import { useState } from 'react';
import { UserPlus, Copy, Check, Share2, Edit, Send, Loader2, ShieldCheck } from 'lucide-react';
import { Link } from 'react-router-dom';
import { nip19 } from 'nostr-tools';
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogHeader,
  DialogTitle,
  DialogTrigger,
} from '@/components/ui/dialog';
import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Textarea } from '@/components/ui/textarea';
import { Switch } from '@/components/ui/switch';
import { Label } from '@/components/ui/label';
import { Avatar, AvatarFallback, AvatarImage } from '@/components/ui/avatar';
import { useToast } from '@/hooks/useToast';
import { useAuthor } from '@/hooks/useAuthor';
import { useSendCrewInvite } from '@/hooks/useCrewInvites';
import { genUserName } from '@/lib/genUserName';
import { cn } from '@/lib/utils';
import type { SkateCrew } from '@/lib/types';

interface CrewInviteDialogProps {
  crew: SkateCrew;
  /** Whether the viewer is the founder (gets the extra "add member" edit link + admin toggle). */
  isFounder: boolean;
  triggerClassName?: string;
}

/** Try to resolve a raw string (npub / nprofile / hex) to a hex pubkey. */
function resolvePubkey(input: string): string | null {
  const trimmed = input.trim();
  if (!trimmed) return null;
  // Bare hex
  if (/^[0-9a-f]{64}$/i.test(trimmed)) return trimmed.toLowerCase();
  try {
    const decoded = nip19.decode(trimmed);
    if (decoded.type === 'npub') return decoded.data.toLowerCase();
    if (decoded.type === 'nprofile') return decoded.data.pubkey.toLowerCase();
  } catch {
    return null;
  }
  return null;
}

/** Small live preview of who a pubkey resolves to (avatar + name). */
function InviteePreview({ pubkey }: { pubkey: string }) {
  const author = useAuthor(pubkey);
  const name = author.data?.metadata?.name ?? genUserName(pubkey);
  const pic = author.data?.metadata?.picture;
  return (
    <div className="flex items-center gap-2 rounded-lg border border-teal-500/25 bg-teal-500/5 px-3 py-2">
      <Avatar className="h-8 w-8">
        <AvatarImage src={pic} alt={name} />
        <AvatarFallback className="text-[10px]">{name.slice(0, 2).toUpperCase()}</AvatarFallback>
      </Avatar>
      <div className="min-w-0">
        <p className="truncate text-sm font-bold text-white">{name}</p>
        <p className="truncate font-mono text-[10px] text-gray-500">{nip19.npubEncode(pubkey)}</p>
      </div>
    </div>
  );
}

/**
 * Invite flow for crew moderators (founder + admins).
 *
 * Two ways to invite:
 *  1. **Send invite** — publishes a structured invite (kind 36229) addressed to a
 *     specific npub. That person gets a notification with Accept / Decline.
 *     When the FOUNDER sends it, the invitee is pre-listed so accepting instantly
 *     confirms membership. Admins can invite too (founder auto-confirms on accept).
 *  2. **Share link** — copy/share a link for people not yet on Nostr.
 */
export function CrewInviteDialog({ crew, isFounder, triggerClassName }: CrewInviteDialogProps) {
  const { toast } = useToast();
  const [open, setOpen] = useState(false);
  const [copiedLink, setCopiedLink] = useState(false);
  const [copiedMsg, setCopiedMsg] = useState(false);

  // Send-invite state
  const [inviteeInput, setInviteeInput] = useState('');
  const [note, setNote] = useState('');
  const [asAdmin, setAsAdmin] = useState(false);
  const { mutateAsync: sendInvite, isPending: sending } = useSendCrewInvite();

  const resolvedPubkey = resolvePubkey(inviteeInput);
  const inputLooksLikeKey = inviteeInput.trim().length > 0;
  const invalidKey = inputLooksLikeKey && !resolvedPubkey;

  const crewUrl = `${window.location.origin}/crew/${crew.pubkey}/${crew.identifier}`;
  const inviteMessage =
    `Yo — join the ${crew.name} crew on SkateSpots 🛹\n${crewUrl}\n\n` +
    `Log in with your Nostr key, then confirm your membership on the crew page.`;

  const copy = async (text: string, which: 'link' | 'msg') => {
    try {
      await navigator.clipboard.writeText(text);
      if (which === 'link') {
        setCopiedLink(true);
        setTimeout(() => setCopiedLink(false), 2000);
      } else {
        setCopiedMsg(true);
        setTimeout(() => setCopiedMsg(false), 2000);
      }
      toast({ title: 'Copied!' });
    } catch {
      toast({ title: 'Copy failed', variant: 'destructive' });
    }
  };

  const nativeShare = async () => {
    if (navigator.share) {
      try {
        await navigator.share({ title: `Join ${crew.name}`, text: inviteMessage, url: crewUrl });
      } catch {
        /* cancelled */
      }
    } else {
      copy(inviteMessage, 'msg');
    }
  };

  const handleSend = async () => {
    if (!resolvedPubkey) return;
    try {
      await sendInvite({
        crew,
        invitee: resolvedPubkey,
        role: asAdmin ? 'admin' : 'member',
        note,
        isFounder,
      });
      toast({
        title: 'Invite sent! 🛹',
        description: "They'll get a notification to accept or decline.",
      });
      setInviteeInput('');
      setNote('');
      setAsAdmin(false);
      setOpen(false);
    } catch (err) {
      toast({
        title: 'Could not send invite',
        description: err instanceof Error ? err.message : 'Please try again.',
        variant: 'destructive',
      });
    }
  };

  return (
    <Dialog open={open} onOpenChange={setOpen}>
      <DialogTrigger asChild>
        <Button
          type="button"
          variant="outline"
          size="sm"
          className={cn('gap-1.5 border-teal-500/40 text-teal-400 hover:bg-teal-500/10', triggerClassName)}
        >
          <UserPlus className="h-3.5 w-3.5" /> Invite
        </Button>
      </DialogTrigger>
      <DialogContent className="max-h-[90vh] overflow-y-auto">
        <DialogHeader>
          <DialogTitle className="flex items-center gap-2">
            <UserPlus className="h-5 w-5 text-teal-400" /> Invite to {crew.name}
          </DialogTitle>
          <DialogDescription>
            Send an invite to someone's Nostr key, or share a link.
          </DialogDescription>
        </DialogHeader>

