import { useState } from 'react';
import { formatDistanceToNow } from 'date-fns';
import { Megaphone, Loader2, Send, CalendarClock, MapPin, XCircle, Info } from 'lucide-react';
import { Textarea } from '@/components/ui/textarea';
import { Button } from '@/components/ui/button';
import { Avatar, AvatarFallback, AvatarImage } from '@/components/ui/avatar';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useAuthor } from '@/hooks/useAuthor';
import { useToast } from '@/hooks/useToast';
import { useEventUpdates, usePostEventUpdate } from '@/hooks/useEventUpdates';
import { useEventRsvps, eventCoord } from '@/hooks/useEventRsvps';
import { genUserName } from '@/lib/genUserName';
import { isAdminPubkey } from '@/lib/admins';
import { cn } from '@/lib/utils';
import type { EventUpdate, EventUpdateKind, SkateEvent } from '@/lib/types';

const UPDATE_KIND_META: Record<
  EventUpdateKind,
  { icon: typeof Info; label: string; color: string; ring: string }
> = {
  update: { icon: Info, label: 'Update', color: 'text-sky-400', ring: 'bg-sky-500/15' },
  reschedule: { icon: CalendarClock, label: 'New time', color: 'text-amber-400', ring: 'bg-amber-500/15' },
  relocation: { icon: MapPin, label: 'New spot', color: 'text-[#ff0040]', ring: 'bg-[#ff0040]/15' },
  cancelled: { icon: XCircle, label: 'Cancelled', color: 'text-red-400', ring: 'bg-red-500/15' },
};

function UpdateItem({ update }: { update: EventUpdate }) {
  const author = useAuthor(update.pubkey);
  const name = author.data?.metadata?.name ?? genUserName(update.pubkey);
  const pic = author.data?.metadata?.picture;
  const meta = UPDATE_KIND_META[update.updateKind];
  const Icon = meta.icon;

  return (
    <div className="flex gap-3">
      <div className="relative flex-shrink-0">
        <Avatar className="h-8 w-8">
          <AvatarImage src={pic} alt={name} />
          <AvatarFallback className="text-[10px] font-bold">
            {name.slice(0, 2).toUpperCase()}
          </AvatarFallback>
        </Avatar>
        <span
          className={cn(
            'absolute -bottom-1 -right-1 flex h-4 w-4 items-center justify-center rounded-full ring-2 ring-background',
            meta.ring,
          )}
        >
          <Icon className={cn('h-2.5 w-2.5', meta.color)} />
        </span>
      </div>
      <div className="min-w-0 flex-1">
        <div className="flex items-center gap-2">
          <span className="text-sm font-bold text-white">{name}</span>
          {update.authorRole === 'admin' && (
            <span className="rounded-full border border-yellow-500/40 bg-yellow-500/15 px-1.5 py-0.5 text-[9px] font-black uppercase tracking-wide text-yellow-400">
              Admin
            </span>
          )}
          {update.updateKind !== 'update' && (
            <span
              className={cn(
                'rounded-full px-1.5 py-0.5 text-[9px] font-black uppercase tracking-wide',
                meta.ring,
                meta.color,
              )}
            >
              {meta.label}
            </span>
          )}
          <span className="text-[11px] text-gray-600">
            {formatDistanceToNow(new Date(update.createdAt * 1000), { addSuffix: true })}
          </span>
        </div>
        <p className="mt-0.5 whitespace-pre-wrap break-words text-sm text-gray-300">
          {update.message}
        </p>
      </div>
    </div>
  );
}

/**
 * Host update composer (only for the event author) + a public feed of updates.
 * Posting p-tags every RSVPer so they get a notification.
 */
export function EventUpdates({ event }: { event: SkateEvent }) {
  const { user } = useCurrentUser();
  const { toast } = useToast();
  const coord = eventCoord(event);
  const { data: updates, isLoading } = useEventUpdates(coord);
  const { going, tentative } = useEventRsvps(coord);
  const { mutateAsync: post, isPending } = usePostEventUpdate();

  const [message, setMessage] = useState('');
  const [kind, setKind] = useState<EventUpdateKind>('update');

  const isHost = user?.pubkey === event.pubkey;
  const isAdmin = isAdminPubkey(user?.pubkey);
  // Admins can moderate any event; the host runs their own.
  const canPost = isHost || isAdmin;

