import { NextRequest, NextResponse } from 'next/server'
import { exec } from 'child_process'
import { promisify } from 'util'
import sqlite3 from 'sqlite3'
import { open, Database } from 'sqlite'
import path from 'path'

const execAsync = promisify(exec)

export const dynamic = 'force-dynamic'

interface WorkerStatus {
  name: string
  host: string
  cpuUsage: number
  loadAverage: string
  activeProcesses: number
  status: 'active' | 'idle' | 'offline'
}

interface ChunkResult {
  rank: number
  pnl_per_1k: number
  win_rate: number
  trades: number
  profit_factor: number
  max_drawdown: number
  params: {
    flip_threshold: number
    ma_gap: number
    adx_min: number
    long_pos_max: number
    short_pos_min: number
  }
}

async function getWorkerStatus(workerName: string, sshCommand: string): Promise<WorkerStatus> {
  try {
    // Get CPU usage
    const cpuCmd = `${sshCommand} "top -bn1 | grep 'Cpu(s)' | awk '{print 100-\\$8}'"`
    const { stdout: cpuOut } = await execAsync(cpuCmd)
    const cpuUsage = parseFloat(cpuOut.trim()) || 0

    // Get load average
    const loadCmd = `${sshCommand} "uptime | awk -F'load average:' '{print \\$2}'"`
    const { stdout: loadOut } = await execAsync(loadCmd)
    const loadAverage = loadOut.trim()

    // Get worker processes
    const procCmd = `${sshCommand} "ps aux | grep distributed_worker | grep -v grep | wc -l"`
    const { stdout: procOut } = await execAsync(procCmd)
    const activeProcesses = parseInt(procOut.trim()) || 0

    const status: 'active' | 'idle' | 'offline' = 
      activeProcesses > 0 ? 'active' : 
      cpuUsage > 10 ? 'active' : 'idle'

    return {
      name: workerName,
      host: sshCommand.includes('10.20.254.100') ? 'bd-host01 (32 cores)' : 'pve-nu-monitor01 (32 cores)',
      cpuUsage,
      loadAverage,
      activeProcesses,
      status
    }
  } catch (error) {
    return {
      name: workerName,
      host: sshCommand.includes('10.20.254.100') ? 'bd-host01' : 'pve-nu-monitor01',
      cpuUsage: 0,
      loadAverage: 'N/A',
      activeProcesses: 0,
      status: 'offline'
    }
  }
}

async function getExplorationData() {
  try {
    const dbPath = path.join(process.cwd(), 'cluster', 'exploration.db')
    
    const db = await open({
      filename: dbPath,
      driver: sqlite3.Database
    })
    
    // UPDATED (Dec 3, 2025): Track comprehensive v9_advanced sweep (1,693 chunks, 1.693M combos)
    // Get total combos and chunk statistics from v9_advanced tables
    // NOTE: v9_advanced_chunks uses start_combo/end_combo (not chunk_start/chunk_end)
    const totalCombosRow = await db.get('SELECT SUM(total_combos) as total FROM v9_advanced_chunks')
    const totalCombos = totalCombosRow?.total || 0
    
    const chunks = await db.all('SELECT * FROM v9_advanced_chunks ORDER BY start_combo')
    const completedChunks = chunks.filter(c => c.status === 'completed').length
    const runningChunks = chunks.filter(c => c.status === 'running').length
    const pendingChunks = chunks.filter(c => c.status === 'pending').length
    
    // Try to get strategies from v9_advanced_strategies table
    let strategies: any[] = []
    let testedCombos = 0
    
    try {
      const strategiesCount = await db.get('SELECT COUNT(*) as count FROM v9_advanced_strategies')
      testedCombos = strategiesCount?.count || 0
      
      strategies = await db.all(`
        SELECT * FROM v9_advanced_strategies 
        WHERE total_trades >= 700 
        ORDER BY pnl_per_1k DESC 
        LIMIT 10
      `)
    } catch (e) {
      // Strategies table doesn't exist yet - this is fine
      console.log('Strategies table not yet available')
    }
    
    await db.close()
    
    const progress = totalCombos > 0 ? Math.round((testedCombos / totalCombos) * 100) : 0
    
    return {
      totalCombos,
      testedCombos,
      progress,
      chunks: {
        total: chunks.length,
        completed: completedChunks,
        running: runningChunks,
        pending: pendingChunks
      },
      strategies
    }
  } catch (error) {
    console.error('Error reading exploration database:', error)
    return {
      totalCombos: 0,
      testedCombos: 0,
      progress: 0,
      chunks: { total: 0, completed: 0, running: 0, pending: 0 },
      strategies: []
    }
  }
}

interface ChunkResult {
  rank: number
  pnl_per_1k: number
  win_rate: number
  trades: number
  profit_factor: number
  max_drawdown: number
  params: {
    flip_threshold: number
    ma_gap: number
    adx_min: number
    long_pos_max: number
    short_pos_min: number
  }
}

function generateRecommendation(results: ChunkResult[]): string {
  if (results.length === 0) {
    return "Cluster is processing parameter combinations. Check back soon for optimization recommendations."
  }

  const best = results[0]
  const avgWinRate = results.reduce((sum, r) => sum + r.win_rate, 0) / results.length
  const avgPnL = results.reduce((sum, r) => sum + r.pnl_per_1k, 0) / results.length

