/**
 * Optimized S3 Search and Pagination
 * Provides efficient search and pagination capabilities for S3-compatible storage
 */

import { HNSWNoun, GraphVerb } from '../../coreTypes.js'
import { createModuleLogger } from '../../utils/logger.js'

const logger = createModuleLogger('OptimizedS3Search')

/**
 * Pagination result interface
 */
export interface PaginationResult<T> {
  items: T[]
  totalCount?: number
  hasMore: boolean
  nextCursor?: string
}

/**
 * Filter interface for nouns
 */
export interface NounFilter {
  nounType?: string | string[]
  service?: string | string[]
  metadata?: Record<string, any>
}

/**
 * Filter interface for verbs
 */
export interface VerbFilter {
  verbType?: string | string[]
  sourceId?: string | string[]
  targetId?: string | string[]
  service?: string | string[]
  metadata?: Record<string, any>
}

/**
 * Interface for storage operations needed by optimized search
 */
export interface StorageOperations {
  listObjectKeys(prefix: string, limit: number, cursor?: string): Promise<{
    keys: string[]
    hasMore: boolean
    nextCursor?: string
  }>
  getObject<T>(key: string): Promise<T | null>
  getMetadata(id: string, type: 'noun' | 'verb'): Promise<any | null>
}

/**
 * Optimized search implementation for S3-compatible storage
 */
export class OptimizedS3Search {
  constructor(private storage: StorageOperations) {}

  /**
   * Get nouns with optimized pagination and filtering
   */
  async getNounsWithPagination(options: {
    limit?: number
    cursor?: string
    filter?: NounFilter
  } = {}): Promise<PaginationResult<HNSWNoun>> {
    const limit = options.limit || 100
    const cursor = options.cursor
    
    try {
      // List noun objects with pagination
      const listResult = await this.storage.listObjectKeys('nouns/', limit * 2, cursor)
      
      if (!listResult.keys.length) {
        return {
          items: [],
          hasMore: false
        }
      }
      
      // Load nouns in parallel batches
      const nouns: HNSWNoun[] = []
      const batchSize = 10
      
      for (let i = 0; i < listResult.keys.length && nouns.length < limit; i += batchSize) {
        const batch = listResult.keys.slice(i, i + batchSize)
        const batchPromises = batch.map(key => this.storage.getObject<HNSWNoun>(key))
        
        const batchResults = await Promise.all(batchPromises)
        
        for (const noun of batchResults) {
          if (!noun) continue
          
          // Apply filters
          if (options.filter && !(await this.matchesNounFilter(noun, options.filter))) {
            continue
          }
          
          nouns.push(noun)
          
          if (nouns.length >= limit) {
            break
          }
        }
      }
      
      // Determine if there are more items
      const hasMore = listResult.hasMore || nouns.length >= limit
      
      // Set next cursor
      let nextCursor: string | undefined
      if (hasMore && nouns.length > 0) {
        nextCursor = nouns[nouns.length - 1].id
      }
      
      return {
        items: nouns.slice(0, limit),
        hasMore,
        nextCursor
      }
    } catch (error) {
      logger.error('Failed to get nouns with pagination:', error)
      return {
        items: [],
        hasMore: false
      }
    }
  }

  /**
   * Get verbs with optimized pagination and filtering
   */
  async getVerbsWithPagination(options: {
    limit?: number
    cursor?: string
    filter?: VerbFilter
  } = {}): Promise<PaginationResult<GraphVerb>> {
    const limit = options.limit || 100
    const cursor = options.cursor
    
    try {
      // List verb objects with pagination
      const listResult = await this.storage.listObjectKeys('verbs/', limit * 2, cursor)
      
      if (!listResult.keys.length) {
        return {
          items: [],
          hasMore: false
        }
      }
      
      // Load verbs in parallel batches
      const verbs: GraphVerb[] = []
      const batchSize = 10
      
      for (let i = 0; i < listResult.keys.length && verbs.length < limit; i += batchSize) {
        const batch = listResult.keys.slice(i, i + batchSize)
        
        // Load verbs and their metadata in parallel
        const batchPromises = batch.map(async (key) => {
          const verbData = await this.storage.getObject<any>(key)
          if (!verbData) return null
          
          // Get metadata
          const verbId = key.replace('verbs/', '').replace('.json', '')
          const metadata = await this.storage.getMetadata(verbId, 'verb')
          
