/**
 * Position Manager
 * 
 * Tracks active trades and manages automatic exits
 */

import { getDriftService } from '../drift/client'
import { closePosition } from '../drift/orders'
import { getPythPriceMonitor, PriceUpdate } from '../pyth/price-monitor'
import { getMergedConfig, TradingConfig, getMarketConfig } from '../../config/trading'
import { updateTradeExit, updateTradeState, getOpenTrades } from '../database/trades'

export interface ActiveTrade {
  id: string
  positionId: string // Transaction signature
  symbol: string
  direction: 'long' | 'short'
  
  // Entry details
  entryPrice: number
  entryTime: number
  positionSize: number
  leverage: number
  
  // Targets
  stopLossPrice: number
  tp1Price: number
  tp2Price: number
  emergencyStopPrice: number
  
  // State
  currentSize: number // Changes after TP1
  tp1Hit: boolean
  tp2Hit: boolean
  slMovedToBreakeven: boolean
  slMovedToProfit: boolean
  trailingStopActive: boolean
  
  // P&L tracking
  realizedPnL: number
  unrealizedPnL: number
  peakPnL: number
  peakPrice: number // Track highest price reached (for trailing)
  
  // Monitoring
  priceCheckCount: number
  lastPrice: number
  lastUpdateTime: number
}

export interface ExitResult {
  success: boolean
  reason: 'TP1' | 'TP2' | 'SL' | 'SOFT_SL' | 'HARD_SL' | 'emergency' | 'manual' | 'error'
  closePrice?: number
  closedSize?: number
  realizedPnL?: number
  transactionSignature?: string
  error?: string
}

export class PositionManager {
  private activeTrades: Map<string, ActiveTrade> = new Map()
  private config: TradingConfig
  private isMonitoring: boolean = false
  private initialized: boolean = false

  constructor(config?: Partial<TradingConfig>) {
    this.config = getMergedConfig(config)
    console.log('✅ Position manager created')
  }

  /**
   * Initialize and restore active trades from database
   */
  async initialize(): Promise<void> {
    if (this.initialized) {
      return
    }

    console.log('🔄 Restoring active trades from database...')
    
    try {
      const openTrades = await getOpenTrades()
      
      for (const dbTrade of openTrades) {
        // Extract Position Manager state from configSnapshot
        const pmState = (dbTrade.configSnapshot as any)?.positionManagerState
        
        // Reconstruct ActiveTrade object
        const activeTrade: ActiveTrade = {
          id: dbTrade.id,
          positionId: dbTrade.positionId,
          symbol: dbTrade.symbol,
          direction: dbTrade.direction as 'long' | 'short',
          entryPrice: dbTrade.entryPrice,
          entryTime: dbTrade.entryTime.getTime(),
          positionSize: dbTrade.positionSizeUSD,
          leverage: dbTrade.leverage,
          stopLossPrice: pmState?.stopLossPrice ?? dbTrade.stopLossPrice,
          tp1Price: dbTrade.takeProfit1Price,
          tp2Price: dbTrade.takeProfit2Price,
          emergencyStopPrice: dbTrade.stopLossPrice * (dbTrade.direction === 'long' ? 0.98 : 1.02),
          currentSize: pmState?.currentSize ?? dbTrade.positionSizeUSD,
          tp1Hit: pmState?.tp1Hit ?? false,
          tp2Hit: pmState?.tp2Hit ?? false,
          slMovedToBreakeven: pmState?.slMovedToBreakeven ?? false,
          slMovedToProfit: pmState?.slMovedToProfit ?? false,
          trailingStopActive: pmState?.trailingStopActive ?? false,
          realizedPnL: pmState?.realizedPnL ?? 0,
          unrealizedPnL: pmState?.unrealizedPnL ?? 0,
          peakPnL: pmState?.peakPnL ?? 0,
          peakPrice: pmState?.peakPrice ?? dbTrade.entryPrice,
          priceCheckCount: 0,
          lastPrice: pmState?.lastPrice ?? dbTrade.entryPrice,
          lastUpdateTime: Date.now(),
        }
        
        this.activeTrades.set(activeTrade.id, activeTrade)
        console.log(`✅ Restored trade: ${activeTrade.symbol} ${activeTrade.direction} at $${activeTrade.entryPrice}`)
      }
      
      if (this.activeTrades.size > 0) {
        console.log(`🎯 Restored ${this.activeTrades.size} active trades`)
        await this.startMonitoring()
      } else {
        console.log('✅ No active trades to restore')
      }
      
