/* =============================================================================
 * design_calc_server.ts
 * 계산 자리 「서버」 길(PLAN 511-A) — 판(`design_calc_sites.ts`)이 묶음을 server 로 둔 때 조작 중 계산을 서버
 * 창구(`POST /projects/{id}/calc` · `B06_Section_Router_Calc.py`)가 같은 TS 로 셈. 판이 both 면 지금 그대로.
 *   serverCalc   한 번 묻기(signal 로 끊음 · 왕복 흉내 `delayMs` · 기록)
 *   afterQuiet   잠잠 뒤 — 같은 칸 새 부름이 앞 것을 끊음(앞 것 = undefined · 늦은 답 버림)
 *   calcChecked  동기 자리 — 브라우저 값 바로 · server 면 잠잠 뒤 같은 입력 서버 셈 → 대조 · 다르면 apply
 *   calcOnServerOnly 비동기 자리 — server 면 서버 값만(잠잠 뒤 · 끊긴 부름 = undefined)
 *   calcFromServer 그리기 자리 — server 면 서버 값만(입력 같은 답 · 없으면 앞 답) · 답 오면 redraw
 * 기록 = `window.__aisloCalcServer`(calls · local = 브라우저 ms · delayMs) — 시간 표 · 화면 검증용.
 * 조작 중 왕복 = 지침 5장 「네트워크 왕복 금지」의 시험용 예외(판 기본값 both).
 * ========================================================================== */

import { API_BASE_URL } from "@config/config_frontend";
import { calcOnServerNow, calcProjectId } from "./design_calc_sites";
import { plain } from "./logic/design_calc_node_trial";

/** 편집이 멈춘 것으로 볼 시간(ms) — 배분 선반입과 같은 값(`B05_Profile_Api_HaulPlan.ts`). */
export const QUIET_MS = 400;
const LOG_SIZE = 200;
const LOCAL_SIZE = 20;

export interface CalcServerCall {
  key: string;
  id: string;
  /** 브라우저 셈 ms(같이 셈한 자리만). */
  browserMs: number | null;
  /** 보내기 → 답(흉내 지연 포함). */
  roundMs: number;
  /** Node 셈 · 파이썬 ↔ Node(창구 답). */
  nodeMs: number | null;
  wallMs: number | null;
  bytes: number;
  /** 브라우저 값 = 서버 값(대조 자리만 · 아니면 null). */
  same: boolean | null;
  applied: boolean;
}

interface CalcServerLog {
  calls: CalcServerCall[];
  local: Record<string, number[]>;
  delayMs: number;
}

const log = (): CalcServerLog =>
  ((globalThis as { __aisloCalcServer?: CalcServerLog }).__aisloCalcServer ??= {
    calls: [],
    local: {},
    delayMs: 0,
  });

const now = (): number => performance.now();
const r2 = (value: number): number => Math.round(value * 100) / 100;

function wait(ms: number, signal?: AbortSignal): Promise<void> {
  return new Promise((resolve, reject) => {
    if (signal?.aborted) return reject(new DOMException("끊김", "AbortError"));
    const timer = setTimeout(resolve, ms);
    signal?.addEventListener("abort", () => {
      clearTimeout(timer);
      reject(new DOMException("끊김", "AbortError"));
    });
  });
}

function record(call: CalcServerCall): void {
  const calls = log().calls;
  calls.push(call);
  if (calls.length > LOG_SIZE) calls.splice(0, calls.length - LOG_SIZE);
}

/** 서버 계산 한 번 — `{id: 값}` · 실패 = throw · `body` = 이미 굳힌 본문(입력이 뒤에 바뀌어도 그때 값). */
export async function serverCalc(
  key: string,
  run: string[],
  inputs: Record<string, unknown> | string,
  signal?: AbortSignal,
  extra: Partial<CalcServerCall> = {},
): Promise<Record<string, unknown>> {
  const body = typeof inputs === "string" ? inputs : JSON.stringify({ run, inputs });
  const t0 = now();
  if (log().delayMs > 0) await wait(log().delayMs, signal);
  const response = await fetch(`${API_BASE_URL}/projects/${calcProjectId()}/calc`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body,
    signal,
  });
  const data = (await response.json()) as {
    results?: Record<string, unknown>;
    ms?: number;
    wall_ms?: number;
    message?: string;
  };
  if (!response.ok || !data.results) throw new Error(data.message ?? `HTTP ${response.status}`);
  // extra 그 객체로 기록 — 대조 뒤 같음 · apply 를 부른 쪽이 그 자리에서 채움
  record(
    Object.assign(extra, {
      key,
      id: run.join("+"),
      browserMs: null,
      roundMs: r2(now() - t0),
      nodeMs: data.ms ?? null,
      wallMs: data.wall_ms ?? null,
      bytes: body.length,
      same: null,
      applied: true,
      ...extra,
    }),
  );
  return data.results;
}

const quiet = new Map<string, AbortController>();

