index.js

import { env, AutoTokenizer, RawImage, Tensor } from 'https://cdn.jsdelivr.net/npm/@huggingface/transformers';
import { getModelJSON, getModelFile } from "https://cdn.jsdelivr.net/npm/@huggingface/transformers@3.0.2/src/utils/hub.js";
import * as ort from "https://cdn.jsdelivr.net/npm/onnxruntime-web@1.20.0/dist/ort.webgpu.mjs";

const EXAMPLE_URL = "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/transformers/tasks/car.jpg";
const INPUT_IMAGE_SIZE = [960, 960];
const HEIGHT_FACTOR = 10;
const WIDTH_FACTOR = 10;
const IMAGE_EMBED_SIZE = WIDTH_FACTOR * HEIGHT_FACTOR;
const MAX_SEQ_LENGTH = 1024;
const BASE_MODEL = "Qwen/Qwen2-VL-2B-Instruct";
const ONNX_MODEL = "pdufour/Qwen2-VL-2B-Instruct-ONNX-Q4-F16";
const QUANT = "q4f16";
const MAX_SINGLE_CHAT_LENGTH = 10;

// UI Elements
const exampleButton = document.getElementById('example');
const promptInput = document.querySelector('input[type="text"]');
const status = document.getElementById('status');
const imageContainer = document.getElementById('container');
const example = document.getElementById('example');
const uploadInput = document.getElementById('upload');

let ortSessionA, ortSessionB, ortSessionC, ortSessionD, ortSessionE;
let config;
let currentImage = '';
let currentQuery = '';

async function initializeSessions() {
  status.textContent = 'Loading model...';
  
  ortSessionA = await ort.InferenceSession.create(
    await getModelFile(ONNX_MODEL, `onnx/QwenVL_A_${QUANT}.onnx`),
    { executionProviders: ["webgpu"] }
  );

  ortSessionB = await ort.InferenceSession.create(
    await getModelFile(ONNX_MODEL, `onnx/QwenVL_B_${QUANT}.onnx`),
    { executionProviders: ["webgpu"] }
  );

  ortSessionC = await ort.InferenceSession.create(
    await getModelFile(ONNX_MODEL, `onnx/QwenVL_C_${QUANT}.onnx`),
    { executionProviders: ["webgpu"] }
  );

  config = (await getModelJSON(BASE_MODEL, "config.json"));

  status.textContent = 'Ready';
}

export function int64ToFloat16(int64Value) {
  // Convert BigInt to Number (float64)
  const float64Value = Number(int64Value);

  // Handle special cases
  if (!isFinite(float64Value)) return float64Value > 0 ? 0x7c00 : 0xfc00; // +/- infinity
  if (float64Value === 0) return 0; // Zero is represented as 0

  // Get sign, exponent, and mantissa from float64
  const sign = float64Value < 0 ? 1 : 0;
  const absValue = Math.abs(float64Value);
  const exponent = Math.floor(Math.log2(absValue));
  const mantissa = absValue / Math.pow(2, exponent) - 1;

  // Convert exponent and mantissa to float16 format
  const float16Exponent = exponent + 15; // Offset exponent by 15 (float16 bias)
  const float16Mantissa = Math.round(mantissa * 1024); // 10-bit mantissa for float16

  // Handle overflow/underflow
  if (float16Exponent <= 0) {
    // Subnormal numbers (exponent <= 0)
    return (sign << 15) | (float16Mantissa >> 1);
  } else if (float16Exponent >= 31) {
    // Overflow, set to infinity
    return (sign << 15) | 0x7c00;
  } else {
    // Normalized numbers
    return (sign << 15) | (float16Exponent << 10) | (float16Mantissa & 0x3ff);
  }
}

export function float16ToInt64(float16Value) {
  // Extract components from float16
  const sign = (float16Value & 0x8000) >> 15;
  const exponent = (float16Value & 0x7c00) >> 10;
  const mantissa = float16Value & 0x03ff;

  // Handle special cases
  if (exponent === 0 && mantissa === 0) return BigInt(0); // Zero
  if (exponent === 0x1f) return sign ? BigInt("-Infinity") : BigInt("Infinity"); // Infinity

  // Convert back to number
  let value;
  if (exponent === 0) {
    // Subnormal numbers
    value = Math.pow(2, -14) * (mantissa / 1024);
  } else {
    // Normalized numbers
    value = Math.pow(2, exponent - 15) * (1 + mantissa / 1024);
  }