    } catch (error) {
      console.error('❌ Failed to restore active trades:', error)
    }
    
    this.initialized = true
  }

  /**
   * Add a new trade to monitor
   */
  async addTrade(trade: ActiveTrade): Promise<void> {
    console.log(`📊 Adding trade to monitor: ${trade.symbol} ${trade.direction}`)
    
    this.activeTrades.set(trade.id, trade)
    
    // Note: Initial state is saved by the API endpoint that creates the trade
    // We don't save here to avoid race condition (trade may not be in DB yet)
    
    console.log(`✅ Trade added. Active trades: ${this.activeTrades.size}`)
    
    // Start monitoring if not already running
    if (!this.isMonitoring && this.activeTrades.size > 0) {
      await this.startMonitoring()
    }
  }

  /**
   * Remove a trade from monitoring
   */
  async removeTrade(tradeId: string): Promise<void> {
    const trade = this.activeTrades.get(tradeId)
    if (trade) {
      console.log(`🗑️ Removing trade: ${trade.symbol}`)
      
      // Cancel all orders for this symbol (cleanup orphaned orders)
      try {
        const { cancelAllOrders } = await import('../drift/orders')
        const cancelResult = await cancelAllOrders(trade.symbol)
        if (cancelResult.success && cancelResult.cancelledCount! > 0) {
          console.log(`✅ Cancelled ${cancelResult.cancelledCount} orphaned orders`)
        }
      } catch (error) {
        console.error('❌ Failed to cancel orders during trade removal:', error)
        // Continue with removal even if cancel fails
      }
      
      this.activeTrades.delete(tradeId)
      
      // Stop monitoring if no more trades
      if (this.activeTrades.size === 0 && this.isMonitoring) {
        this.stopMonitoring()
      }
    }
  }

  /**
   * Get all active trades
   */
  getActiveTrades(): ActiveTrade[] {
    return Array.from(this.activeTrades.values())
  }

  /**
   * Get specific trade
   */
  getTrade(tradeId: string): ActiveTrade | null {
    return this.activeTrades.get(tradeId) || null
  }

  /**
   * Start price monitoring for all active trades
   */
  private async startMonitoring(): Promise<void> {
    if (this.isMonitoring) {
      return
    }

    // Get unique symbols from active trades
    const symbols = [...new Set(
      Array.from(this.activeTrades.values()).map(trade => trade.symbol)
    )]

    if (symbols.length === 0) {
      return
    }

    console.log('🚀 Starting price monitoring for:', symbols)

    const priceMonitor = getPythPriceMonitor()

    await priceMonitor.start({
      symbols,
      onPriceUpdate: async (update: PriceUpdate) => {
        await this.handlePriceUpdate(update)
      },
      onError: (error: Error) => {
        console.error('❌ Price monitor error:', error)
      },
    })

    this.isMonitoring = true
    console.log('✅ Position monitoring active')
  }

  /**
   * Stop price monitoring
   */
  private async stopMonitoring(): Promise<void> {
    if (!this.isMonitoring) {
      return
    }

    console.log('🛑 Stopping position monitoring...')

    const priceMonitor = getPythPriceMonitor()
    await priceMonitor.stop()

    this.isMonitoring = false
    console.log('✅ Position monitoring stopped')
  }

  /**
   * Handle price update for all relevant trades
   */
  private async handlePriceUpdate(update: PriceUpdate): Promise<void> {
    // Find all trades for this symbol
    const tradesForSymbol = Array.from(this.activeTrades.values())
      .filter(trade => trade.symbol === update.symbol)

    for (const trade of tradesForSymbol) {
      try {
        await this.checkTradeConditions(trade, update.price)
      } catch (error) {
        console.error(`❌ Error checking trade ${trade.id}:`, error)
      }
    }
  }