          // Combine into GraphVerb
          return this.combineVerbWithMetadata(verbData, metadata)
        })
        
        const batchResults = await Promise.all(batchPromises)
        
        for (const verb of batchResults) {
          if (!verb) continue
          
          // Apply filters
          if (options.filter && !this.matchesVerbFilter(verb, options.filter)) {
            continue
          }
          
          verbs.push(verb)
          
          if (verbs.length >= limit) {
            break
          }
        }
      }
      
      // Determine if there are more items
      const hasMore = listResult.hasMore || verbs.length >= limit
      
      // Set next cursor
      let nextCursor: string | undefined
      if (hasMore && verbs.length > 0) {
        nextCursor = verbs[verbs.length - 1].id
      }
      
      return {
        items: verbs.slice(0, limit),
        hasMore,
        nextCursor
      }
    } catch (error) {
      logger.error('Failed to get verbs with pagination:', error)
      return {
        items: [],
        hasMore: false
      }
    }
  }

  /**
   * Check if a noun matches the filter criteria
   */
  private async matchesNounFilter(noun: HNSWNoun, filter: NounFilter): Promise<boolean> {
    // Get metadata for filtering
    const metadata = await this.storage.getMetadata(noun.id, 'noun')
    
    // Filter by noun type
    if (filter.nounType) {
      const nounTypes = Array.isArray(filter.nounType) ? filter.nounType : [filter.nounType]
      const nounType = metadata?.type || metadata?.noun
      if (!nounType || !nounTypes.includes(nounType)) {
        return false
      }
    }
    
    // Filter by service
    if (filter.service) {
      const services = Array.isArray(filter.service) ? filter.service : [filter.service]
      if (!metadata?.service || !services.includes(metadata.service)) {
        return false
      }
    }
    
    // Filter by metadata
    if (filter.metadata) {
      if (!metadata) return false
      
      for (const [key, value] of Object.entries(filter.metadata)) {
        if (metadata[key] !== value) {
          return false
        }
      }
    }
    
    return true
  }

  /**
   * Check if a verb matches the filter criteria
   */
  private matchesVerbFilter(verb: GraphVerb, filter: VerbFilter): boolean {
    // Filter by verb type
    if (filter.verbType) {
      const verbTypes = Array.isArray(filter.verbType) ? filter.verbType : [filter.verbType]
      if (!verb.type || !verbTypes.includes(verb.type)) {
        return false
      }
    }
    
    // Filter by source ID
    if (filter.sourceId) {
      const sourceIds = Array.isArray(filter.sourceId) ? filter.sourceId : [filter.sourceId]
      if (!verb.sourceId || !sourceIds.includes(verb.sourceId)) {
        return false
      }
    }
    
    // Filter by target ID
    if (filter.targetId) {
      const targetIds = Array.isArray(filter.targetId) ? filter.targetId : [filter.targetId]
      if (!verb.targetId || !targetIds.includes(verb.targetId)) {
        return false
      }
    }
    
    // Filter by service
    if (filter.service) {
      const services = Array.isArray(filter.service) ? filter.service : [filter.service]
      if (!verb.metadata?.service || !services.includes(verb.metadata.service)) {
        return false
      }
    }
    
    // Filter by metadata
    if (filter.metadata) {
      if (!verb.metadata) return false
      
      for (const [key, value] of Object.entries(filter.metadata)) {
        if (verb.metadata[key] !== value) {
          return false
        }
      }
    }
    
    return true
  }

  /**
   * Combine HNSWVerb data with metadata to create GraphVerb
   */
  private combineVerbWithMetadata(verbData: any, metadata: any): GraphVerb | null {
    if (!verbData || !metadata) return null
    
    // Create default timestamp if not present
    const defaultTimestamp = {
      seconds: Math.floor(Date.now() / 1000),
      nanoseconds: (Date.now() % 1000) * 1000000
    }
    
    // Create default createdBy if not present
    const defaultCreatedBy = {
      augmentation: 'unknown',
      version: '1.0'
    }
    
    return {
      id: verbData.id,
      vector: verbData.vector,
      sourceId: metadata.sourceId,
      targetId: metadata.targetId,
      source: metadata.source,
      target: metadata.target,
      verb: metadata.verb,
      type: metadata.type,
      weight: metadata.weight || 1.0,
      metadata: metadata.metadata || {},
      createdAt: metadata.createdAt || defaultTimestamp,
      updatedAt: metadata.updatedAt || defaultTimestamp,
      createdBy: metadata.createdBy || defaultCreatedBy,
      data: metadata.data,
      embedding: verbData.vector
    }
  }
}