import { History, Trash2, X } from "lucide-react";
import { type FormEvent, type ReactNode, useCallback, useEffect, useRef, useState } from "react";

import { platformApiClient } from "../api/client";
import type { JobResponse, LogEntryBody, LogStreamResponse } from "../api/types";
import { scumSourceRCONCommandRequest } from "../schemas/scumManagementRcon";
import { cx } from "../utils/classes";
import { mergeLogStreams, parseLogSessionEvent, parseLogStreamEvent, parseServerLogEvent, streamFromServerLogEvent } from "../utils/logEvents";
import { formatTerminalLogTime, formatTerminalServerTime } from "../utils/logTime";
import { ResultBadge } from "./StateViews";

type LoadState<T> = { status: "loading" } | { status: "error"; reason: string } | { status: "ready"; data: T };
type HistoryLineState = { status: "idle" } | LoadState<TerminalLine[]>;
type TerminalLine = { id: string; tone: "input" | "info" | "success" | "warn" | "error"; text: string; at: string; sortKey: number; streamKey?: string; level?: string; seq?: number };

const terminalHistoryWindow = 500;
const maxTerminalLines = 10000;
const terminalJobResultPollMs = 1000;
const terminalJobResultPollAttempts = 30;
// Game command catalogs are plugin-owned; this extension point intentionally
// contains no platform-provided game commands.
const terminalQuickCommandCatalog: Record<string, never[]> = {};

function terminalQuickCommandsForPlugin(pluginId: string): never[] {
  return terminalQuickCommandCatalog[pluginId] ?? [];
}

interface LiveOperationDrawerProps {
  open: boolean;
  title: string;
  description?: string;
  onClose: () => void;
  children: ReactNode;
  backdropClassName?: string;
  panelClassName?: string;
  bodyClassName?: string;
  hideHeader?: boolean;
}

function LiveOperationDrawer({ open, title, description, onClose, children, backdropClassName, panelClassName, bodyClassName, hideHeader }: LiveOperationDrawerProps) {
  useEffect(() => {
    if (!open) return undefined;
    const previous = document.body.style.overflow;
    const handleKeyDown = (event: KeyboardEvent) => {
      if (event.key === "Escape") onClose();
    };
    document.body.style.overflow = "hidden";
    document.addEventListener("keydown", handleKeyDown);
    return () => {
      document.body.style.overflow = previous;
      document.removeEventListener("keydown", handleKeyDown);
    };
  }, [onClose, open]);

  if (!open) return null;
  return (
    <div className={cx("drawer-backdrop", backdropClassName)} role="presentation" onClick={onClose}>
      <aside className={cx("drawer-panel live-operation-drawer", panelClassName)} role="dialog" aria-modal="true" aria-label={title} onClick={(event) => event.stopPropagation()}>
        {!hideHeader && (
          <div className="panel-header">
            <div>
              <h2>{title}</h2>
              {description && <p className="page-status">{description}</p>}
            </div>
            <button type="button" className="theme-upload drawer-close" aria-label={`关闭${title}`} onClick={onClose}><X size={14} /><span>关闭</span></button>
          </div>
        )}
        <div className={cx("live-operation-content", bodyClassName)}>{children}</div>
      </aside>
    </div>
  );
}

interface ServerManagementTerminalDrawerProps {
  open: boolean;
  serverId: string;
  serverName: string;
  onClose: () => void;
}

export function ServerManagementTerminalDrawer({ open, serverId, serverName, onClose }: ServerManagementTerminalDrawerProps) {
  const [command, setCommand] = useState("");
  const [pending, setPending] = useState(false);
  const [result, setResult] = useState<{ status: "pending" | "succeeded" | "failed"; label: string } | null>(null);
  const [lines, setLines] = useState<TerminalLine[]>([]);
  const [streams, setStreams] = useState<LoadState<LogStreamResponse[]>>({ status: "loading" });
  const [followLatest, setFollowLatest] = useState(true);
  const [liveSessionId, setLiveSessionId] = useState<string | null>(null);
  const [historyOpen, setHistoryOpen] = useState(false);
  const [historyStreams, setHistoryStreams] = useState<LoadState<LogStreamResponse[]>>({ status: "loading" });
  const [historyLines, setHistoryLines] = useState<HistoryLineState>({ status: "idle" });
  const [selectedHistoryStreamId, setSelectedHistoryStreamId] = useState("");
  const outputRef = useRef<HTMLDivElement>(null);
  const followLatestRef = useRef(true);
  const serverTimeRef = useRef<string | undefined>(undefined);
  const initialHistoryPendingRef = useRef(false);
  const liveSessionRef = useRef<string | null | undefined>(undefined);
  const historyRequestRef = useRef(0);

