// lib/sync-service.ts (시스템별 분리 버전 - DOLCE 업로드 통합)
import db from "@/db/db"
import {
  changeLogs,
  syncBatches,
  type ChangeLog,
  type SyncBatch
} from "@/db/schema/vendorDocu"
import { documents, revisions, documentAttachments } from "@/db/schema/vendorDocu"
import { eq, and, lt, desc, sql, inArray } from "drizzle-orm"

export interface SyncableEntity {
  entityType: 'document' | 'revision' | 'attachment'
  entityId: number
  action: 'CREATE' | 'UPDATE' | 'DELETE'
  data: any
  metadata?: Record<string, any>
}

export interface SyncResult {
  batchId: number
  success: boolean
  successCount: number
  failureCount: number
  errors?: string[]
  endpointResults?: Record<string, any>
}

class SyncService {
  private readonly CHUNK_SIZE = 50

  /**
   * 동기화 활성화 여부 확인
   */
  private isSyncEnabled(targetSystem: string): boolean {
    const upperSystem = targetSystem.toUpperCase()
    const enabled = process.env[`SYNC_${upperSystem}_ENABLED`]
    return enabled === 'true' || enabled === '1'
  }

  /**
   * 변경사항을 change_logs에 기록
   */
  async logChange(
    projectId: number,
    entityType: 'document' | 'revision' | 'attachment',
    entityId: number,
    action: 'CREATE' | 'UPDATE' | 'DELETE',
    newValues?: any,
    oldValues?: any,
    userId?: number,
    userName?: string,
    targetSystems: string[] = ["DOLCE", "SWP"]
  ) {
    try {
      const changedFields = this.detectChangedFields(oldValues, newValues)

      await db.insert(changeLogs).values({
        projectId,
        entityType,
        entityId,
        action,
        changedFields,
        oldValues,
        newValues,
        userId,
        userName,
        targetSystems,
      })

      console.log(`Change logged: ${entityType}/${entityId} - ${action}`)
    } catch (error) {
      console.error('Failed to log change:', error)
      throw error
    }
  }

  /**
   * 변경된 필드 감지
   */
  private detectChangedFields(oldValues: any, newValues: any): Record<string, any> | null {
    if (!oldValues || !newValues) return null

    const changes: Record<string, any> = {}

    for (const [key, newValue] of Object.entries(newValues)) {
      if (JSON.stringify(oldValues[key]) !== JSON.stringify(newValue)) {
        changes[key] = {
          from: oldValues[key],
          to: newValue
        }
      }
    }

    return Object.keys(changes).length > 0 ? changes : null
  }

  /**
   * 동기화할 변경사항 조회 (증분)
   */
  async getPendingChanges(
    projectId: number,
    targetSystem: string = 'DOLCE',
    limit?: number
  ): Promise<ChangeLog[]> {
    const query = db
      .select()
      .from(changeLogs)
      .where(and(
        eq(changeLogs.projectId, projectId),
        eq(changeLogs.isSynced, false),
        lt(changeLogs.syncAttempts, 3),
        sql`(${changeLogs.targetSystems} IS NULL OR ${changeLogs.targetSystems} @> ${JSON.stringify([targetSystem])})`
      ))
      .orderBy(changeLogs.createdAt)

    if (limit) {
      query.limit(limit)
    }

    return await query
  }

  /**
   * 배열을 청크 단위로 분할
   */
  private chunkArray<T>(array: T[], chunkSize: number): T[][] {
    const chunks: T[][] = []
    for (let i = 0; i < array.length; i += chunkSize) {
      chunks.push(array.slice(i, i + chunkSize))
    }
    return chunks
  }

  /**
   * 동기화 배치 생성
   */
  async createSyncBatch(
    projectId: number,
    targetSystem: string,
    changeLogIds: number[]
  ): Promise<number> {
    const [batch] = await db
      .insert(syncBatches)
      .values({
        projectId,
        targetSystem,
        batchSize: changeLogIds.length,
        changeLogIds,
        status: 'PENDING'
      })
      .returning({ id: syncBatches.id })

    return batch.id
  }

  /**
   * 메인 동기화 실행 함수 (청크 처리 포함)
   */
  async syncToExternalSystem(
    projectId: number,
    targetSystem: string = 'DOLCE',
    manualTrigger: boolean = false
  ): Promise<SyncResult> {
    try {
      // 1. 동기화 활성화 확인
      if (!this.isSyncEnabled(targetSystem)) {
        throw new Error(`Sync not enabled for ${targetSystem}`)
      }

