import 'vendor/golang'

const go = new Go();

const decoder = new TextDecoder("utf-8");

const getInt64 = (mem, addr) => {
  const low = mem.getUint32(addr + 0, true);
  const high = mem.getInt32(addr + 4, true);
  return low + high * 4294967296;
}

const loadString = (mem, addr) => {
  const saddr = getInt64(mem, addr + 0);
  const len = getInt64(mem, addr + 8);
  return decoder.decode(new DataView(mem.buffer, saddr, len));
}

const loadValue = (mem, addr) => {
  const f = mem.getFloat64(addr, true);
  if (f === 0) {
    return undefined;
  }
  if (!isNaN(f)) {
    return f;
  }

  const id = mem.getUint32(addr, true);
  return go._values[id];
}

go.importObject.go['main.defineClass'] = function(sp) {
  const mem = new DataView(go._inst.exports.mem.buffer)

  const name = loadString(mem, sp + 8);

  const constructor = loadValue(mem, sp + 24)
  const prototypes = loadValue(mem, sp + 40)

  window[name] = (new Function(
    'constructor', 'prototypes',
    `
      function ${name}() {
        if(!(this instanceof ${name})) {
          throw new TypeError("Cannot call a class as a function")
        }

        return constructor.apply(this, arguments)
      }

      prototypes.call(${name}.prototype)

      return ${name}
    `
  ))(constructor, prototypes);
}

WebAssembly
  .instantiateStreaming(
    fetch(require('./main.wasm')),
    go.importObject,
  )
  .then(result => {
    go.run(result.instance);
  });