  const appendLines = useCallback((incoming: TerminalLine[]) => {
    if (incoming.length === 0) return;
    setLines((current) => mergeTerminalLines(current, incoming));
  }, []);

  const lockTerminalFollow = useCallback(() => {
    followLatestRef.current = true;
    setFollowLatest(true);
    window.requestAnimationFrame(() => {
      const output = outputRef.current;
      if (output) output.scrollTop = output.scrollHeight;
      window.requestAnimationFrame(() => {
        const innerOutput = outputRef.current;
        if (innerOutput) innerOutput.scrollTop = innerOutput.scrollHeight;
        initialHistoryPendingRef.current = false;
      });
    });
  }, []);

  useEffect(() => {
    if (!open) return;
    setStreams({ status: "loading" });
    setCommand("");
    setPending(false);
    setResult(null);
    setLiveSessionId(null);
    setHistoryOpen(false);
    setHistoryStreams({ status: "loading" });
    setHistoryLines({ status: "idle" });
    setSelectedHistoryStreamId("");
    liveSessionRef.current = undefined;
    serverTimeRef.current = undefined;
    historyRequestRef.current += 1;
    initialHistoryPendingRef.current = true;
    followLatestRef.current = true;
    setFollowLatest(true);
    setLines([terminalSystemLine("info", "正在连接当前受管进程输出。", "SYSTEM", undefined, serverTimeRef.current)]);
  }, [open]);

  useEffect(() => {
    if (!open || initialHistoryPendingRef.current || !followLatestRef.current) return undefined;
    const frame = window.requestAnimationFrame(() => {
      const output = outputRef.current;
      if (output) output.scrollTop = output.scrollHeight;
    });
    return () => window.cancelAnimationFrame(frame);
  }, [lines, open]);

  useEffect(() => {
    if (!open) return undefined;
    let ready = false;
    const events = platformApiClient.openServerLogEvents(serverId);
    events.addEventListener("session", (event) => {
      const session = parseLogSessionEvent(event);
      if (!session) return;
      ready = true;
      serverTimeRef.current = session.serverTime;
      const nextSessionId = normalizeLogSessionId(session.logSessionId);
      const previousSessionId = liveSessionRef.current;
      liveSessionRef.current = nextSessionId;
      setLiveSessionId(nextSessionId);
      if (previousSessionId === nextSessionId) return;
      setStreams({ status: "ready", data: [] });
      setLines(nextSessionId
        ? [terminalSystemLine("info", previousSessionId === undefined ? "已跟随当前受管进程输出会话。" : "Run 已切换到新的受管进程输出会话。", "SYSTEM", `session-${nextSessionId}`, serverTimeRef.current)]
        : [terminalSystemLine("warn", "当前没有可跟随的受管进程输出；旧日志可从历史查看。", "SYSTEM", "session-empty", serverTimeRef.current)]);
      lockTerminalFollow();
    });
    events.addEventListener("stream", (event) => {
      const stream = parseLogStreamEvent(event);
      if (!stream || !eventBelongsToLiveSession(stream.logSessionId, liveSessionRef.current)) return;
      ready = true;
      setStreams((current) => ({ status: "ready", data: mergeLogStreams(current.status === "ready" ? current.data : [], stream) }));
    });
    events.addEventListener("ready", () => {
      ready = true;
      setStreams((current) => current.status === "ready" ? current : { status: "ready", data: [] });
      lockTerminalFollow();
    });
    events.addEventListener("log", (event) => {
      const payload = parseServerLogEvent(event);
      if (!payload || !eventBelongsToLiveSession(payload.logSessionId, liveSessionRef.current)) return;
      ready = true;
      const stream = streamFromServerLogEvent(payload);
      setStreams((current) => ({ status: "ready", data: mergeLogStreams(current.status === "ready" ? current.data : [], stream) }));
      appendLines([terminalLineFromLog(stream, payload.entry)]);
    });
    events.onerror = () => {
      if (!ready) setStreams({ status: "error", reason: "实时日志推送连接失败" });
    };
    return () => events.close();
  }, [appendLines, lockTerminalFollow, open, serverId]);

