import { useState, useRef, useEffect, useCallback } from 'react';
import {
  Dialog,
  DialogContent,
  DialogTitle,
  DialogDescription,
} from '@/components/ui/dialog';
import { Button } from '@/components/ui/button';
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from '@/components/ui/select';
import { Terminal as XTerm } from 'xterm';
import { FitAddon } from 'xterm-addon-fit';
import 'xterm/css/xterm.css';
import {
  Terminal, Maximize2, Minimize2, X, Loader2, RotateCw, Box,
} from 'lucide-react';
import { cn } from '@/lib/utils';
import { kubernetesApi } from '@/services/api';
import { useToast } from '@/hooks/use-toast';

/**
 * Pod 级 exec 终端 — 进入容器执行命令 (kubectl exec -it)
 *
 * 复用 KubectlTerminal.tsx 的 xterm.js 模式，连接 Pod exec WebSocket 通道：
 *   ws://host/ws/kubernetes-exec/:clusterId/namespaces/:ns/pods/:pod?container=&token=
 *
 * 支持：
 * - 容器选择下拉（默认第一个容器，可切换）
 * - 自定义 shell（默认 bash，可切 sh）
 * - Dialog/Modal 形式，全屏切换
 * - 终端 resize 透传（ResizeObserver + fit）
 *
 * @author Logan <admin@attacker.club>
 */
interface PodExecTerminalProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  /** 集群 ID（用于 ws 路由 :clusterId） */
  clusterId: number | string;
  /** 集群 code（备用，部分后端用 code） */
  clusterCode?: string;
  namespace: string;
  podName: string;
  /** 可选：Pod 容器名列表，缺省时仅显示 shell 选择 */
  containers?: string[];
  /** 初始容器 */
  initialContainer?: string;
}

type ConnState = 'idle' | 'connecting' | 'connected' | 'error' | 'closed';

const SHELLS = [
  { value: 'bash', label: '/bin/bash' },
  { value: 'sh', label: '/bin/sh' },
  { value: 'sh', label: '/bin/ash' },
];

export function PodExecTerminal({
  open,
  onOpenChange,
  clusterId,
  namespace,
  podName,
  containers = [],
  initialContainer,
}: PodExecTerminalProps) {
  const { toast } = useToast();
  const containerRef = useRef<HTMLDivElement>(null);
  const termRef = useRef<XTerm | null>(null);
  const wsRef = useRef<WebSocket | null>(null);
  const fitRef = useRef<FitAddon | null>(null);

  const [connState, setConnState] = useState<ConnState>('idle');
  const [fullscreen, setFullscreen] = useState(false);
  const [container, setContainer] = useState<string>(initialContainer || containers[0] || '');
  const [shell, setShell] = useState<string>('bash');

  // 重置全屏状态
  useEffect(() => {
    if (!open) setFullscreen(false);
  }, [open]);

  // 容器列表变化时同步默认值
  useEffect(() => {
    if (open && !container && containers.length > 0) {
      setContainer(initialContainer || containers[0]);
    }
  }, [open, containers, initialContainer, container]);

  // 创建 xterm 实例（仅在 open 时创建一次，容器/shell 变化时重连 ws）
  const connect = useCallback(() => {
    if (!termRef.current) return;
    const term = termRef.current;

    // 关闭旧连接
    if (wsRef.current) {
      try { wsRef.current.close(); } catch { /* noop */ }
      wsRef.current = null;
    }

    setConnState('connecting');
    term.clear();
    term.writeln(`\x1b[36m[正在连接 ${podName}${container ? '/' + container : ''} ...]\x1b[0m`);

    const wsUrl = kubernetesApi.buildPodExecWsUrl(clusterId, namespace, podName, container || undefined, shell);
    const ws = new WebSocket(wsUrl);
    wsRef.current = ws;

    ws.onopen = () => {
      setConnState('connected');
      term.reset();
      // 发送初始 resize（command/shell 已在 WS URL 参数中指定）
      try {
        const { cols, rows } = term;
        ws.send(JSON.stringify({ status: 1, cols, rows }));
      } catch { /* noop */ }
      setTimeout(() => { try { term.focus(); } catch { /* noop */ } }, 100);
    };

