import { LlamaCppWasm } from "https://esm.sh/llama-cpp-wasm@0.0.4";

const C = window.GGUF_CONFIG;
const $ = id => document.getElementById(id);

let engine = null;
let active = false;

function status(s) {
  $("status").textContent = s;
}
function info(s) {
  $("info").textContent = s;
}
function progress(v) {
  $("bar").style.width = Math.max(0, Math.min(100, v)) + "%";
}

async function createEngine() {
  if (engine) return engine;
  engine = await LlamaCppWasm.create({
    moduleUrl: new URL("https://esm.sh/llama-cpp-wasm@0.0.3/wasm/llama-cpp-wasm.js").href,
    wasmUrl: new URL("https://esm.sh/llama-cpp-wasm@0.0.3/wasm/llama-cpp-wasm.wasm").href
  });
  return engine;
}

async function loadModel(source) {
  $("load").disabled = true;
  status("loading runtime");
  info("Starting WebAssembly runtime…");
  progress(0);

  const e = await createEngine();
  status("downloading model");
  info("Downloading GGUF into browser memory…");

  await e.load(source, {
    contextSize: C.contextSize,
    batchSize: C.batchSize,
    threads: C.threads
  }, p => {
    if (p && p.totalBytes) {
      progress((p.loadedBytes / p.totalBytes) * 100);
    }
  });

  progress(100);
  status("ready");
  info("Model loaded locally in this browser.");
  $("send").disabled = false;
  $("load").disabled = false;
}

$("load").onclick = async () => {
  try {
    const f = $("file").files[0];
    await loadModel(f ? {file: f} : {url: C.modelUrl});
  } catch (e) {
    console.error(e);
    status("error");
    info(String(e?.message || e));
    $("load").disabled = false;
  }
};

$("file").onchange = () => {
  if ($("file").files[0]) info("Selected local GGUF: " + $("file").files[0].name);
};

$("send").onclick = async () => {
  if (!engine || active) return;

  active = true;
  $("send").disabled = true;
  $("stop").disabled = false;
  $("output").textContent = "";

  const temperature = Number($("temp").value) || C.defaultTemperature;
  const maxTokens = Number($("max").value) || C.defaultMaxTokens;
  const prompt = $("prompt").value;

  try {
    for await (const text of engine.completion(prompt, {
      maxTokens,
      temperature,
      topK: C.defaultTopK,
      topP: C.defaultTopP
    })) {
      $("output").textContent += text;
    }
  } catch (e) {
    if (!String(e?.message || e).toLowerCase().includes("cancel")) {
      $("output").textContent += "\n\n[ERROR] " + String(e?.message || e);
    }
  } finally {
    active = false;
    $("send").disabled = false;
    $("stop").disabled = true;
  }
};

$("stop").onclick = () => {
  try { engine?.cancel(); } catch {}
};

window.MyGGUFAPI = {
  async chat(prompt, options = {}) {
    if (!engine) throw new Error("Model is not loaded.");
    let text = "";
    for await (const chunk of engine.completion(String(prompt), {
      maxTokens: options.maxTokens ?? C.defaultMaxTokens,
      temperature: options.temperature ?? C.defaultTemperature,
      topK: options.topK ?? C.defaultTopK,
      topP: options.topP ?? C.defaultTopP,
      seed: options.seed
    })) text += chunk;
    return {
      text,
      model: C.modelName
    };
  },
  model() {
    return C.modelName;
  },
  loaded() {
    return !!engine;
  }
};