/**
 * NIP-30 Custom Emoji Support
 * 
 * NIP-30 defines custom emojis using:
 * - Kind 10030: Emoji sets (replaceable, one per user)
 * - Kind 30030: Emoji packs (replaceable, parameterized)
 * 
 * Each emoji set/pack maps shortcodes (e.g., "turtlehappy_sm") to image URLs.
 * 
 * Format: :shortcode: in reactions/content
 */

import { nostrClient } from './nostr-client.js';
import { relayManager } from './relay-manager.js';
import type { NostrEvent } from '../../types/nostr.js';
import { matchAll } from 'nostr-tools/nip30';

export interface EmojiDefinition {
  shortcode: string; // Without colons, e.g., "turtlehappy_sm"
  url: string; // Image URL
}

export interface EmojiSet {
  pubkey: string;
  emojis: Map<string, EmojiDefinition>; // shortcode -> definition
}

// Cache of emoji sets by pubkey
const emojiSetCache = new Map<string, EmojiSet>();

/**
 * Parse a kind 10030 emoji set event or kind 30030 emoji pack
 */
export function parseEmojiSet(event: NostrEvent): EmojiSet | null {
  if (event.kind !== 10030 && event.kind !== 30030) return null;
  
  const emojis = new Map<string, EmojiDefinition>();
  
  // Parse emoji tags: ["emoji", "shortcode", "url"]
  for (const tag of event.tags) {
    if (tag[0] === 'emoji' && tag[1] && tag[2]) {
      const shortcode = tag[1];
      const url = tag[2];
      emojis.set(shortcode, { shortcode, url });
    }
  }
  
  if (emojis.size === 0) return null;
  
  return {
    pubkey: event.pubkey,
    emojis
  };
}

/**
 * Fetch emoji set for a pubkey
 */
export async function fetchEmojiSet(pubkey: string): Promise<EmojiSet | null> {
  // Check cache first
  if (emojiSetCache.has(pubkey)) {
    return emojiSetCache.get(pubkey)!;
  }
  
  try {
    const relays = relayManager.getFeedReadRelays();
    // Fetch both emoji sets (10030) and emoji packs (30030)
    const events = await nostrClient.fetchEvents(
      [{ kinds: [10030, 30030], authors: [pubkey], limit: 10 }], // Get multiple in case of packs
      relays,
      { useCache: true, cacheResults: true, timeout: 5000 }
    );
    
    if (events.length === 0) return null;
    
    // Get the most recent event (replaceable events)
    const event = events.sort((a, b) => b.created_at - a.created_at)[0];
    const emojiSet = parseEmojiSet(event);
    
    if (emojiSet) {
      emojiSetCache.set(pubkey, emojiSet);
    }
    
    return emojiSet;
  } catch (error) {
    console.error('Error fetching emoji set:', error);
    return null;
  }
}

/**
 * Resolve a shortcode to an image URL
 * Tries to find the emoji in emoji sets from the given pubkeys
 */
export async function resolveEmojiShortcode(
  shortcode: string,
  pubkeys: string[] = []
): Promise<string | null> {
  // Remove colons if present
  const cleanShortcode = shortcode.replace(/^:|:$/g, '');
  
  // Try each pubkey's emoji set
  for (const pubkey of pubkeys) {
    const emojiSet = await fetchEmojiSet(pubkey);
    if (emojiSet?.emojis.has(cleanShortcode)) {
      return emojiSet.emojis.get(cleanShortcode)!.url;
    }
  }
  
  return null;
}

/**
 * Get all unique pubkeys from reactions to fetch their emoji sets
 */
export function extractPubkeysFromReactions(reactions: Map<string, { content: string; pubkeys: Set<string>; eventIds?: Map<string, string> }>): string[] {
  const pubkeys = new Set<string>();
  for (const { pubkeys: reactionPubkeys } of reactions.values()) {
    for (const pubkey of reactionPubkeys) {
      pubkeys.add(pubkey);
    }
  }
  return Array.from(pubkeys);
}

/**
 * Resolve all custom emoji shortcodes in reactions to their URLs
 */
export async function resolveCustomEmojis(
  reactions: Map<string, { content: string; pubkeys: Set<string>; eventIds?: Map<string, string> }>
): Promise<Map<string, string>> {
  // Extract all pubkeys that have reactions
  const pubkeys = extractPubkeysFromReactions(reactions);
  
  // Fetch all emoji sets in parallel
  const emojiSetPromises = pubkeys.map(pubkey => fetchEmojiSet(pubkey));
  await Promise.all(emojiSetPromises);
  
  // Build map of shortcode -> URL
  const emojiMap = new Map<string, string>();
  
  for (const [content] of reactions.entries()) {
    if (content.startsWith(':') && content.endsWith(':')) {
      const shortcode = content.slice(1, -1); // Remove colons
      
      // Try to find in any emoji set
      for (const pubkey of pubkeys) {
        const emojiSet = emojiSetCache.get(pubkey);
        if (emojiSet?.emojis.has(shortcode)) {
          emojiMap.set(content, emojiSet.emojis.get(shortcode)!.url);
          break;
        }
      }
    }
  }
  
  return emojiMap;
}