'use strict';

const index = (options = {}) => (tree) => {
  options.attributes = options.attributes || ["prevent-widows", "no-widows"];
  options.minWords = options.minWords || 4;
  options.createWidows = options.createWidows || false;
  options.ignore = options.ignore || [
    { start: "{{", end: "}}" },
    // Handlebars, Liquid, Nunjucks, Twig, Jinja2, Mustache
    { start: "{%", end: "%}" },
    // Liquid, Nunjucks, Twig, Jinja2
    { start: "<%=", end: "%>" },
    // EJS, ERB
    { start: "<%", end: "%>" },
    // EJS, ERB
    { start: "{$", end: "}" },
    // Smarty
    { start: "<\\?", end: "\\?>" },
    // PHP
    { start: "#{", end: "}" }
    // Pug
  ];
  const process = (node, shouldReplace = false) => {
    let replace = shouldReplace;
    if (typeof node === "string") {
      let parts = [node];
      for (const pattern of options.ignore) {
        const regex = new RegExp(`(${pattern.start}.*?${pattern.end})`, "g");
        parts = parts.flatMap((part) => part.split(regex));
      }
      const processedParts = parts.map((part) => {
        for (const pattern of options.ignore) {
          const ignorePattern = new RegExp(`^${pattern.start}.*?${pattern.end}$`);
          if (ignorePattern.test(part)) {
            return part;
          }
        }
        const partWords = part.trim().split(/\s+/);
        if (replace && partWords.length >= options.minWords) {
          return options.createWidows ? part.replace(/&nbsp;([^ ]+)$/g, " $1") : part.replace(/ ([^ ]+)$/gm, "&nbsp;$1");
        }
        return part;
      });
      return processedParts.join("");
    }
    if (node.tag && node.attrs) {
      for (const attr of options.attributes) {
        if (attr in node.attrs) {
          delete node.attrs[attr];
          replace = true;
          break;
        }
      }
    }
    if (Array.isArray(node.content)) {
      node.content = node.content.map((child) => process(child, replace));
    }
    return node;
  };
  return tree.walk(process);
};

module.exports = index;