import { useMutation, useQueryClient } from '@tanstack/react-query';
import { nip19 } from 'nostr-tools';

import { useNostrPublish } from '@/hooks/useNostrPublish';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useToast } from '@/hooks/useToast';
import { useTranslation } from '@/contexts/language';
import { NIP85_PROVIDER_LIST_KIND, NIP85_USER_ASSERTION_KIND, type TrustProvider } from '@/lib/nip85';

/** The assertion types we designate (the normative kind-30382 set). */
const ASSERTION_TYPES = ['rank', 'followers', 'reporters', 'muters', 'hops'] as const;

/** Accept an npub or a 64-char hex pubkey; return hex or null. */
export function normalizeProviderPubkey(input: string): string | null {
  const value = input.trim();
  if (/^[0-9a-f]{64}$/i.test(value)) return value.toLowerCase();
  if (value.startsWith('npub1')) {
    try {
      const decoded = nip19.decode(value);
      if (decoded.type === 'npub') return decoded.data;
    } catch {
      return null;
    }
  }
  return null;
}

/** A relay hint must be a websocket URL. */
export function normalizeProviderRelay(input: string): string | null {
  const value = input.trim();
  if (/^wss?:\/\/.+/i.test(value)) return value;
  return null;
}

/**
 * Publish (or clear) the viewer's NIP-85 kind-10040 provider designation.
 * Passing `null` clears it, so the app falls back to the community provider.
 * This is a signed action, so it prompts the signer like any other publish.
 */
export function useSetTrustProvider() {
  const { mutateAsync: publish } = useNostrPublish();
  const { user } = useCurrentUser();
  const { toast } = useToast();
  const { t } = useTranslation();
  const queryClient = useQueryClient();

  const mutation = useMutation({
    mutationFn: async (provider: TrustProvider | null) => {
      if (!user) throw new Error(t('trustUi.loggedOutProvider'));

      const relay = provider?.relay;
      const tags: string[][] =
        provider && relay
          ? ASSERTION_TYPES.map((type) => [`${NIP85_USER_ASSERTION_KIND}:${type}`, provider.pubkey, relay])
          : [];

      await publish({ kind: NIP85_PROVIDER_LIST_KIND, content: '', tags });
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ['trust-provider', user?.pubkey] });
      queryClient.invalidateQueries({ queryKey: ['trust-assertions-batch', user?.pubkey ?? ''] });
      toast({ title: t('trustUi.providerSaved') });
    },
    onError: (error) => {
      toast({
        title: t('trustUi.publishFailed'),
        description: error instanceof Error ? error.message : undefined,
        variant: 'destructive',
      });
    },
  });

  return mutation;
}