/**
 * Advanced Auction System for Dynamic Pricing
 * Supports multiple auction types for AI agent services and marketplace items
 */

import type { Address } from '@solana/addresses';
import type { Rpc, SolanaRpcApi } from '@solana/rpc';
import type { Commitment } from '@solana/rpc-types';
import type { KeyPairSigner } from '@solana/signers';
import { sendAndConfirmTransactionFactory } from '../utils/transaction-helpers.js';

/**
 * Auction types supported by the system
 */
export type AuctionType = 
  | 'english'          // Traditional ascending bid auction
  | 'dutch'            // Descending price auction
  | 'sealed_bid'       // Sealed bid auction
  | 'reverse'          // Reverse auction (buyers compete)
  | 'vickrey'          // Second-price sealed bid
  | 'candle'           // Random end time auction
  | 'reserve'          // Auction with reserve price
  | 'buy_now';         // Auction with immediate purchase option

/**
 * Auction status states
 */
export type AuctionStatus = 
  | 'created'          // Auction created but not started
  | 'active'           // Currently accepting bids
  | 'ending'           // In final countdown period
  | 'ended'            // Auction completed
  | 'cancelled'        // Auction cancelled
  | 'settled'          // Winner determined and payment processed
  | 'disputed';        // Under dispute resolution

/**
 * Bid information
 */
export interface IAuctionBid {
  bidId: Address;
  bidder: Address;
  amount: bigint;
  timestamp: number;
  isWinning: boolean;
  bidData?: {
    maxBid?: bigint;        // For proxy bidding
    conditions?: string[];   // Special bid conditions
    autoIncrement?: bigint;  // Auto-increment amount
  };
}

/**
 * Comprehensive auction configuration
 */
export interface IAuctionConfig {
  // Basic auction settings
  auctionType: AuctionType;
  title: string;
  description: string;
  category: string;
  
  // Item being auctioned
  itemType: 'agent' | 'service' | 'nft' | 'bulk_package' | 'subscription';
  itemId: Address;
  itemMetadata: {
    name: string;
    description: string;
    imageUri?: string;
    attributes?: Record<string, any>;
  };

  // Pricing and economic settings
  startingPrice: bigint;
  reservePrice?: bigint;
  buyNowPrice?: bigint;
  minimumIncrement: bigint;
  paymentToken: Address;

  // Timing configuration
  startTime: number;
  duration: number;           // Duration in milliseconds
  extensionTrigger?: number;  // Extend if bid in last X ms
  extensionTime?: number;     // How much to extend by
  
  // Advanced features
  allowProxyBidding: boolean;
  requireDeposit: boolean;
  depositAmount?: bigint;
  maxBidsPerUser?: number;
  
  // Access control
  isPrivate: boolean;
  whitelist?: Address[];
  blacklist?: Address[];
  minimumReputation?: number;
  
  // Special conditions
  multiWinner?: {
    enabled: boolean;
    maxWinners: number;
    winnerSelection: 'highest_bids' | 'lottery' | 'proportional';
  };
}

/**
 * Complete auction state
 */
export interface IAuction {
  auctionId: Address;
  seller: Address;
  config: IAuctionConfig;
  status: AuctionStatus;
  
  // Current auction state
  currentPrice: bigint;
  highestBid?: IAuctionBid;
  totalBids: number;
  uniqueBidders: number;
  
  // Timing information
  createdAt: number;
  startedAt?: number;
  endsAt: number;
  actualEndTime?: number;
  
  // Financial tracking
  totalVolume: bigint;
  escrowAmount: bigint;
  feesCollected: bigint;
  
  // Participants
  bidders: Address[];
  watchers: Address[];
  
  // Resolution
  winners?: Array<{
    bidder: Address;
    winningBid: bigint;
    rank: number;
  }>;
  
  // Metadata
  viewCount: number;
  socialEngagement: {
    likes: number;
    shares: number;
    comments: number;
  };
}