  useEffect(() => {
    if (!open || !historyOpen) return;
    let cancelled = false;
    setHistoryStreams({ status: "loading" });
    void platformApiClient.listLogStreams(serverId).then((response) => {
      if (!cancelled) setHistoryStreams({ status: "ready", data: [...response.items].sort((left, right) => Date.parse(right.updatedAt) - Date.parse(left.updatedAt)) });
    }).catch((error) => {
      if (!cancelled) setHistoryStreams({ status: "error", reason: error instanceof Error ? error.message : "历史日志列表加载失败" });
    });
    return () => { cancelled = true; };
  }, [historyOpen, open, serverId]);

  async function selectHistoryStream(streamId: string) {
    const stream = historyStreams.status === "ready" ? historyStreams.data.find((item) => item.id === streamId) : undefined;
    if (!stream) return;
    const requestId = historyRequestRef.current + 1;
    historyRequestRef.current = requestId;
    setSelectedHistoryStreamId(streamId);
    setHistoryLines({ status: "loading" });
    try {
      const response = await platformApiClient.queryLogStream({ logStreamId: streamId, afterSeq: Math.max(0, stream.latestSeq - terminalHistoryWindow), limit: terminalHistoryWindow });
      if (historyRequestRef.current !== requestId) return;
      setHistoryLines({ status: "ready", data: response.entries.map((entry) => terminalLineFromLog(stream, entry)) });
    } catch (error) {
      if (historyRequestRef.current !== requestId) return;
      setHistoryLines({ status: "error", reason: error instanceof Error ? error.message : "历史日志加载失败" });
    }
  }

  function clearTerminalBuffer() {
    if (historyOpen) {
      setHistoryLines({ status: "ready", data: [] });
      return;
    }
    setLines([]);
  }

  function toggleHistory() {
    historyRequestRef.current += 1;
    setHistoryOpen((current) => !current);
    setSelectedHistoryStreamId("");
    setHistoryLines({ status: "idle" });
  }

  function handleTerminalScroll() {
    const output = outputRef.current;
    if (!output || initialHistoryPendingRef.current) return;
    const nextFollowLatest = output.scrollHeight - output.clientHeight - output.scrollTop <= 24;
    followLatestRef.current = nextFollowLatest;
    setFollowLatest(nextFollowLatest);
  }

  async function submitCommand(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    if (pending || !command.trim()) return;
    const submitted = command.trim();
    setCommand("");
    setPending(true);
    setResult({ status: "pending", label: "正在提交命令" });
    try {
      const response = await platformApiClient.dispatchSourceRCONCommand(serverId, scumSourceRCONCommandRequest(serverId, submitted));
      const label = `已${response.status === "queued" ? "排队" : "提交"} · RCON 任务 ${response.jobId}`;
      setResult({ status: "pending", label });
      const finalJob = await waitForRCONJobTerminal(response.jobId);
      if (finalJob) setResult({ status: finalJob.state === "succeeded" ? "succeeded" : "failed", label: finalJob.progress.message || finalJob.executionResult?.summary || finalJob.state });
    } catch (error) {
      setResult({ status: "failed", label: error instanceof Error ? error.message : "命令提交失败" });
    } finally {
      setPending(false);
    }
  }

  async function waitForRCONJobTerminal(jobId: string): Promise<JobResponse | null> {
    for (let attempt = 0; attempt < terminalJobResultPollAttempts; attempt += 1) {
      const current = await platformApiClient.getJob(jobId);
      if (current.state === "succeeded" || current.state === "failed" || current.state === "cancelled") return current;
      await new Promise((resolve) => window.setTimeout(resolve, terminalJobResultPollMs));
    }
    return null;
  }

