let textbox;
let textconsole;
let text = "# welcome to gride!\n# type your code here and click run!\n";
let filebutton;
let fileinput;
let firstRun = true;

// Function to save cursor position
function saveCursorPosition() {
  const selection = window.getSelection();
  if (selection.rangeCount === 0) return null;

  const range = selection.getRangeAt(0);
  const preCaretRange = range.cloneRange();
  preCaretRange.selectNodeContents(textbox);
  preCaretRange.setEnd(range.startContainer, range.startOffset);

  return preCaretRange.toString().length;
}

// Function to restore cursor position
function restoreCursorPosition(savedPos) {
  if (savedPos === null || !textbox) return;

  const textNodes = [];
  const walker = document.createTreeWalker(
    textbox,
    NodeFilter.SHOW_TEXT,
    null,
    false,
  );

  let node;
  while ((node = walker.nextNode())) {
    textNodes.push(node);
  }

  let currentPos = 0;
  for (const textNode of textNodes) {
    const nodeLength = textNode.textContent.length;
    if (currentPos + nodeLength >= savedPos) {
      const range = document.createRange();
      const selection = window.getSelection();

      try {
        range.setStart(textNode, Math.min(savedPos - currentPos, nodeLength));
        range.collapse(true);
        selection.removeAllRanges();
        selection.addRange(range);
      } catch (e) {
        // If positioning fails, just focus the element
        textbox.focus();
      }
      return;
    }
    currentPos += nodeLength;
  }

  // If we couldn't find the exact position, focus at the end
  const range = document.createRange();
  const selection = window.getSelection();
  try {
    range.selectNodeContents(textbox);
    range.collapse(false);
    selection.removeAllRanges();
    selection.addRange(range);
  } catch (e) {
    textbox.focus();
  }
}

function renderHighlightedText() {
  if (!textbox) return;

  // Save cursor position before updating
  const cursorPos = saveCursorPosition();

  let renderedText = "";
  const lines = text.split("\n");

  for (let i = 0; i < lines.length; i++) {
    const line = lines[i];
    if (line.trim() === "") {
      renderedText += "<div>&nbsp;</div>"; // Preserve empty lines
    } else {
      const commentIndex = line.indexOf("#");
      if (commentIndex !== -1) {
        const beforeComment = line.substring(0, commentIndex);
        const comment = line.substring(commentIndex);
        renderedText += `<div>${highlightTokens(beforeComment)}<span style="color: ${colours.comment}">${comment}</span></div>`;
      } else {
        renderedText += `<div>${highlightTokens(line)}</div>`;
      }
    }
  }

  textbox.innerHTML = renderedText;

  // Restore cursor position after a brief delay to let the DOM update
  setTimeout(() => {
    restoreCursorPosition(cursorPos);
  }, 0);
}

function getTextFromEditor() {
  let newText = "";
  for (let i = 0; i < textbox.childNodes.length; i++) {
    const div = textbox.childNodes[i];
    if (div.nodeType === Node.ELEMENT_NODE && div.tagName === 'DIV') {
      let line = "";
      for (let j = 0; j < div.childNodes.length; j++) {
        line += div.childNodes[j].textContent;
      }
      newText += line + (i < textbox.childNodes.length - 1 ? "\n" : "");
    } else if (div.nodeType === Node.TEXT_NODE) {
      newText += div.textContent;
    }
  }
  return newText;
}

// Wait for the window to load before doing anything
window.addEventListener("load", function () {
  // Get all the elements
  textbox = document.getElementById("editor");
  textconsole = document.getElementById("console");
  filebutton = document.getElementById("buttonTrigger");
  fileinput = document.getElementById("fileInput");

  // Check if elements exist
  if (!textbox || !textconsole || !filebutton || !fileinput) {
    console.error("Some required elements not found!");
    return;
  }

  textbox.innerText = text;

  // Initial render
  renderHighlightedText();

  // Set up watchers for everything
  filebutton.addEventListener("click", () => {
    fileinput.click();
  });

  fileinput.addEventListener("change", () => {
    const file = fileinput.files[0];
    if (file) {
      const reader = new FileReader();
      reader.onload = function (e) {
        text = e.target.result;
        textbox.innerText = text;
        renderHighlightedText();
      };
      reader.readAsText(file);
    } else {
      console.log("No file selected");
    }
  });

  // When we press a key, start doing stuff
  textbox.addEventListener("input", () => {
    text = getTextFromEditor();
    renderHighlightedText();
  });