/**
 * Auction analytics and insights
 */
export interface IAuctionAnalytics {
  // Performance metrics
  participationRate: number;
  averageBidIncrement: bigint;
  bidFrequency: number; // Bids per hour
  priceAppreciation: number; // Percentage increase
  
  // Bidder behavior
  bidderTypes: {
    aggressive: number;    // High increment bidders
    conservative: number;  // Low increment bidders
    lastMinute: number;   // Bid in final moments
    proxy: number;        // Using proxy bidding
  };
  
  // Market insights
  marketComparison: {
    similarAuctions: number;
    averagePrice: bigint;
    priceVariance: number;
  };
  
  // Predictions
  predictedEndPrice?: bigint;
  demandLevel: 'low' | 'medium' | 'high' | 'exceptional';
  recommendedActions: string[];
}

/**
 * Auction search and filtering options
 */
export interface IAuctionFilters {
  // Status and timing
  statuses?: AuctionStatus[];
  endingWithin?: number;     // Milliseconds
  startedAfter?: number;
  
  // Economic filters
  minCurrentPrice?: bigint;
  maxCurrentPrice?: bigint;
  paymentTokens?: Address[];
  hasBuyNow?: boolean;
  hasReserve?: boolean;
  
  // Item and category filters
  categories?: string[];
  itemTypes?: IAuctionConfig['itemType'][];
  sellerReputation?: { min: number; max?: number };
  
  // Auction type filters
  auctionTypes?: AuctionType[];
  features?: Array<'proxy_bidding' | 'multi_winner' | 'private' | 'verified_seller'>;
  
  // Sorting options
  sortBy?: 'ending_soon' | 'newest' | 'price_low' | 'price_high' | 'most_bids' | 'most_watched';
  sortOrder?: 'asc' | 'desc';
}

/**
 * Advanced Auction Service
 */
export class AuctionService {
  constructor(
    private readonly rpc: Rpc<SolanaRpcApi>,
    private readonly _programId: Address,
    private readonly commitment: Commitment = 'confirmed'
  ) {}

  /**
   * Create a new auction with comprehensive configuration
   */
  async createAuction(
    seller: KeyPairSigner,
    config: IAuctionConfig
  ): Promise<{
    auctionId: Address;
    signature: string;
  }> {
    try {
      console.log(`🏛️ Creating ${config.auctionType} auction: ${config.title}`);

      // Validate auction configuration
      this.validateAuctionConfig(config);

      // Generate auction PDA
      const auctionId = `auction_${Date.now()}_${Math.random().toString(36).substr(2, 9)}` as Address;

      // In a real implementation, this would call a createAuction smart contract instruction
      const mockInstruction = {
        programAddress: this._programId,
        accounts: [
          { address: auctionId, role: 'writable' as const },
          { address: seller.address, role: 'writable_signer' as const },
        ],
        data: new Uint8Array([1, 2, 3]) // Mock instruction data
      };

      // Build and send transaction
      const sendTransactionFactory = sendAndConfirmTransactionFactory('https://api.devnet.solana.com');
      const result = await sendTransactionFactory([mockInstruction], [seller]);
      const signature = result.signature;

      console.log('✅ Auction created:', { auctionId, signature });
      return { auctionId, signature };
    } catch (error) {
      throw new Error(`Auction creation failed: ${String(error)}`);
    }
  }

  /**
   * Place a bid on an active auction
   */
  async placeBid(
    bidder: KeyPairSigner,
    auctionId: Address,
    bidAmount: bigint,
    bidOptions: {
      maxBid?: bigint;           // For proxy bidding
      conditions?: string[];      // Special conditions
      autoIncrement?: bigint;     // Auto-increment settings
    } = {}
  ): Promise<{
    bidId: Address;
    signature: string;
    isWinning: boolean;
    nextMinimumBid: bigint;
  }> {
    try {
      console.log(`💰 Placing bid of ${bidAmount} on auction: ${auctionId}`);

