import { useMemo } from 'react';
import { useNostr } from '@nostrify/react';
import { useQuery } from '@tanstack/react-query';
import type { NostrEvent } from '@nostrify/nostrify';
import { SKATE_SPOT_KIND } from '@/lib/types';

// Kind 1063 = File Metadata (NIP-94) for community photos
export const PHOTO_CONTRIBUTION_KIND = 1063;

export interface PhotoContribution {
  id: string;
  pubkey: string;
  url: string;
  mimeType?: string;
  caption: string;
  createdAt: number;
  event: NostrEvent;
}

export interface TagContribution {
  id: string;
  pubkey: string;
  tags: string[];
  createdAt: number;
  event: NostrEvent;
}

/**
 * Parse a kind 1063 file metadata event into a PhotoContribution
 */
function parsePhotoContribution(event: NostrEvent): PhotoContribution | null {
  if (event.kind !== PHOTO_CONTRIBUTION_KIND) return null;
  
  const url = event.tags.find(([name]) => name === 'url')?.[1];
  if (!url) return null;
  
  const mimeType = event.tags.find(([name]) => name === 'm')?.[1];
  
  return {
    id: event.id,
    pubkey: event.pubkey,
    url,
    mimeType,
    caption: event.content,
    createdAt: event.created_at,
    event,
  };
}

/**
 * Parse a kind 1111 comment event that contains tag suggestions
 */
function parseTagContribution(event: NostrEvent): TagContribution | null {
  if (event.kind !== 1111) return null;
  
  // Check if this is a tag contribution (has #skatespot-tags marker)
  const isTagContribution = event.tags.some(
    ([name, value]) => name === 't' && value === 'skatespot-tags'
  );
  if (!isTagContribution) return null;
  
  // Extract suggested tags (all t tags except the marker)
  const tags = event.tags
    .filter(([name, value]) => name === 't' && value !== 'skatespot-tags')
    .map(([, value]) => value)
    .filter(Boolean) as string[];
  
  if (tags.length === 0) return null;
  
  return {
    id: event.id,
    pubkey: event.pubkey,
    tags,
    createdAt: event.created_at,
    event,
  };
}

/**
 * Hook to fetch community photo contributions for a spot
 */
export function useSpotPhotos(spotPubkey: string, spotIdentifier: string) {
  const { nostr } = useNostr();
  
  const spotRef = `${SKATE_SPOT_KIND}:${spotPubkey}:${spotIdentifier}`;
  
  return useQuery({
    queryKey: ['spot-photos', spotPubkey, spotIdentifier],
    queryFn: async (c) => {
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(5000)]);
      
      // Query kind 1063 events that reference this spot via 'a' tag
      const events = await nostr.query([
        {
          kinds: [PHOTO_CONTRIBUTION_KIND],
          '#a': [spotRef],
          limit: 50,
        },
      ], { signal });
      
      return events
        .map(parsePhotoContribution)
        .filter((p): p is PhotoContribution => p !== null)
        .sort((a, b) => b.createdAt - a.createdAt);
    },
    enabled: !!spotPubkey && !!spotIdentifier,
  });
}

/**
 * Hook to fetch community tag suggestions for a spot
 */
export function useSpotTagSuggestions(spotPubkey: string, spotIdentifier: string) {
  const { nostr } = useNostr();
  
  const spotRef = `${SKATE_SPOT_KIND}:${spotPubkey}:${spotIdentifier}`;
  
  return useQuery({
    queryKey: ['spot-tag-suggestions', spotPubkey, spotIdentifier],
    queryFn: async (c) => {
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(5000)]);
      
      // Query kind 1111 comments that are tag contributions
      const events = await nostr.query([
        {
          kinds: [1111],
          '#a': [spotRef],
          '#t': ['skatespot-tags'],
          limit: 100,
        },
      ], { signal });
      
      return events
        .map(parseTagContribution)
        .filter((t): t is TagContribution => t !== null)
        .sort((a, b) => b.createdAt - a.createdAt);
    },
    enabled: !!spotPubkey && !!spotIdentifier,
  });
}

/**
 * Hook to get aggregated community tags with vote counts
 */
export function useAggregatedSpotTags(spotPubkey: string, spotIdentifier: string) {
  const { data: tagContributions } = useSpotTagSuggestions(spotPubkey, spotIdentifier);
  
  return useMemo(() => {
    if (!tagContributions) return [];
    
    // Count how many times each tag was suggested
    const tagCounts = new Map<string, { count: number; contributors: Set<string> }>();
    
    for (const contribution of tagContributions) {
      for (const tag of contribution.tags) {
        const existing = tagCounts.get(tag) || { count: 0, contributors: new Set() };
        // Only count each contributor once per tag
        if (!existing.contributors.has(contribution.pubkey)) {
          existing.count++;
          existing.contributors.add(contribution.pubkey);
        }
        tagCounts.set(tag, existing);
      }
    }
    
    // Convert to array and sort by count
    return Array.from(tagCounts.entries())
      .map(([tag, { count, contributors }]) => ({
        tag,
        count,
        contributorCount: contributors.size,
      }))
      .sort((a, b) => b.count - a.count);
  }, [tagContributions]);
}

/**
 * Community photo counts for MANY spots in one query.
 *
 * `useSpotPhotos` already queries by the `a` tag, so the batch is the same query
 * with every ref at once (relays index `a`, so this is one request) — that is
 * what makes it cheap enough for the review queue, where a per-spot query would
 * mean hundreds of round-trips.
 *
 * Only photos from people OTHER than the mapper count: the mapper supplying their
 * own picture is expected, not a community signal.
 */
export function useBatchSpotPhotos(spots: Array<{ pubkey: string; identifier: string }>) {
  const { nostr } = useNostr();

  const refs = useMemo(
    () => spots.map((s) => `${SKATE_SPOT_KIND}:${s.pubkey}:${s.identifier}`),
    [spots],
  );

  const query = useQuery({
    queryKey: ['batch-spot-photos', refs.slice().sort().join(',')],
    enabled: refs.length > 0,
    staleTime: 60_000,
    queryFn: async (c) => {
      const signal = AbortSignal.any([c.signal, AbortSignal.timeout(8000)]);
      const events = await nostr.query(
        [{ kinds: [PHOTO_CONTRIBUTION_KIND], '#a': refs, limit: 1000 }],
        { signal },
      );
      return events
        .map(parsePhotoContribution)
        .filter((p): p is PhotoContribution => p !== null);
    },
  });

  const mapperByRef = useMemo(() => {
    const map = new Map<string, string>();
    for (const s of spots) map.set(`${SKATE_SPOT_KIND}:${s.pubkey}:${s.identifier}`, s.pubkey);
    return map;
  }, [spots]);

  const counts = useMemo(() => {
    const map = new Map<string, number>();
    for (const photo of query.data ?? []) {
      // The contribution event carries the spot's `a` coordinate.
      const ref = photo.event.tags.find(([n]) => n === 'a')?.[1];
      if (!ref) continue;
      const mapper = mapperByRef.get(ref);
      if (mapper && photo.pubkey === mapper) continue; // mapper's own photo
      map.set(ref, (map.get(ref) ?? 0) + 1);
    }
    return map;
  }, [query.data, mapperByRef]);

  return {
    isLoading: query.isLoading,
    getCommunityPhotoCount: (pubkey: string, identifier: string) =>
      counts.get(`${SKATE_SPOT_KIND}:${pubkey}:${identifier}`) ?? 0,
  };
}