/**
 * Validate Positions API Endpoint
 * 
 * Compares current open positions against configured settings
 * POST /api/trading/validate-positions
 */

import { NextRequest, NextResponse } from 'next/server'
import { getMergedConfig } from '@/config/trading'
import { getInitializedPositionManager } from '@/lib/trading/position-manager'
import { getDriftService } from '@/lib/drift/client'

interface ValidationIssue {
  type: 'error' | 'warning'
  field: string
  expected: number | string
  actual: number | string
  message: string
}

interface PositionValidation {
  symbol: string
  direction: 'long' | 'short'
  entryPrice: number
  isValid: boolean
  issues: ValidationIssue[]
}

interface ValidationResponse {
  success: boolean
  timestamp: string
  config: {
    leverage: number
    positionSize: number
    tp1Percent: number
    tp2Percent: number
    stopLossPercent: number
    useDualStops: boolean
    hardStopPercent?: number
  }
  positions: PositionValidation[]
  summary: {
    totalPositions: number
    validPositions: number
    positionsWithIssues: number
  }
}

function calculateExpectedPrice(entry: number, percent: number, direction: 'long' | 'short'): number {
  if (direction === 'long') {
    return entry * (1 + percent / 100)
  } else {
    return entry * (1 - percent / 100)
  }
}

function calculateActualPercent(entry: number, price: number, direction: 'long' | 'short'): number {
  if (direction === 'long') {
    return ((price - entry) / entry) * 100
  } else {
    return ((entry - price) / entry) * 100
  }
}

export async function POST(request: NextRequest): Promise<NextResponse<ValidationResponse>> {
  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,
          timestamp: new Date().toISOString(),
          config: {} as any,
          positions: [],
          summary: {
            totalPositions: 0,
            validPositions: 0,
            positionsWithIssues: 0,
          },
        },
        { status: 401 }
      )
    }

    console.log('🔍 Validating positions against settings...')
    
    // Get current configuration
    const config = getMergedConfig()
    
    // Get active positions from Position Manager
    const positionManager = await getInitializedPositionManager()
    const activeTrades = Array.from(positionManager.getActiveTrades().values())
    
    console.log(`📊 Found ${activeTrades.length} active positions to validate`)
    
    const validations: PositionValidation[] = []
    
    for (const trade of activeTrades) {
      const issues: ValidationIssue[] = []
      
      // Validate leverage
      const expectedLeverage = config.leverage
      if (trade.leverage !== expectedLeverage) {
        issues.push({
          type: 'warning',
          field: 'leverage',
          expected: expectedLeverage,
          actual: trade.leverage,
          message: `Leverage mismatch: expected ${expectedLeverage}x, got ${trade.leverage}x`,
        })
      }
      
      // Calculate expected prices based on current config
      const expectedTP1 = calculateExpectedPrice(trade.entryPrice, config.takeProfit1Percent, trade.direction)
      const expectedTP2 = calculateExpectedPrice(trade.entryPrice, config.takeProfit2Percent, trade.direction)
      const expectedSL = calculateExpectedPrice(trade.entryPrice, config.stopLossPercent, trade.direction)
      
      // Validate TP1 (allow 0.1% tolerance)
      const tp1Diff = Math.abs((trade.tp1Price - expectedTP1) / expectedTP1) * 100
      if (tp1Diff > 0.1) {
        const actualTP1Percent = calculateActualPercent(trade.entryPrice, trade.tp1Price, trade.direction)
        issues.push({
          type: 'error',
          field: 'takeProfit1',
          expected: `${config.takeProfit1Percent}% ($${expectedTP1.toFixed(2)})`,
          actual: `${actualTP1Percent.toFixed(2)}% ($${trade.tp1Price.toFixed(2)})`,
          message: `TP1 price mismatch: expected ${config.takeProfit1Percent}%, actual ${actualTP1Percent.toFixed(2)}%`,
        })
      }
      