      // Get current auction state
      const auction = await this.getAuction(auctionId);
      if (!auction) {
        throw new Error('Auction not found');
      }

      // Validate bid
      this.validateBid(auction, bidder.address, bidAmount, bidOptions);

      // Generate bid ID
      const bidId = `bid_${Date.now()}_${Math.random().toString(36).substr(2, 9)}` as Address;

      // Determine if this is the winning bid
      const isWinning = this.calculateWinningStatus(auction, bidAmount);
      const nextMinimumBid = this.calculateNextMinimumBid(auction, bidAmount);

      // In a real implementation, this would call a placeBid smart contract instruction
      const mockInstruction = {
        programAddress: this._programId,
        accounts: [
          { address: bidId, role: 'writable' as const },
          { address: auctionId, role: 'writable' as const },
          { address: bidder.address, role: 'writable_signer' as const },
        ],
        data: new Uint8Array([2, 3, 4]) // Mock instruction data
      };

      const sendTransactionFactory = sendAndConfirmTransactionFactory('https://api.devnet.solana.com');
      const result = await sendTransactionFactory([mockInstruction], [bidder]);
      const signature = result.signature;

      console.log('✅ Bid placed:', { bidId, signature, isWinning });
      return { bidId, signature, isWinning, nextMinimumBid };
    } catch (error) {
      throw new Error(`Bid placement failed: ${String(error)}`);
    }
  }

  /**
   * Execute buy-now purchase for auctions with immediate purchase option
   */
  async buyNow(
    buyer: KeyPairSigner,
    auctionId: Address
  ): Promise<{
    transactionId: Address;
    signature: string;
    finalPrice: bigint;
  }> {
    try {
      console.log(`⚡ Executing buy-now for auction: ${auctionId}`);

      const auction = await this.getAuction(auctionId);
      if (!auction) {
        throw new Error('Auction not found');
      }

      if (!auction.config.buyNowPrice) {
        throw new Error('This auction does not support buy-now');
      }

      if (auction.status !== 'active') {
        throw new Error('Auction is not active');
      }

      const transactionId = `txn_buynow_${Date.now()}` as Address;
      
      // In a real implementation, this would end the auction and process payment
      const mockInstruction = {
        programAddress: this._programId,
        accounts: [
          { address: transactionId, role: 'writable' as const },
          { address: auctionId, role: 'writable' as const },
          { address: buyer.address, role: 'writable_signer' as const },
        ],
        data: new Uint8Array([3, 4, 5]) // Mock instruction data
      };

      const sendTransactionFactory = sendAndConfirmTransactionFactory('https://api.devnet.solana.com');
      const result = await sendTransactionFactory([mockInstruction], [buyer]);
      const signature = result.signature;

      console.log('✅ Buy-now executed:', { transactionId, signature });
      return { 
        transactionId, 
        signature, 
        finalPrice: auction.config.buyNowPrice 
      };
    } catch (error) {
      throw new Error(`Buy-now execution failed: ${String(error)}`);
    }
  }

  /**
   * End an auction (for seller or automatic ending)
   */
  async endAuction(
    authority: KeyPairSigner,
    auctionId: Address,
    reason: 'time_expired' | 'buy_now' | 'reserve_not_met' | 'seller_cancelled' = 'time_expired'
  ): Promise<{
    signature: string;
    winners: Array<{
      bidder: Address;
      winningBid: bigint;
      rank: number;
    }>;
    totalPayout: bigint;
  }> {
    try {
      console.log(`🏁 Ending auction: ${auctionId} (reason: ${reason})`);

      const auction = await this.getAuction(auctionId);
      if (!auction) {
        throw new Error('Auction not found');
      }

      // Determine winners based on auction type and configuration
      const winners = await this.determineWinners(auction);
      const totalPayout = winners.reduce((sum, winner) => sum + winner.winningBid, 0n);

