function readInt(id) {
  return parseInt(document.getElementById(id).value, 10) || 0;
}

function updateScaleHint() {
  const total = readInt("hotspot_limit") * readInt("item_limit_per_hotspot") * readInt("comment_limit_per_item");
  const target = document.getElementById("scale-calc");
  if (target) target.textContent = total.toLocaleString();
}

function validateRange(input) {
  const value = readInt(input.id);
  const min = parseInt(input.min, 10);
  const max = parseInt(input.max, 10);
  const valid = value >= min && value <= max;
  input.classList.toggle("is-invalid", !valid);
  return valid;
}

async function submitTask(event) {
  event.preventDefault();
  const btn = document.getElementById("submit-btn");
  const errorBox = document.getElementById("form-error");
  const inputs = Array.from(document.querySelectorAll(".scale-input"));
  if (!inputs.every(validateRange)) {
    errorBox.textContent = "参数超出范围，请检查配置。";
    errorBox.classList.remove("d-none");
    return;
  }

  btn.disabled = true;
  btn.textContent = "提交中...";
  errorBox.classList.add("d-none");
  const payload = {
    platform: document.getElementById("platform").value,
    hotspot_limit: readInt("hotspot_limit"),
    item_limit_per_hotspot: readInt("item_limit_per_hotspot"),
    comment_limit_per_item: readInt("comment_limit_per_item"),
  };

  try {
    const resp = await fetch("/api/tasks", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    if (resp.ok) {
      const data = await resp.json();
      window.location.href = `/tasks/${data.task_id}`;
      return;
    }
    const data = await resp.json();
    errorBox.textContent = resp.status === 422 ? "参数错误，请检查配置。" : (data.detail || "服务器错误，请稍后重试。");
    errorBox.classList.remove("d-none");
  } catch (_error) {
    errorBox.textContent = "网络异常，请检查连接后重试。";
    errorBox.classList.remove("d-none");
  } finally {
    btn.disabled = false;
    btn.textContent = "开始抓取";
  }
}

document.addEventListener("DOMContentLoaded", () => {
  document.querySelectorAll(".scale-input").forEach((input) => {
    input.addEventListener("input", () => {
      validateRange(input);
      updateScaleHint();
    });
  });
  updateScaleHint();
});

async function downloadExport(url, defaultFilename, event) {
  if (event) event.preventDefault();
  const resp = await fetch(url);
  if (!resp.ok) {
    alert("导出失败，请稍后重试。");
    return;
  }
  const blob = await resp.blob();
  const disposition = resp.headers.get("Content-Disposition") || "";
  const match = disposition.match(/filename\*=UTF-8''([^;]+)/);
  const filename = match ? decodeURIComponent(match[1]) : defaultFilename;
  const blobUrl = URL.createObjectURL(blob);
  const link = document.createElement("a");
  link.href = blobUrl;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  document.body.removeChild(link);
  URL.revokeObjectURL(blobUrl);
}