  return (
    <LiveOperationDrawer open={open} title="打开终端" onClose={onClose} backdropClassName="terminal-drawer-backdrop" panelClassName="management-terminal-drawer" bodyClassName="management-terminal-body" hideHeader>
      <section className="terminal-output-panel" aria-label="terminal output">
        <div className="terminal-output-topbar">
          <div>
            <strong>{serverName}</strong>
            <span>{historyOpen ? "历史日志（独立于实时终端）" : `当前受管进程会话${liveSessionId ? " · SSE 实时推送" : " · 等待 Run 输出"}`} · {streams.status === "ready" ? "已连接" : streams.status === "loading" ? "连接日志流" : "日志流异常"} · {followLatest ? "自动置底" : "已解锁滚动"}</span>
          </div>
          <div>
            <button type="button" className="terminal-output-action" onClick={clearTerminalBuffer}><Trash2 size={14} /><span>清屏</span></button>
            <button type="button" className="terminal-output-action" onClick={toggleHistory}><History size={14} /><span>{historyOpen ? "实时输出" : "查看历史"}</span></button>
            <button type="button" className="terminal-output-action" aria-label="关闭打开终端" onClick={onClose}><X size={14} /><span>关闭</span></button>
          </div>
        </div>
        <div ref={outputRef} className="terminal-output" role="log" aria-live="polite" onScroll={handleTerminalScroll}>
          {!historyOpen && streams.status === "error" && <div className="terminal-line terminal-line-error terminal-source-system"><time>{formatTerminalServerTime(serverTimeRef.current)}</time><span className="terminal-text">{streams.reason}</span></div>}
          {historyOpen && <HistoryLogView streams={historyStreams} lines={historyLines} selectedStreamId={selectedHistoryStreamId} onSelect={selectHistoryStream} serverTime={serverTimeRef.current} />}
          {!historyOpen && streams.status === "ready" && lines.length === 0 && <div className="terminal-line terminal-line-warn terminal-source-system"><time>{formatTerminalServerTime(serverTimeRef.current)}</time><span className="terminal-text">{liveSessionId ? "当前受管进程会话暂无输出，后续输出会自动追加。" : "当前没有可跟随的受管进程输出；旧日志可从历史查看。"}</span></div>}
          {!historyOpen && lines.map((line) => <div key={line.id} className={terminalLineClassName(line)}><time>{line.at}</time><span className="terminal-text">{line.text}</span></div>)}
       </div>
      </section>
      <section className="terminal-command-dock" aria-label="terminal command controls">
        <div className="terminal-command-dock-header"><span>插件命令通道</span>{result && <ResultBadge status={result.status} label={result.label} />}</div>
        <form className="terminal-command-form" onSubmit={(event) => void submitCommand(event)}>
          <label><span>插件声明的命令</span><small>命令正文由插件解释，平台仅负责授权、排队和转发。</small><input value={command} disabled={pending} placeholder="输入插件命令" onChange={(event) => setCommand(event.target.value)} /></label>
          <button type="submit" className="primary-command" disabled={pending || !command.trim()}>{pending ? "提交中…" : "发送"}</button>
        </form>
      </section>
    </LiveOperationDrawer>
  );
}

interface HistoryLogViewProps {
  streams: LoadState<LogStreamResponse[]>;
  lines: HistoryLineState;
  selectedStreamId: string;
  onSelect: (streamId: string) => Promise<void>;
  serverTime?: string;
}