  // Handle tab key to insert 4 spaces
  textbox.addEventListener("keydown", (e) => {
    if (e.key === "Tab") {
      e.preventDefault();

      // Insert 4 spaces at cursor position
      const selection = window.getSelection();
      const range = selection.getRangeAt(0);

      // Create a text node with 4 spaces
      const textNode = document.createTextNode("    ");
      range.insertNode(textNode);

      // Move cursor to after the inserted spaces
      range.setStartAfter(textNode);
      range.collapse(true);
      selection.removeAllRanges();
      selection.addRange(range);

      // Update our text variable and re-render
      text = getTextFromEditor();
      renderHighlightedText();
    }
  });

  // Handle paste events
  textbox.addEventListener("paste", (e) => {
    e.preventDefault();
    const paste = (e.clipboardData || window.clipboardData).getData("text");
    document.execCommand("insertText", false, paste);
    text = getTextFromEditor();
    renderHighlightedText();
  });
});

const keywords = [
  "if",
  "jump",
  "end",
  "input",
  "stdin",
  "print",
  "stdout",
  "println",
  "stdlnout",
  "set",
  "gettype",
  "exists",
  "setlist",
  "setlistat",
  "getlistat",
  "getlistsize",
  "listappend",
  "getstrsize",
  "getstrcharat",
  "add",
  "subtract",
  "multiply",
  "divide",
  "equal",
  "inequal",
  "not",
  "greater",
  "lesser",
  "stoi",
  "stod",
  "tostring",
  "fun",
  "return",
  "endfun",
  "pusharg",
  "call",
  "struct",
  "endstruct",
  "init",
  "use",
  "extern",
  "catch",
];

const colours = {
  keyword: "#42fff2",
  comment: "#383838",
  number: "#42ff62",
  string: "#42ff62",
  valref: "#9544c7",
  dirref: "#f587ff",
  lineref: "#9bf542",
  label: "#fff67d",
  function: "#ffa640",
  typeref: "#ff40ac",
};

function highlightTokens(line) {
  const tokens = line.split(/(\s+|"[^"]*"|'[^']*')/).filter(Boolean);
  let instring = false;
  return tokens.map(token => {
    if (token.startsWith('"') || token.startsWith("'")) {
      instring = !instring;
      return `<span style="color: ${colours.string}">${token}</span>`;
    }
    if (instring) {
      return `<span style="color: ${colours.string}">${token}</span>`;
    }
    if (keywords.includes(token)) {
      return `<span style="color: ${colours.keyword}">${token}</span>`;
    }
    if (!isNaN(token) && token.trim() !== "") {
      return `<span style="color: ${colours.number}">${token}</span>`;
    }
    if (token.startsWith('&')) {
      return `<span style="color: ${colours.dirref}">${token}</span>`;
    }
    if (token.startsWith('$')) {
      return `<span style="color: ${colours.valref}">${token}</span>`;
    }
    if (token.startsWith('-')) {
      return `<span style="color: ${colours.typeref}">${token}</span>`;
    }
    if (token.startsWith('!')) {
      return `<span style="color: ${colours.function}">${token}</span>`;
    }
    if (token.startsWith('%')) {
      return `<span style="color: ${colours.lineref}">${token}</span>`;
    }
    if (token.startsWith('@')) {
      return `<span style="color: ${colours.label}">${token}</span>`;
    }
    return token;
  }).join('');
}

// Function to run code on the server
async function runCode() {
  if (!textconsole) {
    console.error("Console element not found!");
    return;
  }

  // Make sure we have the latest text
  // The `text` variable is now the single source of truth.

  if (firstRun) {
    textconsole.innerHTML = "";
    firstRun = false;
  }

  console.log("Running code:", text);

  try {
    const result = await fetch("/runProgram", {
      method: "POST",
      headers: {
        "Content-Type": "text/plain",
      },
      body: text,
    });

    if (!result.ok) {
      throw new Error(`HTTP error! status: ${result.status}`);
    }

    const data = await result.json();
    const output = data.stdout.split('\n').join('</div><div>');
    const timestamp = new Date().toLocaleTimeString();
    textconsole.innerHTML += `<div>[${timestamp}]</div><div>${output}</div>`;
    textconsole.scrollTop = textconsole.scrollHeight; // Scroll to bottom
  } catch (error) {
    console.error("Error running code:", error);
    textconsole.innerHTML =
      "<div style='color: #ff4444'>Error: " + error.message + "</div>";
  }
}