onClose();
    window.addEventListener('keydown', onKey);
    return () => {
      window.removeEventListener('keydown', onKey);
      prev?.focus?.();
    };
  }, [onClose]);
  return (
    <div className="sheet-backdrop" onClick={(e) => e.target === e.currentTarget && onClose()}>
      <div className="sheet" role="dialog" aria-modal="true" aria-label={label} tabIndex={-1} ref={ref}>
        {children}
      </div>
    </div>
  );
}

export function ConfirmSheet({
  title,
  body,
  confirm,
  cancel = '취소',
  danger,
  onConfirm,
  onClose,
}: {
  title: string;
  body?: ReactNode;
  confirm: string;
  cancel?: string;
  danger?: boolean;
  onConfirm: () => void;
  onClose: () => void;
}) {
  return (
    <Sheet onClose={onClose} label={title}>
      <h2>{title}</h2>
      {body && <div className="muted">{body}</div>}
      <div className="stack">
        <button
          className={`btn btn-block ${danger ? 'btn-danger' : 'btn-primary'}`}
          onClick={() => {
            onConfirm();
            onClose();
          }}
        >
          {confirm}
        </button>
        <button className="btn btn-block btn-secondary" onClick={onClose}>
          {cancel}
        </button>
      </div>
    </Sheet>
  );
}

export function Toasts() {
  const toasts = useToasts((s) => s.toasts);
  return (
    <div className="toasts" role="status" aria-live="polite">
      {toasts.map((t) => (
        <div key={t.id} className={`toast ${t.kind === 'error' ? 'error' : ''}`}>
          {t.text}
        </div>
      ))}
    </div>
  );
}

export function ConnectionBanner() {
  const status = useRoom((s) => s.status);
  const code = useRoom((s) => s.code);
  const online = useOnline();
  if (!code) return online ? null : <div className="conn-banner" role="status">인터넷 연결이 없어요. 연결되면 다시 쓸 수 있어요.</div>;
  if (status === 'reconnecting' || status === 'connecting') return <div className="conn-banner">다시 연결하는 중…</div>;
  if (status === 'offline') return <div className="conn-banner">인터넷 연결이 끊겼어요. 연결되면 자동으로 이어져요.</div>;
  return null;
}

export function CodeLabel({ code }: { code: string }) {
  return <span style={{ fontVariantNumeric: 'tabular-nums', letterSpacing: '0.08em' }}>{formatRoomCode(code)}</span>;
}

export function TopBar({ title, onBack, right }: { title: ReactNode; onBack?: () => void; right?: ReactNode }) {
  return (
    <nav className="topbar" aria-label="페이지 메뉴">
      {onBack && (
        <button className="icon-btn" onClick={onBack} aria-label="뒤로">
          ←<span className="lbl">뒤로</span>
        </button>
      )}
      <div className="topbar-title">{title}</div>
      {right}
    </nav>
  );
}