/**
 * Risk Check API Endpoint
 * 
 * Called by n8n workflow before executing trade
 * POST /api/trading/check-risk
 */

import { NextRequest, NextResponse } from 'next/server'
import { getMergedConfig, TradingConfig } from '@/config/trading'
import { getInitializedPositionManager, ActiveTrade } from '@/lib/trading/position-manager'
import { getLastTradeTime, getLastTradeTimeForSymbol, getTradesInLastHour, getTodayPnL, createBlockedSignal } from '@/lib/database/trades'
import { getPythPriceMonitor } from '@/lib/pyth/price-monitor'
import { scoreSignalQuality, SignalQualityResult } from '@/lib/trading/signal-quality'

export interface RiskCheckRequest {
  symbol: string
  direction: 'long' | 'short'
  timeframe?: string // e.g., "5" for 5min, "60" for 1H, "D" for daily
  // Optional context metrics from TradingView
  atr?: number
  adx?: number
  rsi?: number
  volumeRatio?: number
  pricePosition?: number
}

export interface RiskCheckResponse {
  allowed: boolean
  reason?: string
  details?: string
  qualityScore?: number
  qualityReasons?: string[]
}

/**
 * Position Scaling Validation
 * Determines if adding to an existing position is allowed
 */
async function shouldAllowScaling(
  existingTrade: ActiveTrade,
  newSignal: RiskCheckRequest,
  config: TradingConfig
): Promise<{ allowed: boolean; reasons: string[]; qualityScore?: number; qualityReasons?: string[] }> {
  const reasons: string[] = []
  
  // Check if we have context metrics
  if (!newSignal.atr || !newSignal.adx || !newSignal.pricePosition) {
    reasons.push('Missing signal metrics for scaling validation')
    return { allowed: false, reasons }
  }
  
  // 1. Calculate new signal quality score
  const qualityScore = await scoreSignalQuality({
    atr: newSignal.atr,
    adx: newSignal.adx,
    rsi: newSignal.rsi || 50,
    volumeRatio: newSignal.volumeRatio || 1,
    pricePosition: newSignal.pricePosition,
    direction: newSignal.direction,
    symbol: newSignal.symbol,
    minScore: config.minScaleQualityScore,
  })
  
  // 2. Check quality score (higher bar than initial entry)
  if (qualityScore.score < config.minScaleQualityScore) {
    reasons.push(`Quality score too low: ${qualityScore.score} (need ${config.minScaleQualityScore}+)`)
    return { allowed: false, reasons, qualityScore: qualityScore.score, qualityReasons: qualityScore.reasons }
  }
  
  // 3. Check current position profitability
  const priceMonitor = getPythPriceMonitor()
  const latestPrice = priceMonitor.getCachedPrice(newSignal.symbol)
  const currentPrice = latestPrice?.price
  
  if (!currentPrice) {
    reasons.push('Unable to fetch current price')
    return { allowed: false, reasons, qualityScore: qualityScore.score }
  }
  
  const pnlPercent = existingTrade.direction === 'long'
    ? ((currentPrice - existingTrade.entryPrice) / existingTrade.entryPrice) * 100
    : ((existingTrade.entryPrice - currentPrice) / existingTrade.entryPrice) * 100
  
  if (pnlPercent < config.minProfitForScale) {
    reasons.push(`Position not profitable enough: ${pnlPercent.toFixed(2)}% (need ${config.minProfitForScale}%+)`)
    return { allowed: false, reasons, qualityScore: qualityScore.score }
  }
  
  // 4. Check ADX trend strengthening
  const originalAdx = existingTrade.originalAdx || 0
  const adxIncrease = newSignal.adx - originalAdx
  
  if (adxIncrease < config.minAdxIncrease) {
    reasons.push(`ADX not strengthening enough: +${adxIncrease.toFixed(1)} (need +${config.minAdxIncrease})`)
    return { allowed: false, reasons, qualityScore: qualityScore.score }
  }
  
  // 5. Check price position (don't chase near resistance)
  if (newSignal.pricePosition > config.maxPricePositionForScale) {
    reasons.push(`Price too high in range: ${newSignal.pricePosition.toFixed(0)}% (max ${config.maxPricePositionForScale}%)`)
    return { allowed: false, reasons, qualityScore: qualityScore.score }
  }
  
  // 6. Check max position size (if already scaled)
  const totalScaled = existingTrade.timesScaled || 0
  const currentMultiplier = 1 + (totalScaled * (config.scaleSizePercent / 100))
  const newMultiplier = currentMultiplier + (config.scaleSizePercent / 100)
  
  if (newMultiplier > config.maxScaleMultiplier) {
    reasons.push(`Max position size reached: ${(currentMultiplier * 100).toFixed(0)}% (max ${(config.maxScaleMultiplier * 100).toFixed(0)}%)`)
    return { allowed: false, reasons, qualityScore: qualityScore.score }
  }
  