      // In a real implementation, this would call endAuction instruction and process payments
      const mockInstruction = {
        programAddress: this._programId,
        accounts: [
          { address: auctionId, role: 'writable' as const },
          { address: authority.address, role: 'writable_signer' as const },
        ],
        data: new Uint8Array([4, 5, 6]) // Mock instruction data
      };

      const sendTransactionFactory = sendAndConfirmTransactionFactory('https://api.devnet.solana.com');
      const result = await sendTransactionFactory([mockInstruction], [authority]);
      const signature = result.signature;

      console.log('✅ Auction ended:', { signature, winners: winners.length, totalPayout });
      return { signature, winners, totalPayout };
    } catch (error) {
      throw new Error(`Auction ending failed: ${String(error)}`);
    }
  }

  /**
   * Get detailed auction information
   */
  async getAuction(auctionId: Address): Promise<IAuction | null> {
    try {
      // In a real implementation, this would fetch from blockchain
      const accountInfo = await this.rpc
        .getAccountInfo(auctionId, {
          commitment: this.commitment,
          encoding: 'base64',
        })
        .send();

      if (!accountInfo.value) {
        return null;
      }

      // Simulate auction data parsing
      return this.generateMockAuction(auctionId);
    } catch (error) {
      console.error('Failed to get auction:', error);
      return null;
    }
  }

  /**
   * Search and filter auctions with advanced criteria
   */
  async searchAuctions(
    filters: IAuctionFilters = {},
    limit: number = 50,
    offset: number = 0
  ): Promise<{
    auctions: IAuction[];
    totalCount: number;
    hasMore: boolean;
    searchMetadata: {
      filters: IAuctionFilters;
      executionTime: number;
      qualityScore: number;
    };
  }> {
    const startTime = Date.now();
    
    try {
      console.log('🔍 Searching auctions with filters:', filters);

      // Get all auctions (in production, this would use efficient indexing)
      const allAuctions = await this.getAllAuctions(1000);
      
      // Apply filters
      let filteredAuctions = this.applyAuctionFilters(allAuctions, filters);
      
      // Apply sorting
      filteredAuctions = this.sortAuctions(filteredAuctions, filters);
      
      // Apply pagination
      const totalCount = filteredAuctions.length;
      const paginatedAuctions = filteredAuctions.slice(offset, offset + limit);
      
      const executionTime = Date.now() - startTime;
      const qualityScore = this.calculateSearchQuality(paginatedAuctions, filters);

      return {
        auctions: paginatedAuctions,
        totalCount,
        hasMore: offset + limit < totalCount,
        searchMetadata: {
          filters,
          executionTime,
          qualityScore,
        },
      };
    } catch (error) {
      throw new Error(`Auction search failed: ${String(error)}`);
    }
  }

  /**
   * Get comprehensive auction analytics
   */
  async getAuctionAnalytics(auctionId: Address): Promise<IAuctionAnalytics> {
    try {
      console.log(`📊 Generating analytics for auction: ${auctionId}`);

      const auction = await this.getAuction(auctionId);
      if (!auction) {
        throw new Error('Auction not found');
      }

      // Get all bids for analysis
      const bids = await this.getAuctionBids(auctionId);
      
      // Calculate performance metrics
      const participationRate = this.calculateParticipationRate(auction, bids);
      const averageBidIncrement = this.calculateAverageBidIncrement(bids);
      const bidFrequency = this.calculateBidFrequency(auction, bids);
      const priceAppreciation = this.calculatePriceAppreciation(auction);

      // Analyze bidder behavior
      const bidderTypes = this.analyzeBidderTypes(bids);
      
      // Generate market insights
      const marketComparison = await this.getMarketComparison(auction);
      
      // Make predictions
      const predictedEndPrice = this.predictEndPrice(auction, bids);
      const demandLevel = this.assessDemandLevel(auction, bids);
      const recommendedActions = this.generateRecommendations(auction, bids);

      return {
        participationRate,
        averageBidIncrement,
        bidFrequency,
        priceAppreciation,
        bidderTypes,
        marketComparison,
        predictedEndPrice,
        demandLevel,
        recommendedActions,
      };
    } catch (error) {
      throw new Error(`Analytics generation failed: ${String(error)}`);
    }
  }

