import { Scalar } from '../../nodes/Scalar.mjs';
import { stringifyString } from '../../stringify/stringifyString.mjs';

const binary = {
  identify: value => value instanceof Uint8Array,
  // Buffer inherits from Uint8Array
  default: false,
  tag: 'tag:yaml.org,2002:binary',
  /**
   * Returns a Buffer in node and an Uint8Array in browsers
   *
   * To use the resulting buffer as an image, you'll want to do something like:
   *
   *   const blob = new Blob([buffer], { type: 'image/jpeg' })
   *   document.querySelector('#photo').src = URL.createObjectURL(blob)
   */
  resolve(src, onError) {
    if (typeof atob === 'function') {
      // On IE 11, atob() can't handle newlines
      const str = atob(src.replace(/[\n\r]/g, ''));
      const buffer = new Uint8Array(str.length);
      for (let i = 0; i < str.length; ++i) buffer[i] = str.charCodeAt(i);
      return buffer;
    } else {
      onError('This environment does not support reading binary tags; either Buffer or atob is required');
      return src;
    }
  },
  stringify({
    comment,
    type,
    value
  }, ctx, onComment, onChompKeep) {
    const buf = value; // checked earlier by binary.identify()
    let str;
    if (typeof btoa === 'function') {
      let s = '';
      for (let i = 0; i < buf.length; ++i) s += String.fromCharCode(buf[i]);
      str = btoa(s);
    } else {
      throw new Error('This environment does not support writing binary tags; either Buffer or btoa is required');
    }
    if (!type) type = Scalar.BLOCK_LITERAL;
    if (type !== Scalar.QUOTE_DOUBLE) {
      const lineWidth = Math.max(ctx.options.lineWidth - ctx.indent.length, ctx.options.minContentWidth);
      const n = Math.ceil(str.length / lineWidth);
      const lines = new Array(n);
      for (let i = 0, o = 0; i < n; ++i, o += lineWidth) {
        lines[i] = str.substr(o, lineWidth);
      }
      str = lines.join(type === Scalar.BLOCK_LITERAL ? '\n' : ' ');
    }
    return stringifyString({
      comment,
      type,
      value: str
    }, ctx, onComment, onChompKeep);
  }
};

export { binary };
