/**
 * ╔═══════════════════════════════════════════════════════════════════════════╗
 * ║                    LOG STREAM VIEWER                                       ║
 * ║═══════════════════════════════════════════════════════════════════════════║
 * ║  Real-time log streaming with filtering and syntax highlighting           ║
 * ║  Part of the Liquid UI Arsenal                                            ║
 * ╚═══════════════════════════════════════════════════════════════════════════╝
 */

import { useEffect, useRef, useState } from 'react';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Badge } from '@/components/ui/badge';
import { ScrollArea } from '@/components/ui/scroll-area';
import { cn } from '@/lib/utils';
import {
  Play, Pause, Trash2, Search, Filter,
  ChevronDown, AlertTriangle, Info, Bug, Zap
} from 'lucide-react';

export interface LogEntry {
  id: string;
  timestamp: string;
  level: 'debug' | 'info' | 'warn' | 'error' | 'fatal';
  source: string;
  message: string;
  metadata?: Record<string, unknown>;
}

export interface LogStreamViewerProps {
  logs: LogEntry[];
  maxLines?: number;
  autoScroll?: boolean;
  showTimestamps?: boolean;
  showSource?: boolean;
  title?: string;
  onClear?: () => void;
}

const levelConfig = {
  debug: { icon: Bug, color: 'text-gray-400', bg: 'bg-gray-500/10', badge: 'bg-gray-500/20' },
  info: { icon: Info, color: 'text-blue-400', bg: 'bg-blue-500/10', badge: 'bg-blue-500/20' },
  warn: { icon: AlertTriangle, color: 'text-yellow-400', bg: 'bg-yellow-500/10', badge: 'bg-yellow-500/20' },
  error: { icon: Zap, color: 'text-red-400', bg: 'bg-red-500/10', badge: 'bg-red-500/20' },
  fatal: { icon: Zap, color: 'text-red-500', bg: 'bg-red-600/20', badge: 'bg-red-600/30' },
};

export function LogStreamViewer({
  logs,
  maxLines = 500,
  autoScroll: initialAutoScroll = true,
  showTimestamps = true,
  showSource = true,
  title = 'System Logs',
  onClear,
}: LogStreamViewerProps) {
  const scrollRef = useRef<HTMLDivElement>(null);
  const [autoScroll, setAutoScroll] = useState(initialAutoScroll);
  const [isPaused, setIsPaused] = useState(false);
  const [filter, setFilter] = useState('');
  const [levelFilter, setLevelFilter] = useState<Set<string>>(new Set(['debug', 'info', 'warn', 'error', 'fatal']));
  const [showFilters, setShowFilters] = useState(false);

  // Auto-scroll to bottom
  useEffect(() => {
    if (autoScroll && !isPaused && scrollRef.current) {
      scrollRef.current.scrollTop = scrollRef.current.scrollHeight;
    }
  }, [logs, autoScroll, isPaused]);

  // Filter logs
  const filteredLogs = logs
    .filter(log => levelFilter.has(log.level))
    .filter(log =>
      !filter ||
      log.message.toLowerCase().includes(filter.toLowerCase()) ||
      log.source.toLowerCase().includes(filter.toLowerCase())
    )
    .slice(-maxLines);

  // Level counts
  const levelCounts = logs.reduce((acc, log) => {
    acc[log.level] = (acc[log.level] || 0) + 1;
    return acc;
  }, {} as Record<string, number>);

  const toggleLevel = (level: string) => {
    const newFilter = new Set(levelFilter);
    if (newFilter.has(level)) {
      newFilter.delete(level);
    } else {
      newFilter.add(level);
    }
    setLevelFilter(newFilter);
  };

  const formatTimestamp = (ts: string) => {
    try {
      return new Date(ts).toLocaleTimeString('da-DK', {
        hour: '2-digit',
        minute: '2-digit',
        second: '2-digit',
        fractionalSecondDigits: 3
      });
    } catch {
      return ts;
    }
  };