  /**
   * Get trending auctions based on activity and engagement
   */
  async getTrendingAuctions(
    category?: string,
    limit: number = 20
  ): Promise<IAuction[]> {
    try {
      console.log(`🔥 Getting trending auctions for category: ${category || 'all'}`);

      const filters: IAuctionFilters = {
        statuses: ['active', 'ending'],
        sortBy: 'most_bids',
        sortOrder: 'desc',
      };

      if (category) {
        filters.categories = [category];
      }

      const result = await this.searchAuctions(filters, limit);
      return result.auctions.filter(auction => 
        this.calculateTrendingScore(auction) > 70
      );
    } catch (error) {
      throw new Error(`Trending auctions retrieval failed: ${String(error)}`);
    }
  }

  /**
   * Get auctions ending soon
   */
  async getEndingSoonAuctions(
    withinMinutes: number = 60,
    limit: number = 20
  ): Promise<IAuction[]> {
    try {
      console.log(`⏰ Getting auctions ending within ${withinMinutes} minutes`);

      const filters: IAuctionFilters = {
        statuses: ['active', 'ending'],
        endingWithin: withinMinutes * 60 * 1000,
        sortBy: 'ending_soon',
        sortOrder: 'asc',
      };

      const result = await this.searchAuctions(filters, limit);
      return result.auctions;
    } catch (error) {
      throw new Error(`Ending soon auctions retrieval failed: ${String(error)}`);
    }
  }

  /**
   * Private helper methods
   */
  
  private validateAuctionConfig(config: IAuctionConfig): void {
    if (!config.title || config.title.length < 3) {
      throw new Error('Auction title must be at least 3 characters');
    }

    if (config.startingPrice <= 0n) {
      throw new Error('Starting price must be positive');
    }

    if (config.reservePrice && config.reservePrice < config.startingPrice) {
      throw new Error('Reserve price cannot be less than starting price');
    }

    if (config.buyNowPrice && config.buyNowPrice <= config.startingPrice) {
      throw new Error('Buy-now price must be higher than starting price');
    }

    if (config.duration < 60000) { // Minimum 1 minute
      throw new Error('Auction duration must be at least 1 minute');
    }

    if (config.startTime < Date.now() - 60000) {
      throw new Error('Start time cannot be in the past');
    }
  }

  private validateBid(
    auction: IAuction,
    bidder: Address,
    bidAmount: bigint,
    bidOptions: any
  ): void {
    if (auction.status !== 'active') {
      throw new Error('Auction is not active');
    }

    if (auction.seller === bidder) {
      throw new Error('Seller cannot bid on their own auction');
    }

    if (Date.now() > auction.endsAt) {
      throw new Error('Auction has ended');
    }

    const minimumBid = this.calculateNextMinimumBid(auction, auction.currentPrice);
    if (bidAmount < minimumBid) {
      throw new Error(`Bid must be at least ${minimumBid}`);
    }

    if (auction.config.isPrivate && auction.config.whitelist) {
      if (!auction.config.whitelist.includes(bidder)) {
        throw new Error('Bidder not whitelisted for private auction');
      }
    }

    if (auction.config.blacklist?.includes(bidder)) {
      throw new Error('Bidder is blacklisted from this auction');
    }
  }

  private calculateWinningStatus(auction: IAuction, bidAmount: bigint): boolean {
    return !auction.highestBid || bidAmount > auction.highestBid.amount;
  }

  private calculateNextMinimumBid(auction: IAuction, currentBid: bigint): bigint {
    return currentBid + auction.config.minimumIncrement;
  }

  private async determineWinners(auction: IAuction): Promise<Array<{
    bidder: Address;
    winningBid: bigint;
    rank: number;
  }>> {
    // Simulate winner determination
    if (!auction.highestBid) {
      return [];
    }

    const winners = [{
      bidder: auction.highestBid.bidder,
      winningBid: auction.highestBid.amount,
      rank: 1,
    }];

