async function jsonOrThrow(response, fallbackMessage) {
  if (response.ok) {
    if (response.status === 204) return null;
    return response.json();
  }
  let detail = "";
  try {
    const body = await response.json();
    detail = body?.message || body?.err_msg || JSON.stringify(body);
  } catch {
    detail = await response.text();
  }
  throw new Error(`${fallbackMessage}: ${response.status} ${detail || response.statusText}`);
}

async function get(path, label) {
  const response = await fetch(path);
  return jsonOrThrow(response, label);
}

async function postJson(path, body, label) {
  const response = await fetch(path, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: body === undefined ? undefined : JSON.stringify(body),
  });
  return jsonOrThrow(response, label);
}

async function putJson(path, body, label) {
  const response = await fetch(path, {
    method: "PUT",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(body),
  });
  return jsonOrThrow(response, label);
}

async function del(path, label) {
  const response = await fetch(path, { method: "DELETE" });
  return jsonOrThrow(response, label);
}

export const runtimeApi = {
  fetchOverview: () => get("/api/runtime/overview", "加载段运行态失败"),
};

export const segmentControl = {
  startAuto: (id) => postJson(`/api/control/segment/${id}/start-auto`, undefined, "启动自动控制失败"),
  stopAuto: (id) => postJson(`/api/control/segment/${id}/stop-auto`, undefined, "停止自动控制失败"),
  ackFault: (id) => postJson(`/api/control/segment/${id}/ack-fault`, undefined, "故障确认失败"),
  reset: (id) => postJson(`/api/control/segment/${id}/reset`, undefined, "复位失败"),
  batchStart: () => postJson(`/api/control/segment/batch-start-auto`, undefined, "批量启动失败"),
  batchStop: () => postJson(`/api/control/segment/batch-stop-auto`, undefined, "批量停止失败"),
};

export const stationApi = {
  list: (lineCode) => {
    const q = lineCode ? `?line_code=${encodeURIComponent(lineCode)}` : "";
    return get(`/api/station${q}`, "加载工位失败");
  },
  detail: (id) => get(`/api/station/${id}`, "加载工位详情失败"),
  create: (payload) => postJson("/api/station", payload, "新增工位失败"),
  update: (id, payload) => putJson(`/api/station/${id}`, payload, "更新工位失败"),
  remove: (id) => del(`/api/station/${id}`, "删除工位失败"),
  upsertSignal: (id, payload) =>
    postJson(`/api/station/${id}/signal`, payload, "绑定工位信号失败"),
  deleteSignal: (id, role) =>
    del(`/api/station/${id}/signal/${encodeURIComponent(role)}`, "解除工位信号绑定失败"),
};

export const segmentApi = {
  list: (lineCode) => {
    const q = lineCode ? `?line_code=${encodeURIComponent(lineCode)}` : "";
    return get(`/api/segment${q}`, "加载段配置失败");
  },
  detail: (id) => get(`/api/segment/${id}/detail`, "加载段详情失败"),
  create: (payload) => postJson("/api/segment", payload, "新增段失败"),
  update: (id, payload) => putJson(`/api/segment/${id}`, payload, "更新段失败"),
  remove: (id) => del(`/api/segment/${id}`, "删除段失败"),
  createStep: (id, payload) =>
    postJson(`/api/segment/${id}/step`, payload, "新增步骤失败"),
  updateStep: (id, stepNo, payload) =>
    putJson(`/api/segment/${id}/step/${stepNo}`, payload, "更新步骤失败"),
  deleteStep: (id, stepNo) =>
    del(`/api/segment/${id}/step/${stepNo}`, "删除步骤失败"),
  createInterlock: (id, payload) =>
    postJson(`/api/segment/${id}/interlock`, payload, "新增联锁失败"),
  deleteInterlock: (id, interlockId) =>
    del(`/api/segment/${id}/interlock/${interlockId}`, "删除联锁失败"),
  replaceResources: (id, keys) =>
    putJson(`/api/segment/${id}/resource`, { resource_keys: keys }, "更新资源声明失败"),
};