// spark-control front-end
// - polls /api/status every 5s for current model + health
// - lists models from /api/models as cards
// - POST /api/swap to start a swap, then opens SSE /api/swap/{id}/stream

const state = {
  models: {},
  defaults: {},
  current_model_key: null,
  swap_job_id: null,
  swap_eventsource: null,
  configured: true,
};

function el(sel) { return document.querySelector(sel); }
function $(sel) { return document.querySelectorAll(sel); }

async function fetchJSON(url, opts) {
  const r = await fetch(url, opts);
  if (!r.ok) {
    const text = await r.text().catch(() => "");
    throw new Error(`${r.status} ${r.statusText}: ${text}`);
  }
  return r.json();
}

function renderCards() {
  const root = el("#cards");
  root.innerHTML = "";
  const keys = Object.keys(state.models);
  for (const key of keys) {
    const m = state.models[key];
    const isActive = key === state.current_model_key;
    const isSwapping = !!state.swap_job_id;
    const card = document.createElement("div");
    card.className = "card" + (isActive ? " active" : "");
    card.innerHTML = `
      <div class="name">${m.display_name}</div>
      <div class="meta">
        <span class="tag mode-${m.mode}">${m.mode}</span>
        <span class="tag">${m.size_gb} GB</span>
        ${(m.capabilities || []).map(c => `<span class="tag cap">${c}</span>`).join("")}
      </div>
      <div class="muted small" style="word-break:break-all">${m.repo}</div>
      <div class="spacer"></div>
      <button class="btn ${isActive ? "" : "primary"}" data-key="${key}" ${isActive || isSwapping ? "disabled" : ""}>
        ${isActive ? "Current" : "Switch to this"}
      </button>
    `;
    root.appendChild(card);
  }
  for (const btn of $(".card .btn")) {
    btn.addEventListener("click", () => triggerSwap(btn.dataset.key));
  }
}

function renderCurrent(status) {
  const c = el("#current");
  if (!status.configured) {
    c.innerHTML = `<span class="muted">not configured</span>`;
    return;
  }
  if (status.current_swap_job) {
    c.innerHTML = `<span class="muted">swap in progress</span>`;
    return;
  }
  const v = status.vllm || {};
  if (!v.ok) {
    c.innerHTML = `<span class="muted">vLLM unreachable</span>`;
    return;
  }
  const key = status.current_model_key;
  const m = key ? state.models[key] : null;
  const label = m ? m.display_name : (v.current_model || "(unknown)");
  c.innerHTML = `<strong>${label}</strong>`;
}

function renderHealth(status) {
  function setDot(id, ok) {
    const item = el(id);
    if (!item) return;
    const dot = item.querySelector(".dot");
    dot.classList.remove("ok", "bad", "warn");
    if (ok === true) dot.classList.add("ok");
    else if (ok === false) dot.classList.add("bad");
    else dot.classList.add("warn");
    item.title = JSON.stringify(status[id.replace("#h-", "")] || {}, null, 2);
  }
  setDot("#h-vllm", status.vllm && status.vllm.ok);
  setDot("#h-parakeet", status.parakeet && status.parakeet.ok);
  setDot("#h-magpie", status.magpie && status.magpie.ok);
  el("#updated").textContent = `updated ${new Date().toLocaleTimeString()}`;
}

function renderBanner(status) {
  el("#setup-banner").classList.toggle("hidden", !!status.configured);
}

async function pollStatus() {
  try {
    const status = await fetchJSON("/api/status");
    state.current_model_key = status.current_model_key;
    state.configured = status.configured;
    renderBanner(status);
    renderCurrent(status);
    renderHealth(status);
    if (status.current_swap_job && status.current_swap_job !== state.swap_job_id) {
      attachToSwap(status.current_swap_job);
    } else if (!status.current_swap_job && state.swap_job_id && !state.swap_eventsource) {
      // someone else's swap finished; clear local
      state.swap_job_id = null;
      el("#swap-panel").classList.add("hidden");
    }
    renderCards();
  } catch (e) {
    console.error("status poll failed", e);
  }
}

async function loadModels() {
  const data = await fetchJSON("/api/models");
  state.defaults = data.defaults || {};
  state.models = data.models || {};
}

async function triggerSwap(modelKey) {
  if (state.swap_job_id) return;
  try {
    const r = await fetchJSON("/api/swap", {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify({ model_key: modelKey }),
    });
    attachToSwap(r.job_id);
  } catch (e) {
    alert("Failed to start swap: " + e.message);
  }
}

function attachToSwap(jobId) {
  if (state.swap_eventsource) {
    state.swap_eventsource.close();
    state.swap_eventsource = null;
  }
  state.swap_job_id = jobId;
  el("#swap-panel").classList.remove("hidden");
  el("#swap-log").textContent = "";
  el("#swap-state").textContent = "starting";

  const es = new EventSource(`/api/swap/${jobId}/stream`);
  state.swap_eventsource = es;

  es.onmessage = (ev) => {
    try {
      const d = JSON.parse(ev.data);
      if (d.state) el("#swap-state").textContent = d.state;
      if (d.line) appendLog(d.line);
    } catch {}
  };
  es.addEventListener("done", (ev) => {
    try {
      const d = JSON.parse(ev.data);
      el("#swap-state").textContent = d.state + ` (rc=${d.returncode})`;
    } catch {}
    es.close();
    state.swap_eventsource = null;
    state.swap_job_id = null;
    setTimeout(() => {
      el("#swap-panel").classList.add("hidden");
      pollStatus();
    }, 4000);
    pollStatus();
  });
  es.onerror = () => {
    // SSE drops happen on tab background; reconnect on next poll
    es.close();
    state.swap_eventsource = null;
  };

  renderCards();
}

function appendLog(line) {
  const log = el("#swap-log");
  log.textContent += line + "\n";
  log.scrollTop = log.scrollHeight;
}

async function init() {
  await loadModels();
  await pollStatus();
  setInterval(pollStatus, 5000);
}

init();