import { StringDecoder } from "node:string_decoder";
import { Buffer } from "node:buffer";

export function report() {
  const bom = Buffer.from([0xef, 0xbb, 0xbf, 0x61]);
  console.log('buffer-bom', JSON.stringify(bom.toString('utf8')), JSON.stringify(bom.toString('utf8', 0, 3)), JSON.stringify(bom.toString('utf8', 3)));
  const inputs = [
    [0xef, 0xbb, 0xbf, 0x61], [0xc2, 0xa2], [0xe2, 0x82, 0xac],
    [0xf0, 0x9f, 0x98, 0x80], [0xe0, 0x80, 0x61], [0xed, 0xa0, 0x80],
    [0xf4, 0x90, 0x80, 0x80], [0xc0, 0xaf], [0xff, 0x80, 0xe2, 0x82],
    [0x61, 0, 0x3d, 0xd8, 0, 0xde, 0x62, 0], [0x3d, 0xd8], [0x61],
    [0x3d, 0xd8, 0, 0xde, 0x3d, 0xd8, 0, 0xde],
  ];
  for (const enc of ['utf8', 'utf16le', 'base64', 'base64url', 'latin1', 'ascii', 'hex']) {
    for (const input of inputs) {
      const bytes = Buffer.from(input);
      for (let a = 0; a <= bytes.length; a++) {
        for (let b = a; b <= bytes.length; b++) {
          const d = new StringDecoder(enc);
          console.log(enc, a, b, JSON.stringify([
            d.write(bytes.subarray(0, a)), d.write(bytes.subarray(a, b)),
            d.end(bytes.subarray(b)), d.end(), d.end(Buffer.from('ok')),
          ]));
        }
      }
    }
  }
  const d = new StringDecoder();
  console.log('strings', JSON.stringify([d.write(Buffer.from([0xe2])), d.write('middle'), d.end('last'), d.end()]));
  console.log('empty', JSON.stringify([d.write(Buffer.from([0xe0])), d.write(Buffer.alloc(0)), d.write(Buffer.from([0x80])), d.end(undefined)]));
  const backing = new Uint8Array([0, 0x68, 0x69, 0]);
  console.log('views', d.end(new DataView(backing.buffer, 1, 2)), d.end(new Uint16Array([0x6968])), d.end(backing.subarray(1, 3)));
  for (const encoding of [undefined, null, '', 'UTF-8', 'UCS-2', 'BINARY', 'nope', false, 0]) {
    try { console.log('encoding', String(encoding), new StringDecoder(encoding).encoding); }
    catch (e) { console.log('encoding-error', e.name, e.code, e.message); }
  }
  for (const input of [undefined, null, 1, {}, [], new ArrayBuffer(2)]) {
    try { d.write(input); console.log('unexpected'); }
    catch (e) { console.log('input-error', e.name, e.code, e.message); }
  }
  d.encoding = 'hex';
  console.log('encoding-property', d.encoding, d.end(Buffer.from('hi')));
}