/**
 * Federation Coordinator Service
 * Manages multi-region data federation and sovereignty
 */

import { getDb } from '../db/index.js'
import { logger } from '../lib/logger.js'
import { Context } from '../types/context.js'

export interface SovereigntyZone {
  id: string
  name: string
  country: string
  region: string
  regulatoryFrameworks: string[]
  dataResidency: DataResidencyConfig
  datacenterIds: string[]
}

export interface DataResidencyConfig {
  required: boolean
  allowedRegions: string[]
  prohibitedRegions: string[]
}

export interface DataResidencyRule {
  id: string
  dataType: string
  sourceRegion: string
  allowedRegions: string[]
  prohibitedRegions: string[]
  encryptionRequired: boolean
}

export interface ReplicationRequest {
  sourceRegion: string
  targetRegion: string
  data: any
  dataType: string
  operation: 'INSERT' | 'UPDATE' | 'DELETE'
}

export interface ReplicationResult {
  success: boolean
  replicationId: string
  complianceCheck: ComplianceResult
  errors?: string[]
}

export interface ComplianceResult {
  compliant: boolean
  violations: string[]
  warnings: string[]
}

class FederationCoordinator {
  /**
   * Replicate data across regions with compliance checks
   */
  async replicateData(
    context: Context,
    request: ReplicationRequest
  ): Promise<ReplicationResult> {
    logger.info('Replicating data', {
      sourceRegion: request.sourceRegion,
      targetRegion: request.targetRegion,
      dataType: request.dataType,
    })

    // Check compliance
    const compliance = await this.checkCompliance(
      request.dataType,
      request.sourceRegion,
      request.targetRegion
    )

    if (!compliance.compliant) {
      return {
        success: false,
        replicationId: '',
        complianceCheck: compliance,
        errors: compliance.violations,
      }
    }

    // Perform replication
    const replicationId = await this.performReplication(request)

    return {
      success: true,
      replicationId,
      complianceCheck: compliance,
    }
  }

  /**
   * Check data residency compliance
   */
  async checkCompliance(
    dataType: string,
    sourceRegion: string,
    targetRegion: string
  ): Promise<ComplianceResult> {
    const db = getDb()

    // Get data residency rules
    const rulesResult = await db.query(
      `SELECT * FROM data_residency_rules 
       WHERE data_type = $1 AND source_region = $2`,
      [dataType, sourceRegion]
    )

    const violations: string[] = []
    const warnings: string[] = []

    if (rulesResult.rows.length > 0) {
      const rule = rulesResult.rows[0]

      // Check if target region is prohibited
      if (rule.prohibited_regions && rule.prohibited_regions.includes(targetRegion)) {
        violations.push(
          `Data type ${dataType} cannot be replicated to ${targetRegion}`
        )
      }

      // Check if target region is allowed
      if (
        rule.allowed_regions &&
        rule.allowed_regions.length > 0 &&
        !rule.allowed_regions.includes(targetRegion)
      ) {
        violations.push(
          `Data type ${dataType} can only be replicated to: ${rule.allowed_regions.join(', ')}`
        )
      }

      // Check encryption requirement
      if (rule.encryption_required) {
        warnings.push('Encryption required for this data type')
      }
    }

    return {
      compliant: violations.length === 0,
      violations,
      warnings,
    }
  }

  /**
   * Perform actual replication
   */
  private async performReplication(
    request: ReplicationRequest
  ): Promise<string> {
    const db = getDb()

    // Get federated stores for both regions
    const sourceStore = await this.getFederatedStore(request.sourceRegion)
    const targetStore = await this.getFederatedStore(request.targetRegion)

    if (!sourceStore || !targetStore) {
      throw new Error('Federated stores not found for regions')
    }

    // Create replication log entry
    const result = await db.query(
      `INSERT INTO replication_logs (
        source_store_id, target_store_id, data_id, operation,
        status, compliance_check
      ) VALUES ($1, $2, $3, $4, $5, $6)
      RETURNING id`,
      [
        sourceStore.id,
        targetStore.id,
        request.data.id || 'unknown',
        request.operation,
        'PENDING',
        JSON.stringify({ compliant: true }),
      ]
    )

    const replicationId = result.rows[0].id

    // Perform replication based on store type
    await this.replicateToStore(sourceStore, targetStore, request.data)

    // Update replication log
    await db.query(
      `UPDATE replication_logs SET status = $1, completed_at = NOW() WHERE id = $2`,
      ['COMPLETED', replicationId]
    )

    return replicationId
  }

  /**
   * Get federated store for region
   */
  private async getFederatedStore(region: string): Promise<any> {
    const db = getDb()
    const result = await db.query(
      `SELECT * FROM federated_stores 
       WHERE zone_id IN (
         SELECT id FROM sovereignty_zones WHERE region = $1
       ) AND role = 'PRIMARY'`,
      [region]
    )

    return result.rows[0] || null
  }

  /**
   * Replicate data to target store
   */
  private async replicateToStore(
    sourceStore: any,
    targetStore: any,
    data: any
  ): Promise<void> {
    // In production, this would:
    // 1. Connect to source store
    // 2. Read data
    // 3. Transform if needed
    // 4. Write to target store
    // 5. Handle conflicts

    logger.info('Replicating data to store', {
      sourceStore: sourceStore.id,
      targetStore: targetStore.id,
    })
  }

  /**
   * Route query to appropriate stores
   */
  async routeQuery(
    context: Context,
    query: any,
    userRegion: string
  ): Promise<any> {
    // Check if data is in user's region
    const localStore = await this.getFederatedStore(userRegion)

    // Try local store first
    if (localStore) {
      const localResult = await this.queryStore(localStore, query)
      if (localResult) {
        return localResult
      }
    }

    // Check metadata store for data location
    const metadataStore = await this.getMetadataStore()
    const dataLocation = await this.findDataLocation(metadataStore, query)

    // Route to appropriate store
    if (dataLocation) {
      const targetStore = await this.getFederatedStore(dataLocation.region)
      return this.queryStore(targetStore, query)
    }

    // Cross-region query (with compliance check)
    return this.performCrossRegionQuery(query, userRegion)
  }

  /**
   * Get metadata store
   */
  private async getMetadataStore(): Promise<any> {
    const db = getDb()
    const result = await db.query(
      `SELECT * FROM federated_stores WHERE role = 'METADATA' LIMIT 1`
    )
    return result.rows[0] || null
  }

  /**
   * Find data location in metadata store
   */
  private async findDataLocation(metadataStore: any, query: any): Promise<any> {
    // Query metadata store to find where data is stored
    return null
  }

  /**
   * Query a specific store
   */
  private async queryStore(store: any, query: any): Promise<any> {
    // Execute query against store
    return null
  }

  /**
   * Perform cross-region query
   */
  private async performCrossRegionQuery(query: any, userRegion: string): Promise<any> {
    // Check compliance for cross-region access
    // Aggregate results from multiple regions
    // Return combined results
    return null
  }
}

export const federationCoordinator = new FederationCoordinator()