  let recommendation = `🎯 **Top Strategy Found:**\n\n`
  recommendation += `- **Expected Profit:** $${best.pnl_per_1k.toFixed(2)} per $1,000 capital\n`
  recommendation += `- **Win Rate:** ${(best.win_rate * 100).toFixed(1)}%\n`
  recommendation += `- **Profit Factor:** ${best.profit_factor.toFixed(2)}x\n`
  recommendation += `- **Max Drawdown:** $${Math.abs(best.max_drawdown).toFixed(2)}\n\n`
  
  recommendation += `📊 **Optimal Parameters:**\n`
  recommendation += `- Flip Threshold: ${best.params.flip_threshold}%\n`
  recommendation += `- MA Gap: ${best.params.ma_gap}\n`
  recommendation += `- Min ADX: ${best.params.adx_min}\n`
  recommendation += `- Long Max Position: ${best.params.long_pos_max}%\n`
  recommendation += `- Short Min Position: ${best.params.short_pos_min}%\n\n`

  if (best.pnl_per_1k > avgPnL * 1.5) {
    recommendation += `✅ **Action:** This strategy shows exceptional performance (${((best.pnl_per_1k / avgPnL) * 100 - 100).toFixed(0)}% better than average). Consider implementing these parameters in production.`
  } else if (best.win_rate > 0.6) {
    recommendation += `✅ **Action:** Strong win rate detected. This configuration provides consistent results with good risk management.`
  } else {
    recommendation += `⚠️ **Action:** Continue exploration. Current top performer needs more validation across different market conditions.`
  }

  return recommendation
}

export async function GET(request: NextRequest) {
  try {
    // CRITICAL FIX (Nov 30, 2025): Check database FIRST before SSH detection
    // Database is the source of truth - SSH may timeout but workers are still running
    const explorationData = await getExplorationData()
    const hasRunningChunks = explorationData.chunks.running > 0
    
    // Get status from both workers (SSH for supplementary metrics only)
    const [worker1Status, worker2Status] = await Promise.all([
      getWorkerStatus('worker1', 'ssh root@10.10.254.106'),
      getWorkerStatus('worker2', 'ssh root@10.10.254.106 "ssh root@10.20.254.100"')
    ])

    // If database shows running chunks but SSH shows offline, override to active
    // This prevents false "idle" status when SSH detection times out
    const workers = [worker1Status, worker2Status].map(w => {
      if (hasRunningChunks && w.status === 'offline') {
        console.log(`✅ ${w.name}: Database shows running chunks - overriding SSH offline to active`)
        return {
          ...w,
          status: 'active' as const,
          activeProcesses: w.activeProcesses || 1 // Assume at least 1 process if chunks running
        }
      }
      return w
    })
    
    const totalCPU = workers.reduce((sum, w) => sum + w.cpuUsage, 0) / workers.length
    const totalProcesses = workers.reduce((sum, w) => sum + w.activeProcesses, 0)
    const activeWorkers = workers.filter(w => w.status === 'active').length

    // Determine cluster status: DATABASE-FIRST APPROACH
    // If running chunks exist, cluster is active regardless of SSH detection
    let clusterStatus: 'active' | 'idle' = 'idle'
    if (hasRunningChunks) {
      clusterStatus = 'active'
      console.log('✅ Cluster status: ACTIVE (database shows running chunks)')
    } else if (activeWorkers > 0) {
      clusterStatus = 'active'
      console.log('✅ Cluster status: ACTIVE (SSH detected active workers)')
    } else {
      console.log('⏸️ Cluster status: IDLE (no running chunks or active workers)')
    }
    
    // Convert strategies to ChunkResult format for recommendation
    const topStrategies: ChunkResult[] = explorationData.strategies.map((s: any, idx: number) => ({
      rank: idx + 1,
      pnl_per_1k: s.pnl_per_1k || 0,
      win_rate: s.win_rate || 0,
      trades: s.total_trades || 0,
      profit_factor: s.profit_factor || 0,
      max_drawdown: s.max_drawdown || 0,
      params: {
        flip_threshold: s.flip_threshold || 0,
        ma_gap: s.ma_gap || 0,
        adx_min: s.momentum_adx || 0,
        long_pos_max: s.momentum_long_pos || 0,
        short_pos_min: s.momentum_short_pos || 0
      }
    }))
    
    const recommendation = generateRecommendation(topStrategies)

    return NextResponse.json({
      cluster: {
        totalCores: 64,
        activeCores: Math.round(totalCPU * 0.64), // 70% of 64 cores
        cpuUsage: totalCPU,
        activeWorkers,
        totalWorkers: 2,
        workerProcesses: totalProcesses,
        status: clusterStatus // Use database-aware status
      },
      workers,
      exploration: {
        totalCombinations: explorationData.totalCombos,
        testedCombinations: explorationData.testedCombos,
        progress: explorationData.progress,
        chunks: explorationData.chunks
      },
      topStrategies: topStrategies.slice(0, 5),
      recommendation,
      lastUpdate: new Date().toISOString()
    }, { status: 200 })
  } catch (error) {
    console.error('Error fetching cluster status:', error)
    return NextResponse.json({
      error: 'Failed to fetch cluster status',
      details: error instanceof Error ? error.message : 'Unknown error'
    }, { status: 500 })
  }
}