/**
 * 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, updateTradeExit } from '@/lib/database/trades'

/**
 * Calculate signal quality score (same logic as check-risk endpoint)
 */
function calculateQualityScore(params: {
  atr?: number
  adx?: number
  rsi?: number
  volumeRatio?: number
  pricePosition?: number
  direction: 'long' | 'short'
}): number | undefined {
  // If no metrics provided, return undefined
  if (!params.atr || params.atr === 0) {
    return undefined
  }
  
  let score = 50 // Base score
  
  // ATR check
  if (params.atr < 0.6) {
    score -= 15
  } else if (params.atr > 2.5) {
    score -= 20
  } else {
    score += 10
  }
  
  // ADX check
  if (params.adx && params.adx > 0) {
    if (params.adx > 25) {
      score += 15
    } else if (params.adx < 18) {
      score -= 15
    } else {
      score += 5
    }
  }
  
  // RSI check
  if (params.rsi && params.rsi > 0) {
    if (params.direction === 'long') {
      if (params.rsi > 50 && params.rsi < 70) {
        score += 10
      } else if (params.rsi > 70) {
        score -= 10
      }
    } else {
      if (params.rsi < 50 && params.rsi > 30) {
        score += 10
      } else if (params.rsi < 30) {
        score -= 10
      }
    }
  }
  
  // Volume check
  if (params.volumeRatio && params.volumeRatio > 0) {
    if (params.volumeRatio > 1.2) {
      score += 10
    } else if (params.volumeRatio < 0.8) {
      score -= 10
    }
  }
  
  // Price position check
  if (params.pricePosition && params.pricePosition > 0) {
    if (params.direction === 'long' && params.pricePosition > 90) {
      score -= 15
    } else if (params.direction === 'short' && params.pricePosition < 10) {
      score -= 15
    } else {
      score += 5
    }
  }
  
  return score
}

export interface ExecuteTradeRequest {
  symbol: string // TradingView symbol (e.g., 'SOLUSDT')
  direction: 'long' | 'short'
  timeframe: string // e.g., '5'
  signalStrength?: 'strong' | 'moderate' | 'weak'
  signalPrice?: number
  // Context metrics from TradingView
  atr?: number
  adx?: number
  rsi?: number
  volumeRatio?: number
  pricePosition?: 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()
    
    // Get symbol-specific position sizing
    const { getPositionSizeForSymbol } = await import('@/config/trading')
    const { size: positionSize, leverage, enabled } = getPositionSizeForSymbol(driftSymbol, config)
    
    // Check if trading is enabled for this symbol
    if (!enabled) {
      console.log(`⛔ Trading disabled for ${driftSymbol}`)
      return NextResponse.json(
        {
          success: false,
          error: 'Symbol trading disabled',
          message: `Trading is currently disabled for ${driftSymbol}. Enable it in settings.`,
        },
        { status: 400 }
      )
    }
    
    console.log(`📐 Symbol-specific sizing for ${driftSymbol}:`)
    console.log(`   Enabled: ${enabled}`)
    console.log(`   Position size: $${positionSize}`)
    console.log(`   Leverage: ${leverage}x`)
    
    // 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
    )
    
    // Check for same direction position (scaling vs duplicate)
    const sameDirectionPosition = existingTrades.find(
      trade => trade.symbol === driftSymbol && trade.direction === body.direction
    )
    
    if (sameDirectionPosition) {
      // Position scaling enabled - scale into existing position
      if (config.enablePositionScaling) {
        console.log(`📈 POSITION SCALING: Adding to existing ${body.direction} position on ${driftSymbol}`)
        
        // Calculate scale size
        const scaleSize = (positionSize * leverage) * (config.scaleSizePercent / 100)
        
        console.log(`💰 Scaling position:`)
        console.log(`   Original size: $${sameDirectionPosition.positionSize}`)
        console.log(`   Scale size: $${scaleSize} (${config.scaleSizePercent}% of original)`)
        console.log(`   Leverage: ${leverage}x`)
        
