feat(gateway): add agent image attachments + live probe

src/gateway/live-image-probe.ts

@@ -0,0 +1,206 @@
+import { deflateSync } from "node:zlib";
+
+const CRC_TABLE = (() => {
+  const table = new Uint32Array(256);
+  for (let i = 0; i < 256; i += 1) {
+    let c = i;
+    for (let k = 0; k < 8; k += 1) {
+      c = c & 1 ? 0xedb88320 ^ (c >>> 1) : c >>> 1;
+    }
+    table[i] = c >>> 0;
+  }
+  return table;
+})();
+
+function crc32(buf: Buffer) {
+  let crc = 0xffffffff;
+  for (let i = 0; i < buf.length; i += 1) {
+    crc = CRC_TABLE[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
+  }
+  return (crc ^ 0xffffffff) >>> 0;
+}
+
+function pngChunk(type: string, data: Buffer) {
+  const typeBuf = Buffer.from(type, "ascii");
+  const len = Buffer.alloc(4);
+  len.writeUInt32BE(data.length, 0);
+  const crc = crc32(Buffer.concat([typeBuf, data]));
+  const crcBuf = Buffer.alloc(4);
+  crcBuf.writeUInt32BE(crc, 0);
+  return Buffer.concat([len, typeBuf, data, crcBuf]);
+}
+
+function encodePngRgba(buffer: Buffer, width: number, height: number) {
+  const stride = width * 4;
+  const raw = Buffer.alloc((stride + 1) * height);
+  for (let row = 0; row < height; row += 1) {
+    const rawOffset = row * (stride + 1);
+    raw[rawOffset] = 0; // filter: none
+    buffer.copy(raw, rawOffset + 1, row * stride, row * stride + stride);
+  }
+  const compressed = deflateSync(raw);
+
+  const signature = Buffer.from([
+    0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a,
+  ]);
+  const ihdr = Buffer.alloc(13);
+  ihdr.writeUInt32BE(width, 0);
+  ihdr.writeUInt32BE(height, 4);
+  ihdr[8] = 8; // bit depth
+  ihdr[9] = 6; // color type RGBA
+  ihdr[10] = 0; // compression
+  ihdr[11] = 0; // filter
+  ihdr[12] = 0; // interlace
+
+  return Buffer.concat([
+    signature,
+    pngChunk("IHDR", ihdr),
+    pngChunk("IDAT", compressed),
+    pngChunk("IEND", Buffer.alloc(0)),
+  ]);
+}
+
+function fillPixel(
+  buf: Buffer,
+  x: number,
+  y: number,
+  width: number,
+  r: number,
+  g: number,
+  b: number,
+  a = 255,
+) {
+  if (x < 0 || y < 0) return;
+  if (x >= width) return;
+  const idx = (y * width + x) * 4;
+  if (idx < 0 || idx + 3 >= buf.length) return;
+  buf[idx] = r;
+  buf[idx + 1] = g;
+  buf[idx + 2] = b;
+  buf[idx + 3] = a;
+}
+
+const GLYPH_ROWS_5X7: Record<string, number[]> = {
+  "0": [0b01110, 0b10001, 0b10011, 0b10101, 0b11001, 0b10001, 0b01110],
+  "1": [0b00100, 0b01100, 0b00100, 0b00100, 0b00100, 0b00100, 0b01110],
+  "2": [0b01110, 0b10001, 0b00001, 0b00010, 0b00100, 0b01000, 0b11111],
+  "3": [0b11110, 0b00001, 0b00001, 0b01110, 0b00001, 0b00001, 0b11110],
+  "4": [0b00010, 0b00110, 0b01010, 0b10010, 0b11111, 0b00010, 0b00010],
+  "5": [0b11111, 0b10000, 0b11110, 0b00001, 0b00001, 0b10001, 0b01110],
+  "6": [0b00110, 0b01000, 0b10000, 0b11110, 0b10001, 0b10001, 0b01110],
+  "7": [0b11111, 0b00001, 0b00010, 0b00100, 0b01000, 0b01000, 0b01000],
+  "8": [0b01110, 0b10001, 0b10001, 0b01110, 0b10001, 0b10001, 0b01110],
+  "9": [0b01110, 0b10001, 0b10001, 0b01111, 0b00001, 0b00010, 0b01100],