  const handlePost = async () => {
    const text = message.trim();
    if (!text) return;
    try {
      await post({
        event,
        message: text,
        updateKind: kind,
        notifyPubkeys: [...going, ...tentative],
      });
      setMessage('');
      setKind('update');
      const reach = new Set([...going, ...tentative]).size;
      toast({
        title: 'Update posted',
        description: reach > 0 ? `${reach} ${reach === 1 ? 'person' : 'people'} notified.` : 'Everyone will see it on the event.',
      });
    } catch (err) {
      toast({
        title: 'Could not post update',
        description: err instanceof Error ? err.message : 'Please try again.',
        variant: 'destructive',
      });
    }
  };

  const hasUpdates = (updates?.length ?? 0) > 0;

  return (
    <div className="space-y-4">
      {/* Composer — host or SkateSpots admin */}
      {canPost && (
        <div
          className={cn(
            'rounded-xl border p-3',
            isHost
              ? 'border-[#ccff00]/25 bg-[#ccff00]/[0.04]'
              : 'border-yellow-500/30 bg-yellow-500/[0.05]',
          )}
        >
          <div
            className={cn(
              'mb-2 flex items-center gap-2 text-sm font-black uppercase tracking-wide',
              isHost ? 'text-[#ccff00]' : 'text-yellow-400',
            )}
          >
            <Megaphone className="h-4 w-4" />
            {isHost ? 'Post an update' : 'Post an admin update'}
          </div>
          {!isHost && (
            <p className="mb-2 text-[11px] text-yellow-200/80">
              You're posting as a SkateSpots admin. It'll be clearly labelled as an admin
              notice, not from the host.
            </p>
          )}
          <div className="mb-2 flex flex-wrap gap-1.5">
            {(Object.keys(UPDATE_KIND_META) as EventUpdateKind[]).map((k) => {
              const m = UPDATE_KIND_META[k];
              const Icon = m.icon;
              const active = kind === k;
              return (
                <button
                  key={k}
                  type="button"
                  onClick={() => setKind(k)}
                  className={cn(
                    'flex items-center gap-1 rounded-full border px-2.5 py-1 text-[10px] font-bold uppercase tracking-wide transition-all active:scale-95',
                    active
                      ? cn('border-transparent', m.ring, m.color)
                      : 'border-white/10 bg-white/5 text-gray-500 hover:text-white',
                  )}
                >
                  <Icon className="h-3 w-3" />
                  {m.label}
                </button>
              );
            })}
          </div>
          <Textarea
            value={message}
            onChange={(e) => setMessage(e.target.value)}
            placeholder="Rain — moved to Sunday 2pm. Meet at the back ledge…"
            rows={3}
            maxLength={500}
            className="resize-none border-white/10 bg-black/40 text-sm"
          />
          <div className="mt-2 flex items-center justify-between">
            <span className="text-[11px] text-gray-500">
              {going.length + tentative.length > 0
                ? `Notifies ${new Set([...going, ...tentative]).size} RSVP${new Set([...going, ...tentative]).size === 1 ? '' : "'s"}`
                : 'Visible to everyone on this event'}
            </span>
            <Button
              size="sm"
              onClick={handlePost}
              disabled={isPending || !message.trim()}
              className={cn(
                'gap-1.5 font-bold text-black',
                isHost
                  ? 'bg-[#ccff00] hover:bg-[#ccff00]/90'
                  : 'bg-yellow-400 hover:bg-yellow-400/90',
              )}
            >
              {isPending ? <Loader2 className="h-3.5 w-3.5 animate-spin" /> : <Send className="h-3.5 w-3.5" />}
              Post
            </Button>
          </div>
        </div>
      )}

      {/* Feed */}
      {isLoading && !hasUpdates ? (
        <div className="flex items-center gap-2 py-4 text-sm text-gray-500">
          <Loader2 className="h-4 w-4 animate-spin" /> Loading updates…
        </div>
      ) : hasUpdates ? (
        <div className="space-y-4">
          {updates!.map((u) => (
            <UpdateItem key={u.id} update={u} />
          ))}
        </div>
      ) : (
        !canPost && (
          <p className="text-sm text-muted-foreground">
            No updates from the host yet. RSVP and you'll be notified if anything changes.
          </p>
        )
      )}
    </div>
  );
}