/**
 * Drift State Verifier Service
 * 
 * Double-checks that positions marked as closed in our database
 * are actually closed on Drift Protocol. If mismatches found,
 * attempts to close the position again.
 * 
 * Background: Drift occasionally confirms close transactions but
 * doesn't actually close the position (state propagation delay or
 * partial fill issues). This service detects and fixes those cases.
 * 
 * Created: Dec 7, 2025
 */

import { getDriftService } from '../drift/client'
import { getPrismaClient } from '../database/trades'
import { closePosition } from '../drift/orders'
import { sendTelegramMessage } from '../notifications/telegram'

export interface DriftStateMismatch {
  tradeId: string
  symbol: string
  expectedState: 'closed' | 'open'
  actualState: 'closed' | 'open'
  driftSize: number
  dbExitReason: string | null
  timeSinceExit: number // milliseconds
}

class DriftStateVerifier {
  private isRunning: boolean = false
  private checkIntervalMs: number = 10 * 60 * 1000 // 10 minutes
  private intervalId: NodeJS.Timeout | null = null

  /**
   * Start the periodic verification service
   */
  start(): void {
    if (this.isRunning) {
      console.log('🔍 Drift state verifier already running')
      return
    }

    console.log('🔍 Starting Drift state verifier (checks every 10 minutes)')
    this.isRunning = true

    // Run first check after 2 minutes (allow time for initial startup)
    setTimeout(() => {
      this.runVerification().catch(err => {
        console.error('❌ Error in initial Drift state verification:', err)
      })
    }, 2 * 60 * 1000)

    // Then run every 10 minutes
    this.intervalId = setInterval(() => {
      this.runVerification().catch(err => {
        console.error('❌ Error in Drift state verification:', err)
      })
    }, this.checkIntervalMs)
  }

  /**
   * Stop the periodic verification service
   */
  stop(): void {
    if (this.intervalId) {
      clearInterval(this.intervalId)
      this.intervalId = null
    }
    this.isRunning = false
    console.log('🔍 Drift state verifier stopped')
  }

  /**
   * Run verification check once (can be called manually)
   */
  async runVerification(): Promise<DriftStateMismatch[]> {
    console.log('🔍 Running Drift state verification...')

    const mismatches: DriftStateMismatch[] = []

    try {
      const driftService = await getDriftService()
      const prisma = getPrismaClient()

      // Check 1: Find trades marked as closed in last 24 hours
      // These should definitely not exist on Drift anymore
      const recentlyClosedTrades = await prisma.trade.findMany({
        where: {
          exitReason: { not: null },
          exitTime: {
            gte: new Date(Date.now() - 24 * 60 * 60 * 1000)
          }
        },
        select: {
          id: true,
          positionId: true,
          symbol: true,
          exitReason: true,
          exitTime: true,
        },
      })

      console.log(`   Checking ${recentlyClosedTrades.length} recently closed trades...`)

      for (const trade of recentlyClosedTrades) {
        try {
          // Extract market index from symbol (SOL-PERP → 0, ETH-PERP → 1, etc.)
          const marketIndex = this.getMarketIndex(trade.symbol)
          if (marketIndex === null) continue

          // Query Drift for position
          const driftPosition = await driftService.getPosition(marketIndex)
          
          if (driftPosition && Math.abs(driftPosition.size) >= 0.01) {
            // MISMATCH: DB says closed, Drift says open
            const timeSinceExit = Date.now() - new Date(trade.exitTime!).getTime()
            
            mismatches.push({
              tradeId: trade.id,
              symbol: trade.symbol,
              expectedState: 'closed',
              actualState: 'open',
              driftSize: Math.abs(driftPosition.size),
              dbExitReason: trade.exitReason,
              timeSinceExit,
            })

            console.error(`🚨 MISMATCH DETECTED: ${trade.symbol}`)
            console.error(`   DB: Closed ${(timeSinceExit / 60000).toFixed(1)}min ago (${trade.exitReason})`)
            console.error(`   Drift: Still open with size ${driftPosition.size}`)
          }
        } catch (err) {
          console.error(`   Error checking ${trade.symbol}:`, err)
        }
      }

      // Check 2: Find trades marked as open but actually closed on Drift
      // (Less critical but worth detecting)
      const openTrades = await prisma.trade.findMany({
        where: {
          exitReason: null,
        },
        select: {
          id: true,
          positionId: true,
          symbol: true,
          createdAt: true,
        },
      })

      console.log(`   Checking ${openTrades.length} open trades...`)

      for (const trade of openTrades) {
        try {
          const marketIndex = this.getMarketIndex(trade.symbol)
          if (marketIndex === null) continue

          const driftPosition = await driftService.getPosition(marketIndex)
          
          if (!driftPosition || Math.abs(driftPosition.size) < 0.01) {
            // MISMATCH: DB says open, Drift says closed
            const timeSinceExit = Date.now() - new Date(trade.createdAt).getTime()
            