        // Open additional position
        const scaleResult = await openPosition({
          symbol: driftSymbol,
          direction: body.direction,
          sizeUSD: scaleSize,
          slippageTolerance: config.slippageTolerance,
        })
        
        if (!scaleResult.success) {
          console.error('❌ Failed to scale position:', scaleResult.error)
          return NextResponse.json(
            {
              success: false,
              error: 'Position scaling failed',
              message: scaleResult.error,
            },
            { status: 500 }
          )
        }
        
        console.log(`✅ Scaled into position at $${scaleResult.fillPrice?.toFixed(4)}`)
        
        // Update Position Manager tracking
        const timesScaled = (sameDirectionPosition.timesScaled || 0) + 1
        const totalScaleAdded = (sameDirectionPosition.totalScaleAdded || 0) + scaleSize
        const newTotalSize = sameDirectionPosition.currentSize + (scaleResult.fillSize || 0)
        
        // Update the trade tracking (simplified - just update the active trade object)
        sameDirectionPosition.timesScaled = timesScaled
        sameDirectionPosition.totalScaleAdded = totalScaleAdded
        sameDirectionPosition.currentSize = newTotalSize
        
        console.log(`📊 Position scaled: ${timesScaled}x total, $${totalScaleAdded.toFixed(2)} added`)
        
        return NextResponse.json({
          success: true,
          action: 'scaled',
          positionId: sameDirectionPosition.positionId,
          symbol: driftSymbol,
          direction: body.direction,
          scalePrice: scaleResult.fillPrice,
          scaleSize: scaleSize,
          totalSize: newTotalSize,
          timesScaled: timesScaled,
          timestamp: new Date().toISOString(),
        })
      }
      
      // Scaling disabled - block duplicate
      console.log(`⛔ DUPLICATE POSITION BLOCKED: Already have ${body.direction} position on ${driftSymbol}`)
      return NextResponse.json(
        {
          success: false,
          error: 'Duplicate position detected',
          message: `Already have an active ${body.direction} position on ${driftSymbol}. Enable position scaling in settings to add to this position.`,
        },
        { status: 400 }
      )
    }
    
    if (oppositePosition) {
      console.log(`🔄 Signal flip detected! Closing ${oppositePosition.direction} to open ${body.direction}`)
      
      // CRITICAL: Remove from Position Manager FIRST to prevent race condition
      // where Position Manager detects "external closure" while we're deliberately closing it
      console.log(`🗑️ Removing ${oppositePosition.direction} position from Position Manager before flip...`)
      await positionManager.removeTrade(oppositePosition.id)
      console.log(`✅ Removed from Position Manager`)
      
      // Close opposite position on Drift
      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)})`)
        
        // Save the closure to database
        try {
          const holdTimeSeconds = Math.floor((Date.now() - oppositePosition.entryTime) / 1000)
          const profitPercent = ((closeResult.closePrice! - oppositePosition.entryPrice) / oppositePosition.entryPrice) * 100
          const accountPnL = profitPercent * oppositePosition.leverage * (oppositePosition.direction === 'long' ? 1 : -1)
          const realizedPnL = (oppositePosition.currentSize * accountPnL) / 100
          
          await updateTradeExit({
            positionId: oppositePosition.positionId,
            exitPrice: closeResult.closePrice!,
            exitReason: 'manual', // Manually closed for flip
            realizedPnL: realizedPnL,
            exitOrderTx: closeResult.transactionSignature || 'FLIP_CLOSE',
            holdTimeSeconds,
            maxDrawdown: Math.abs(Math.min(0, oppositePosition.maxAdverseExcursion)),
            maxGain: Math.max(0, oppositePosition.maxFavorableExcursion),
            maxFavorableExcursion: oppositePosition.maxFavorableExcursion,
            maxAdverseExcursion: oppositePosition.maxAdverseExcursion,
            maxFavorablePrice: oppositePosition.maxFavorablePrice,
            maxAdversePrice: oppositePosition.maxAdversePrice,
          })
          console.log(`💾 Saved opposite position closure to database`)
        } catch (dbError) {
          console.error('❌ Failed to save opposite position closure:', dbError)
        }
      }
      
