"use strict";

const SKILL_LINK_RE = /\[\$([^\]\n]+)\]\(([^)\n]*)\)/g;
const LEADING_SKILL_LINK_RE = /^\s*\[\$([^\]\n]+)\]\(([^)\n]*)\)\s*/;
const TRUNCATED_LEADING_SKILL_LINK_RE = /^\s*\[\$([^\]\n]+)\]\([^)\n]*$/;
const LEADING_SKILL_TOKEN_RE = /^\s*\$[A-Za-z][\w:.-]*(?:\s+|$)/;

function normalizeInlineText(text) {
  return String(text || "")
    .replace(/\s+/g, " ")
    .trim();
}

function cleanSkillLinks(text) {
  return String(text || "").replace(SKILL_LINK_RE, (_m, name) => `$${String(name || "").trim()}`);
}

function stripLeadingSkillMentions(text) {
  let out = cleanSkillLinks(text);
  let changed = true;
  while (changed) {
    changed = false;
    const before = out;
    out = out.replace(LEADING_SKILL_LINK_RE, "");
    out = out.replace(TRUNCATED_LEADING_SKILL_LINK_RE, "");
    out = out.replace(LEADING_SKILL_TOKEN_RE, "");
    out = out.replace(/^\s*[:：,，;；|｜\-–—]+\s*/, "");
    changed = out !== before;
  }
  return out;
}

function cleanUserVisibleText(text) {
  return cleanSkillLinks(text);
}

// 某些中转模型会把内部思考误当成普通正文，用 XML 风格标签直接输出。
// 只清理明确的内部块，不改动普通文本中的尖括号内容。
function stripInternalThoughtBlocks(text) {
  let out = String(text || "");
  for (const name of ["thinking", "analysis", "reasoning"]) {
    const re = new RegExp("<" + name + "\\b[^>]*>[\\s\\S]*?</" + name + "\\s*>", "gi");
    out = out.replace(re, "");
  }
  return out.replace(/<\/?(?:thinking|analysis|reasoning)\b[^>]*>/gi, "");
}

// 流式内容可能把标签拆在多个 chunk 中：未闭合的内部块整体暂不输出。
function stripInternalThoughtStreaming(text) {
  const source = String(text || "");
  let out = "";
  let cursor = 0;
  const openRe = /<(thinking|analysis|reasoning)\b[^>]*>/gi;
  while (true) {
    openRe.lastIndex = cursor;
    const open = openRe.exec(source);
    if (!open) {
      out += source.slice(cursor);
      break;
    }
    out += source.slice(cursor, open.index);
    const closeRe = new RegExp("</" + open[1] + "\\s*>", "i");
    const tail = source.slice(openRe.lastIndex);
    const close = closeRe.exec(tail);
    if (!close) break;
    cursor = openRe.lastIndex + close.index + close[0].length;
  }
  return stripInternalThoughtBlocks(out);
}

function cleanThreadTitle(title, fallback = "", maxLen = 80) {
  const primary = normalizeInlineText(stripLeadingSkillMentions(title));
  const secondary = normalizeInlineText(stripLeadingSkillMentions(fallback));
  const cleaned = primary || secondary || normalizeInlineText(cleanSkillLinks(title)) || normalizeInlineText(cleanSkillLinks(fallback));
  return cleaned ? cleaned.slice(0, maxLen) : "";
}

function looksLikeSkillMentionTitle(title) {
  const text = normalizeInlineText(title);
  return /^\[\$[^\]]+\]\(/.test(text) || /^\$[A-Za-z][\w:.-]*(?:\s|$)/.test(text);
}

module.exports = {
  cleanSkillLinks,
  cleanThreadTitle,
  cleanUserVisibleText,
  stripInternalThoughtBlocks,
  stripInternalThoughtStreaming,
  looksLikeSkillMentionTitle,
};