    // Handle multi-winner auctions
    if (auction.config.multiWinner?.enabled && auction.config.multiWinner.maxWinners > 1) {
      // Add additional winners based on strategy
      const additionalWinners = Math.min(
        auction.config.multiWinner.maxWinners - 1,
        auction.uniqueBidders - 1
      );
      
      for (let i = 0; i < additionalWinners; i++) {
        winners.push({
          bidder: `winner_${i + 2}` as Address,
          winningBid: auction.highestBid.amount - BigInt((i + 1) * 100000000),
          rank: i + 2,
        });
      }
    }

    return winners;
  }

  private generateMockAuction(auctionId: Address): IAuction {
    const now = Date.now();
    const auctionTypes: AuctionType[] = ['english', 'dutch', 'sealed_bid', 'reverse'];
    const itemTypes = ['agent', 'service', 'nft', 'bulk_package'] as const;
    
    const randomType = auctionTypes[Math.floor(Math.random() * auctionTypes.length)];
    const randomItemType = itemTypes[Math.floor(Math.random() * itemTypes.length)];
    
    return {
      auctionId,
      seller: `seller_${Date.now()}` as Address,
      config: {
        auctionType: randomType,
        title: `Premium ${randomItemType} Auction`,
        description: `High-quality ${randomItemType} available for bidding`,
        category: 'AI Services',
        itemType: randomItemType,
        itemId: `item_${Date.now()}` as Address,
        itemMetadata: {
          name: `Premium ${randomItemType}`,
          description: 'Top-tier AI service with advanced capabilities',
          imageUri: 'https://example.com/image.jpg',
        },
        startingPrice: BigInt(Math.floor(Math.random() * 1000000000) + 100000000),
        reservePrice: BigInt(Math.floor(Math.random() * 2000000000) + 500000000),
        buyNowPrice: BigInt(Math.floor(Math.random() * 3000000000) + 1000000000),
        minimumIncrement: BigInt(50000000),
        paymentToken: 'So11111111111111111111111111111111111111112' as Address,
        startTime: now - Math.random() * 3600000,
        duration: Math.floor(Math.random() * 86400000) + 3600000,
        allowProxyBidding: Math.random() > 0.5,
        requireDeposit: Math.random() > 0.7,
        depositAmount: BigInt(Math.floor(Math.random() * 100000000)),
        isPrivate: Math.random() > 0.8,
      },
      status: Math.random() > 0.3 ? 'active' : 'ending',
      currentPrice: BigInt(Math.floor(Math.random() * 1500000000) + 200000000),
      totalBids: Math.floor(Math.random() * 50) + 1,
      uniqueBidders: Math.floor(Math.random() * 20) + 1,
      createdAt: now - Math.random() * 86400000,
      startedAt: now - Math.random() * 3600000,
      endsAt: now + Math.random() * 3600000,
      totalVolume: BigInt(Math.floor(Math.random() * 5000000000)),
      escrowAmount: BigInt(Math.floor(Math.random() * 1000000000)),
      feesCollected: BigInt(Math.floor(Math.random() * 50000000)),
      bidders: [],
      watchers: [],
      viewCount: Math.floor(Math.random() * 1000) + 10,
      socialEngagement: {
        likes: Math.floor(Math.random() * 100),
        shares: Math.floor(Math.random() * 50),
        comments: Math.floor(Math.random() * 30),
      },
    };
  }

  private async getAllAuctions(limit: number): Promise<IAuction[]> {
    // Simulate getting auctions from blockchain
    return Array.from({ length: Math.min(limit, 30) }, (_, i) => 
      this.generateMockAuction(`auction_${i + 1}_${Date.now()}` as Address)
    );
  }

  private applyAuctionFilters(auctions: IAuction[], filters: IAuctionFilters): IAuction[] {
    return auctions.filter(auction => {
      // Status filtering
      if (filters.statuses && !filters.statuses.includes(auction.status)) return false;
      
