/**
 * 巡检调度器 Hook（前端侧）
 *
 * 为什么调度器在前端？因为 vault 主机数据在渲染进程的 localStorage 里，
 * 主进程拿不到完整的主机连接信息（密码/私钥）。
 *
 * 调度器职责：
 *   - 每 30 秒检查一次哪些设备到期需要巡检
 *   - 按并发限制依次调用主进程的 inspection:runInspection 执行
 *   - 维护运行状态、上次执行时间
 */

import { useRef, useCallback, useEffect, useState, useMemo } from "react";
import { inspectionExecApi, inspectionDeviceApi } from "../../infrastructure/inspection/inspectionApi";
import type { Host } from "../../domain/models";
import type { SSHKey } from "../../domain/models/key";
import type { DeviceExtension } from "../../infrastructure/inspection/inspectionApi";

const POLL_INTERVAL_MS = 30 * 1000; // 30 秒轮询
const DEFAULT_CONCURRENCY = 3; // 默认并发数
const SYS_DEFAULT_INTERVAL = 5; // 系统默认周期（分钟）

const TIER_DEFAULT_INTERVAL: Record<string, number> = {
  core: 5,
  aggregation: 10,
  access: 15,
};

export interface SchedulerStatus {
  running: boolean;
  totalDevices: number;
  activeDevices: number;
  lastScanAt: number | null;
  runningCount: number;
}

interface LastRunInfo {
  [hostId: string]: number; // timestamp
}

/**
 * 计算设备的有效巡检周期（分钟）
 * 优先级：设备自定义 > 分级默认 > 系统默认
 */
function getEffectiveInterval(ext: DeviceExtension | null): number {
  if (!ext || !ext.inspection_enabled) return 0;
  if (ext.inspection_interval && ext.inspection_interval > 0) {
    return ext.inspection_interval;
  }
  if (ext.tier && TIER_DEFAULT_INTERVAL[ext.tier]) {
    return TIER_DEFAULT_INTERVAL[ext.tier];
  }
  return SYS_DEFAULT_INTERVAL;
}

/**
 * 从 Host + keys 拼出巡检需要的连接配置
 */
function buildHostConfig(host: Host, keys: SSHKey[]): {
  id: string;
  label: string;
  hostname: string;
  port: number;
  username: string;
  password?: string;
  privateKeyContent?: string;
  passphrase?: string;
} {
  const config: any = {
    id: host.id,
    label: host.label,
    hostname: host.hostname,
    port: host.port || 22,
    username: host.username,
  };

  // 密码
  if (host.password) {
    config.password = host.password;
  }

  // 私钥（通过 identityFileId 关联）
  if (host.identityFileId) {
    const key = keys.find((k) => k.id === host.identityFileId);
    if (key && key.privateKey) {
      config.privateKeyContent = key.privateKey;
      if (key.passphrase) {
        config.passphrase = key.passphrase;
      }
    }
  }

  return config;
}

export function useInspectionScheduler(hosts: Host[], keys: SSHKey[]) {
  const [status, setStatus] = useState<SchedulerStatus>({
    running: false,
    totalDevices: 0,
    activeDevices: 0,
    lastScanAt: null,
    runningCount: 0,
  });

  const timerRef = useRef<NodeJS.Timeout | null>(null);
  const lastRunRef = useRef<LastRunInfo>({});
  const runningRef = useRef(false);
  const runningCountRef = useRef(0);
  const hostsRef = useRef(hosts);
  const keysRef = useRef(keys);

  // 实时更新 hosts/keys 引用
  useEffect(() => {
    hostsRef.current = hosts;
  }, [hosts]);

  useEffect(() => {
    keysRef.current = keys;
  }, [keys]);

  /**
   * 执行一次单设备巡检
   */
  const runDeviceInspection = useCallback(
    async (hostId: string, catalogId?: string) => {
      const host = hostsRef.current.find((h) => h.id === hostId);
      if (!host) {
        console.warn(`[InspectionScheduler] 未找到主机: ${hostId}`);
        return null;
      }

      const hostConfig = buildHostConfig(host, keysRef.current);
      const actualCatalogId = catalogId || "linux_server";

      runningCountRef.current += 1;
      setStatus((s) => ({ ...s, runningCount: runningCountRef.current }));

      try {
        const result = await inspectionExecApi.runInspection(
          hostId,
          hostConfig,
          actualCatalogId
        );
        lastRunRef.current[hostId] = Date.now();
        return result;
      } catch (e: any) {
        console.error(`[InspectionScheduler] 巡检失败 ${hostId}:`, e.message);
        return { success: false, error: e.message };
      } finally {
        runningCountRef.current = Math.max(0, runningCountRef.current - 1);
        setStatus((s) => ({ ...s, runningCount: runningCountRef.current }));
      }
    },
    []
  );