  // Apply sign
  value = sign ? -value : value;

  return BigInt(Math.round(value));
}

// async function parse(img, txt) {
//   imageContainer.innerHTML = '';
//   imageContainer.style.backgroundImage = `url(${img})`;
//   status.textContent = 'Analysing...';
//   const output = await imageTextToText(img, txt);
//   status.textContent = output;
// }

async function handleQuery(imageUrl, query) {
  if (!imageUrl || !query.trim()) {
    status.textContent = 'Please provide both an image and a prompt';
    return;
  }
  
  try {
    status.textContent = 'Analyzing...';

    // container.style.backgroundImage = `url(${imageUrl})`;
    // container.style.backgroundSize = 'contain';
    // container.style.backgroundRepeat = 'no-repeat';
    // container.style.backgroundPosition = 'center';

    updatePreview(imageUrl);
    
    const result = await imageTextToText(imageUrl, query);
    status.textContent = result;
  } catch (err) {
    status.textContent = 'Error processing request';
    console.error(err);
  }
}


export async function imageTextToText(
  imagePath,
  query,
  vision = true
) {

  const prompt_head_len = new Tensor("int64", new BigInt64Array([5n]), [1]);

  let position_ids;
  let num_decode = 0;
  let history_len = new Tensor("int64", new BigInt64Array([0n]), [1]);

  var pos_factor_v = BigInt(1 - IMAGE_EMBED_SIZE + WIDTH_FACTOR);

  let past_key_states = new ort.Tensor(
    "float16",
    new Uint16Array(
      config.num_hidden_layers *
        config.num_key_value_heads *
        MAX_SEQ_LENGTH *
        (config.hidden_size / config.num_attention_heads)
    ).fill(0),
    [
      config.num_hidden_layers,
      config.num_key_value_heads,
      MAX_SEQ_LENGTH,
      config.hidden_size / config.num_attention_heads,
    ]
  );

  let past_value_states = past_key_states;

  let attention_mask = new ort.Tensor(
    "float16",
    new Uint16Array([0xfbff]),
    [1]
  );

  let pos_factor = new Tensor("float16", new Uint16Array([0]), [1]);
  
  const tokenizer = await AutoTokenizer.from_pretrained(BASE_MODEL);
  const prompt = `\n<|im_start|>user\n<|vision_start|><|vision_end|>${query}<|im_end|>\n<|im_start|>assistant\n`;
  const token = await tokenizer(prompt, {
    return_tensors: "pt",
    add_generation_prompt: false,
    tokenize: true,
  }).input_ids;

  const seq_length = token.dims[1];
  let ids_len = new Tensor("int64", new BigInt64Array([BigInt(seq_length)]), [
    1,
  ]);

  let input_ids = new ort.Tensor(
    "int32",
    new Int32Array(MAX_SEQ_LENGTH).fill(0),
    [MAX_SEQ_LENGTH]
  );

  input_ids.data.set(Array.from(token.data.slice(0, seq_length), Number));

  const dummy = new ort.Tensor("int32", new Int32Array([0]), []);

  let { hidden_states } = await ortSessionB.run({
    input_ids: input_ids,
    ids_len: ids_len,
  });

  ({ position_ids } = await ortSessionC.run({
    dummy: dummy,
  }));

  // Process image
  if (vision) {
    let image = await RawImage.fromURL(imagePath);

    image = await image.resize(INPUT_IMAGE_SIZE[0], INPUT_IMAGE_SIZE[1]);

    image = image.rgb();

    image = image.toTensor("CHW");
    image = image.to("float32");
    image = image.div_(255.0);
    const pixel_values = image.unsqueeze(0);

    const { image_embed } = await ortSessionA.run({
      pixel_values: pixel_values,
    });

    ids_len = ids_len.add(BigInt(IMAGE_EMBED_SIZE));

    const split_factor = new Tensor(
      "int32",
      new Int32Array([
        MAX_SEQ_LENGTH - Number(ids_len.item()) - IMAGE_EMBED_SIZE,
      ]),
      [1]
    );

    const ids_len_minus = new Tensor(
      "int32",
      new Int32Array([Number(ids_len.item()) - Number(prompt_head_len.item())]),
      [1]
    );

    await ortSessionA.release();
    ortSessionA = null;

    ortSessionD = await ort.InferenceSession.create(
      await getModelFile(ONNX_MODEL, `onnx/QwenVL_D_${QUANT}.onnx`),
      {
        executionProviders: ["webgpu"],
      }
    );

