/**
 * Execute Trade API Endpoint
 * 
 * Called by n8n workflow when TradingView signal is received
 * POST /api/trading/execute
 */

import { NextRequest, NextResponse } from 'next/server'
import { initializeDriftService } from '@/lib/drift/client'
import { openPosition, placeExitOrders } from '@/lib/drift/orders'
import { normalizeTradingViewSymbol } from '@/config/trading'
import { getMergedConfig } from '@/config/trading'
import { getInitializedPositionManager, ActiveTrade } from '@/lib/trading/position-manager'
import { createTrade } from '@/lib/database/trades'

export interface ExecuteTradeRequest {
  symbol: string // TradingView symbol (e.g., 'SOLUSDT')
  direction: 'long' | 'short'
  timeframe: string // e.g., '5'
  signalStrength?: 'strong' | 'moderate' | 'weak'
  signalPrice?: number
}

export interface ExecuteTradeResponse {
  success: boolean
  positionId?: string
  symbol?: string
  direction?: 'long' | 'short'
  entryPrice?: number
  positionSize?: number
  leverage?: number
  stopLoss?: number
  takeProfit1?: number
  takeProfit2?: number
  stopLossPercent?: number
  tp1Percent?: number
  tp2Percent?: number
  entrySlippage?: number
  timestamp?: string
  error?: string
  message?: string
}

export async function POST(request: NextRequest): Promise<NextResponse<ExecuteTradeResponse>> {
  try {
    // Verify authorization
    const authHeader = request.headers.get('authorization')
    const expectedAuth = `Bearer ${process.env.API_SECRET_KEY}`
    
    if (!authHeader || authHeader !== expectedAuth) {
      return NextResponse.json(
        {
          success: false,
          error: 'Unauthorized',
          message: 'Invalid API key',
        },
        { status: 401 }
      )
    }

    // Parse request body
    const body: ExecuteTradeRequest = await request.json()
    
    console.log('🎯 Trade execution request received:', body)
    
    // Validate required fields
    if (!body.symbol || !body.direction) {
      return NextResponse.json(
        {
          success: false,
          error: 'Missing required fields',
          message: 'symbol and direction are required',
        },
        { status: 400 }
      )
    }

    // Normalize symbol
    const driftSymbol = normalizeTradingViewSymbol(body.symbol)
    console.log(`📊 Normalized symbol: ${body.symbol} → ${driftSymbol}`)

    // Get trading configuration
    const config = getMergedConfig()
    
    // Initialize Drift service if not already initialized
    const driftService = await initializeDriftService()
    
    // Check account health before trading
    const health = await driftService.getAccountHealth()
    console.log('💊 Account health:', health)
    
    if (health.freeCollateral <= 0) {
      return NextResponse.json(
        {
          success: false,
          error: 'Insufficient collateral',
          message: `Free collateral: $${health.freeCollateral.toFixed(2)}`,
        },
        { status: 400 }
      )
    }

    // AUTO-FLIP: Check for existing opposite direction position
    const positionManager = await getInitializedPositionManager()
    const existingTrades = Array.from(positionManager.getActiveTrades().values())
    const oppositePosition = existingTrades.find(
      trade => trade.symbol === driftSymbol && trade.direction !== body.direction
    )
    
    if (oppositePosition) {
      console.log(`🔄 Signal flip detected! Closing ${oppositePosition.direction} to open ${body.direction}`)
      
      // Close opposite position
      const { closePosition } = await import('@/lib/drift/orders')
      const closeResult = await closePosition({
        symbol: driftSymbol,
        percentToClose: 100,
        slippageTolerance: config.slippageTolerance,
      })
      
      if (!closeResult.success) {
        console.error('❌ Failed to close opposite position:', closeResult.error)
        // Continue anyway - we'll try to open the new position
      } else {
        console.log(`✅ Closed ${oppositePosition.direction} position at $${closeResult.closePrice?.toFixed(4)} (P&L: $${closeResult.realizedPnL?.toFixed(2)})`)
        