  // All checks passed!
  reasons.push(`Quality: ${qualityScore.score}/100`)
  reasons.push(`P&L: +${pnlPercent.toFixed(2)}%`)
  reasons.push(`ADX increased: +${adxIncrease.toFixed(1)}`)
  reasons.push(`Price position: ${newSignal.pricePosition.toFixed(0)}%`)
  
  return { 
    allowed: true, 
    reasons,
    qualityScore: qualityScore.score,
    qualityReasons: qualityScore.reasons 
  }
}

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

    const body: RiskCheckRequest = await request.json()
    
    console.log('🔍 Risk check for:', body)
    
    const config = getMergedConfig()
    
    // Check for existing positions on the same symbol
    const positionManager = await getInitializedPositionManager()
    const existingTrades = Array.from(positionManager.getActiveTrades().values())
    const existingPosition = existingTrades.find(trade => trade.symbol === body.symbol)
    
    if (existingPosition) {
      // SAME direction - check if position scaling is allowed
      if (existingPosition.direction === body.direction) {
        // Position scaling feature
        if (config.enablePositionScaling) {
          const scalingCheck = await shouldAllowScaling(existingPosition, body, config)
          
          if (scalingCheck.allowed) {
            console.log('✅ Position scaling ALLOWED:', scalingCheck.reasons)
            return NextResponse.json({
              allowed: true,
              reason: 'Position scaling',
              details: `Scaling into ${body.direction} position - ${scalingCheck.reasons.join(', ')}`,
              qualityScore: scalingCheck.qualityScore,
              qualityReasons: scalingCheck.qualityReasons,
            })
          } else {
            console.log('🚫 Position scaling BLOCKED:', scalingCheck.reasons)
            return NextResponse.json({
              allowed: false,
              reason: 'Scaling not allowed',
              details: scalingCheck.reasons.join(', '),
              qualityScore: scalingCheck.qualityScore,
            })
          }
        }
        
        // Scaling disabled - block duplicate position
        console.log('🚫 Risk check BLOCKED: Duplicate position (same direction)', {
          symbol: body.symbol,
          existingDirection: existingPosition.direction,
          requestedDirection: body.direction,
          existingEntry: existingPosition.entryPrice,
        })
        
        return NextResponse.json({
          allowed: false,
          reason: 'Duplicate position',
          details: `Already have ${existingPosition.direction} position on ${body.symbol} (entry: $${existingPosition.entryPrice}). Enable scaling in settings to add to position.`,
        })
      }
      
      // OPPOSITE direction - potential signal flip
      // Don't auto-allow! Let it go through normal quality checks below
      console.log('🔄 Potential signal flip detected - checking quality score', {
        symbol: body.symbol,
        existingDirection: existingPosition.direction,
        newDirection: body.direction,
        note: 'Will flip IF signal quality passes',
      })
      
      // Continue to quality checks below instead of returning early
    }
    
    // Check if we have context metrics (used throughout the function)
    const hasContextMetrics = body.atr !== undefined && body.atr > 0
    
    // 1. Check daily drawdown limit
    const todayPnL = await getTodayPnL()
    if (todayPnL < config.maxDailyDrawdown) {
      console.log('🚫 Risk check BLOCKED: Daily drawdown limit reached', {
        todayPnL: todayPnL.toFixed(2),
        maxDrawdown: config.maxDailyDrawdown,
      })
      
      return NextResponse.json({
        allowed: false,
        reason: 'Daily drawdown limit',
        details: `Today's P&L ($${todayPnL.toFixed(2)}) has reached max drawdown limit ($${config.maxDailyDrawdown})`,
      })
    }
    
    // 2. Check trades per hour limit
    const tradesInLastHour = await getTradesInLastHour()
    if (tradesInLastHour >= config.maxTradesPerHour) {
      console.log('🚫 Risk check BLOCKED: Hourly trade limit reached', {
        tradesInLastHour,
        maxTradesPerHour: config.maxTradesPerHour,
      })
      
      // Save blocked signal if we have metrics
      if (hasContextMetrics) {
        const priceMonitor = getPythPriceMonitor()
        const latestPrice = priceMonitor.getCachedPrice(body.symbol)
        
        await createBlockedSignal({
          symbol: body.symbol,
          direction: body.direction,
          timeframe: body.timeframe,
          signalPrice: latestPrice?.price || 0,
          atr: body.atr,
          adx: body.adx,
          rsi: body.rsi,
          volumeRatio: body.volumeRatio,
          pricePosition: body.pricePosition,
          signalQualityScore: 0, // Not calculated yet
          minScoreRequired: config.minSignalQualityScore,
          blockReason: 'HOURLY_TRADE_LIMIT',
          blockDetails: `${tradesInLastHour} trades in last hour (max: ${config.maxTradesPerHour})`,
        })
      }
      
      return NextResponse.json({
        allowed: false,
        reason: 'Hourly trade limit',
        details: `Already placed ${tradesInLastHour} trades in the last hour (max: ${config.maxTradesPerHour})`,
      })
    }
    
