import {
  CaretParser,
  CaretNode,
  CharToken,
  EditorState,
  TokensTag,
  VNode,
  h,
  Transaction,
  Cursor,
  t,
} from "@caret-js/core";
import {
  defaultParselets,
  FractionToken,
  FunctionArgColorsSyntaxHighlighter,
  FunctionDefinitionNode,
  ItalicVariablesSyntaxHighlighter,
  ParenthesesToken,
  RadicalToken,
  SubSupToken,
  toText,
  VariableNode,
} from "@caret-js/math";
import { Strand } from "@caret-js/core";

import "./main.css";

const app = document.getElementById("app") as HTMLDivElement;
const inputArea = document.getElementById("input-area") as HTMLDivElement;
const tokensArea = document.getElementById("tokens-area") as HTMLDivElement;
const parsedArea = document.getElementById("parsed-area") as HTMLDivElement;
// const diagramArea = document.getElementById(
//   "parsed-diagram-area"
// ) as HTMLDivElement;

let editorState = new EditorState();

function updatePreview() {
  let parseResult: CaretNode;
  try {
    const parser = new CaretParser(
      editorState,
      [],
      [...defaultParselets({ funcNames: new Set(["f"]) })]
    );
    parseResult = parser.parse();
  } catch (e) {
    console.error("Error parsing document:", e);
    return;
  }

  // Syntax highlighting
  const syntaxHighlighters = [
    new ItalicVariablesSyntaxHighlighter(),
    new FunctionArgColorsSyntaxHighlighter(),
  ];
  for (const highlighter of syntaxHighlighters) {
    highlighter.process(editorState, parseResult);
  }

  for (const [strand, strandPath] of editorState.content.traverseStrands()) {
    for (const token of strand.tokens) {
      let combinedStyles: Record<string, string> = {};
      for (const highlighter of syntaxHighlighters) {
        const styles = highlighter.getStyles(token);
        combinedStyles = { ...combinedStyles, ...styles };
      }
      if (token instanceof CharToken) {
        const styleString = Object.entries(combinedStyles)
          .map(([key, value]) => `${key}: ${value}`)
          .join("; ");
        token.TEMPORARY_DEBUG_STYLE_STRING = styleString;
      }
    }
  }

  inputArea.innerHTML = "";
  inputArea.appendChild(renderVNode(editorState.renderToDebugHTML()));
  // Token-based MathML
  // inputArea.appendChild(
  //   renderVNode(
  //     h("div", {}, t("Token-based MathML:"), editorState.renderToDebugMathML())
  //   )
  // );
  // Node-based MathML
  // inputArea.appendChild(
  //   renderVNode(
  //     h(
  //       "div",
  //       {},
  //       t("Node-based MathML:"),
  //       h("math", {}, parseResult.toDebugMathML())
  //     )
  //   )
  // );
  // Math to text
  // const text = toText(parseResult);
  // inputArea.appendChild(
  //   renderVNode(h("div", {}, t("Math to text: "), t(text ?? "")))
  // );
  // document.getElementById("math-to-text-readout")!.innerHTML = text ?? "";
  // document.getElementById("math-to-text-readout")!.innerHTML =
  //   text && parseResult instanceof CaretNode
  //     ? `${text} or in MathML ${renderVNodeToHTMLString(
  //         h("math", {}, parseResult.toDebugMathML())
  //       )}`
  //     : "";

  tokensArea.innerHTML = `
    <!--<pre>${JSON.stringify(editorState.selection)}</pre>-->
    <pre>${editorState.renderToDebugText()}</pre>
  `;
  parsedArea.innerHTML = `<pre>${parseResult.toDebugString()}</pre>`;
  // diagramArea.innerHTML = `<div>${parseResult.toDebugHTML()}<div>`;
}

function renderVNode(node: VNode): Node {
  if ("text" in node) {
    return document.createTextNode((node as any).text);
  }

  const elem = node.namespaceURI
    ? document.createElementNS(node.namespaceURI, node.type)
    : document.createElement(node.type);

  for (const [key, value] of Object.entries(node.attributes)) {
    elem.setAttribute(key, value);
  }
  for (const child of node.children) {
    elem.appendChild(renderVNode(child));
  }

  return elem;
}

function renderVNodeToHTMLString(node: VNode): string {
  if ("text" in node) {
    return (node as any).text;
  }

  const attrs = Object.entries(node.attributes)
    .map(([key, value]) => `${key}="${value}"`)
    .join(" ");
  const children = node.children
    .map((child) => renderVNodeToHTMLString(child))
    .join("");

  return `<${node.type}${attrs ? " " + attrs : ""}>${children}</${node.type}>`;
}

document.addEventListener("keydown", (event) => {
  if (event.key === "ArrowRight") {
    event.preventDefault();
    editorState = Transaction.moveCursor(
      editorState,
      "right",
      event.shiftKey
    ).newState;
    updatePreview();
    return;
  }
  if (event.key === "ArrowLeft") {
    event.preventDefault();
    editorState = Transaction.moveCursor(
      editorState,
      "left",
      event.shiftKey
    ).newState;
    updatePreview();
    return;
  }

