import type { Element, ElementContent, Root as HastRoot } from 'hast';
import type { Root as MdastRoot, BlockContent } from 'mdast';
import { visit, CONTINUE, EXIT } from 'unist-util-visit';

export function findTitle(
  node: Element | ElementContent | BlockContent | MdastRoot | HastRoot | undefined,
  opts: { delete: boolean; nodeType?: string; tagName?: string; escaped?: boolean } = {
    delete: true,
    nodeType: undefined,
    tagName: undefined,
  }
): string {
  let title = '';
  if (!node) return title;

  visit(node, opts.nodeType ? opts.nodeType : node, function (subNode) {
    if (opts.tagName && subNode.type === 'element' && subNode.tagName !== opts.tagName) {
      return CONTINUE;
    }

    visit(subNode, 'text', function (textNode, index, parent) {
      title += textNode.value;
      if (opts.delete && parent && typeof index === 'number') {
        parent.children.splice(index, 1);
      }
    });
  });

  title = title.trim();
  if (opts.escaped) {
    return title.replace(/"/g, '\\"');
  } else {
    return title;
  }
}

export function getTitleFromHeading(root: MdastRoot): string {
  let headingElement: BlockContent | undefined = undefined;
  visit(root, 'heading', function (subNode, index, parent) {
    headingElement = subNode;
    if (parent && typeof index === 'number') {
      parent.children.splice(index, 1);
    }
    return EXIT;
  });
  return findTitle(headingElement, { delete: true, escaped: true });
}

export function getDescriptionFromRoot(root: MdastRoot): string {
  let descriptionElement: BlockContent | undefined = undefined;
  visit(root, 'paragraph', function (subNode, index, parent) {
    if (typeof index !== 'number' || index !== 0 || !parent || parent.type !== 'root') return EXIT;

    descriptionElement = subNode;
    if (typeof index === 'number') {
      parent.children.splice(index, 1);
    }
    return EXIT;
  });
  return findTitle(descriptionElement, { delete: true, escaped: true });
}

export function getTitleFromLink(url: string): string {
  if (url.startsWith('http')) {
    url = new URL(url).pathname;
  }
  const lastPathname = url.split('/').at(-1) ?? '';
  const dashSplitPathname = lastPathname.split('-').flatMap((i) => i.split('_'));
  dashSplitPathname.forEach((str, index) => {
    dashSplitPathname[index] = str[0] ? `${str[0].toUpperCase()}${str.substring(1)}` : str;
  });

  return dashSplitPathname.join(' ');
}