/**
 * SL Verification System - Post-Open Safety Checks
 * 
 * Purpose: Verify stop loss orders are actually placed on-chain after position opens
 * Prevents Bug #76 (Silent SL Placement Failure) from leaving positions unprotected
 * 
 * Architecture: Event-driven verification with exponential backoff (30s, 60s, 90s)
 * - Queries Drift on-chain state, not just database
 * - 3 verification attempts with increasing delays
 * - If all fail: Halt trading + close position immediately
 * 
 * Rate Limit Impact: ~3-9 queries per position (vs 360/hour with interval-based)
 * 
 * Created: Dec 16, 2025 (Bug #76 root cause + user mandate "better safe than sorry")
 */

import { getDriftService } from '../drift/client'
import { getMarketConfig } from '../../config/trading'
import { closePosition } from '../drift/orders'
import { updateTradeState } from '../database/trades'
import { sendTelegramMessage } from '../notifications/telegram'
import { OrderType, Order } from '@drift-labs/sdk'

// Global trading halt flag
let tradingHalted = false
let haltReason = ''

export function isTradingHalted(): boolean {
  return tradingHalted
}

export function getHaltReason(): string {
  return haltReason
}

export function resetTradingHalt(): void {
  tradingHalted = false
  haltReason = ''
  console.log('✅ Trading halt reset - system re-enabled')
}

/**
 * Query Drift on-chain state to verify SL orders exist
 * Returns true if at least one SL order found (TRIGGER_MARKET or TRIGGER_LIMIT)
 */
export async function querySLOrdersFromDrift(
  symbol: string,
  marketIndex: number
): Promise<{ exists: boolean; orderCount: number; orderTypes: string[] }> {
  try {
    const driftService = getDriftService()
    const driftClient = driftService.getClient()
    
    // Get open orders from the drift client
    const allOrders = driftClient.getUser().getOpenOrders()
    
    const marketOrders = allOrders.filter(
      (order: Order) => order.marketIndex === marketIndex && order.reduceOnly === true
    )
    
    // Find SL orders (TRIGGER_MARKET or TRIGGER_LIMIT)
    const slOrders = marketOrders.filter(
      (order: Order) => 
        order.orderType === OrderType.TRIGGER_MARKET ||
        order.orderType === OrderType.TRIGGER_LIMIT
    )
    
    const orderTypes = slOrders.map((o: Order) => {
      if (o.orderType === OrderType.TRIGGER_MARKET) return 'TRIGGER_MARKET'
      if (o.orderType === OrderType.TRIGGER_LIMIT) return 'TRIGGER_LIMIT'
      return 'UNKNOWN'
    })
    
    console.log(`🔍 SL Verification for ${symbol}:`)
    console.log(`   Total reduce-only orders: ${marketOrders.length}`)
    console.log(`   SL orders found: ${slOrders.length}`)
    if (slOrders.length > 0) {
      console.log(`   Order types: ${orderTypes.join(', ')}`)
    }
    
    return {
      exists: slOrders.length > 0,
      orderCount: slOrders.length,
      orderTypes,
    }
  } catch (error) {
    console.error(`❌ Error querying SL orders from Drift:`, error)
    // On error, assume SL might exist (fail-open for transient failures)
    return { exists: true, orderCount: 0, orderTypes: [] }
  }
}

/**
 * Halt trading and close position immediately
 * Called when SL verification fails after all retries
 */
async function haltTradingAndClosePosition(
  tradeId: string,
  symbol: string,
  reason: string
): Promise<void> {
  try {
    // Set global halt flag
    tradingHalted = true
    haltReason = reason
    
    console.error(`🚨🚨🚨 TRADING HALTED 🚨🚨🚨`)
    console.error(`   Reason: ${reason}`)
    console.error(`   Trade ID: ${tradeId}`)
    console.error(`   Symbol: ${symbol}`)
    console.error(`   Action: Closing position immediately for safety`)
    
    // Send critical Telegram alert
    await sendTelegramMessage(`🚨🚨🚨 CRITICAL: TRADING HALTED 🚨🚨🚨

Reason: ${reason}

Trade ID: ${tradeId}
Symbol: ${symbol}

Action Taken:
✅ Closing position immediately (safety)
⛔ New trades blocked until manual reset

Position left unprotected - closing to prevent losses.