    ws.onmessage = (event) => {
      try {
        const msg = JSON.parse(event.data);
        if (msg.status === 0 && typeof msg.data === 'string') {
          term.write(msg.data);
        } else if (msg.status === 1) {
          // 服务端 resize 确认，忽略
        } else if (msg.status === 2 || msg.error) {
          const errMsg = msg.data || msg.message || msg.error || '执行错误';
          term.write(errMsg.includes('\\x1b') ? errMsg : `\\r\\n\\x1b[31m${errMsg}\\x1b[0m\\r\\n`);
        }
      } catch {
        if (typeof event.data === 'string') term.write(event.data);
      }
    };

    ws.onclose = () => {
      setConnState((s) => (s === 'error' ? s : 'closed'));
      term.write('\r\n\x1b[33m[连接已断开]\x1b[0m\r\n');
    };

    ws.onerror = () => {
      setConnState('error');
      term.write('\r\n\x1b[31m[连接发生错误]\x1b[0m\r\n');
    };
  }, [clusterId, namespace, podName, container, shell]);

  // 创建/销毁 xterm + 绑定 onData（生命周期跟随 open）
  useEffect(() => {
    if (!open || !clusterId || !podName) return;

    const term = new XTerm({
      cursorBlink: true,
      fontSize: 14,
      fontFamily: 'Menlo, Monaco, "Courier New", monospace',
      allowProposedApi: true,
      scrollback: 5000,
      theme: {
        background: '#0f172a',
        foreground: '#e2e8f0',
        cursor: '#38bdf8',
        selectionBackground: '#1e40af',
        black: '#1e293b', red: '#ef4444', green: '#10b981',
        yellow: '#f59e0b', blue: '#3b82f6', magenta: '#a855f7',
        cyan: '#06b6d4', white: '#e2e8f0',
        brightBlack: '#475569', brightRed: '#f87171', brightGreen: '#34d399',
        brightYellow: '#fbbf24', brightBlue: '#60a5fa', brightMagenta: '#c084fc',
        brightCyan: '#22d3ee', brightWhite: '#f8fafc',
      },
    });
    const fit = new FitAddon();
    term.loadAddon(fit);
    termRef.current = term;
    fitRef.current = fit;

    const onData = (data: string) => {
      if (wsRef.current && wsRef.current.readyState === WebSocket.OPEN) {
        wsRef.current.send(JSON.stringify({ status: 0, data }));
      }
    };
    term.onData(onData);

    if (containerRef.current) {
      term.open(containerRef.current);
      requestAnimationFrame(() => {
        try { fit.fit(); } catch { /* noop */ }
      });
    }

    // 首次连接
    connect();

    return () => {
      try {
        if (wsRef.current && (wsRef.current.readyState === WebSocket.OPEN || wsRef.current.readyState === WebSocket.CONNECTING)) {
          wsRef.current.close();
        }
      } catch { /* noop */ }
      try { term.dispose(); } catch { /* noop */ }
      termRef.current = null;
      wsRef.current = null;
      fitRef.current = null;
      setConnState('idle');
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [open, clusterId, podName]);

  // 容器 / shell 变化时重连（需 term 已就绪）
  useEffect(() => {
    if (open && termRef.current) {
      connect();
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [container, shell]);

  // ResizeObserver 监听容器变化自动 fit + 透传 resize
  useEffect(() => {
    if (!open) return;
    const containerEl = containerRef.current;
    if (!containerEl) return;

    let resizeTimer: ReturnType<typeof setTimeout>;
    const ro = new ResizeObserver(() => {
      clearTimeout(resizeTimer);
      resizeTimer = setTimeout(() => {
        if (fitRef.current && termRef.current && wsRef.current) {
          try {
            fitRef.current.fit();
            termRef.current.focus();
            const { cols, rows } = termRef.current;
            if (wsRef.current.readyState === WebSocket.OPEN) {
              wsRef.current.send(JSON.stringify({ status: 1, cols, rows }));
            }
          } catch { /* noop */ }
        }
      }, 60);
    });

    ro.observe(containerEl);
    return () => {
      clearTimeout(resizeTimer);
      ro.disconnect();
    };
  }, [open, fullscreen]);

