import { h, type VNode } from 'vue';
import { parseDocument } from 'htmlparser2';
import type { Element, Text, Node } from 'domhandler';

/** 标签映射的类型：key=标签名，value=渲染函数 */
export type HtmlRenderMap = Record<
  string,
  (node: Element, children: VNode[]) => VNode
>;

export interface HtmlRenderOptions {
  /** 自定义标签渲染映射 */
  map?: HtmlRenderMap;

  /** 默认是否将未知标签渲染为原生标签（默认 true） */
  allowUnknownTags?: boolean;
}

export const useHtmlRenderer = (
  html: string,
  options: HtmlRenderOptions = {}
) => {
  const { map = {}, allowUnknownTags = true } = options;

  const doc = parseDocument(html);

  function render(node: Node): VNode | string | null {
    // 文本节点
    if (node.type === 'text') {
      const textNode = node as Text;
      const content = textNode.data;

      // ❗忽略"纯空白" 文本(换行、空格)
      if (!content || /^\s+$/.test(content)) {
        return null;
      }

      return content;
    }

    // 标签节点
    if (node.type === 'tag') {
      const elem = node as Element;
      const rawName = elem.name ?? '';
      const name = rawName.trim().toLowerCase();

      // 标签名有效性校验
      const isValidTag = /^[a-zA-Z][a-zA-Z0-9-]*$/.test(name);
      if (!isValidTag) {
        logger.warn(`Invalid tag name ignored: "${rawName}"`);
        return null;
      }

      const children: VNode[] = (elem.children || [])
        .map((child) => render(child))
        .filter(Boolean) as VNode[];

      // 自定义映射
      if (map[name]) {
        return map[name](elem, children);
      }

      // 默认将未知标签渲染为原生标签
      if (allowUnknownTags) {
        return h(name, elem.attribs || {}, children);
      }

      // 忽略无法渲染节点
      return null;
    }

    return null;
  }

  const nodes = doc.children
    .map((child) => render(child))
    .filter(Boolean) as VNode[];

  return nodes;
};