/**
 * End-to-end: build a .td5 from nothing but text, then read it back and check
 * the sign would accept it (CRC), and that the pixels survive intact.
 */
import { writeFileSync } from 'node:fs';
import { FONTS } from '../src/fonts.js';
import { fontFromJSON, renderText, trimX } from '../src/codec/bitfont.mjs';
import { parseTd5, buildTd5, pixelsToFrame, frameToPixels, crc16arc, EFFECT } from '../src/codec/td5.mjs';

const SCREEN = { width: 112, height: 16 };
const font = fontFromJSON(FONTS.ASC1609);

const LIST = [
  'SCHOOL BUS', 'CHARTER', 'RAIL BUS', 'EXPRESS COACH LINES',
  'CARMEL COLLEGE', 'OC1', 'NOT IN SERVICE', 'GO LIONS!',
];

function fit(bmp, height) {
  if (bmp.height === height) return bmp;
  const out = new Uint8Array(bmp.width * height);
  const y0 = Math.floor((height - bmp.height) / 2);
  for (let y = 0; y < bmp.height; y++) {
    const ty = y + y0;
    if (ty >= 0 && ty < height) out.set(bmp.pixels.subarray(y * bmp.width, (y + 1) * bmp.width), ty * bmp.width);
  }
  return { width: bmp.width, height, pixels: out };
}

const destinations = LIST.map((text) => {
  const bmp = fit(trimX(renderText(font, text)), SCREEN.height);
  const frame = pixelsToFrame(bmp.pixels, bmp.width, SCREEN.height);
  const effect = bmp.width > SCREEN.width ? EFFECT.SCROLL : EFFECT.HOLD;
  return { name: text.slice(0, 16), lineName: text.slice(0, 16), frames: [frame], effects: [effect, effect] };
});

// one two-page destination, to exercise the multi-frame path
const pages = ['MORETON BAY', 'BOYS COLLEGE'].map((t) => {
  const b = fit(trimX(renderText(font, t)), SCREEN.height);
  return pixelsToFrame(b.pixels, b.width, SCREEN.height);
});
destinations.push({ name: 'MORETON BAY', lineName: 'MORETON BAY', frames: pages, effects: [EFFECT.HOLD, EFFECT.HOLD, EFFECT.HOLD, EFFECT.HOLD] });

const bytes = buildTd5({ company: 'Test Coaches', screen: SCREEN, destinations });
writeFileSync(new URL('./authored.td5', import.meta.url), bytes);

// ---- read it back as if we were the sign
const back = parseTd5(bytes);
let fails = 0;
const check = (cond, msg) => { if (!cond) { fails++; console.log('   ❌ ' + msg); } };

check(back.company === 'Test Coaches', 'company survived');
check(back.destinations.length === destinations.length, 'destination count');
check(back.screen.width === 112 && back.screen.height === 16, 'screen size');
check(bytes.length % 0x200 === 0, 'file padded to a 512-byte boundary');

for (const d of back.destinations) {
  check(d.crcOk, `${d.name}: CRC verifies`);
  const src = destinations.find((x) => x.name === d.name);
  check(src && d.frames.length === src.frames.length, `${d.name}: frame count`);
  d.frames.forEach((f, i) => {
    const a = Buffer.from(f.data), b = Buffer.from(src.frames[i].data);
    check(a.equals(b), `${d.name}: frame ${i} pixels identical`);
  });
}

// independent CRC verification, byte-for-byte against the stored value
const dv = new DataView(bytes.buffer);
for (let i = 0; i < back.destinations.length; i++) {
  const ptr = dv.getUint32(0x200 + i * 4, true);
  const off = dv.getUint32(ptr + 0x30, true);
  const len = dv.getUint32(ptr + 0x34, true);
  const stored = bytes[off + 1] | (bytes[off + 2] << 8);
  check(stored === crc16arc(bytes.subarray(off + 3, off + len)), `block ${i}: CRC recomputes`);
}

console.log(`authored ${destinations.length} destinations -> ${bytes.length} bytes (test/authored.td5)`);
for (const d of back.destinations) {
  const w = d.frames[0].width;
  console.log(`  ${d.name.padEnd(17)} ${String(w).padStart(3)}px ${w > 112 ? 'scrolls' : 'fits   '} ` +
              `${d.frames.length > 1 ? d.frames.length + ' pages' : ''}`);
}
console.log(fails === 0 ? '\n✅ every check passed — a sign-ready file built from scratch' : `\n❌ ${fails} checks failed`);
process.exit(fails ? 1 : 0);