      // Validate TP2 (allow 0.1% tolerance)
      const tp2Diff = Math.abs((trade.tp2Price - expectedTP2) / expectedTP2) * 100
      if (tp2Diff > 0.1) {
        const actualTP2Percent = calculateActualPercent(trade.entryPrice, trade.tp2Price, trade.direction)
        issues.push({
          type: 'error',
          field: 'takeProfit2',
          expected: `${config.takeProfit2Percent}% ($${expectedTP2.toFixed(2)})`,
          actual: `${actualTP2Percent.toFixed(2)}% ($${trade.tp2Price.toFixed(2)})`,
          message: `TP2 price mismatch: expected ${config.takeProfit2Percent}%, actual ${actualTP2Percent.toFixed(2)}%`,
        })
      }
      
      // Validate Stop Loss (allow 0.1% tolerance)
      const slDiff = Math.abs((trade.stopLossPrice - expectedSL) / expectedSL) * 100
      if (slDiff > 0.1) {
        const actualSLPercent = Math.abs(calculateActualPercent(trade.entryPrice, trade.stopLossPrice, trade.direction))
        issues.push({
          type: 'error',
          field: 'stopLoss',
          expected: `${Math.abs(config.stopLossPercent)}% ($${expectedSL.toFixed(2)})`,
          actual: `${actualSLPercent.toFixed(2)}% ($${trade.stopLossPrice.toFixed(2)})`,
          message: `Stop loss mismatch: expected ${Math.abs(config.stopLossPercent)}%, actual ${actualSLPercent.toFixed(2)}%`,
        })
      }
      
      // Validate position size
      // Note: trade.positionSize is the TOTAL position value in USD (e.g., $800 with 10x leverage)
      // config.positionSize is the COLLATERAL amount (e.g., $80)
      // So: expectedPositionValueUSD = config.positionSize * config.leverage
      const expectedPositionValueUSD = config.positionSize * config.leverage
      const actualPositionValueUSD = trade.positionSize
      const sizeDiff = Math.abs((actualPositionValueUSD - expectedPositionValueUSD) / expectedPositionValueUSD) * 100
      
      if (sizeDiff > 5) { // Allow 5% tolerance for position size
        issues.push({
          type: 'warning',
          field: 'positionSize',
          expected: `$${expectedPositionValueUSD.toFixed(2)}`,
          actual: `$${actualPositionValueUSD.toFixed(2)}`,
          message: `Position size mismatch: expected $${expectedPositionValueUSD.toFixed(2)}, got $${actualPositionValueUSD.toFixed(2)}`,
        })
      }
      
      const validation: PositionValidation = {
        symbol: trade.symbol,
        direction: trade.direction,
        entryPrice: trade.entryPrice,
        isValid: issues.length === 0,
        issues,
      }
      
      validations.push(validation)
      
      if (issues.length > 0) {
        console.log(`⚠️  Position ${trade.symbol} ${trade.direction} has ${issues.length} issue(s):`)
        issues.forEach(issue => {
          console.log(`   ${issue.type === 'error' ? '❌' : '⚠️'} ${issue.message}`)
        })
      } else {
        console.log(`✅ Position ${trade.symbol} ${trade.direction} is valid`)
      }
    }
    
    const summary = {
      totalPositions: validations.length,
      validPositions: validations.filter(v => v.isValid).length,
      positionsWithIssues: validations.filter(v => !v.isValid).length,
    }
    
    console.log(`📊 Validation complete: ${summary.validPositions}/${summary.totalPositions} positions valid`)
    
    return NextResponse.json({
      success: true,
      timestamp: new Date().toISOString(),
      config: {
        leverage: config.leverage,
        positionSize: config.positionSize,
        tp1Percent: config.takeProfit1Percent,
        tp2Percent: config.takeProfit2Percent,
        stopLossPercent: config.stopLossPercent,
        useDualStops: config.useDualStops,
        hardStopPercent: config.useDualStops ? config.hardStopPercent : undefined,
      },
      positions: validations,
      summary,
    })

  } catch (error) {
    console.error('❌ Position validation error:', error)
    
    return NextResponse.json(
      {
        success: false,
        timestamp: new Date().toISOString(),
        config: {} as any,
        positions: [],
        summary: {
          totalPositions: 0,
          validPositions: 0,
          positionsWithIssues: 0,
        },
      },
      { status: 500 }
    )
  }
}