feat: add server log preview

src/components/server/ServerConfigurationTabs.tsx

@@ -9,6 +9,7 @@ import { ServerSettingsEditor } from '@/components/configuration/ServerSettingsE
 import { StatisticsDashboard } from '@/components/statistics/StatisticsDashboard';
 import { LeaderboardManager } from '@/components/leaderboard/LeaderboardManager';
 import { ActivityLogTable } from '@/components/activityLog/ActivityLogTable';
+import { ServerLogViewer } from '@/components/server/ServerLogViewer';
 import { useState } from 'react';
 import { StateHistoryStats } from '@/lib/schemas';
 import { Leaderboard } from '@/lib/schemas/leaderboard';
@@ -28,7 +29,8 @@ const tabs = [
 	{ id: ServerTab.eventRules, name: 'Event Rules', icon: '📋' },
 	{ id: ServerTab.settings, name: 'Server Settings', icon: '🔧' },
 	{ id: ServerTab.leaderboard, name: 'Leaderboard', icon: '🏆' },
-	{ id: ServerTab.activityLog, name: 'History', icon: '📋' }
+	{ id: ServerTab.activityLog, name: 'History', icon: '📋' },
+	{ id: ServerTab.logs, name: 'Logs', icon: '📄' }
 ];
 
 const configTabs = new Set([
@@ -143,6 +145,9 @@ export function ServerConfigurationTabs({
 			case ServerTab.activityLog:
 				return <ActivityLogTable serverId={serverId} />;
 
+			case ServerTab.logs:
+				return <ServerLogViewer serverId={serverId} />;
+
 			default:
 				return (
 					<div className="py-12 text-center">

src/components/server/ServerLogViewer.tsx

@@ -0,0 +1,153 @@
+'use client';
+
+import { useEffect, useRef, useState, useCallback } from 'react';
+import { useWebSocket } from '@/lib/websocket/context';
+import type { WebSocketMessage } from '@/lib/schemas/websocket';
+import { getServerLogAction } from '@/lib/actions/serverLog';
+
+const MAX_BUFFER = 5000;
+const LINE_OPTIONS = [100, 500, 1000, 5000] as const;
+
+interface ServerLogViewerProps {
+	serverId: string;
+}
+
+export function ServerLogViewer({ serverId }: ServerLogViewerProps) {
+	const [lines, setLines] = useState<string[]>([]);
+	const [initialLines, setInitialLines] = useState<number>(100);
+	const [isLoading, setIsLoading] = useState(false);
+	const [error, setError] = useState<string | null>(null);
+	const [isPaused, setIsPaused] = useState(false);
+
+	const { associateWithServer, addMessageHandler, removeMessageHandler } = useWebSocket();
+	const scrollRef = useRef<HTMLDivElement>(null);
+	const isPausedRef = useRef(false);
+
+	const appendLines = useCallback((newLines: string[]) => {
+		setLines((prev) => {
+			const combined = [...prev, ...newLines];
+			return combined.length > MAX_BUFFER ? combined.slice(combined.length - MAX_BUFFER) : combined;
+		});
+	}, []);
+
+	const fetchInitial = useCallback(
+		async (count: number) => {
+			setIsLoading(true);
+			setError(null);
+			const result = await getServerLogAction(serverId, count);
+			setIsLoading(false);
+			if (!result.success) {
+				setError(result.message);
+				return;
+			}
+			setLines(result.lines);
+		},
+		[serverId]
+	);
+
+	useEffect(() => {
+		associateWithServer(serverId);
+		fetchInitial(initialLines);
+	}, [serverId, associateWithServer, fetchInitial, initialLines]);
+
+	const handleMessage = useCallback(
+		(message: WebSocketMessage) => {
+			if (message.type !== 'log_line') return;
+			if (message.server_id !== serverId) return;
+			appendLines([message.data.line]);
+		},
+		[serverId, appendLines]
+	);
+
+	useEffect(() => {
+		addMessageHandler(handleMessage);
+		return () => {
+			removeMessageHandler(handleMessage);
+		};
+	}, [addMessageHandler, removeMessageHandler, handleMessage]);
+
+	// Auto-scroll to bottom when new lines arrive, unless paused
+	useEffect(() => {
+		if (!isPausedRef.current && scrollRef.current) {
+			scrollRef.current.scrollTop = scrollRef.current.scrollHeight;
+		}
+	}, [lines]);
+
+	const handleScroll = () => {
+		if (!scrollRef.current) return;
+		const { scrollTop, scrollHeight, clientHeight } = scrollRef.current;
+		const isAtBottom = scrollHeight - scrollTop - clientHeight < 40;
+		const shouldPause = !isAtBottom;
+		isPausedRef.current = shouldPause;
+		setIsPaused(shouldPause);
+	};
+
+	const jumpToBottom = () => {
+		if (scrollRef.current) {
+			scrollRef.current.scrollTop = scrollRef.current.scrollHeight;
+		}
+		isPausedRef.current = false;
+		setIsPaused(false);
+	};
+
+	const handleLineLimitChange = (e: React.ChangeEvent<HTMLSelectElement>) => {
+		const count = Number(e.target.value);
+		setInitialLines(count);
+	};
+
+	return (
+		<div className="flex flex-col gap-3">
+			<div className="flex items-center gap-3">
+				<label className="text-xs text-subtle">Initial lines</label>
+				<select
+					value={initialLines}
+					onChange={handleLineLimitChange}
+					className="form-input w-28 text-sm"
+				>
+					{LINE_OPTIONS.map((n) => (
+						<option key={n} value={n}>
+							{n}
+						</option>
+					))}
+				</select>
+				<span className="ml-auto text-xs text-subtle">{lines.length} lines buffered</span>
+			</div>
+
+			{error && <p className="text-sm text-red">{error}</p>}
+
+			<div className="relative">
+				<div
+					ref={scrollRef}
+					onScroll={handleScroll}
+					className="h-[calc(100vh-280px)] min-h-64 overflow-y-auto rounded-lg border border-border bg-base p-3 font-mono text-xs text-secondary"
+				>
+					{isLoading ? (
+						<span className="text-muted">Loading…</span>
+					) : lines.length === 0 ? (
+						<span className="text-muted">No log output yet.</span>
+					) : (
+						lines.map((line, i) => (
+							<div key={i} className="leading-5 whitespace-pre-wrap break-all">
+								{line}
+							</div>
+						))
+					)}
+				</div>
+
+				{isPaused && (
+					<div className="absolute bottom-3 left-1/2 flex -translate-x-1/2 items-center gap-2">
+						<div className="flex items-center gap-2 rounded-full border border-border bg-overlay px-3 py-1.5 shadow-lg">
+							<span className="text-xs text-muted">Paused</span>
+							<button
+								onClick={jumpToBottom}
+								className="text-xs font-medium text-blue hover:underline"
+							>
+								Jump to bottom
+							</button>
+						</div>
+					</div>
+				)}
+			</div>
+		</div>
+	);
+}