      // Small delay to ensure position is fully closed on-chain
      await new Promise(resolve => setTimeout(resolve, 2000))
    }

    // Calculate position size with leverage
    const positionSizeUSD = positionSize * leverage
    
    console.log(`💰 Opening ${body.direction} position:`)
    console.log(`   Symbol: ${driftSymbol}`)
    console.log(`   Base size: $${positionSize}`)
    console.log(`   Leverage: ${leverage}x`)
    console.log(`   Total position: $${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 }
      )
    }
    
    // CRITICAL: Check for phantom trade (position opened but size mismatch)
    if (openResult.isPhantom) {
      console.error(`🚨 PHANTOM TRADE DETECTED - Not adding to Position Manager`)
      console.error(`   Expected: $${positionSizeUSD.toFixed(2)}`)
      console.error(`   Actual: $${openResult.actualSizeUSD?.toFixed(2)}`)
      
      // Save phantom trade to database for analysis
      try {
        const qualityScore = calculateQualityScore({
          atr: body.atr,
          adx: body.adx,
          rsi: body.rsi,
          volumeRatio: body.volumeRatio,
          pricePosition: body.pricePosition,
          direction: body.direction,
        })
        
        await createTrade({
          positionId: openResult.transactionSignature!,
          symbol: driftSymbol,
          direction: body.direction,
          entryPrice: openResult.fillPrice!,
          positionSizeUSD: positionSizeUSD,
          leverage: config.leverage,
          stopLossPrice: 0, // Not applicable for phantom
          takeProfit1Price: 0,
          takeProfit2Price: 0,
          tp1SizePercent: 0,
          tp2SizePercent: 0,
          configSnapshot: config,
          entryOrderTx: openResult.transactionSignature!,
          signalStrength: body.signalStrength,
          timeframe: body.timeframe,
          atrAtEntry: body.atr,
          adxAtEntry: body.adx,
          rsiAtEntry: body.rsi,
          volumeAtEntry: body.volumeRatio,
          pricePositionAtEntry: body.pricePosition,
          signalQualityScore: qualityScore,
          // Phantom-specific fields
          status: 'phantom',
          isPhantom: true,
          expectedSizeUSD: positionSizeUSD,
          actualSizeUSD: openResult.actualSizeUSD,
          phantomReason: 'ORACLE_PRICE_MISMATCH', // Likely cause based on logs
        })
        
        console.log(`💾 Phantom trade saved to database for analysis`)
      } catch (dbError) {
        console.error('❌ Failed to save phantom trade:', dbError)
      }
      
      return NextResponse.json(
        {
          success: false,
          error: 'Phantom trade detected',
          message: `Position opened but size mismatch detected. Expected $${positionSizeUSD.toFixed(2)}, got $${openResult.actualSizeUSD?.toFixed(2)}. This usually indicates oracle price was stale or order was rejected by exchange.`,
        },
        { 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,
      // MAE/MFE tracking
      maxFavorableExcursion: 0,
      maxAdverseExcursion: 0,
      maxFavorablePrice: entryPrice,
      maxAdversePrice: entryPrice,
      // Position scaling tracking
      originalAdx: body.adx, // Store for scaling validation
      timesScaled: 0,
      totalScaleAdded: 0,
      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,
        entryPrice: entryPrice,
        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 {
      // Calculate quality score if metrics available
      const qualityScore = calculateQualityScore({
        atr: body.atr,
        adx: body.adx,
        rsi: body.rsi,
        volumeRatio: body.volumeRatio,
        pricePosition: body.pricePosition,
        direction: body.direction,
      })
      
      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,
        // Context metrics from TradingView
        atrAtEntry: body.atr,
        adxAtEntry: body.adx,
        rsiAtEntry: body.rsi,
        volumeAtEntry: body.volumeRatio,
        pricePositionAtEntry: body.pricePosition,
        signalQualityScore: qualityScore,
      })
      
      if (qualityScore !== undefined) {
        console.log(`💾 Trade saved with quality score: ${qualityScore}/100`)
      } else {
        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)
  }
}