  /**
   * Check if any exit conditions are met for a trade
   */
  private async checkTradeConditions(
    trade: ActiveTrade,
    currentPrice: number
  ): Promise<void> {
    // CRITICAL: First check if on-chain position still exists
    // (may have been closed by TP/SL orders without us knowing)
    try {
      const driftService = getDriftService()
      
      // Skip position verification if Drift service isn't initialized yet
      // (happens briefly after restart while service initializes)
      if (!driftService || !(driftService as any).isInitialized) {
        // Service still initializing, skip this check cycle
        return
      }
      
      const marketConfig = getMarketConfig(trade.symbol)
      const position = await driftService.getPosition(marketConfig.driftMarketIndex)
      
      if (position === null || position.size === 0) {
        // Position closed externally (by on-chain TP/SL order)
        console.log(`⚠️ Position ${trade.symbol} was closed externally (by on-chain order)`)
        
        // Save currentSize before it becomes 0
        const sizeBeforeClosure = trade.currentSize
        
        // Determine exit reason based on price
        let exitReason: 'TP1' | 'TP2' | 'SL' | 'SOFT_SL' | 'HARD_SL' = 'SL'
        
        if (trade.direction === 'long') {
          if (currentPrice >= trade.tp2Price) {
            exitReason = 'TP2'
          } else if (currentPrice >= trade.tp1Price) {
            exitReason = 'TP1'
          } else if (currentPrice <= trade.stopLossPrice) {
            exitReason = 'HARD_SL' // Assume hard stop if below SL
          }
        } else {
          // Short
          if (currentPrice <= trade.tp2Price) {
            exitReason = 'TP2'
          } else if (currentPrice <= trade.tp1Price) {
            exitReason = 'TP1'
          } else if (currentPrice >= trade.stopLossPrice) {
            exitReason = 'HARD_SL' // Assume hard stop if above SL
          }
        }
        
        // Calculate final P&L using size BEFORE closure
        const profitPercent = this.calculateProfitPercent(
          trade.entryPrice,
          currentPrice,
          trade.direction
        )
        const accountPnL = profitPercent * trade.leverage
        const realizedPnL = (sizeBeforeClosure * accountPnL) / 100
        
        // Update database
        const holdTimeSeconds = Math.floor((Date.now() - trade.entryTime) / 1000)
        try {
          await updateTradeExit({
            positionId: trade.positionId,
            exitPrice: currentPrice,
            exitReason,
            realizedPnL,
            exitOrderTx: 'ON_CHAIN_ORDER',
            holdTimeSeconds,
            maxDrawdown: 0,
            maxGain: trade.peakPnL,
          })
          console.log(`💾 External closure recorded: ${exitReason} at $${currentPrice} | P&L: $${realizedPnL.toFixed(2)}`)
        } catch (dbError) {
          console.error('❌ Failed to save external closure:', dbError)
        }
        
        // Remove from monitoring
        await this.removeTrade(trade.id)
        return
      }
      
      // Position exists but size mismatch (partial close by TP1?)
      if (position.size < trade.currentSize * 0.95) { // 5% tolerance
        console.log(`⚠️ Position size mismatch: expected ${trade.currentSize}, got ${position.size}`)
        // Update current size to match reality
        trade.currentSize = position.size * (trade.positionSize / trade.currentSize) // Convert to USD
        trade.tp1Hit = true
        await this.saveTradeState(trade)
      }
      
    } catch (error) {
      // If we can't check position, continue with monitoring (don't want to false-positive)
      // This can happen briefly during startup while Drift service initializes
      if ((error as Error).message?.includes('not initialized')) {
        // Silent - expected during initialization
      } else {
        console.error(`⚠️ Could not verify on-chain position for ${trade.symbol}:`, error)
      }
    }
    
    // Update trade data
    trade.lastPrice = currentPrice
    trade.lastUpdateTime = Date.now()
    trade.priceCheckCount++