function HistoryLogView({ streams, lines, selectedStreamId, onSelect, serverTime }: HistoryLogViewProps) {
  if (streams.status === "loading") return <TerminalStatusLine tone="info" label="正在加载历史日志列表。" serverTime={serverTime} />;
  if (streams.status === "error") return <TerminalStatusLine tone="error" label={streams.reason} serverTime={serverTime} />;
  if (streams.data.length === 0) return <TerminalStatusLine tone="warn" label="暂无可查看的历史日志流。" serverTime={serverTime} />;
  return (
    <>
      <div className="terminal-line terminal-line-info terminal-source-system">
        <time>历史</time>
        <span className="terminal-text">
          <select aria-label="选择历史日志流" value={selectedStreamId} onChange={(event) => void onSelect(event.target.value)}>
            <option value="" disabled>选择一个历史日志流</option>
            {streams.data.map((stream) => <option key={stream.id} value={stream.id}>{stream.streamKey} · {stream.updatedAt}</option>)}
          </select>
        </span>
      </div>
      {lines.status === "idle" && <TerminalStatusLine tone="info" label="请选择一个历史日志流。" serverTime={serverTime} />}
      {lines.status === "loading" && <TerminalStatusLine tone="info" label="正在读取所选历史日志。" serverTime={serverTime} />}
      {lines.status === "error" && <TerminalStatusLine tone="error" label={lines.reason} serverTime={serverTime} />}
      {lines.status === "ready" && lines.data.length === 0 && <TerminalStatusLine tone="warn" label="所选历史日志流暂无保留内容。" serverTime={serverTime} />}
      {lines.status === "ready" && lines.data.map((line) => <div key={line.id} className={terminalLineClassName(line)}><time>{line.at}</time><span className="terminal-text">{line.text}</span></div>)}
    </>
  );
}

function TerminalStatusLine({ tone, label, serverTime }: { tone: "info" | "warn" | "error"; label: string; serverTime?: string }) {
  return <div className={`terminal-line terminal-line-${tone} terminal-source-system`}><time>{formatTerminalServerTime(serverTime)}</time><span className="terminal-text">{label}</span></div>;
}

function terminalLineFromLog(stream: LogStreamResponse, entry: LogEntryBody): TerminalLine {
  return {
    id: `log-${stream.id}-${entry.seq}`,
    tone: "info",
    text: entry.line,
    at: formatTerminalLogTime(entry.timestamp),
    sortKey: Date.parse(entry.timestamp) || Date.now(),
    streamKey: stream.streamKey || stream.source,
    level: entry.level,
    seq: entry.seq
  };
}

function terminalSystemLine(tone: TerminalLine["tone"], text: string, streamKey: string, id = `${streamKey.toLowerCase()}-${Date.now()}-${Math.random().toString(36).slice(2, 7)}`, serverTime?: string): TerminalLine {
  const sortKey = serverTime ? Date.parse(serverTime) : 0;
  return { id, tone, text, at: formatTerminalServerTime(serverTime), sortKey, streamKey };
}

function terminalLineClassName(line: TerminalLine): string {
  return `terminal-line terminal-line-${line.tone} terminal-source-${terminalSourceClass(line.streamKey || line.level)}`;
}

function terminalSourceClass(value?: string): string {
  const key = (value ?? "").toLowerCase();
  if (key.includes("stderr") || key === "error") return "stderr";
  if (key.includes("stdout")) return "stdout";
  if (key.includes("command")) return "command";
  if (key.includes("platform")) return "platform";
  if (key.includes("system")) return "system";
  return "log";
}

function normalizeLogSessionId(value?: string): string | null {
  const normalized = value?.trim();
  return normalized || null;
}

function eventBelongsToLiveSession(eventSessionId: string | undefined, liveSessionId: string | null | undefined): boolean {
  const normalizedEventSessionId = normalizeLogSessionId(eventSessionId);
  return Boolean(normalizedEventSessionId && normalizedEventSessionId === liveSessionId);
}

function mergeTerminalLines(current: TerminalLine[], incoming: TerminalLine[]): TerminalLine[] {
  const seen = new Set(current.map((line) => line.id));
  const merged = [...current];
  for (const line of incoming) {
    if (seen.has(line.id)) continue;
    seen.add(line.id);
    merged.push(line);
  }
  return merged.sort(compareTerminalLines).slice(-maxTerminalLines);
}

function compareTerminalLines(a: TerminalLine, b: TerminalLine): number {
  return a.sortKey - b.sortKey || (a.seq ?? 0) - (b.seq ?? 0) || a.id.localeCompare(b.id);
}