        // Position Manager will handle cleanup (including order cancellation)
        // The executeExit method already removes the trade and updates database
      }
      
      // Small delay to ensure position is fully closed
      await new Promise(resolve => setTimeout(resolve, 1000))
    }

    // Calculate position size with leverage
    const positionSizeUSD = config.positionSize * config.leverage
    
    console.log(`💰 Opening ${body.direction} position:`)
    console.log(`   Symbol: ${driftSymbol}`)
    console.log(`   Base size: $${config.positionSize}`)
    console.log(`   Leverage: ${config.leverage}x`)
    console.log(`   Total position: $${positionSizeUSD}`)

    // Open position
    const openResult = await openPosition({
      symbol: driftSymbol,
      direction: body.direction,
      sizeUSD: positionSizeUSD,
      slippageTolerance: config.slippageTolerance,
    })

    if (!openResult.success) {
      return NextResponse.json(
        {
          success: false,
          error: 'Position open failed',
          message: openResult.error,
        },
        { status: 500 }
      )
    }

    // Calculate stop loss and take profit prices
    const entryPrice = openResult.fillPrice!
    
    const stopLossPrice = calculatePrice(
      entryPrice,
      config.stopLossPercent,
      body.direction
    )
    
    // Calculate dual stop prices if enabled
    let softStopPrice: number | undefined
    let hardStopPrice: number | undefined
    
    if (config.useDualStops) {
      softStopPrice = calculatePrice(
        entryPrice,
        config.softStopPercent,
        body.direction
      )
      hardStopPrice = calculatePrice(
        entryPrice,
        config.hardStopPercent,
        body.direction
      )
      console.log('🛡️🛡️ Dual stop system enabled:')
      console.log(`   Soft stop: $${softStopPrice.toFixed(4)} (${config.softStopPercent}%)`)
      console.log(`   Hard stop: $${hardStopPrice.toFixed(4)} (${config.hardStopPercent}%)`)
    }
    
    const tp1Price = calculatePrice(
      entryPrice,
      config.takeProfit1Percent,
      body.direction
    )
    
    const tp2Price = calculatePrice(
      entryPrice,
      config.takeProfit2Percent,
      body.direction
    )

    console.log('📊 Trade targets:')
    console.log(`   Entry: $${entryPrice.toFixed(4)}`)
    console.log(`   SL: $${stopLossPrice.toFixed(4)} (${config.stopLossPercent}%)`)
    console.log(`   TP1: $${tp1Price.toFixed(4)} (${config.takeProfit1Percent}%)`)
    console.log(`   TP2: $${tp2Price.toFixed(4)} (${config.takeProfit2Percent}%)`)

    // Calculate emergency stop
    const emergencyStopPrice = calculatePrice(
      entryPrice,
      config.emergencyStopPercent,
      body.direction
    )

    // Create active trade object
    const activeTrade: ActiveTrade = {
      id: `trade-${Date.now()}`,
      positionId: openResult.transactionSignature!,
      symbol: driftSymbol,
      direction: body.direction,
      entryPrice,
      entryTime: Date.now(),
      positionSize: positionSizeUSD,
      leverage: config.leverage,
      stopLossPrice,
      tp1Price,
      tp2Price,
      emergencyStopPrice,
      currentSize: positionSizeUSD,
      tp1Hit: false,
      tp2Hit: false,
      slMovedToBreakeven: false,
      slMovedToProfit: false,
      trailingStopActive: false,
      realizedPnL: 0,
      unrealizedPnL: 0,
      peakPnL: 0,
      peakPrice: entryPrice,
      priceCheckCount: 0,
      lastPrice: entryPrice,
      lastUpdateTime: Date.now(),
    }

