import dayjs from "dayjs";
import utc from "dayjs/plugin/utc";
import timezone from "dayjs/plugin/timezone";
import config from "@/config/config";
import { apiFetch } from "@/lib/apiFetch";
import { useProjectStore } from "@/store/projectStore";

dayjs.extend(utc);
dayjs.extend(timezone);

export type SimulationRange = { from: Date; to: Date };

export const parseHydraulicStepSeconds = (value: unknown): number | undefined => {
  if (typeof value !== "string" || !/^\d+:\d{1,2}(:\d{1,2})?$/.test(value.trim())) {
    return undefined;
  }
  const [hours, minutes, seconds = 0] = value.trim().split(":").map(Number);
  const step = hours * 3600 + minutes * 60 + seconds;
  return minutes < 60 && seconds < 60 && step > 0 ? step : undefined;
};

/** 与地图时间轴一致，以北京时间零点为基准向外取整，跨日仍保持同一步长。 */
export const alignSimulationRange = (
  range: SimulationRange,
  stepSeconds: number,
): SimulationRange => {
  if (!Number.isFinite(stepSeconds) || stepSeconds <= 0 ||
    !Number.isFinite(range.from.getTime()) || !Number.isFinite(range.to.getTime())) {
    throw new Error("查询时间或水力时间步长无效");
  }
  const start = Math.min(range.from.getTime(), range.to.getTime());
  const end = Math.max(range.from.getTime(), range.to.getTime());
  const origin = dayjs(start).tz("Asia/Shanghai").startOf("day").valueOf();
  const step = stepSeconds * 1000;
  const from = origin + Math.floor((start - origin) / step) * step;
  const to = Math.max(from + step, origin + Math.ceil((end - origin) / step) * step);
  return { from: new Date(from), to: new Date(to) };
};

/** 复用同步在线模拟接口，成功响应表示计算和保存已完成；不自动重试写请求。 */
export const runOnlineSimulation = async (
  range: SimulationRange,
  signal?: AbortSignal,
): Promise<{ range: SimulationRange; stepSeconds: number }> => {
  const projectId = useProjectStore.getState().currentProjectId;
  if (!projectId) throw new Error("请先选择项目，未启动在线模拟");
  const projectHeaders = { "X-Project-Id": projectId };
  const timeResponse = await apiFetch(
    `${config.BACKEND_URL}/api/v1/network-options/time`, {
      signal, headers: projectHeaders, projectHeaderMode: "omit",
    },
  );
  if (!timeResponse.ok) throw new Error("无法读取管网时间步长，未启动在线模拟");
  const payload = await timeResponse.json();
  const stepSeconds = parseHydraulicStepSeconds(
    (payload?.times ?? payload)?.["HYDRAULIC TIMESTEP"],
  );
  if (!stepSeconds) throw new Error("管网水力时间步长无效，未启动在线模拟");
  if (signal?.aborted || useProjectStore.getState().currentProjectId !== projectId) {
    throw new Error("项目已切换或面板已关闭，未启动在线模拟");
  }
  const alignedRange = alignSimulationRange(range, stepSeconds);
  const response = await apiFetch(`${config.BACKEND_URL}/api/v1/simulation-runs`, {
    method: "POST",
    headers: { ...projectHeaders, "Content-Type": "application/json" },
    projectHeaderMode: "omit",
    // 后端循环的结束时间不包含在计算内，多算一个步长以覆盖图表右端点。
    body: JSON.stringify({
      start_time: alignedRange.from.toISOString(),
      duration: Math.ceil((alignedRange.to.getTime() - alignedRange.from.getTime() + stepSeconds * 1000) / 60000),
    }),
    signal,
  });
  const result = await response.json().catch(() => null);
  if (!response.ok || result?.status !== "success") {
    throw new Error(typeof result?.detail === "string" ? result.detail : "在线模拟未确认完成，请刷新查看已生成的数据");
  }
  return { range: alignedRange, stepSeconds };
};