import type { BrowserContext, Page } from "playwright";
import { QUOTE_SESSION_TTL_SECONDS } from "@/lib/constants/quote-session";
import { getRedis } from "@/lib/redis";
import { RpaError } from "@/modules/rpa/errors";
import {
  dismissCookieConsent,
  scrollQuoteWidgetIntoView,
} from "@/workers/rpa/page-prep";

type ParkedEntry = {
  sessionId: string;
  page: Page;
  context: BrowserContext;
  parkedAt: number;
};

const pool = new Map<string, ParkedEntry>();

const PARKED_REDIS_PREFIX = "quote_session:parked:";

function ttlMs(): number {
  return QUOTE_SESSION_TTL_SECONDS * 1_000;
}

function isExpired(entry: ParkedEntry): boolean {
  return Date.now() - entry.parkedAt > ttlMs();
}

/** 仅 rpa-worker 进程可驻留 page（spawn 子进程退出后内存池无效） */
export function canPersistParkedQuoteSession(): boolean {
  return Boolean(process.env.RPA_WORKER_ID?.trim());
}

async function markParkedInRedis(sessionId: string): Promise<void> {
  const workerId = process.env.RPA_WORKER_ID?.trim();
  if (!workerId) {
    return;
  }
  try {
    await getRedis().setex(
      `${PARKED_REDIS_PREFIX}${sessionId}`,
      QUOTE_SESSION_TTL_SECONDS,
      workerId,
    );
  } catch {
    /* Redis 不可用时仍保留进程内驻留 */
  }
}

async function clearParkedInRedis(sessionId: string): Promise<void> {
  try {
    await getRedis().del(`${PARKED_REDIS_PREFIX}${sessionId}`);
  } catch {
    /* ignore */
  }
}

/** Redis 侧是否曾有 worker 驻留（诊断 spawn/跨进程） */
export async function readParkedSessionWorkerId(
  sessionId: string,
): Promise<string | null> {
  try {
    return await getRedis().get(`${PARKED_REDIS_PREFIX}${sessionId}`);
  } catch {
    return null;
  }
}

/** 清理过期驻留会话 */
export function sweepExpiredParkedSessions(): number {
  let removed = 0;
  for (const [id, entry] of pool) {
    if (isExpired(entry)) {
      void releaseParkedQuoteSession(id);
      removed += 1;
    }
  }
  return removed;
}

/** 候选完成后驻留 page/context，供询价 job 同页续跑 */
export async function parkQuoteSession(
  sessionId: string,
  page: Page,
  context: BrowserContext,
): Promise<void> {
  if (!canPersistParkedQuoteSession()) {
    throw new RpaError(
      "STRUCT_CHANGE",
      "非 RPA Worker 进程，无法驻留浏览器会话",
      { retryable: false },
    );
  }
  sweepExpiredParkedSessions();
  await releaseParkedQuoteSession(sessionId);
  pool.set(sessionId, {
    sessionId,
    page,
    context,
    parkedAt: Date.now(),
  });
  await markParkedInRedis(sessionId);
  console.log(
    `[parked-session] 已驻留 session=${sessionId.slice(0, 8)}… count=${pool.size} worker=${process.env.RPA_WORKER_ID}`,
  );
}

/** 询价 job 接管驻留会话（从池中移除） */
export async function takeParkedQuoteSession(
  sessionId: string,
  options?: { waitMs?: number },
): Promise<{ page: Page; context: BrowserContext } | null> {
  const waitMs = options?.waitMs ?? 0;
  const deadline = Date.now() + waitMs;

  while (Date.now() <= deadline) {
    sweepExpiredParkedSessions();
    const entry = pool.get(sessionId);
    if (entry && !isExpired(entry)) {
      pool.delete(sessionId);
      await clearParkedInRedis(sessionId);
      console.log(
        `[parked-session] 已接管 session=${sessionId.slice(0, 8)}…（单次 RPA 续跑）`,
      );
      return { page: entry.page, context: entry.context };
    }
    if (waitMs <= 0) {
      break;
    }
    await new Promise((resolve) => setTimeout(resolve, 200));
  }

  const redisWorker = await readParkedSessionWorkerId(sessionId);
  if (redisWorker && !pool.has(sessionId)) {
    console.warn(
      `[parked-session] Redis 记录 worker=${redisWorker} 但本进程无驻留页（可能 spawn 候选或 worker 已重启）session=${sessionId.slice(0, 8)}…`,
    );
  }
  return null;
}

/** 用户取消或超时：关闭并移除 */
export async function releaseParkedQuoteSession(
  sessionId: string,
): Promise<boolean> {
  const entry = pool.get(sessionId);
  if (!entry) {
    await clearParkedInRedis(sessionId);
    return false;
  }
  pool.delete(sessionId);
  await clearParkedInRedis(sessionId);
  await entry.page.close().catch(() => undefined);
  await entry.context.close().catch(() => undefined);
  console.log(
    `[parked-session] 已释放 session=${sessionId.slice(0, 8)}… count=${pool.size}`,
  );
  return true;
}

export async function releaseAllParkedQuoteSessions(): Promise<void> {
  const ids = [...pool.keys()];
  for (const id of ids) {
    await releaseParkedQuoteSession(id);
  }
}

export function hasParkedQuoteSession(sessionId: string): boolean {
  sweepExpiredParkedSessions();
  const entry = pool.get(sessionId);
  return Boolean(entry && !isExpired(entry));
}

/** 用户确认弹窗期间：轻量维持 widget 就绪 */
export async function preheatParkedQuoteSession(
  sessionId: string,
): Promise<boolean> {
  sweepExpiredParkedSessions();
  const entry = pool.get(sessionId);
  if (!entry || isExpired(entry)) {
    return false;
  }
  await dismissCookieConsent(entry.page);
  await scrollQuoteWidgetIntoView(entry.page, { force: true });
  console.log(
    `[parked-session] 已预热 session=${sessionId.slice(0, 8)}…`,
  );
  return true;
}

/** 驻留页复用前轻量检查（跳过 15~45s widget hydration 轮询） */
export async function prepareParkedQuotePage(page: Page): Promise<void> {
  await dismissCookieConsent(page);
  await scrollQuoteWidgetIntoView(page, { force: true });
}

export function parkedQuoteSessionCount(): number {
  sweepExpiredParkedSessions();
  return pool.size;
}