// SPDX-License-Identifier: GPL-2.0-only

"use strict";

console.log("ASAP: Loaded");

const msgListCb = new MutationObserver(handleMsgList);
msgListCb.observe(document.body, {
  childList: true,
  subtree: true,
});
handleMsgList();

function handleMsgList() {
  const list = document.querySelector(".message-list");
  if (list) {
    console.log("ASAP: Found message list");
    msgListCb.disconnect();
    const msgCb = new MutationObserver(handleMsg);
    msgCb.observe(list, { childList: true, subtree: true });
    handleMsg();
  }
}

function handleMsg() {
  const texts = document.querySelectorAll(".message-parts-container:not(.zbyffrly-done), .parent-text:not(.zbyffrly-done)")
  texts.forEach((text) => {
    text.classList.add("zbyffrly-done");

    // Split up between text and code bits
    const blockBits = text.firstChild.textContent.split(/(?:^|\n)```/);
    const msgOut = document.createElement("div");
    for (let i = 0; i < blockBits.length; i++) {
      let block = blockBits[i];
      if (i & 1) {
        const newlineIdx = block.indexOf("\n");
        const lang = block.slice(0, newlineIdx);
        const code = block.slice(newlineIdx + 1);

        const preEl = document.createElement("pre");
        const codeEl = document.createElement("code");
        if (lang) codeEl.classList.add("language-" + lang);
        codeEl.appendChild(document.createTextNode(code));
        hljs.highlightElement(codeEl);
        preEl.appendChild(codeEl);

        msgOut.appendChild(preEl);
      } else {
        block = block[0] == "\n" ? block.slice(1) : block;
        const inlineBits = block.split("`");
        for (let i = 0; i < inlineBits.length; i++) {
          let inlineEl;
          if (i & 1) {
            inlineEl = document.createElement("code");
            inlineEl.innerText = inlineBits[i];
            if (inlineBits[i + 1]?.startsWith("{:.")) {
              const closingBrace = inlineBits[i + 1].indexOf("}");
              if (closingBrace !== -1) {
                const lang = inlineBits[i + 1].slice(3, closingBrace);
                inlineBits[i + 1] = inlineBits[i + 1].slice(closingBrace + 1);
                inlineEl.classList.add("language-" + lang);
              }
            }
            hljs.highlightElement(inlineEl);
          } else {
            if (inlineBits[i] === "\xa0") continue;
            inlineEl = document.createElement("span");
            inlineEl.innerText = inlineBits[i];
            renderTex(inlineEl);
          }
          msgOut.appendChild(inlineEl);
        }
      }
    }

    if (msgOut.children.length > 1) text.replaceChild(msgOut, text.firstChild);
    else renderTex(text);
  });
}

function renderTex(el) {
  renderMathInElement(el, {
    output: "mathml", // HTML output is broken in Pronto
    delimiters: [
      { left: "$$", right: "$$", display: true },
      { left: "$", right: "$", display: false },
      { left: "\\(", right: "\\)", display: false },
      { left: "\\begin{equation}", right: "\\end{equation}", display: true },
      { left: "\\begin{align}", right: "\\end{align}", display: true },
      { left: "\\begin{alignat}", right: "\\end{alignat}", display: true },
      { left: "\\begin{gather}", right: "\\end{gather}", display: true },
      { left: "\\begin{CD}", right: "\\end{CD}", display: true },
      { left: "\\[", right: "\\]", display: true }
    ],
    errorCallback: (msg) => {
      console.error("ASAP: KaTeX:", msg);
      const span = document.createElement("span");
      span.innerText = msg;
      span.style.color = "red";
      el.prepend(span);
    },
  });
}