import r from 'restructure';

export default class CFFPointer extends r.Pointer {
  constructor(type, options = {}) {
    if (options.type == null) {
      options.type = 'global';
    }

    super(null, type, options);
  }

  decode(stream, parent, operands) {
    this.offsetType = {
      decode: () => operands[0]
    };

    return super.decode(stream, parent, operands);
  }

  encode(stream, value, ctx) {
    if (!stream) {
      // compute the size (so ctx.pointerSize is correct)
      this.offsetType = {
        size: () => 0
      };

      this.size(value, ctx);
      return [new Ptr(0)];
    }

    let ptr = null;
    this.offsetType = {
      encode: (stream, val) => ptr = val
    };

    super.encode(stream, value, ctx);
    return [new Ptr(ptr)];
  }
}

class Ptr {
  constructor(val) {
    this.val = val;
    this.forceLarge = true;
  }

  valueOf() {
    return this.val;
  }
}