    // Calculate P&L
    const profitPercent = this.calculateProfitPercent(
      trade.entryPrice,
      currentPrice,
      trade.direction
    )
    
    const accountPnL = profitPercent * trade.leverage
    trade.unrealizedPnL = (trade.currentSize * profitPercent) / 100

    // Track peak P&L
    if (trade.unrealizedPnL > trade.peakPnL) {
      trade.peakPnL = trade.unrealizedPnL
    }
    
    // Track peak price for trailing stop
    if (trade.direction === 'long') {
      if (currentPrice > trade.peakPrice) {
        trade.peakPrice = currentPrice
      }
    } else {
      if (currentPrice < trade.peakPrice || trade.peakPrice === 0) {
        trade.peakPrice = currentPrice
      }
    }

    // Log status every 10 checks (~20 seconds)
    if (trade.priceCheckCount % 10 === 0) {
      console.log(
        `📊 ${trade.symbol} | ` +
        `Price: ${currentPrice.toFixed(4)} | ` +
        `P&L: ${profitPercent.toFixed(2)}% (${accountPnL.toFixed(1)}% acct) | ` +
        `Unrealized: $${trade.unrealizedPnL.toFixed(2)} | ` +
        `Peak: $${trade.peakPnL.toFixed(2)}`
      )
    }

    // Check exit conditions (in order of priority)

    // 1. Emergency stop (-2%)
    if (this.shouldEmergencyStop(currentPrice, trade)) {
      console.log(`🚨 EMERGENCY STOP: ${trade.symbol}`)
      await this.executeExit(trade, 100, 'emergency', currentPrice)
      return
    }

    // 2. Stop loss
    if (!trade.tp1Hit && this.shouldStopLoss(currentPrice, trade)) {
      console.log(`🔴 STOP LOSS: ${trade.symbol} at ${profitPercent.toFixed(2)}%`)
      await this.executeExit(trade, 100, 'SL', currentPrice)
      return
    }

    // 3. Take profit 1 (closes configured %)
    if (!trade.tp1Hit && this.shouldTakeProfit1(currentPrice, trade)) {
      console.log(`🎉 TP1 HIT: ${trade.symbol} at ${profitPercent.toFixed(2)}%`)
      await this.executeExit(trade, this.config.takeProfit1SizePercent, 'TP1', currentPrice)
      
      // Move SL based on breakEvenTriggerPercent setting
      trade.tp1Hit = true
      trade.currentSize = trade.positionSize * ((100 - this.config.takeProfit1SizePercent) / 100)
      trade.stopLossPrice = this.calculatePrice(
        trade.entryPrice,
        this.config.breakEvenTriggerPercent, // Use configured breakeven level
        trade.direction
      )
      trade.slMovedToBreakeven = true
      
      console.log(`🔒 SL moved to +${this.config.breakEvenTriggerPercent}% (${this.config.takeProfit1SizePercent}% closed, ${100 - this.config.takeProfit1SizePercent}% remaining): ${trade.stopLossPrice.toFixed(4)}`)
      
      // Save state after TP1
      await this.saveTradeState(trade)
      return
    }

    // 4. Profit lock trigger
    if (
      trade.tp1Hit &&
      !trade.slMovedToProfit &&
      profitPercent >= this.config.profitLockTriggerPercent
    ) {
      console.log(`🔐 Profit lock trigger: ${trade.symbol}`)
      
      trade.stopLossPrice = this.calculatePrice(
        trade.entryPrice,
        this.config.profitLockPercent,
        trade.direction
      )
      trade.slMovedToProfit = true
      
      console.log(`🎯 SL moved to +${this.config.profitLockPercent}%: ${trade.stopLossPrice.toFixed(4)}`)
      
      // Save state after profit lock
      await this.saveTradeState(trade)
    }

    // 5. Take profit 2 (remaining position)
    if (trade.tp1Hit && this.shouldTakeProfit2(currentPrice, trade)) {
      console.log(`🎊 TP2 HIT: ${trade.symbol} at ${profitPercent.toFixed(2)}%`)
      
      // Calculate how much to close based on TP2 size percent
      const percentToClose = this.config.takeProfit2SizePercent
      
      await this.executeExit(trade, percentToClose, 'TP2', currentPrice)
      