  const statusColor = connState === 'connected' ? 'bg-emerald-400'
    : connState === 'error' ? 'bg-red-400'
    : connState === 'closed' ? 'bg-slate-500'
    : 'bg-amber-400';
  const statusText = connState === 'connected' ? '已连接'
    : connState === 'connecting' ? '连接中'
    : connState === 'error' ? '连接错误'
    : connState === 'closed' ? '已断开'
    : '空闲';

  return (
    <Dialog open={open} onOpenChange={onOpenChange}>
      <DialogContent
        showCloseButton={false}
        onOpenAutoFocus={(e) => e.preventDefault()}
        className={cn(
          'bg-[var(--dg-bg-secondary)] border-[var(--dg-border)] p-0 gap-0',
          '!duration-0 !transition-none',
          fullscreen
            ? '!max-w-none !w-screen !h-screen !rounded-none !translate-x-0 !translate-y-0 !left-0 !top-0'
            : ''
        )}
        style={fullscreen ? { maxWidth: '100vw', width: '100vw', height: '100vh' } : { maxWidth: '960px', width: '92vw' }}
      >
        <DialogTitle className="sr-only">exec — {podName}</DialogTitle>
        <DialogDescription className="sr-only">进入 Pod 容器执行命令</DialogDescription>

        {/* 头部工具栏 */}
        <div className="flex items-center justify-between gap-2 px-4 py-2 border-b border-[var(--dg-border)] flex-wrap">
          <div className="flex items-center gap-2 text-sm min-w-0">
            <div className={cn('w-2 h-2 rounded-full shrink-0', statusColor)} title={statusText} />
            <Terminal className="h-4 w-4 text-blue-400 shrink-0" />
            <span className="text-[var(--dg-text-primary)] font-medium truncate">
              exec — {podName}
            </span>
            {connState === 'connecting' && <Loader2 className="h-3 w-3 animate-spin text-[var(--dg-text-muted)]" />}
            <span className="text-xs text-[var(--dg-text-muted)]">{statusText}</span>
          </div>

          <div className="flex items-center gap-2">
            {/* 容器选择 */}
            {containers.length > 0 && (
              <Select value={container} onValueChange={setContainer}>
                <SelectTrigger className="h-8 w-[150px] text-xs bg-[var(--dg-bg-hover)] border-[var(--dg-border)]">
                  <Box className="h-3 w-3 mr-1 text-[var(--dg-text-muted)]" />
                  <SelectValue placeholder="容器" />
                </SelectTrigger>
                <SelectContent>
                  {containers.map((c) => (
                    <SelectItem key={c} value={c}>{c}</SelectItem>
                  ))}
                </SelectContent>
              </Select>
            )}

            {/* Shell 选择 */}
            <Select value={shell} onValueChange={setShell}>
              <SelectTrigger className="h-8 w-[100px] text-xs bg-[var(--dg-bg-hover)] border-[var(--dg-border)]">
                <SelectValue />
              </SelectTrigger>
              <SelectContent>
                <SelectItem value="bash">/bin/bash</SelectItem>
                <SelectItem value="sh">/bin/sh</SelectItem>
              </SelectContent>
            </Select>

            {/* 重连 */}
            <Button
              variant="ghost" size="sm"
              className="h-8 px-2 text-[var(--dg-text-secondary)] hover:text-[var(--dg-text-primary)]"
              onClick={() => { connect(); toast({ title: '正在重连…' }); }}
              title="重连"
            >
              <RotateCw className="h-3.5 w-3.5" />
            </Button>

            <button
              onClick={() => setFullscreen(!fullscreen)}
              className="p-1.5 rounded hover:bg-[var(--dg-bg-hover)] text-[var(--dg-text-secondary)]"
              title={fullscreen ? '退出全屏' : '全屏'}
            >
              {fullscreen ? <Minimize2 className="h-4 w-4" /> : <Maximize2 className="h-4 w-4" />}
            </button>
            <button
              onClick={() => onOpenChange(false)}
              className="p-1.5 rounded hover:bg-[var(--dg-bg-hover)] text-[var(--dg-text-secondary)]"
              title="关闭"
            >
              <X className="h-4 w-4" />
            </button>
          </div>
        </div>

        {/* 终端容器 */}
        <div
          ref={containerRef}
          className="bg-[#0f172a]"
          style={{ height: fullscreen ? 'calc(100vh - 49px)' : '480px' }}
        />
      </DialogContent>
    </Dialog>
  );
}