  return (
    <div className="rounded-lg border border-border/30 bg-background/50 overflow-hidden flex flex-col">
      {/* Header */}
      <div className="flex items-center justify-between px-4 py-2 bg-muted/30 border-b border-border/30">
        <div className="flex items-center gap-3">
          <span className="text-sm font-medium">{title}</span>
          <Badge variant="outline" className="text-[10px] font-mono">
            {filteredLogs.length}/{logs.length}
          </Badge>
        </div>
        <div className="flex items-center gap-2">
          <Button
            variant="ghost"
            size="sm"
            onClick={() => setIsPaused(!isPaused)}
            className={cn("h-7 px-2", isPaused && "text-yellow-500")}
          >
            {isPaused ? <Play className="w-3 h-3" /> : <Pause className="w-3 h-3" />}
          </Button>
          <Button
            variant="ghost"
            size="sm"
            onClick={() => setShowFilters(!showFilters)}
            className={cn("h-7 px-2", showFilters && "bg-muted")}
          >
            <Filter className="w-3 h-3" />
          </Button>
          {onClear && (
            <Button
              variant="ghost"
              size="sm"
              onClick={onClear}
              className="h-7 px-2 text-red-400 hover:text-red-300"
            >
              <Trash2 className="w-3 h-3" />
            </Button>
          )}
        </div>
      </div>

      {/* Filter bar */}
      {showFilters && (
        <div className="px-4 py-2 bg-muted/20 border-b border-border/30 space-y-2">
          <div className="flex items-center gap-2">
            <Search className="w-3 h-3 text-muted-foreground" />
            <Input
              value={filter}
              onChange={(e) => setFilter(e.target.value)}
              placeholder="Filter logs..."
              className="h-7 text-xs bg-background/50"
            />
          </div>
          <div className="flex items-center gap-2 flex-wrap">
            {Object.entries(levelConfig).map(([level, config]) => (
              <button
                key={level}
                onClick={() => toggleLevel(level)}
                className={cn(
                  'px-2 py-0.5 rounded text-[10px] font-mono uppercase transition-all',
                  levelFilter.has(level) ? config.badge : 'bg-muted/30 text-muted-foreground opacity-50'
                )}
              >
                {level} ({levelCounts[level] || 0})
              </button>
            ))}
          </div>
        </div>
      )}

      {/* Log entries */}
      <ScrollArea ref={scrollRef} className="flex-1 h-[300px]">
        <div className="font-mono text-xs">
          {filteredLogs.map((log) => {
            const config = levelConfig[log.level];
            const Icon = config.icon;

            return (
              <div
                key={log.id}
                className={cn(
                  'flex items-start gap-2 px-3 py-1.5 border-b border-border/10 hover:bg-muted/20 transition-colors',
                  config.bg
                )}
              >
                <Icon className={cn('w-3 h-3 mt-0.5 flex-shrink-0', config.color)} />

                {showTimestamps && (
                  <span className="text-muted-foreground flex-shrink-0 w-24">
                    {formatTimestamp(log.timestamp)}
                  </span>
                )}

                {showSource && (
                  <span className="text-primary/70 flex-shrink-0 w-20 truncate">
                    [{log.source}]
                  </span>
                )}

                <span className={cn('flex-1', config.color)}>
                  {log.message}
                </span>
              </div>
            );
          })}

          {filteredLogs.length === 0 && (
            <div className="flex items-center justify-center py-8 text-muted-foreground">
              No logs to display
            </div>
          )}
        </div>
      </ScrollArea>

      {/* Footer */}
      <div className="px-4 py-2 bg-muted/20 border-t border-border/30 flex items-center justify-between text-[10px] text-muted-foreground">
        <div className="flex items-center gap-2">
          <button
            onClick={() => setAutoScroll(!autoScroll)}
            className={cn(
              'flex items-center gap-1 px-2 py-0.5 rounded',
              autoScroll ? 'bg-green-500/20 text-green-400' : 'bg-muted/30'
            )}
          >
            <ChevronDown className="w-3 h-3" />
            Auto-scroll
          </button>
          {isPaused && (
            <span className="text-yellow-500 animate-pulse">PAUSED</span>
          )}
        </div>
        <span>Max: {maxLines} lines</span>
      </div>
    </div>
  );
}

export default LogStreamViewer;