      // If some position remains, mark TP2 as hit and activate trailing stop
      if (percentToClose < 100) {
        trade.tp2Hit = true
        trade.currentSize = trade.currentSize * ((100 - percentToClose) / 100)
        
        console.log(`🏃 Runner activated: ${((trade.currentSize / trade.positionSize) * 100).toFixed(1)}% remaining with trailing stop`)
        
        // Save state after TP2
        await this.saveTradeState(trade)
      }
      
      return
    }
    
    // 6. Trailing stop for runner (after TP2)
    if (trade.tp2Hit && this.config.useTrailingStop) {
      // Check if trailing stop should be activated
      if (!trade.trailingStopActive && profitPercent >= this.config.trailingStopActivation) {
        trade.trailingStopActive = true
        console.log(`🎯 Trailing stop activated at +${profitPercent.toFixed(2)}%`)
      }
      
      // If trailing stop is active, adjust SL dynamically
      if (trade.trailingStopActive) {
        const trailingStopPrice = this.calculatePrice(
          trade.peakPrice,
          -this.config.trailingStopPercent, // Trail below peak
          trade.direction
        )
        
        // Only move SL up (for long) or down (for short), never backwards
        const shouldUpdate = trade.direction === 'long' 
          ? trailingStopPrice > trade.stopLossPrice
          : trailingStopPrice < trade.stopLossPrice
        
        if (shouldUpdate) {
          const oldSL = trade.stopLossPrice
          trade.stopLossPrice = trailingStopPrice
          
          console.log(`📈 Trailing SL updated: ${oldSL.toFixed(4)} → ${trailingStopPrice.toFixed(4)} (${this.config.trailingStopPercent}% below peak $${trade.peakPrice.toFixed(4)})`)
          
          // Save state after trailing SL update (every 10 updates to avoid spam)
          if (trade.priceCheckCount % 10 === 0) {
            await this.saveTradeState(trade)
          }
        }
        
        // Check if trailing stop hit
        if (this.shouldStopLoss(currentPrice, trade)) {
          console.log(`🔴 TRAILING STOP HIT: ${trade.symbol} at ${profitPercent.toFixed(2)}%`)
          await this.executeExit(trade, 100, 'SL', currentPrice)
          return
        }
      }
    }
  }

  /**
   * Execute exit (close position)
   */
  private async executeExit(
    trade: ActiveTrade,
    percentToClose: number,
    reason: ExitResult['reason'],
    currentPrice: number
  ): Promise<void> {
    try {
      console.log(`🔴 Executing ${reason} for ${trade.symbol} (${percentToClose}%)`)

      const result = await closePosition({
        symbol: trade.symbol,
        percentToClose,
        slippageTolerance: this.config.slippageTolerance,
      })

      if (!result.success) {
        console.error(`❌ Failed to close ${trade.symbol}:`, result.error)
        return
      }

      // Update trade state
      if (percentToClose >= 100) {
        // Full close - remove from monitoring
        trade.realizedPnL += result.realizedPnL || 0
        
        // Save to database (only for valid exit reasons)
        if (reason !== 'error') {
          try {
            const holdTimeSeconds = Math.floor((Date.now() - trade.entryTime) / 1000)
            await updateTradeExit({
              positionId: trade.positionId,
              exitPrice: result.closePrice || currentPrice,
              exitReason: reason as 'TP1' | 'TP2' | 'SL' | 'SOFT_SL' | 'HARD_SL' | 'manual' | 'emergency',
              realizedPnL: trade.realizedPnL,
              exitOrderTx: result.transactionSignature || 'MANUAL_CLOSE',
              holdTimeSeconds,
              maxDrawdown: 0, // TODO: Track this
              maxGain: trade.peakPnL,
            })
            console.log('💾 Trade saved to database')
          } catch (dbError) {
            console.error('❌ Failed to save trade exit to database:', dbError)
            // Don't fail the close if database fails
          }
        }
        
        await this.removeTrade(trade.id)
        console.log(`✅ Position closed | P&L: $${trade.realizedPnL.toFixed(2)} | Reason: ${reason}`)
      } else {
        // Partial close (TP1)
        trade.realizedPnL += result.realizedPnL || 0
        trade.currentSize -= result.closedSize || 0
        
        console.log(`✅ 50% closed | Realized: $${result.realizedPnL?.toFixed(2)} | Remaining: ${trade.currentSize}`)
      }