    ({ hidden_states, position_ids } = await ortSessionD.run({
      "hidden_states.1": hidden_states,
      image_embed,
      ids_len,
      ids_len_minus,
      split_factor,
    }));

    await ortSessionD.release();
    ortSessionD = null;
  }

  let output = '';

  while (
    num_decode < MAX_SINGLE_CHAT_LENGTH &&
    Number(history_len.data[0]) < MAX_SEQ_LENGTH
  ) {
    let token_id;

    if (!ortSessionE) {
      ortSessionE = await ort.InferenceSession.create(
        await getModelFile(ONNX_MODEL, `onnx/QwenVL_E_${QUANT}.onnx`),
        {
          executionProviders: ["wasm"],
        },
      );
    }

    ({
      max_logit_ids: token_id,
      past_key_states: past_key_states,
      past_value_states: past_value_states,
    } = await ortSessionE.run({
      hidden_states,
      attention_mask,
      "past_key_states.1": past_key_states,
      "past_value_states.1": past_value_states,
      history_len,
      ids_len,
      position_ids,
      pos_factor,
    }));

    if (token_id === 151643 || token_id === 151645) {
      break;
    }

    num_decode++;
    if (num_decode < 2) {
      history_len = history_len.add(BigInt(ids_len.data[0]));

      ids_len = new ort.Tensor("int64", new BigInt64Array([1n]), [1]);

      attention_mask = new ort.Tensor("float16", new Uint16Array([0]), [1]);

      if (vision) {
        pos_factor = new Tensor(
          "float16",
          new Uint16Array([int64ToFloat16(pos_factor_v + ids_len.data[0])]),
          [1]
        );
      } else {
        pos_factor = new Tensor(
          "float16",
          new Uint16Array([int64ToFloat16(history_len.data[0] + BigInt(1))]),
          [1]
        );
      }

    } else {
      history_len = history_len.add(BigInt(1));
      pos_factor = pos_factor.map((v) =>
        int64ToFloat16(float16ToInt64(v) + BigInt(1))
      );
    }
    (input_ids.data)[0] = Number(token_id.data[0]);

    const result_B = await ortSessionB.run({
      input_ids: input_ids,
      ids_len: ids_len,
    });
    hidden_states = result_B.hidden_states;

    if (
      !Number.isInteger(token_id.data[0]) &&
      !["bigint", "number"].includes(typeof token_id.data[0])
    ) {
      throw new Error(`Token ID is not an integer`);
    } else {
      const decoded = tokenizer.decode([...token_id.data]);
      console.log({decoded});
      
      output += decoded;
    }
  }
}

async function updatePreview(url) {
  const image = await RawImage.fromURL(url);
  const ar = image.width / image.height;
  const [cw, ch] = (ar > 1) ? [640, 640 / ar] : [640 * ar, 640];
  imageContainer.style.width = `${cw}px`;
  imageContainer.style.height = `${ch}px`;
  imageContainer.style.backgroundImage = `url(${url})`;
}

await initializeSessions();

// UI Event Handlers
exampleButton.addEventListener('click', (e) => {
  e.preventDefault();
  e.stopPropagation();
  currentImage = EXAMPLE_URL;
  status.textContent = promptInput.value.trim() ? 'Press Enter to analyze' : 'Add a prompt and press Enter';
});

uploadInput.addEventListener('change', (e) => {
  const file = e.target.files[0];
  if (!file) return;

  const reader = new FileReader();
  reader.onload = (e2) => {
    currentImage = e2.target.result;
    status.textContent = promptInput.value.trim() ? 'Press Enter to analyze' : 'Add a prompt and press Enter';
  };
  reader.readAsDataURL(file);
});

promptInput.addEventListener('keypress', (e) => {
  currentQuery = e.target.value;
  if (e.key === 'Enter') {
    if (!currentImage) {
      status.textContent = 'Please select an image first';
      return;
    }
    handleQuery(currentImage, currentQuery);
  }
});

promptInput.addEventListener('input', () => {
  if (currentImage && !promptInput.value.trim()) {
    status.textContent = 'Add a prompt and press Enter';
  } else if (currentImage && promptInput.value.trim()) {
    status.textContent = 'Press Enter to analyze';
  }
});