+
+  A: [0b01110, 0b10001, 0b10001, 0b11111, 0b10001, 0b10001, 0b10001],
+  B: [0b11110, 0b10001, 0b10001, 0b11110, 0b10001, 0b10001, 0b11110],
+  C: [0b01110, 0b10001, 0b10000, 0b10000, 0b10000, 0b10001, 0b01110],
+  D: [0b11110, 0b10001, 0b10001, 0b10001, 0b10001, 0b10001, 0b11110],
+  E: [0b11111, 0b10000, 0b10000, 0b11110, 0b10000, 0b10000, 0b11111],
+  F: [0b11111, 0b10000, 0b10000, 0b11110, 0b10000, 0b10000, 0b10000],
+  T: [0b11111, 0b00100, 0b00100, 0b00100, 0b00100, 0b00100, 0b00100],
+};
+
+function drawGlyph5x7(params: {
+  buf: Buffer;
+  width: number;
+  x: number;
+  y: number;
+  char: string;
+  scale: number;
+  color: { r: number; g: number; b: number; a?: number };
+}) {
+  const rows = GLYPH_ROWS_5X7[params.char];
+  if (!rows) return;
+  for (let row = 0; row < 7; row += 1) {
+    const bits = rows[row] ?? 0;
+    for (let col = 0; col < 5; col += 1) {
+      const on = (bits & (1 << (4 - col))) !== 0;
+      if (!on) continue;
+      for (let dy = 0; dy < params.scale; dy += 1) {
+        for (let dx = 0; dx < params.scale; dx += 1) {
+          fillPixel(
+            params.buf,
+            params.x + col * params.scale + dx,
+            params.y + row * params.scale + dy,
+            params.width,
+            params.color.r,
+            params.color.g,
+            params.color.b,
+            params.color.a ?? 255,
+          );
+        }
+      }
+    }
+  }
+}
+
+function drawText(params: {
+  buf: Buffer;
+  width: number;
+  x: number;
+  y: number;
+  text: string;
+  scale: number;
+  color: { r: number; g: number; b: number; a?: number };
+}) {
+  const text = params.text.toUpperCase();
+  let cursorX = params.x;
+  for (const raw of text) {
+    const ch = raw in GLYPH_ROWS_5X7 ? raw : raw.toUpperCase();
+    drawGlyph5x7({
+      buf: params.buf,
+      width: params.width,
+      x: cursorX,
+      y: params.y,
+      char: ch,
+      scale: params.scale,
+      color: params.color,
+    });
+    cursorX += 6 * params.scale;
+  }
+}
+
+function measureTextWidthPx(text: string, scale: number) {
+  return text.length * 6 * scale - scale; // 5px glyph + 1px space
+}
+
+export function renderCatNoncePngBase64(nonce: string): string {
+  const top = "CAT";
+  const bottom = nonce.toUpperCase();
+
+  const scale = 12;
+  const pad = 18;
+  const gap = 18;
+
+  const topWidth = measureTextWidthPx(top, scale);
+  const bottomWidth = measureTextWidthPx(bottom, scale);
+  const width = Math.max(topWidth, bottomWidth) + pad * 2;
+  const height = pad * 2 + 7 * scale + gap + 7 * scale;
+
+  const buf = Buffer.alloc(width * height * 4, 255);
+  const black = { r: 0, g: 0, b: 0 };
+
+  drawText({
+    buf,
+    width,
+    x: Math.floor((width - topWidth) / 2),
+    y: pad,
+    text: top,
+    scale,
+    color: black,
+  });
+
+  drawText({
+    buf,
+    width,
+    x: Math.floor((width - bottomWidth) / 2),
+    y: pad + 7 * scale + gap,
+    text: bottom,
+    scale,
+    color: black,
+  });
+
+  const png = encodePngRgba(buf, width, height);
+  return png.toString("base64");
+}