            mismatches.push({
              tradeId: trade.id,
              symbol: trade.symbol,
              expectedState: 'open',
              actualState: 'closed',
              driftSize: 0,
              dbExitReason: null,
              timeSinceExit,
            })

            console.error(`🚨 MISMATCH DETECTED: ${trade.symbol}`)
            console.error(`   DB: Open since ${(timeSinceExit / 60000).toFixed(1)}min ago`)
            console.error(`   Drift: Position closed (size 0)`)
          }
        } catch (err) {
          console.error(`   Error checking ${trade.symbol}:`, err)
        }
      }

      if (mismatches.length === 0) {
        console.log('   ✅ No mismatches found - DB and Drift states match')
      } else {
        console.error(`   ❌ Found ${mismatches.length} mismatches!`)
        await this.handleMismatches(mismatches)
      }

    } catch (error) {
      console.error('❌ Error running Drift state verification:', error)
    }

    return mismatches
  }

  /**
   * Handle detected mismatches
   */
  private async handleMismatches(mismatches: DriftStateMismatch[]): Promise<void> {
    for (const mismatch of mismatches) {
      if (mismatch.expectedState === 'closed' && mismatch.actualState === 'open') {
        // CRITICAL: Position should be closed but is still open on Drift
        await this.retryClose(mismatch)
      } else if (mismatch.expectedState === 'open' && mismatch.actualState === 'closed') {
        // Position closed externally - this is handled by Position Manager's ghost detection
        console.log(`   ℹ️ ${mismatch.symbol}: Ghost position (will be cleaned by Position Manager)`)
      }
    }

    // Send Telegram alert
    await this.sendMismatchAlert(mismatches)
  }

  /**
   * Retry closing a position that should be closed but isn't
   */
  private async retryClose(mismatch: DriftStateMismatch): Promise<void> {
    console.log(`🔄 Retrying close for ${mismatch.symbol}...`)

    try {
      const result = await closePosition({
        symbol: mismatch.symbol,
        percentToClose: 100,
        slippageTolerance: 0.05 // 5% slippage tolerance for market order
      })

      if (result.success) {
        console.log(`   ✅ Successfully closed ${mismatch.symbol}`)
        console.log(`   P&L: $${result.realizedPnL?.toFixed(2) || 0}`)
        
        // Update database with retry close info
        const prisma = getPrismaClient()
        await prisma.trade.update({
          where: { id: mismatch.tradeId },
          data: {
            exitOrderTx: result.transactionSignature || 'RETRY_CLOSE',
            realizedPnL: result.realizedPnL || 0,
            configSnapshot: {
              ...(await prisma.trade.findUnique({
                where: { id: mismatch.tradeId },
                select: { configSnapshot: true }
              }))?.configSnapshot as any,
              retryCloseAttempted: true,
              retryCloseTime: new Date().toISOString(),
            }
          }
        })
      } else {
        console.error(`   ❌ Failed to close ${mismatch.symbol}: ${result.error}`)
      }
    } catch (error) {
      console.error(`   ❌ Error retrying close for ${mismatch.symbol}:`, error)
    }
  }

  /**
   * Send Telegram alert about mismatches
   */
  private async sendMismatchAlert(mismatches: DriftStateMismatch[]): Promise<void> {
    const criticalMismatches = mismatches.filter(m => 
      m.expectedState === 'closed' && m.actualState === 'open'
    )

    if (criticalMismatches.length === 0) return

    const message = `
🚨 DRIFT STATE MISMATCH ALERT

Found ${criticalMismatches.length} position(s) that should be closed but are still open on Drift:

${criticalMismatches.map(m => `
📊 ${m.symbol}
   DB Status: Closed (${m.dbExitReason})
   Drift Status: Open (${m.driftSize.toFixed(2)} tokens)
   Time since exit: ${(m.timeSinceExit / 60000).toFixed(1)} minutes
   
   ⚠️ Retry close attempted automatically
`).join('\n')}

This indicates Drift Protocol state propagation issues.
Check Drift UI to verify actual position status.
`.trim()

    try {
      await sendTelegramMessage(message)
    } catch (error) {
      console.error('Failed to send Telegram alert:', error)
    }
  }

  /**
   * Get Drift market index from symbol
   */
  private getMarketIndex(symbol: string): number | null {
    const marketMap: Record<string, number> = {
      'SOL-PERP': 0,
      'BTC-PERP': 1,
      'ETH-PERP': 2,
    }
    return marketMap[symbol] ?? null
  }
}

// Singleton instance
let verifierInstance: DriftStateVerifier | null = null

export function getDriftStateVerifier(): DriftStateVerifier {
  if (!verifierInstance) {
    verifierInstance = new DriftStateVerifier()
  }
  return verifierInstance
}

export function startDriftStateVerifier(): void {
  const verifier = getDriftStateVerifier()
  verifier.start()
}