      // Price filtering
      if (filters.minCurrentPrice && auction.currentPrice < filters.minCurrentPrice) return false;
      if (filters.maxCurrentPrice && auction.currentPrice > filters.maxCurrentPrice) return false;
      
      // Category filtering
      if (filters.categories && !filters.categories.includes(auction.config.category)) return false;
      
      // Item type filtering
      if (filters.itemTypes && !filters.itemTypes.includes(auction.config.itemType)) return false;
      
      // Auction type filtering
      if (filters.auctionTypes && !filters.auctionTypes.includes(auction.config.auctionType)) return false;
      
      // Timing filtering
      if (filters.endingWithin && auction.endsAt - Date.now() > filters.endingWithin) return false;
      if (filters.startedAfter && (!auction.startedAt || auction.startedAt < filters.startedAfter)) return false;
      
      // Feature filtering
      if (filters.features) {
        if (filters.features.includes('proxy_bidding') && !auction.config.allowProxyBidding) return false;
        if (filters.features.includes('private') && !auction.config.isPrivate) return false;
        if (filters.features.includes('multi_winner') && !auction.config.multiWinner?.enabled) return false;
      }

      return true;
    });
  }

  private sortAuctions(auctions: IAuction[], filters: IAuctionFilters): IAuction[] {
    const sortedAuctions = [...auctions];

    switch (filters.sortBy) {
      case 'ending_soon':
        sortedAuctions.sort((a, b) => a.endsAt - b.endsAt);
        break;
      case 'newest':
        sortedAuctions.sort((a, b) => b.createdAt - a.createdAt);
        break;
      case 'price_low':
        sortedAuctions.sort((a, b) => Number(a.currentPrice - b.currentPrice));
        break;
      case 'price_high':
        sortedAuctions.sort((a, b) => Number(b.currentPrice - a.currentPrice));
        break;
      case 'most_bids':
        sortedAuctions.sort((a, b) => b.totalBids - a.totalBids);
        break;
      case 'most_watched':
        sortedAuctions.sort((a, b) => b.watchers.length - a.watchers.length);
        break;
      default:
        sortedAuctions.sort((a, b) => a.endsAt - b.endsAt);
    }

    if (filters.sortOrder === 'desc' && filters.sortBy !== 'price_high' && filters.sortBy !== 'most_bids' && filters.sortBy !== 'most_watched') {
      sortedAuctions.reverse();
    }

    return sortedAuctions;
  }

  private calculateSearchQuality(auctions: IAuction[], filters: IAuctionFilters): number {
    if (auctions.length === 0) return 0;
    
    const diversityScore = Math.min(auctions.length / 20, 1) * 30;
    const relevanceScore = auctions.length > 0 ? 70 : 0;
    
    return Math.round(diversityScore + relevanceScore);
  }

  private async getAuctionBids(auctionId: Address): Promise<IAuctionBid[]> {
    // Simulate getting bids for an auction
    const bidCount = Math.floor(Math.random() * 20) + 1;
    return Array.from({ length: bidCount }, (_, i) => ({
      bidId: `bid_${i + 1}_${Date.now()}` as Address,
      bidder: `bidder_${i + 1}` as Address,
      amount: BigInt(Math.floor(Math.random() * 1000000000) + 100000000),
      timestamp: Date.now() - Math.random() * 3600000,
      isWinning: i === bidCount - 1,
    }));
  }

  private calculateParticipationRate(auction: IAuction, bids: IAuctionBid[]): number {
    return Math.min((auction.uniqueBidders / auction.viewCount) * 100, 100);
  }

  private calculateAverageBidIncrement(bids: IAuctionBid[]): bigint {
    if (bids.length < 2) return 0n;
    
    const sortedBids = bids.sort((a, b) => a.timestamp - b.timestamp);
    let totalIncrement = 0n;
    
    for (let i = 1; i < sortedBids.length; i++) {
      totalIncrement += sortedBids[i].amount - sortedBids[i - 1].amount;
    }
    
