import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Calendar, MapPin, Building2, Tag, Milestone, ArrowRight } from "lucide-react";
import { format } from "date-fns";

export type HistoryEventType = 'name_change' | 'status_change' | 'ownership_change' | 'relocation' | 'milestone';

export interface HistoryEvent {
  date: string;
  title: string;
  description?: string;
  type: HistoryEventType;
  from?: string;
  to?: string;
}

interface EntityHistoryTimelineProps {
  events: HistoryEvent[];
  entityName: string;
}

const eventTypeConfig: Record<HistoryEventType, { icon: typeof Tag; color: string; label: string }> = {
  name_change: { icon: Tag, color: 'text-blue-500', label: 'Name Change' },
  status_change: { icon: Calendar, color: 'text-amber-500', label: 'Status Change' },
  ownership_change: { icon: Building2, color: 'text-purple-500', label: 'Ownership Change' },
  relocation: { icon: MapPin, color: 'text-green-500', label: 'Relocation' },
  milestone: { icon: Milestone, color: 'text-pink-500', label: 'Milestone' },
};

// Fallback config for unknown event types
const defaultEventConfig = { icon: Tag, color: 'text-gray-500', label: 'Event' };

export function EntityHistoryTimeline({ events, entityName }: EntityHistoryTimelineProps) {
  if (events.length === 0) {
    return (
      <Card>
        <CardHeader>
          <CardTitle>No Historical Events</CardTitle>
          <CardDescription>
            No historical events recorded for {entityName}
          </CardDescription>
        </CardHeader>
      </Card>
    );
  }

  // Sort events by date (most recent first)
  const sortedEvents = [...events].sort((a, b) => {
    const dateA = new Date(a.date);
    const dateB = new Date(b.date);
    return dateB.getTime() - dateA.getTime();
  });

  return (
    <div className="space-y-4">
      <div className="relative space-y-4">
        {/* Timeline line */}
        <div className="absolute left-6 top-0 bottom-0 w-0.5 bg-border" />

        {sortedEvents.map((event, index) => {
          // Safety check: verify event.type exists in eventTypeConfig, use fallback if not
          const config = event.type && eventTypeConfig[event.type] 
            ? eventTypeConfig[event.type] 
            : defaultEventConfig;
          const Icon = config.icon;

          return (
            <div key={index} className="relative flex gap-4">
              {/* Timeline dot */}
              <div className="relative flex-shrink-0">
                <div className={`flex h-12 w-12 items-center justify-center rounded-full border-2 border-background bg-card ${config.color}`}>
                  <Icon className="h-5 w-5" />
                </div>
              </div>

              {/* Event content */}
              <Card className="flex-1">
                <CardHeader className="pb-3">
                  <div className="flex items-start justify-between gap-4">
                    <div className="space-y-1">
                      <CardTitle className="text-lg">{event.title}</CardTitle>
                      <CardDescription className="flex items-center gap-2">
                        <Calendar className="h-3 w-3" />
                        {formatEventDate(event.date)}
                        <span className="text-xs">•</span>
                        <span className={config.color}>{config.label}</span>
                      </CardDescription>
                    </div>
                  </div>
                </CardHeader>
                {(event.description || (event.from && event.to)) && (
                  <CardContent className="pt-0">
                    {event.from && event.to && (
                      <div className="flex items-center gap-2 text-sm text-muted-foreground mb-2">
                        <span className="font-medium">{event.from}</span>
                        <ArrowRight className="h-4 w-4" />
                        <span className="font-medium">{event.to}</span>
                      </div>
                    )}
                    {event.description && (
                      <p className="text-sm text-muted-foreground">{event.description}</p>
                    )}
                  </CardContent>
                )}
              </Card>
            </div>
          );
        })}
      </div>
    </div>
  );
}

function formatEventDate(dateString: string): string {
  // Safety check: validate dateString exists and is a string
  if (!dateString || typeof dateString !== 'string') {
    return 'Unknown date';
  }

  try {
    // Handle year-only dates
    if (/^\d{4}$/.test(dateString)) {
      return dateString;
    }
    
    // Validate date string before creating Date object
    const date = new Date(dateString);
    
    // Check if date is valid
    if (isNaN(date.getTime())) {
      return dateString;
    }
    
    return format(date, 'MMMM d, yyyy');
  } catch {
    return dateString;
  }
}