/** 잠잠 뒤 task — 같은 칸 새 부름 · outer 끊김 = 앞 것 끊음(undefined) · 실패도 undefined(경고 한 줄). */
export async function afterQuiet<T>(
  slot: string,
  task: (signal: AbortSignal) => Promise<T>,
  outer?: AbortSignal,
): Promise<T | undefined> {
  quiet.get(slot)?.abort();
  const controller = new AbortController();
  quiet.set(slot, controller);
  outer?.addEventListener("abort", () => controller.abort());
  try {
    await wait(QUIET_MS, controller.signal);
    return await task(controller.signal);
  } catch (error) {
    if (!controller.signal.aborted) console.warn(`[calc-server] ${slot} 실패`, error);
    return undefined;
  } finally {
    if (quiet.get(slot) === controller) quiet.delete(slot);
  }
}

/** 서버 묻는 꼴 — 없으면 시험 길(`inputs.args[id]` = 함수 인자 · 답 = `results[id]`). */
export interface CalcRequest {
  run: string[];
  inputs: Record<string, unknown>;
  pick: (results: Record<string, unknown>) => unknown;
}

/** F7 구조물 면적 · C4 소단 구간 — 등록부 `node:` 입력 그대로. */
export const areasRequest = (rows: unknown[]): CalcRequest => ({
  run: ["structure.layouts"],
  inputs: { detail: { cross_sections: rows } },
  pick: (results) => (results["structure.layouts"] as { areas: unknown }).areas,
});
export const bermRequest = (structures: unknown[]): CalcRequest => ({
  run: ["cross.berm_spans"],
  inputs: { berm: { structures, chainages: [] } },
  pick: (results) => (results["cross.berm_spans"] as { spans: unknown }).spans,
});

export const trialRequest = (id: string, args: unknown[]): CalcRequest => ({
  run: [id],
  inputs: { args: { [id]: args } },
  pick: (results) => results[id],
});

/** 브라우저 셈 + 시간 기록(판 상관없이) · server 면 잠잠 뒤 서버 대조 · 다르면 apply(서버 값). */
export function calcChecked<A extends unknown[], R>(
  key: string,
  id: string,
  fn: (...args: A) => R,
  args: A,
  options: { apply?: (value: R) => void; request?: CalcRequest } = {},
): R {
  const t0 = now();
  const value = fn(...args);
  const browserMs = r2(now() - t0);
  const local = (log().local[id] ??= []);
  local.push(browserMs);
  if (local.length > LOCAL_SIZE) local.shift();
  if (!calcOnServerNow(key)) return value;
  const request = options.request ?? trialRequest(id, args);
  const body = JSON.stringify({ run: request.run, inputs: request.inputs });
  const mine = JSON.stringify(plain(value));
  const extra: Partial<CalcServerCall> = { browserMs, same: null, applied: false };
  void afterQuiet(id, (signal) => serverCalc(key, request.run, body, signal, extra)).then(
    (results) => {
      if (!results) return;
      const theirs = request.pick(results);
      extra.same = JSON.stringify(theirs) === mine;
      if (!extra.same && options.apply) {
        options.apply(theirs as R);
        extra.applied = true;
      }
    },
  );
  return value;
}

/** 서버 값만(비동기 자리) — 잠잠 뒤 묻고 고른 값 · 새 부름 · outer 끊김 · 실패 = undefined. */
export async function calcOnServerOnly<R>(
  key: string,
  slot: string,
  request: CalcRequest,
  outer?: AbortSignal,
): Promise<R | undefined> {
  const body = JSON.stringify({ run: request.run, inputs: request.inputs });
  const results = await afterQuiet(
    slot,
    (signal) => serverCalc(key, request.run, body, signal),
    outer,
  );
  return results ? (request.pick(results) as R) : undefined;
}

const held = new Map<string, { body: string; value: unknown }>();
const asked = new Map<string, string>();

/** 그리기 자리 서버 값 — 같은 입력 답이면 fresh · 아니면 앞 답(없으면 undefined) + 잠잠 뒤 묻고 redraw. */
export function calcFromServer<R>(
  key: string,
  id: string,
  args: unknown[],
  redraw: () => void,
): { value: R | undefined; fresh: boolean } {
  const request = trialRequest(id, args);
  const body = JSON.stringify({ run: request.run, inputs: request.inputs });
  const hold = held.get(id);
  if (hold?.body === body) return { value: hold.value as R, fresh: true };
  if (asked.get(id) !== body) {
    asked.set(id, body);
    void afterQuiet(id, (signal) => serverCalc(key, [id], body, signal)).then((results) => {
      if (asked.get(id) === body) asked.delete(id);
      if (!results) return;
      held.set(id, { body, value: results[id] });
      redraw();
    });
  }
  return { value: hold?.value as R | undefined, fresh: false };
}