    // CRITICAL FIX: Place on-chain TP/SL orders BEFORE adding to Position Manager
    // This prevents race condition where Position Manager detects "external closure"
    // while orders are still being placed, leaving orphaned stop loss orders
    let exitOrderSignatures: string[] = []
    try {
      const exitRes = await placeExitOrders({
        symbol: driftSymbol,
        positionSizeUSD: positionSizeUSD,
        tp1Price,
        tp2Price,
        stopLossPrice,
        tp1SizePercent: config.takeProfit1SizePercent || 50,
        tp2SizePercent: config.takeProfit2SizePercent || 100,
        direction: body.direction,
        // Dual stop parameters
        useDualStops: config.useDualStops,
        softStopPrice: softStopPrice,
        softStopBuffer: config.softStopBuffer,
        hardStopPrice: hardStopPrice,
      })

      if (!exitRes.success) {
        console.error('❌ Failed to place on-chain exit orders:', exitRes.error)
      } else {
        console.log('📨 Exit orders placed on-chain:', exitRes.signatures)
        exitOrderSignatures = exitRes.signatures || []
      }
    } catch (err) {
      console.error('❌ Unexpected error placing exit orders:', err)
    }

    // Add to position manager for monitoring AFTER orders are placed
    await positionManager.addTrade(activeTrade)
    
    console.log('✅ Trade added to position manager for monitoring')

    // Create response object
    const response: ExecuteTradeResponse = {
      success: true,
      positionId: openResult.transactionSignature,
      symbol: driftSymbol,
      direction: body.direction,
      entryPrice: entryPrice,
      positionSize: positionSizeUSD,
      leverage: config.leverage,
      stopLoss: stopLossPrice,
      takeProfit1: tp1Price,
      takeProfit2: tp2Price,
      stopLossPercent: config.stopLossPercent,
      tp1Percent: config.takeProfit1Percent,
      tp2Percent: config.takeProfit2Percent,
      entrySlippage: openResult.slippage,
      timestamp: new Date().toISOString(),
    }

    // Attach exit order signatures to response
    if (exitOrderSignatures.length > 0) {
      (response as any).exitOrderSignatures = exitOrderSignatures
    }

    // Save trade to database
    try {
      await createTrade({
        positionId: openResult.transactionSignature!,
        symbol: driftSymbol,
        direction: body.direction,
        entryPrice,
        positionSizeUSD: positionSizeUSD,
        leverage: config.leverage,
        stopLossPrice,
        takeProfit1Price: tp1Price,
        takeProfit2Price: tp2Price,
        tp1SizePercent: config.takeProfit1SizePercent || 50,
        tp2SizePercent: config.takeProfit2SizePercent || 100,
        configSnapshot: config,
        entryOrderTx: openResult.transactionSignature!,
        tp1OrderTx: exitOrderSignatures[0],
        tp2OrderTx: exitOrderSignatures[1],
        slOrderTx: config.useDualStops ? undefined : exitOrderSignatures[2],
        softStopOrderTx: config.useDualStops ? exitOrderSignatures[2] : undefined,
        hardStopOrderTx: config.useDualStops ? exitOrderSignatures[3] : undefined,
        softStopPrice,
        hardStopPrice,
        signalStrength: body.signalStrength,
        timeframe: body.timeframe,
      })
      
      console.log('💾 Trade saved to database')
    } catch (dbError) {
      console.error('❌ Failed to save trade to database:', dbError)
      // Don't fail the trade if database save fails
    }

    console.log('✅ Trade executed successfully!')
    
    return NextResponse.json(response)

  } catch (error) {
    console.error('❌ Trade execution error:', error)
    
    return NextResponse.json(
      {
        success: false,
        error: 'Internal server error',
        message: error instanceof Error ? error.message : 'Unknown error',
      },
      { status: 500 }
    )
  }
}

/**
 * Helper function to calculate price based on percentage
 */
function calculatePrice(
  entryPrice: number,
  percent: number,
  direction: 'long' | 'short'
): number {
  if (direction === 'long') {
    return entryPrice * (1 + percent / 100)
  } else {
    return entryPrice * (1 - percent / 100)
  }
}