      // 2. 대기 중인 변경사항 조회 (전체)
      const pendingChanges = await this.getPendingChanges(projectId, targetSystem)

      if (pendingChanges.length === 0) {
        return {
          batchId: 0,
          success: true,
          successCount: 0,
          failureCount: 0
        }
      }

      // 3. 배치 생성
      const batchId = await this.createSyncBatch(
        projectId,
        targetSystem,
        pendingChanges.map(c => c.id)
      )

      // 4. 배치 상태를 PROCESSING으로 업데이트
      await db
        .update(syncBatches)
        .set({
          status: 'PROCESSING',
          startedAt: new Date(),
          updatedAt: new Date()
        })
        .where(eq(syncBatches.id, batchId))

      // 5. 청크 단위로 동기화 수행 - 시스템별 분기
      const chunks = this.chunkArray(pendingChanges, this.CHUNK_SIZE)
      let totalSuccessCount = 0
      let totalFailureCount = 0
      const allErrors: string[] = []
      const endpointResults: Record<string, any> = {}

      for (let i = 0; i < chunks.length; i++) {
        const chunk = chunks[i]
        console.log(`Processing chunk ${i + 1}/${chunks.length} (${chunk.length} items) for ${targetSystem}`)

        try {
          let chunkResult;
          
          // 시스템별로 다른 동기화 메서드 호출
          switch (targetSystem.toUpperCase()) {
            case 'DOLCE':
              chunkResult = await this.performSyncDOLCE(chunk, projectId)
              break
            case 'SWP':
              chunkResult = await this.performSyncSWP(chunk, projectId)
              break
            default:
              throw new Error(`Unsupported target system: ${targetSystem}`)
          }
          
          totalSuccessCount += chunkResult.successCount
          totalFailureCount += chunkResult.failureCount
          
          if (chunkResult.errors) {
            allErrors.push(...chunkResult.errors)
          }

          // 엔드포인트별 결과 병합
          Object.assign(endpointResults, chunkResult.endpointResults || {})

          // 성공한 변경사항들을 동기화 완료로 표시
          if (chunkResult.successCount > 0) {
            const successfulChangeIds = chunk
              .slice(0, chunkResult.successCount)
              .map(c => c.id)

            await this.markChangesAsSynced(successfulChangeIds)
          }

          // 실패한 변경사항들의 재시도 횟수 증가
          if (chunkResult.failureCount > 0) {
            const failedChangeIds = chunk
              .slice(chunkResult.successCount)
              .map(c => c.id)

            await this.incrementSyncAttempts(failedChangeIds, chunkResult.errors?.[0])
          }

        } catch (error) {
          console.error(`Chunk ${i + 1} failed for ${targetSystem}:`, error)
          totalFailureCount += chunk.length
          allErrors.push(`Chunk ${i + 1}: ${error instanceof Error ? error.message : 'Unknown error'}`)
          
          // 전체 청크 실패 시 재시도 횟수 증가
          await this.incrementSyncAttempts(chunk.map(c => c.id), error instanceof Error ? error.message : 'Unknown error')
        }
      }

      const overallSuccess = totalFailureCount === 0

      // 6. 배치 상태 업데이트
      await db
        .update(syncBatches)
        .set({
          status: overallSuccess ? 'SUCCESS' : (totalSuccessCount > 0 ? 'PARTIAL' : 'FAILED'),
          completedAt: new Date(),
          successCount: totalSuccessCount,
          failureCount: totalFailureCount,
          errorMessage: allErrors.length > 0 ? allErrors.join('; ') : null,
          updatedAt: new Date()
        })
        .where(eq(syncBatches.id, batchId))

      return {
        batchId,
        success: overallSuccess,
        successCount: totalSuccessCount,
        failureCount: totalFailureCount,
        errors: allErrors.length > 0 ? allErrors : undefined,
        endpointResults
      }

    } catch (error) {
      console.error('Sync failed:', error)
      throw error
    }
  }

