import BinaryStream from '../../../common/binarystream';
import { byteLengthUtf8 } from '../../../common/utf8';

/**
 * A modification.
 */
export default class Modification {
  id: string = '\0\0\0\0';
  variableType: number = 0;
  levelOrVariation: number = 0;
  dataPointer: number = 0;
  value: number | string = 0;
  u1: number = 0;

  load(stream: BinaryStream, useOptionalInts: boolean) {
    this.id = stream.readBinary(4);
    this.variableType = stream.readInt32();

    if (useOptionalInts) {
      this.levelOrVariation = stream.readInt32();
      this.dataPointer = stream.readInt32();
    }

    if (this.variableType === 0) {
      this.value = stream.readInt32();
    } else if (this.variableType === 1 || this.variableType === 2) {
      this.value = stream.readFloat32();
    } else if (this.variableType === 3) {
      this.value = stream.readNull();
    } else {
      throw new Error(`Modification: unknown variable type ${this.variableType}`);
    }

    this.u1 = stream.readInt32();
  }

  save(stream: BinaryStream, useOptionalInts: boolean) {
    stream.writeBinary(this.id);
    stream.writeInt32(this.variableType);

    if (useOptionalInts) {
      stream.writeInt32(this.levelOrVariation);
      stream.writeInt32(this.dataPointer);
    }

    if (this.variableType === 0) {
      stream.writeInt32(<number>this.value);
    } else if (this.variableType === 1 || this.variableType === 2) {
      stream.writeFloat32(<number>this.value);
    } else if (this.variableType === 3) {
      stream.writeNull(<string>this.value);
    } else {
      throw new Error(`Modification: unknown variable type ${this.variableType}`);
    }

    stream.writeInt32(this.u1);
  }

  getByteLength(useOptionalInts: boolean) {
    let size = 12;

    if (useOptionalInts) {
      size += 8;
    }

    if (this.variableType === 3) {
      size += byteLengthUtf8(<string>this.value) + 1;
    } else {
      size += 4;
    }

    return size;
  }
}