Manual reset required: Check logs and reset via API or Telegram.`)
    
    // Close position immediately
    console.log(`🔒 Closing ${symbol} position for safety...`)
    const closeResult = await closePosition({
      symbol,
      percentToClose: 100,
      slippageTolerance: 0.02, // 2% slippage tolerance for emergency closes
    })
    
    if (closeResult.success) {
      console.log(`✅ Position closed successfully: ${closeResult.transactionSignature}`)
      console.log(`   Emergency closure reason: ${reason}`)
      
      // Update database with emergency exit reason
      const { getPrismaClient } = await import('../database/trades')
      const prisma = getPrismaClient()
      await prisma.trade.update({
        where: { id: tradeId },
        data: {
          exitReason: 'emergency',
        }
      })
    } else {
      console.error(`❌ Failed to close position: ${closeResult.error}`)
      await sendTelegramMessage(`❌ CRITICAL: Failed to close position ${symbol}

Close Error: ${closeResult.error}

MANUAL INTERVENTION REQUIRED IMMEDIATELY`)
    }
  } catch (error) {
    console.error(`❌ Error in haltTradingAndClosePosition:`, error)
    await sendTelegramMessage(`❌ CRITICAL: Error halting trading and closing position

Error: ${error instanceof Error ? error.message : String(error)}

MANUAL INTERVENTION REQUIRED IMMEDIATELY`)
  }
}

/**
 * Verify SL orders exist with exponential backoff (30s, 60s, 90s)
 * If all 3 attempts fail: Halt trading + close position
 * 
 * Usage: Call after position opened successfully
 * Example: await verifySLWithRetries(tradeId, symbol, marketIndex)
 */
export async function verifySLWithRetries(
  tradeId: string,
  symbol: string,
  marketIndex: number
): Promise<void> {
  const delays = [30000, 60000, 90000] // 30s, 60s, 90s
  const maxAttempts = 3
  
  console.log(`🛡️ Starting SL verification for ${symbol} (Trade: ${tradeId})`)
  console.log(`   Verification schedule: 30s, 60s, 90s (3 attempts)`)
  
  for (let attempt = 1; attempt <= maxAttempts; attempt++) {
    const delay = delays[attempt - 1]
    
    console.log(`⏱️ Verification attempt ${attempt}/${maxAttempts} - waiting ${delay/1000}s...`)
    
    // Wait for scheduled delay
    await new Promise(resolve => setTimeout(resolve, delay))
    
    // Query Drift on-chain state
    const slStatus = await querySLOrdersFromDrift(symbol, marketIndex)
    
    if (slStatus.exists) {
      console.log(`✅ SL VERIFIED on attempt ${attempt}/${maxAttempts}`)
      console.log(`   Found ${slStatus.orderCount} SL order(s): ${slStatus.orderTypes.join(', ')}`)
      console.log(`   Verification timing: ${delay/1000}s after position open`)
      
      // Success - verification details logged above
      return // Success - exit retry loop
    }
    
    console.warn(`⚠️ SL NOT FOUND on attempt ${attempt}/${maxAttempts}`)
    console.warn(`   Reduce-only orders: ${slStatus.orderCount}`)
    
    if (attempt < maxAttempts) {
      console.log(`   Retrying in ${delays[attempt]/1000}s...`)
    } else {
      // All 3 attempts failed - CRITICAL FAILURE
      console.error(`❌ SL VERIFICATION FAILED after ${maxAttempts} attempts`)
      console.error(`   Position is UNPROTECTED - initiating emergency procedures`)
      
      // Halt trading + close position
      await haltTradingAndClosePosition(
        tradeId,
        symbol,
        `SL verification failed after ${maxAttempts} attempts (30s, 60s, 90s). Position left unprotected - Bug #76 detected.`
      )
    }
  }
}

/**
 * Check if trading is halted before accepting new trades
 * Returns { allow: boolean, reason: string }
 */
export function checkTradingAllowed(): { allow: boolean; reason: string } {
  if (tradingHalted) {
    return {
      allow: false,
      reason: `Trading halted: ${haltReason}. Manual reset required.`,
    }
  }
  
  return { allow: true, reason: '' }
}