  /**
   * DOLCE 시스템 전용 동기화 수행 - 실제 업로드 서비스 사용
   */
  private async performSyncDOLCE(
    changes: ChangeLog[],
    projectId: number
  ): Promise<{ success: boolean; successCount: number; failureCount: number; errors?: string[]; endpointResults?: Record<string, any> }> {
    const errors: string[] = []
    const endpointResults: Record<string, any> = {}

    try {
      // DOLCE 업로드 서비스 동적 임포트
      const { dolceUploadService } = await import('./dolce-upload-service')
      
      if (!dolceUploadService.isUploadEnabled()) {
        throw new Error('DOLCE upload is not enabled')
      }

      // 변경사항에서 리비전 ID들 추출
      const revisionIds = changes
        .filter(change => change.entityType === 'revision')
        .map(change => change.entityId)

      if (revisionIds.length === 0) {
        return {
          success: true,
          successCount: 0,
          failureCount: 0,
          endpointResults: { message: 'No revisions to upload' }
        }
      }

      // DOLCE 업로드 실행
      const uploadResult = await dolceUploadService.uploadToDoLCE(
        projectId,
        revisionIds,
        'system_user', // 시스템 사용자 ID
        'System Upload'
      )

      endpointResults['dolce_upload'] = uploadResult

      if (uploadResult.success) {
        console.log(`✅ DOLCE upload successful: ${uploadResult.uploadedDocuments} documents, ${uploadResult.uploadedFiles} files`)
        
        return {
          success: true,
          successCount: changes.length,
          failureCount: 0,
          endpointResults
        }
      } else {
        console.error(`❌ DOLCE upload failed:`, uploadResult.errors)
        
        return {
          success: false,
          successCount: 0,
          failureCount: changes.length,
          errors: uploadResult.errors,
          endpointResults
        }
      }

    } catch (error) {
      const errorMessage = `DOLCE upload failed: ${error instanceof Error ? error.message : 'Unknown error'}`
      errors.push(errorMessage)
      console.error(`❌ DOLCE upload error:`, error)

      return {
        success: false,
        successCount: 0,
        failureCount: changes.length,
        errors,
        endpointResults
      }
    }
  }

  /**
   * SWP 시스템 전용 동기화 수행
   */
  private async performSyncSWP(
    changes: ChangeLog[],
    projectId: number
  ): Promise<{ success: boolean; successCount: number; failureCount: number; errors?: string[]; endpointResults?: Record<string, any> }> {
    // SWP 동기화 로직 구현
    // 현재는 플레이스홀더
    return {
      success: true,
      successCount: changes.length,
      failureCount: 0,
      endpointResults: { message: 'SWP sync placeholder' }
    }
  }

  /**
   * 성공한 변경사항들을 동기화 완료로 표시
   */
  private async markChangesAsSynced(changeIds: number[]) {
    if (changeIds.length === 0) return

    await db
      .update(changeLogs)
      .set({
        isSynced: true,
        syncedAt: new Date()
      })
      .where(inArray(changeLogs.id, changeIds))

    // 리비전 상태 업데이트
    const revisionChanges = await db
      .select({ entityId: changeLogs.entityId })
      .from(changeLogs)
      .where(and(
        inArray(changeLogs.id, changeIds),
        eq(changeLogs.entityType, 'revision')
      ))

    if (revisionChanges.length > 0) {
      const revisionIds = revisionChanges.map(c => c.entityId)
      await db.update(revisions)
        .set({
          revisionStatus: "SUBMITTED",
          submittedDate: new Date().toISOString().slice(0, 10)
        })
        .where(inArray(revisions.id, revisionIds))
    }
  }

  /**
   * 실패한 변경사항들의 재시도 횟수 증가
   */
  private async incrementSyncAttempts(changeIds: number[], errorMessage?: string) {
    if (changeIds.length === 0) return

    await db
      .update(changeLogs)
      .set({
        syncAttempts: sql`${changeLogs.syncAttempts} + 1`,
        lastSyncError: errorMessage || 'Unknown error'
      })
      .where(inArray(changeLogs.id, changeIds))
  }

  /**
   * 동기화 상태 조회
   */
  async getSyncStatus(projectId: number, targetSystem: string = 'DOLCE') {
    try {
      // 대기 중인 변경사항 수 조회
      const pendingCount = await db.$count(
        changeLogs,
        and(
          eq(changeLogs.projectId, projectId),
          eq(changeLogs.isSynced, false),
          lt(changeLogs.syncAttempts, 3),
          sql`(${changeLogs.targetSystems} IS NULL OR ${changeLogs.targetSystems} @> ${JSON.stringify([targetSystem])})`
        )
      )

