// Downlink viewer: hex dump of the ship's transmit buffer, with download.

import { api } from './api.js';
import { h, clear, toast, download } from './dom.js';
import { hexView } from './hexview.js';

export function downlinkView(ctx) {
  const ship = ctx.ship;
  const body = h('div', { class: 'panel-body' }, h('p', { class: 'dim' }, ship ? 'ACQUIRING SIGNAL...' : 'YOU HAVE NO SHIP.'));
  const meta = h('span', { class: 'dim' });
  const dl = h('button', { class: 'btn', type: 'button', disabled: true }, 'DOWNLOAD .BIN');
  const refresh = h('button', { class: 'btn', type: 'button', disabled: !ship }, 'REFRESH');

  let current = null;
  async function fetchIt() {
    if (!ship) return;
    refresh.disabled = true;
    try {
      const { bytes, day } = await api.downlink(ship.id);
      current = { bytes, day };
      const allZero = bytes.every((b) => b === 0);
      meta.textContent = `SHIP #${ship.id}  //  FROM THE RUN OF DAY ${day}  //  ${bytes.length} BYTES`;
      dl.disabled = false;
      clear(body).append(
        ...(allZero ? [h('p', { class: 'warn' }, 'BUFFER IS ALL ZEROS: THE SHIP HAS NOT WRITTEN ANYTHING TO ITS DOWNLINK BUFFER.')] : []),
        hexView(bytes).el,
        h('p', { class: 'hint' }, 'OFFSETS ARE INTO THE 1 KB DOWNLINK BUFFER (SHIP RAM 1024-2047). MULTI-BYTE VALUES ARE LITTLE-ENDIAN.'),
      );
    } catch (e) {
      current = null;
      dl.disabled = true;
      meta.textContent = '';
      clear(body).append(
        e.status === 404
          ? h('div', { class: 'nosignal' },
              h('p', { class: 'big' }, 'NO SIGNAL'),
              h('p', { class: 'dim' }, 'THIS SHIP HAS NOT TRANSMITTED YET. A SHIP\'S FIRST DOWNLINK ARRIVES AFTER ITS FIRST DAY IN THE BELT.'))
          : h('p', { class: 'bad' }, `ERROR: ${e.message}`),
      );
    } finally {
      refresh.disabled = false;
    }
  }

  // Reloading the account too keeps the ship's status and the day current.
  refresh.addEventListener('click', () => ctx.refresh().catch((e) => toast(e.message, 'err')));
  dl.addEventListener('click', () => {
    if (!current) return;
    download(`ship-${ship.id}-day-${current.day}-downlink.bin`, current.bytes);
    toast(`SAVED ${current.bytes.length} BYTES`);
  });
  fetchIt();

  return h('section', { class: 'panel' },
    h('div', { class: 'panel-title' }, 'DOWNLINK RECEIVER', h('span', { class: 'spacer' }), meta),
    h('div', { class: 'toolbar pad' }, refresh, h('span', { class: 'spacer' }), dl),
    body,
  );
}