// Per-camera exposure/gain settings tabs — mirrors the QTabWidget layout in
// scan_gui_triple.py (auto-exposure toggle, brightness/exp_min/exp_max vs.
// exp_time mutually exclusive groups, gain; Apply = live ros2 param set,
// Save = persist into the base YAML).

async function getJSON(url, opts) {
  const res = await fetch(url, opts);
  if (!res.ok) throw new Error(`${url}: ${res.status} ${await res.text()}`);
  return res.json();
}

function field(labelText, id, type, step) {
  const wrap = document.createDocumentFragment();
  const label = document.createElement("label");
  label.textContent = labelText;
  label.htmlFor = id;
  const input = document.createElement("input");
  input.type = type;
  input.id = id;
  if (step) input.step = step;
  wrap.appendChild(label);
  wrap.appendChild(input);
  return { wrap, input };
}

export async function buildCameraTabs(cameras) {
  const tabBar = document.getElementById("camera-tabs");
  const panelsRoot = document.getElementById("camera-tab-panels");
  tabBar.innerHTML = "";
  panelsRoot.innerHTML = "";

  for (let i = 0; i < cameras.length; i++) {
    const cam = cameras[i];
    const tabBtn = document.createElement("button");
    tabBtn.className = "tab-btn" + (i === 0 ? " active" : "");
    tabBtn.textContent = cam.id;
    tabBtn.onclick = () => {
      document.querySelectorAll(".tab-btn").forEach((b) => b.classList.remove("active"));
      document.querySelectorAll(".tab-panel").forEach((p) => p.classList.remove("active"));
      tabBtn.classList.add("active");
      document.getElementById(`cam-panel-${cam.id}`).classList.add("active");
    };
    tabBar.appendChild(tabBtn);

    const panel = document.createElement("div");
    panel.className = "tab-panel" + (i === 0 ? " active" : "");
    panel.id = `cam-panel-${cam.id}`;
    panelsRoot.appendChild(panel);

    await buildCameraPanel(panel, cam.id);
  }
}

async function buildCameraPanel(panel, camId) {
  const values = await getJSON(`/api/camera/${camId}/params`);

  const autoLabel = document.createElement("label");
  const autoChk = document.createElement("input");
  autoChk.type = "checkbox";
  autoChk.checked = values.exposure_auto;
  autoLabel.appendChild(autoChk);
  autoLabel.appendChild(document.createTextNode(" 자동 노출"));
  panel.appendChild(autoLabel);

  const grid = document.createElement("div");
  grid.className = "cam-field-grid";
  panel.appendChild(grid);

  const fBrightness = field("목표 밝기:", `${camId}-brightness`, "number");
  fBrightness.input.min = 0; fBrightness.input.max = 255; fBrightness.input.value = values.exposure_auto_target_brightness;
  const fExpMin = field("노출 하한 (us):", `${camId}-exp-min`, "number");
  fExpMin.input.min = 10; fExpMin.input.max = 1000000; fExpMin.input.step = 100; fExpMin.input.value = values.exposure_auto_min;
  const fExpMax = field("노출 상한 (us):", `${camId}-exp-max`, "number");
  fExpMax.input.min = 10; fExpMax.input.max = 1000000; fExpMax.input.step = 1000; fExpMax.input.value = values.exposure_auto_max;
  const fExpTime = field("노출 시간 (us):", `${camId}-exp-time`, "number");
  fExpTime.input.min = 10; fExpTime.input.max = 1000000; fExpTime.input.value = values.exposure_time;
  const fGain = field("게인 (dB):", `${camId}-gain`, "number");
  fGain.input.min = 0; fGain.input.max = 16.9; fGain.input.step = 0.5; fGain.input.value = values.gain;

  for (const f of [fBrightness, fExpMin, fExpMax, fExpTime, fGain]) grid.appendChild(f.wrap);

  const autoWidgets = [fBrightness.input, fExpMin.input, fExpMax.input];
  const manualWidgets = [fExpTime.input];

  function applyToggleState(checked) {
    autoWidgets.forEach((w) => (w.disabled = !checked));
    manualWidgets.forEach((w) => (w.disabled = checked));
  }
  autoChk.onchange = () => applyToggleState(autoChk.checked);
  applyToggleState(values.exposure_auto);

  const btnRow = document.createElement("div");
  btnRow.className = "btn-row";
  const btnApply = document.createElement("button");
  btnApply.className = "btn btn-blue";
  btnApply.textContent = "적용";
  const btnSave = document.createElement("button");
  btnSave.className = "btn btn-green";
  btnSave.textContent = "저장";
  btnRow.appendChild(btnApply);
  btnRow.appendChild(btnSave);
  panel.appendChild(btnRow);

  const result = document.createElement("div");
  result.className = "cam-result";
  panel.appendChild(result);

  function collect() {
    return {
      exposure_auto: autoChk.checked,
      exposure_auto_target_brightness: parseInt(fBrightness.input.value, 10),
      exposure_auto_min: parseFloat(fExpMin.input.value),
      exposure_auto_max: parseFloat(fExpMax.input.value),
      exposure_time: parseInt(fExpTime.input.value, 10),
      gain: parseFloat(fGain.input.value),
    };
  }

  btnApply.onclick = async () => {
    result.textContent = "적용 중…";
    try {
      await getJSON(`/api/camera/${camId}/params`, {
        method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify(collect()),
      });
      const r = await getJSON(`/api/camera/${camId}/params/apply`, { method: "POST" });
      result.textContent = r.ok ? "적용 완료" : r.results.filter(x => !x.ok).map(x => `${x.name}: ${x.message}`).join(" / ");
      result.style.color = r.ok ? "var(--color-success)" : "var(--color-danger)";
    } catch (e) {
      result.textContent = String(e);
      result.style.color = "var(--color-danger)";
    }
  };

  btnSave.onclick = async () => {
    result.textContent = "저장 중…";
    try {
      await getJSON(`/api/camera/${camId}/params`, {
        method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify(collect()),
      });
      const r = await getJSON(`/api/camera/${camId}/params/save`, { method: "POST" });
      result.textContent = `저장됨 → ${r.path}`;
      result.style.color = "var(--color-success)";
    } catch (e) {
      result.textContent = String(e);
      result.style.color = "var(--color-danger)";
    }
  };
}