        <Tabs defaultValue="send" className="w-full">
          <TabsList className="grid w-full grid-cols-2">
            <TabsTrigger value="send" className="gap-1.5">
              <Send className="h-3.5 w-3.5" /> Send invite
            </TabsTrigger>
            <TabsTrigger value="share" className="gap-1.5">
              <Share2 className="h-3.5 w-3.5" /> Share link
            </TabsTrigger>
          </TabsList>

          {/* ── Send a structured invite to an npub ── */}
          <TabsContent value="send" className="space-y-4 pt-2">
            <div className="space-y-1.5">
              <label className="text-xs font-bold uppercase tracking-wide text-gray-500">
                Skater's npub
              </label>
              <Input
                value={inviteeInput}
                onChange={(e) => setInviteeInput(e.target.value)}
                placeholder="npub1… or nprofile1…"
                className={cn('font-mono text-xs', invalidKey && 'border-red-500/50')}
                autoComplete="off"
                spellCheck={false}
              />
              {invalidKey && (
                <p className="text-xs text-red-400">That doesn't look like a valid npub.</p>
              )}
            </div>

            {resolvedPubkey && <InviteePreview pubkey={resolvedPubkey} />}

            <div className="space-y-1.5">
              <label className="text-xs font-bold uppercase tracking-wide text-gray-500">
                Note <span className="font-normal text-gray-600">(optional)</span>
              </label>
              <Textarea
                value={note}
                onChange={(e) => setNote(e.target.value.slice(0, 500))}
                placeholder="Come skate with us…"
                rows={2}
                className="text-sm"
              />
            </div>

            {isFounder && (
              <div className="flex items-center justify-between rounded-lg border border-teal-500/25 bg-teal-500/5 px-3 py-2.5">
                <div className="flex items-center gap-2">
                  <ShieldCheck className="h-4 w-4 text-teal-400" />
                  <div>
                    <Label htmlFor="invite-admin" className="text-sm font-bold text-white">
                      Invite as admin
                    </Label>
                    <p className="text-[11px] text-gray-500">Can manage the crew &amp; invite others.</p>
                  </div>
                </div>
                <Switch id="invite-admin" checked={asAdmin} onCheckedChange={setAsAdmin} />
              </div>
            )}

            <Button
              type="button"
              onClick={handleSend}
              disabled={!resolvedPubkey || sending}
              className="w-full gap-1.5 bg-teal-500 font-bold text-black hover:bg-teal-600"
            >
              {sending ? <Loader2 className="h-4 w-4 animate-spin" /> : <Send className="h-4 w-4" />}
              Send invite
            </Button>
            <p className="text-center text-[11px] text-gray-500">
              They'll get a notification to accept or decline. Membership only counts once they accept.
            </p>
          </TabsContent>

          {/* ── Share a link (for people not on Nostr yet) ── */}
          <TabsContent value="share" className="space-y-4 pt-2">
            <div className="space-y-1.5">
              <label className="text-xs font-bold uppercase tracking-wide text-gray-500">Invite link</label>
              <div className="flex gap-2">
                <Input readOnly value={crewUrl} className="font-mono text-xs" onFocus={(e) => e.target.select()} />
                <Button type="button" variant="outline" size="icon" className="shrink-0" onClick={() => copy(crewUrl, 'link')}>
                  {copiedLink ? <Check className="h-4 w-4 text-green-400" /> : <Copy className="h-4 w-4" />}
                </Button>
              </div>
            </div>

            <div className="space-y-1.5">
              <label className="text-xs font-bold uppercase tracking-wide text-gray-500">Message</label>
              <Textarea readOnly value={inviteMessage} rows={4} className="text-sm" />
              <div className="flex gap-2">
                <Button type="button" variant="outline" className="flex-1 gap-1.5" onClick={() => copy(inviteMessage, 'msg')}>
                  {copiedMsg ? <Check className="h-4 w-4 text-green-400" /> : <Copy className="h-4 w-4" />}
                  Copy message
                </Button>
                <Button type="button" className="flex-1 gap-1.5 bg-teal-500 hover:bg-teal-600 text-black" onClick={nativeShare}>
                  <Share2 className="h-4 w-4" /> Share
                </Button>
              </div>
            </div>

            {isFounder && (
              <div className="rounded-lg border border-teal-500/30 bg-teal-500/5 p-3">
                <p className="mb-2 text-xs text-gray-400">
                  As founder you can also add a member's key directly, then they confirm.
                </p>
                <Link to={`/edit-crew/${crew.pubkey}/${crew.identifier}`}>
                  <Button type="button" variant="outline" size="sm" className="w-full gap-1.5 border-teal-500/40 text-teal-400 hover:bg-teal-500/10">
                    <Edit className="h-3.5 w-3.5" /> Add member in crew settings
                  </Button>
                </Link>
              </div>
            )}
          </TabsContent>
        </Tabs>
      </DialogContent>
    </Dialog>
  );
}