import { useNostr } from '@nostrify/react';
import { useCurrentUser } from '@/hooks/useCurrentUser';
import { useAppContext } from '@/hooks/useAppContext';
import { SKATE_RELAY } from '@/lib/types';
import type { NostrEvent, NostrFilter } from '@nostrify/nostrify';

/**
 * Hook that provides relay-aware query functions for skate-specific content.
 * 
 * Logic:
 * - Logged out: Always use community relay only (bootstrap)
 * - Logged in + useSkateRelay=true: Community relay + user relays (default)
 * - Logged in + useSkateRelay=false: User relays only (opted out)
 */
export function useSkateRelays() {
  const { nostr } = useNostr();
  const { user } = useCurrentUser();
  const { config } = useAppContext();

  const isLoggedIn = !!user;
  const useSkateRelay = config.useSkateRelay ?? true;

  /**
   * Get the list of relay URLs to query for skate content
   */
  const getReadRelays = (): string[] => {
    // Logged out: always use community relay only
    if (!isLoggedIn) {
      return [SKATE_RELAY];
    }

    // Logged in: check setting
    const userRelays = config.relayMetadata.relays
      .filter(r => r.read)
      .map(r => r.url);

    if (useSkateRelay) {
      // Include community relay + user relays (deduplicated)
      const relaySet = new Set([SKATE_RELAY, ...userRelays]);
      return Array.from(relaySet);
    } else {
      // User opted out - only their relays
      // If they have no relays configured, fall back to community relay
      return userRelays.length > 0 ? userRelays : [SKATE_RELAY];
    }
  };

  /**
   * Get the list of relay URLs to publish skate content to
   */
  const getWriteRelays = (): string[] => {
    // Logged out shouldn't be publishing, but just in case
    if (!isLoggedIn) {
      return [SKATE_RELAY];
    }

    const userRelays = config.relayMetadata.relays
      .filter(r => r.write)
      .map(r => r.url);

    if (useSkateRelay) {
      // Include community relay + user relays (deduplicated)
      const relaySet = new Set([SKATE_RELAY, ...userRelays]);
      return Array.from(relaySet);
    } else {
      // User opted out - only their relays
      // If they have no relays configured, fall back to community relay
      return userRelays.length > 0 ? userRelays : [SKATE_RELAY];
    }
  };

  /**
   * Query skate content from appropriate relays based on user state/settings.
   * Automatically handles parallel queries and deduplication for addressable events.
   */
  const querySkateContent = async (
    filters: NostrFilter[],
    options: { signal: AbortSignal }
  ): Promise<NostrEvent[]> => {
    const relays = getReadRelays();

    console.log(`[useSkateRelays] Querying ${relays.length} relay(s):`, relays);

    // Query all relays in parallel
    const queryPromises = relays.map(async (relayUrl) => {
      try {
        const relay = nostr.relay(relayUrl);
        const events = await relay.query(filters, options);
        console.log(`[useSkateRelays] ${relayUrl} returned ${events.length} events`);
        return events;
      } catch (error) {
        console.warn(`[useSkateRelays] Failed to query ${relayUrl}:`, error);
        return [];
      }
    });

    const results = await Promise.all(queryPromises);
    const allEvents = results.flat();

    // Deduplicate addressable events by pubkey+kind+d-tag
    const eventMap = new Map<string, NostrEvent>();
    for (const event of allEvents) {
      const dTag = event.tags.find(([name]) => name === 'd')?.[1];
      if (dTag) {
        // Addressable event - dedupe by coordinate
        const key = `${event.pubkey}:${event.kind}:${dTag}`;
        const existing = eventMap.get(key);
        if (!existing || event.created_at > existing.created_at) {
          eventMap.set(key, event);
        }
      } else {
        // Regular event - dedupe by id
        eventMap.set(event.id, event);
      }
    }

    const uniqueEvents = Array.from(eventMap.values());
    console.log(`[useSkateRelays] Total unique events: ${uniqueEvents.length}`);

    return uniqueEvents;
  };

  /**
   * Generate a stable query key suffix based on relay configuration.
   * Used to invalidate cache when relay settings change.
   */
  const getQueryKeySuffix = (): string => {
    const relays = getReadRelays();
    return relays.sort().join(',');
  };

  return {
    getReadRelays,
    getWriteRelays,
    querySkateContent,
    getQueryKeySuffix,
    isLoggedIn,
    useSkateRelay,
  };
}