      // TODO: Send notification

    } catch (error) {
      console.error(`❌ Error executing exit for ${trade.symbol}:`, error)
    }
  }

  /**
   * Decision helpers
   */
  private shouldEmergencyStop(price: number, trade: ActiveTrade): boolean {
    if (trade.direction === 'long') {
      return price <= trade.emergencyStopPrice
    } else {
      return price >= trade.emergencyStopPrice
    }
  }

  private shouldStopLoss(price: number, trade: ActiveTrade): boolean {
    if (trade.direction === 'long') {
      return price <= trade.stopLossPrice
    } else {
      return price >= trade.stopLossPrice
    }
  }

  private shouldTakeProfit1(price: number, trade: ActiveTrade): boolean {
    if (trade.direction === 'long') {
      return price >= trade.tp1Price
    } else {
      return price <= trade.tp1Price
    }
  }

  private shouldTakeProfit2(price: number, trade: ActiveTrade): boolean {
    if (trade.direction === 'long') {
      return price >= trade.tp2Price
    } else {
      return price <= trade.tp2Price
    }
  }

  /**
   * Calculate profit percentage
   */
  private calculateProfitPercent(
    entryPrice: number,
    currentPrice: number,
    direction: 'long' | 'short'
  ): number {
    if (direction === 'long') {
      return ((currentPrice - entryPrice) / entryPrice) * 100
    } else {
      return ((entryPrice - currentPrice) / entryPrice) * 100
    }
  }

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

  /**
   * Emergency close all positions
   */
  async closeAll(): Promise<void> {
    console.log('🚨 EMERGENCY: Closing all positions')

    const trades = Array.from(this.activeTrades.values())
    
    for (const trade of trades) {
      await this.executeExit(trade, 100, 'emergency', trade.lastPrice)
    }

    console.log('✅ All positions closed')
  }

  /**
   * Save trade state to database (for persistence across restarts)
   */
  private async saveTradeState(trade: ActiveTrade): Promise<void> {
    try {
      await updateTradeState({
        positionId: trade.positionId,
        currentSize: trade.currentSize,
        tp1Hit: trade.tp1Hit,
        slMovedToBreakeven: trade.slMovedToBreakeven,
        slMovedToProfit: trade.slMovedToProfit,
        stopLossPrice: trade.stopLossPrice,
        realizedPnL: trade.realizedPnL,
        unrealizedPnL: trade.unrealizedPnL,
        peakPnL: trade.peakPnL,
        lastPrice: trade.lastPrice,
      })
    } catch (error) {
      console.error('❌ Failed to save trade state:', error)
      // Don't throw - state save is non-critical
    }
  }

  /**
   * Get monitoring status
   */
  getStatus(): {
    isMonitoring: boolean
    activeTradesCount: number
    symbols: string[]
  } {
    const symbols = [...new Set(
      Array.from(this.activeTrades.values()).map(t => t.symbol)
    )]

    return {
      isMonitoring: this.isMonitoring,
      activeTradesCount: this.activeTrades.size,
      symbols,
    }
  }
}

// Singleton instance
let positionManagerInstance: PositionManager | null = null
let initPromise: Promise<void> | null = null

export function getPositionManager(): PositionManager {
  if (!positionManagerInstance) {
    positionManagerInstance = new PositionManager()
    
    // Initialize asynchronously (restore trades from database)
    if (!initPromise) {
      initPromise = positionManagerInstance.initialize().catch(error => {
        console.error('❌ Failed to initialize Position Manager:', error)
      })
    }
  }
  return positionManagerInstance
}

export async function getInitializedPositionManager(): Promise<PositionManager> {
  const manager = getPositionManager()
  if (initPromise) {
    await initPromise
  }
  return manager
}