    // 3. Check cooldown period PER SYMBOL (not global)
    const lastTradeTimeForSymbol = await getLastTradeTimeForSymbol(body.symbol)
    if (lastTradeTimeForSymbol && config.minTimeBetweenTrades > 0) {
      const timeSinceLastTrade = Date.now() - lastTradeTimeForSymbol.getTime()
      const cooldownMs = config.minTimeBetweenTrades * 60 * 1000 // Convert minutes to milliseconds
      
      if (timeSinceLastTrade < cooldownMs) {
        const remainingMs = cooldownMs - timeSinceLastTrade
        const remainingMinutes = Math.ceil(remainingMs / 60000)
        
        console.log('🚫 Risk check BLOCKED: Cooldown period active for', body.symbol, {
          lastTradeTime: lastTradeTimeForSymbol.toISOString(),
          timeSinceLastTradeMs: timeSinceLastTrade,
          cooldownMs,
          remainingMinutes,
        })
        
        // Save blocked signal if we have metrics
        if (hasContextMetrics) {
          const priceMonitor = getPythPriceMonitor()
          const latestPrice = priceMonitor.getCachedPrice(body.symbol)
          
          await createBlockedSignal({
            symbol: body.symbol,
            direction: body.direction,
            timeframe: body.timeframe,
            signalPrice: latestPrice?.price || 0,
            atr: body.atr,
            adx: body.adx,
            rsi: body.rsi,
            volumeRatio: body.volumeRatio,
            pricePosition: body.pricePosition,
            signalQualityScore: 0, // Not calculated yet
            minScoreRequired: config.minSignalQualityScore,
            blockReason: 'COOLDOWN_PERIOD',
            blockDetails: `Wait ${remainingMinutes} more min (cooldown: ${config.minTimeBetweenTrades} min)`,
          })
        }
        
        return NextResponse.json({
          allowed: false,
          reason: 'Cooldown period',
          details: `Must wait ${remainingMinutes} more minute(s) before next ${body.symbol} trade (cooldown: ${config.minTimeBetweenTrades} min)`,
        })
      }
    }
    
    // 4. Check signal quality (if context metrics provided)
    if (hasContextMetrics) {
      const qualityScore = await scoreSignalQuality({
        atr: body.atr || 0,
        adx: body.adx || 0,
        rsi: body.rsi || 0,
        volumeRatio: body.volumeRatio || 0,
        pricePosition: body.pricePosition || 0,
        direction: body.direction,
        symbol: body.symbol,
        timeframe: body.timeframe, // Pass timeframe for context-aware scoring
        minScore: config.minSignalQualityScore // Use config value
      })
      
      if (!qualityScore.passed) {
        console.log('🚫 Risk check BLOCKED: Signal quality too low', {
          score: qualityScore.score,
          threshold: config.minSignalQualityScore,
          reasons: qualityScore.reasons
        })
        
        // Get current price for the blocked signal record
        const priceMonitor = getPythPriceMonitor()
        const latestPrice = priceMonitor.getCachedPrice(body.symbol)
        
        // Save blocked signal to database for future analysis
        await createBlockedSignal({
          symbol: body.symbol,
          direction: body.direction,
          timeframe: body.timeframe,
          signalPrice: latestPrice?.price || 0,
          atr: body.atr,
          adx: body.adx,
          rsi: body.rsi,
          volumeRatio: body.volumeRatio,
          pricePosition: body.pricePosition,
          signalQualityScore: qualityScore.score,
          signalQualityVersion: 'v4', // Update this when scoring logic changes
          scoreBreakdown: { reasons: qualityScore.reasons },
          minScoreRequired: config.minSignalQualityScore,
          blockReason: 'QUALITY_SCORE_TOO_LOW',
          blockDetails: `Score: ${qualityScore.score}/${config.minSignalQualityScore} - ${qualityScore.reasons.join(', ')}`,
        })
        
        return NextResponse.json({
          allowed: false,
          reason: 'Signal quality too low',
          details: `Score: ${qualityScore.score}/100 - ${qualityScore.reasons.join(', ')}`,
          qualityScore: qualityScore.score,
          qualityReasons: qualityScore.reasons
        })
      }
      
      console.log(`✅ Risk check PASSED: All checks passed`, {
        todayPnL: todayPnL.toFixed(2),
        tradesLastHour: tradesInLastHour,
        cooldownPassed: lastTradeTimeForSymbol ? 'yes' : `no previous ${body.symbol} trades`,
        qualityScore: qualityScore.score,
        qualityReasons: qualityScore.reasons
      })
      
      return NextResponse.json({
        allowed: true,
        details: 'All risk checks passed',
        qualityScore: qualityScore.score,
        qualityReasons: qualityScore.reasons
      })
    }
    
    console.log(`✅ Risk check PASSED: All checks passed`, {
      todayPnL: todayPnL.toFixed(2),
      tradesLastHour: tradesInLastHour,
      cooldownPassed: lastTradeTimeForSymbol ? 'yes' : `no previous ${body.symbol} trades`,
    })
    
    return NextResponse.json({
      allowed: true,
      details: 'All risk checks passed',
    })

  } catch (error) {
    console.error('❌ Risk check error:', error)
    
    return NextResponse.json(
      {
        allowed: false,
        reason: 'Server error',
        details: error instanceof Error ? error.message : 'Unknown error',
      },
      { status: 500 }
    )
  }
}