  /**
   * 主循环：检查到期设备并执行
   */
  const scanLoop = useCallback(async (hosts?: typeof hosts) => {
    // 如果还没启动，自动启动调度器
    if (!runningRef.current) {
      runningRef.current = true;
      setStatus((s) => ({ ...s, running: true }));
      console.log("[InspectionScheduler] 调度器自动启动");
    }
    // 使用传入的 hosts 参数，或者用 ref
    const currentHosts = hosts ?? hostsRef.current;
    // hosts 还没加载，跳过
    if (!currentHosts || currentHosts.length === 0) {
      console.log('[InspectionScheduler] hosts 还未加载，当前 hosts:', currentHosts?.length);
      return;
    }
    console.log('[InspectionScheduler] 开始巡检，设备数:', currentHosts.length);

    const allExts = await inspectionDeviceApi.getAll();
    const extsMap = allExts || {}; // Record<string, DeviceExtension>

    // 调试：统计启用了巡检的设备数量
    let enabledCount = 0;
    for (const host of currentHosts) {
      const ext = extsMap[host.id];
      if (ext?.inspection_enabled) enabledCount++;
    }
    console.log('[InspectionScheduler] 扩展配置数量:', Object.keys(extsMap).length, '| 启用巡检设备数:', enabledCount);

    const now = Date.now();
    const dueDevices: { hostId: string; catalogId: string }[] = [];

    for (const host of currentHosts) {
      const ext = extsMap[host.id];
      if (!ext || !ext.inspection_enabled) continue;

      const intervalMin = getEffectiveInterval(ext);
      if (intervalMin <= 0) {
        console.log('[InspectionScheduler] 跳过（周期为0）:', host.label, '| intervalMin:', intervalMin);
        continue;
      }

      const lastRun = lastRunRef.current[host.id] || ext.last_scan_at || 0;
      const intervalMs = intervalMin * 60 * 1000;
      const elapsed = now - lastRun;
      const needRun = elapsed >= intervalMs;

      console.log('[InspectionScheduler] 设备:', host.label, '| 周期:', intervalMin, 'min | 距上次:', Math.round(elapsed/60000), 'min | 需要巡检:', needRun);

      if (needRun) {
        dueDevices.push({
          hostId: host.id,
          catalogId: ext.catalog_id || "linux_server",
        });
      }
    }

    console.log('[InspectionScheduler] 到期设备数:', dueDevices.length);
    if (dueDevices.length === 0) {
      setStatus((s) => ({ ...s, lastScanAt: now }));
      return;
    }

    // 并发执行（简单的并发控制）
    const queue = [...dueDevices];
    const workers: Promise<any>[] = [];

    const processQueue = async () => {
      while (queue.length > 0) {
        const device = queue.shift();
        if (!device) break;
        await runDeviceInspection(device.hostId, device.catalogId);
      }
    };

    for (let i = 0; i < Math.min(DEFAULT_CONCURRENCY, dueDevices.length); i++) {
      workers.push(processQueue());
    }

    await Promise.all(workers);
    setStatus((s) => ({ ...s, lastScanAt: now }));
  }, [runDeviceInspection]);

  /**
   * 启动调度器
   */
  const start = useCallback(() => {
    if (runningRef.current) return;
    runningRef.current = true;

    // 立即执行一次
    scanLoop();

    // 定时轮询
    timerRef.current = setInterval(() => {
      scanLoop();
    }, POLL_INTERVAL_MS);

    setStatus((s) => ({ ...s, running: true }));
    console.log("[InspectionScheduler] 已启动");
  }, [scanLoop]);

  /**
   * 停止调度器
   */
  const stop = useCallback(() => {
    runningRef.current = false;
    if (timerRef.current) {
      clearInterval(timerRef.current);
      timerRef.current = null;
    }
    setStatus((s) => ({ ...s, running: false }));
    console.log("[InspectionScheduler] 已停止");
  }, []);

  /**
   * 立即巡检指定设备
   */
  const scanNow = useCallback(
    async (hostId: string, catalogId?: string) => {
      return await runDeviceInspection(hostId, catalogId);
    },
    [runDeviceInspection]
  );

  // 组件卸载时清理
  useEffect(() => {
    return () => {
      if (timerRef.current) {
        clearInterval(timerRef.current);
      }
      runningRef.current = false;
    };
  }, []);

  // 计算状态
  useEffect(() => {
    const activeCount = hosts.filter((h) => {
      // 这里没法同步拿到 extensions，先按 hosts 总数显示
      return true;
    }).length;

    setStatus((s) => ({
      ...s,
      totalDevices: hosts.length,
      activeDevices: activeCount,
    }));
  }, [hosts]);

  return useMemo(
    () => ({
      status,
      start,
      stop,
      scanNow,
      scanLoop,
    }),
    [status, start, stop, scanNow, scanLoop]
  );
}