      // 동기화된 변경사항 수 조회
      const syncedCount = await db.$count(
        changeLogs,
        and(
          eq(changeLogs.projectId, projectId),
          eq(changeLogs.isSynced, true),
          sql`(${changeLogs.targetSystems} IS NULL OR ${changeLogs.targetSystems} @> ${JSON.stringify([targetSystem])})`
        )
      )

      // 실패한 변경사항 수 조회
      const failedCount = await db.$count(
        changeLogs,
        and(
          eq(changeLogs.projectId, projectId),
          eq(changeLogs.isSynced, false),
          sql`${changeLogs.syncAttempts} >= 3`,
          sql`(${changeLogs.targetSystems} IS NULL OR ${changeLogs.targetSystems} @> ${JSON.stringify([targetSystem])})`
        )
      )

      // 마지막 성공한 배치 조회
      const [lastSuccessfulBatch] = await db
        .select()
        .from(syncBatches)
        .where(and(
          eq(syncBatches.projectId, projectId),
          eq(syncBatches.targetSystem, targetSystem),
          eq(syncBatches.status, 'SUCCESS')
        ))
        .orderBy(desc(syncBatches.completedAt))
        .limit(1)

      return {
        projectId,
        targetSystem,
        totalChanges: pendingCount + syncedCount + failedCount,
        pendingChanges: pendingCount,
        syncedChanges: syncedCount,
        failedChanges: failedCount,
        lastSyncAt: lastSuccessfulBatch?.completedAt?.toISOString() || null,
        syncEnabled: this.isSyncEnabled(targetSystem)
      }
    } catch (error) {
      console.error('Failed to get sync status:', error)
      throw error
    }
  }

  /**
   * 최근 동기화 배치 목록 조회
   */
  async getRecentSyncBatches(projectId: number, targetSystem: string = 'DOLCE', limit: number = 10) {
    try {
      const batches = await db
        .select()
        .from(syncBatches)
        .where(and(
          eq(syncBatches.projectId, projectId),
          eq(syncBatches.targetSystem, targetSystem)
        ))
        .orderBy(desc(syncBatches.createdAt))
        .limit(limit)

      // Date 객체를 문자열로 변환
      return batches.map(batch => ({
        id: Number(batch.id),
        projectId: batch.projectId,
        targetSystem: batch.targetSystem,
        batchSize: batch.batchSize,
        status: batch.status,
        startedAt: batch.startedAt?.toISOString() || null,
        completedAt: batch.completedAt?.toISOString() || null,
        errorMessage: batch.errorMessage,
        retryCount: batch.retryCount,
        successCount: batch.successCount,
        failureCount: batch.failureCount,
        createdAt: batch.createdAt.toISOString(),
        updatedAt: batch.updatedAt.toISOString()
      }))
    } catch (error) {
      console.error('Failed to get sync batches:', error)
      throw error
    }
  }
}

export const syncService = new SyncService()

// 편의 함수들 (기본 타겟 시스템을 DOLCE로 변경)
export async function logDocumentChange(
  projectId: number,
  documentId: number,
  action: 'CREATE' | 'UPDATE' | 'DELETE',
  newValues?: any,
  oldValues?: any,
  userId?: number,
  userName?: string,
  targetSystems: string[] = ["DOLCE", "SWP"]
) {
  return syncService.logChange(projectId, 'document', documentId, action, newValues, oldValues, userId, userName, targetSystems)
}

export async function logRevisionChange(
  projectId: number,
  revisionId: number,
  action: 'CREATE' | 'UPDATE' | 'DELETE',
  newValues?: any,
  oldValues?: any,
  userId?: number,
  userName?: string,
  targetSystems: string[] = ["DOLCE", "SWP"]
) {
  return syncService.logChange(projectId, 'revision', revisionId, action, newValues, oldValues, userId, userName, targetSystems)
}

export async function logAttachmentChange(
  projectId: number,
  attachmentId: number,
  action: 'CREATE' | 'UPDATE' | 'DELETE',
  newValues?: any,
  oldValues?: any,
  userId?: number,
  userName?: string,
  targetSystems: string[] = ["DOLCE", "SWP"]
) {
  return syncService.logChange(projectId, 'attachment', attachmentId, action, newValues, oldValues, userId, userName, targetSystems)
}