  if (event.key === "Backspace") {
    event.preventDefault();
    editorState = Transaction.deleteAtSelection(
      editorState,
      "backward"
    ).newState;
    updatePreview();
    return;
  }
  if (event.key === "Delete") {
    event.preventDefault();
    editorState = Transaction.deleteAtSelection(
      editorState,
      "forward"
    ).newState;
    updatePreview();
    return;
  }
  if (event.key === "a" && (event.ctrlKey || event.metaKey)) {
    event.preventDefault();
    const transaction = Transaction.selectAll(editorState);
    editorState = transaction.newState;
    updatePreview();
    return;
  }

  const typeableChars =
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+-*=.,".split(
      ""
    );

  if (typeableChars.includes(event.key) && !event.ctrlKey && !event.metaKey) {
    event.preventDefault();
    // Check for "sqrt" completion
    if (event.key === "t") {
      if (editorState.selection.isCollapsed()) {
        const cursor = editorState.selection.head;
        const strand = editorState.content.getStrand(cursor.strandPath);
        if (strand) {
          const priorThreeTokens = strand.tokens
            .slice(Math.max(0, cursor.pos - 3), cursor.pos)
            .map((t) => (t instanceof CharToken ? t.char : ""))
            .join("");
          if (priorThreeTokens === "sqr") {
            // Replace "sqr" with a square root token
            const transaction = new Transaction(
              editorState,
              [
                {
                  strandPath: cursor.strandPath,
                  fromPos: cursor.pos - 3,
                  toPos: cursor.pos,
                  newTokens: [new RadicalToken(null, new Strand([]))],
                },
              ],
              new Cursor(
                [
                  ...cursor.strandPath,
                  { tokenIndex: cursor.pos - 3, childIndex: 0 },
                ],
                0
              )
            );

            editorState = transaction.newState;
            updatePreview();
            return;
          }
        }
      }
    }

    // Check for "cbrt" completion
    if (event.key === "t") {
      if (editorState.selection.isCollapsed()) {
        const cursor = editorState.selection.head;
        const strand = editorState.content.getStrand(cursor.strandPath);
        if (strand) {
          const priorThreeTokens = strand.tokens
            .slice(Math.max(0, cursor.pos - 3), cursor.pos)
            .map((t) => (t instanceof CharToken ? t.char : ""))
            .join("");
          if (priorThreeTokens === "cbr") {
            // Replace "cbr" with a cube root token
            const transaction = new Transaction(
              editorState,
              [
                {
                  strandPath: cursor.strandPath,
                  fromPos: cursor.pos - 3,
                  toPos: cursor.pos,
                  newTokens: [
                    new RadicalToken(
                      new Strand([new CharToken("3")]),
                      new Strand([])
                    ),
                  ],
                },
              ],
              new Cursor(
                [
                  ...cursor.strandPath,
                  { tokenIndex: cursor.pos - 3, childIndex: 1 },
                ],
                0
              )
            );

            editorState = transaction.newState;
            updatePreview();
            return;
          }
        }
      }
    }

    editorState = Transaction.insertAtSelection(editorState, [
      new CharToken(event.key),
    ]).newState;
    updatePreview();
    return;
  }

  if (event.key === "/" && !event.ctrlKey && !event.metaKey) {
    event.preventDefault();
    editorState = Transaction.insertAtSelection(editorState, [
      new FractionToken(new Strand([]), new Strand([])),
    ]).setNewSelection(
      new Cursor(
        [
          ...editorState.selection.commonStrandPath,
          { tokenIndex: editorState.selection.commonStartPos, childIndex: 0 },
        ],
        0
      )
    ).newState;
    updatePreview();
    return;
  }

  if (event.key === "(" && !event.ctrlKey && !event.metaKey) {
    event.preventDefault();
    editorState = Transaction.insertAtSelection(editorState, [
      new ParenthesesToken(new Strand([])),
    ]).setNewSelection(
      new Cursor(
        [
          ...editorState.selection.head.strandPath,
          { tokenIndex: editorState.selection.head.pos, childIndex: 0 },
        ],
        0
      )
    ).newState;
    updatePreview();
    return;
  }

  if (event.key === "^" && !event.ctrlKey && !event.metaKey) {
    event.preventDefault();
    editorState = Transaction.insertAtSelection(
      editorState,
      ({ setCursor }) => [new SubSupToken(null, new Strand([setCursor()]))]
    ).setNewSelection(new Cursor()).newState;
    updatePreview();
    return;
  }
  if (event.key === "_" && !event.ctrlKey && !event.metaKey) {
    event.preventDefault();
    editorState = Transaction.insertAtSelection(
      editorState,
      ({ setCursor }) => [new SubSupToken(new Strand([setCursor()]), null)]
    ).newState;
    updatePreview();
    return;
  }
});

updatePreview();