import { useEffect, useId, useState, type ReactNode } from 'react';
import { useOverlay } from '~/lib/overlay';
import { Portal, layerStyle, useDismiss, useLayerPosition } from '~/lib/layer';

interface Props {
  /** 触发器文字 */
  trigger: ReactNode;
  /** 浮层标题；也是 dialog 的可访问名 */
  title?: string;
  children: ReactNode;
  placement?: 'top' | 'bottom';
  className?: string;
}

export function MinimalPopover({
  trigger,
  title,
  children,
  placement = 'bottom',
  className = '',
}: Props) {
  const id = useId();
  const [open, setOpen] = useState(false);
  const { mounted, entering, leaving } = useOverlay(open);
  const { triggerRef, layerRef, pos } = useLayerPosition(mounted, { placement });
  useDismiss({
    open,
    onClose: () => setOpen(false),
    trigger: triggerRef,
    layer: layerRef,
  });

  // 打开即把焦点交给浮层：Esc 与 Tab 从浮层里开始走，关掉时再还给触发器。
  // 等定位算完（浮层可见）再给焦点，hidden 元素上的 focus() 会被静默吞掉。
  useEffect(() => {
    if (mounted && pos) layerRef.current?.focus();
  }, [mounted, pos]);

  const attachTrigger = (node: HTMLButtonElement | null) => {
    triggerRef.current = node;
  };

  return (
    <>
      <button
        ref={attachTrigger}
        type="button"
        aria-haspopup="dialog"
        aria-expanded={open}
        aria-controls={open ? id : undefined}
        onClick={() => setOpen((v) => !v)}
        className="
          press-feedback px-3.5 py-2 rounded-lg text-xs
          border border-[var(--glass-border)] bg-[var(--color-surface)] text-[var(--color-text-muted)]
          hover:text-[var(--color-text)] transition-colors cursor-pointer
        "
      >
        {trigger}
      </button>

      {mounted && (
        <Portal>
          <div
            ref={layerRef}
            id={id}
            role="dialog"
            aria-label={title ?? '浮层'}
            tabIndex={-1}
            style={layerStyle(pos)}
            className={`
              z-50 w-64 p-4 rounded-xl outline-none
              bg-[var(--color-surface)] border border-[var(--color-divider)]
              shadow-[var(--shadow-lg)]
              transition-[opacity,transform] duration-[var(--dur-fast)] ease-[var(--ease-standard)]
              ${entering || leaving ? 'opacity-0 translate-y-1' : 'opacity-100 translate-y-0'}
              ${className}
            `}
          >
            {title && <h3 className="text-sm font-medium mb-2">{title}</h3>}
            <div className="text-xs text-[var(--color-text-muted)] leading-relaxed">{children}</div>
          </div>
        </Portal>
      )}
    </>
  );
}