import { Cbor, CborByte, CborInteger, CborSet } from ".";
import { CborText } from "./text";

const readArraySize = (value: string) => {
  if (value.charAt(0) === "8") {
    return parseInt(value.charAt(1), 16);
  } else if (value.charAt(0) === "9") {
    switch (value.charAt(1)) {
      case "8":
        return parseInt(value.substring(2, 4), 16);
      case "9":
        return parseInt(value.substring(2, 6), 16);
      case "a":
        return parseInt(value.substring(2, 10), 16);
      case "b":
        return parseInt(value.substring(2, 18), 16);
      case "f":
        return Cbor.countItemsUntilBreak(value);
      default:
        return parseInt(value.charAt(1), 16) + 16;
    }
  } else {
    throw "Not an array";
  }
};

const sizeToCbor = (arrayLength: number) => {
  if (arrayLength <= 15) {
    return `8${arrayLength.toString(16)}`;
  } else if (arrayLength >= 16 && arrayLength <= 23) {
    return `9${(arrayLength - 16).toString(16)}`;
  } else if (arrayLength >= 24 && arrayLength <= 255) {
    return `98${arrayLength.toString(16).padStart(2, "0")}`;
  } else if (arrayLength >= 256 && arrayLength <= 65535) {
    return `99${arrayLength.toString(16).padStart(4, "0")}`;
  } else {
    throw "Array is too long, not supported.";
  }
};

const decode = <T>(cborArray: string): Array<T> => {
  const size = readArraySize(cborArray);
  const arrayBody = cborArray.substring(2);

  let cursor = 0;
  let finalArray = [];
  for (let i = 0; i < size; i++) {
    const nextValue = arrayBody.substring(cursor);
    const setItemLength = Cbor.readNextItemStringLength(nextValue);

    if (Cbor.identifyType(nextValue) === "set") {
      finalArray.push(CborSet.read(nextValue));
    } else if (
      Cbor.identifyType(nextValue) === "integer" ||
      Cbor.identifyType(nextValue) === "unsigned"
    ) {
      finalArray.push(CborInteger.read(nextValue));
    } else if (Cbor.identifyType(nextValue) === "array") {
      finalArray.push(decode(nextValue));
    } else if (Cbor.identifyType(nextValue) === "byte") {
      finalArray.push(CborByte.read(nextValue));
    } else if (Cbor.identifyType(nextValue) === "text") {
      finalArray.push(CborText.read(nextValue));
    } else if (Cbor.identifyType(nextValue) === "primitive") {
      const val = nextValue.substring(0, 2).toLowerCase();
      finalArray.push(val === "f4" ? false : true);
    } else {
      throw `Unidentified array value ${nextValue}`;
    }

    cursor += setItemLength;
  }

  return finalArray;
};

export const CborArray = {
  decode,
  sizeToCbor,
};