import {
  INITIAL,
  parseRawGrammar,
  Registry,
} from "https://ghc.deno.dev/dcdunkan/deno_textmate/mod.ts";
import {
  loadWASM,
  OnigScanner,
  OnigString,
} from "https://esm.sh/[email protected]";

// https://github.com/microsoft/vscode-oniguruma/blob/main/out/onig.wasm
const wasmFile = await Deno.readFile("./onig.wasm");
const wasmBin = wasmFile.buffer;
const vscodeOnigurumaLib = loadWASM(wasmBin).then(() => {
  return {
    createOnigScanner(patterns: string[]) {
      return new OnigScanner(patterns);
    },
    createOnigString(str: string) {
      return new OnigString(str);
    },
  };
});

// Create a registry that can create a grammar from a scope name.
const registry = new Registry({
  onigLib: vscodeOnigurumaLib,
  loadGrammar: async (scopeName) => {
    if (scopeName === "source.js") {
      // https://github.com/textmate/javascript.tmbundle/blob/master/Syntaxes/JavaScript.plist
      const grammarFileContent = await Deno.readTextFile("./JavaScript.plist");
      return parseRawGrammar(grammarFileContent);
    }

    console.log(`Unknown scope name: ${scopeName}`);
  },
});

// Load the JavaScript grammar and any other grammars included by it async.
const grammar = await registry.loadGrammar("source.js");

const text = [
  `function sayHello(name) {`,
  `\treturn "Hello, " + name;`,
  `}`,
];
let ruleStack = INITIAL;
for (let i = 0; i < text.length; i++) {
  const line = text[i];
  const lineTokens = grammar!.tokenizeLine(line, ruleStack);
  console.log(`\nTokenizing line: ${line}`);
  for (let j = 0; j < lineTokens.tokens.length; j++) {
    const token = lineTokens.tokens[j];
    console.log(
      ` - token from ${token.startIndex} to ${token.endIndex} ` +
        `(${line.substring(token.startIndex, token.endIndex)}) ` +
        `with scopes ${token.scopes.join(", ")}`,
    );
  }
  ruleStack = lineTokens.ruleStack;
}