    return totalIncrement / BigInt(sortedBids.length - 1);
  }

  private calculateBidFrequency(auction: IAuction, bids: IAuctionBid[]): number {
    if (!auction.startedAt || bids.length === 0) return 0;
    
    const hoursActive = (Date.now() - auction.startedAt) / (1000 * 60 * 60);
    return bids.length / Math.max(hoursActive, 0.1);
  }

  private calculatePriceAppreciation(auction: IAuction): number {
    if (auction.config.startingPrice === 0n) return 0;
    
    const appreciation = Number(auction.currentPrice - auction.config.startingPrice);
    const starting = Number(auction.config.startingPrice);
    
    return (appreciation / starting) * 100;
  }

  private analyzeBidderTypes(bids: IAuctionBid[]): IAuctionAnalytics['bidderTypes'] {
    // Simulate bidder type analysis
    return {
      aggressive: Math.floor(bids.length * 0.2),
      conservative: Math.floor(bids.length * 0.5),
      lastMinute: Math.floor(bids.length * 0.2),
      proxy: Math.floor(bids.length * 0.1),
    };
  }

  private async getMarketComparison(auction: IAuction): Promise<IAuctionAnalytics['marketComparison']> {
    // Simulate market comparison
    return {
      similarAuctions: Math.floor(Math.random() * 50) + 10,
      averagePrice: BigInt(Math.floor(Math.random() * 1000000000) + 500000000),
      priceVariance: Math.random() * 0.5 + 0.1,
    };
  }

  private predictEndPrice(auction: IAuction, bids: IAuctionBid[]): bigint {
    // Simple prediction based on current trajectory
    const appreciationRate = this.calculatePriceAppreciation(auction) / 100;
    const timeRemaining = (auction.endsAt - Date.now()) / (auction.endsAt - (auction.startedAt || auction.createdAt));
    
    const predictedAppreciation = appreciationRate * (1 + timeRemaining * 0.5);
    return auction.config.startingPrice + BigInt(Math.floor(Number(auction.config.startingPrice) * predictedAppreciation));
  }

  private assessDemandLevel(auction: IAuction, bids: IAuctionBid[]): IAuctionAnalytics['demandLevel'] {
    const bidFrequency = this.calculateBidFrequency(auction, bids);
    const participationRate = this.calculateParticipationRate(auction, bids);
    
    if (bidFrequency > 5 && participationRate > 15) return 'exceptional';
    if (bidFrequency > 2 && participationRate > 10) return 'high';
    if (bidFrequency > 1 && participationRate > 5) return 'medium';
    return 'low';
  }

  private generateRecommendations(auction: IAuction, bids: IAuctionBid[]): string[] {
    const recommendations: string[] = [];
    
    const demandLevel = this.assessDemandLevel(auction, bids);
    
    if (demandLevel === 'low') {
      recommendations.push('Consider lowering reserve price to attract more bidders');
      recommendations.push('Improve item description and add more images');
    }
    
    if (auction.endsAt - Date.now() < 3600000) { // Less than 1 hour
      recommendations.push('Consider extending auction duration to maximize final price');
    }
    
    if (auction.config.buyNowPrice && auction.currentPrice > auction.config.buyNowPrice * 80n / 100n) {
      recommendations.push('Buy-now price may be reached soon - monitor closely');
    }
    
    return recommendations;
  }

  private calculateTrendingScore(auction: IAuction): number {
    const bidActivity = Math.min((auction.totalBids / 20) * 40, 40);
    const timeRemaining = Math.max(0, Math.min((auction.endsAt - Date.now()) / (24 * 60 * 60 * 1000), 1)) * 20;
    const engagement = Math.min((auction.socialEngagement.likes + auction.socialEngagement.shares) / 10, 20);
    const viewActivity = Math.min(auction.viewCount / 50, 20);
    
    return bidActivity + timeRemaining + engagement + viewActivity;
  }
}