import { NextRequest, NextResponse } from 'next/server'
import { exec } from 'child_process'
import { promisify } from 'util'
import fs from 'fs/promises'

const execAsync = promisify(exec)

export async function GET(request: NextRequest) {
  const { searchParams } = new URL(request.url)
  const type = searchParams.get('type')
  const limit = parseInt(searchParams.get('limit') || '100')
  const since = searchParams.get('since') || undefined // timestamp
  
  try {
    switch (type) {
      case 'firewall':
        return await getFirewallLogs(limit, since)
        
      case 'lfd':
        return await getLfdLogs(limit, since)
        
      case 'system':
        return await getSystemLogs(limit, since)
        
      case 'blocked':
        return await getBlockedIPs(limit)
        
      case 'connections':
        return await getActiveConnections()
        
      default:
        return await getAllLogs(limit, since)
    }
    
  } catch (error: any) {
    console.error('Logs API error:', error)
    return NextResponse.json({
      success: false,
      error: `Failed to retrieve logs: ${error.message}`
    }, { status: 500 })
  }
}

async function getFirewallLogs(limit: number, since?: string) {
  try {
    // Get iptables logs from syslog
    let command = `grep "CSF\\|iptables" /var/log/syslog | tail -${limit}`
    if (since) {
      const sinceDate = new Date(since).toISOString().split('T')[0]
      command = `grep "CSF\\|iptables" /var/log/syslog | grep "${sinceDate}" | tail -${limit}`
    }
    
    const { stdout } = await execAsync(command)
    const logs = parseFirewallLogs(stdout)
    
    return NextResponse.json({
      success: true,
      data: {
        logs,
        total: logs.length,
        type: 'firewall'
      }
    })
  } catch (error: any) {
    return NextResponse.json({
      success: false,
      error: `Failed to get firewall logs: ${error.message}`
    }, { status: 500 })
  }
}

async function getLfdLogs(limit: number, since?: string) {
  try {
    let command = `grep "lfd" /var/log/lfd.log 2>/dev/null | tail -${limit} || echo ""`
    if (since) {
      const sinceDate = new Date(since).toISOString().split('T')[0]
      command = `grep "lfd" /var/log/lfd.log 2>/dev/null | grep "${sinceDate}" | tail -${limit} || echo ""`
    }
    
    const { stdout } = await execAsync(command)
    const logs = parseLfdLogs(stdout)
    
    return NextResponse.json({
      success: true,
      data: {
        logs,
        total: logs.length,
        type: 'lfd'
      }
    })
  } catch (error: any) {
    return NextResponse.json({
      success: false,
      error: `Failed to get LFD logs: ${error.message}`
    }, { status: 500 })
  }
}

async function getSystemLogs(limit: number, since?: string) {
  try {
    let command = `grep "kernel\\|iptables" /var/log/syslog | tail -${limit}`
    if (since) {
      const sinceDate = new Date(since).toISOString().split('T')[0]
      command = `grep "kernel\\|iptables" /var/log/syslog | grep "${sinceDate}" | tail -${limit}`
    }
    
    const { stdout } = await execAsync(command)
    const logs = parseSystemLogs(stdout)
    
    return NextResponse.json({
      success: true,
      data: {
        logs,
        total: logs.length,
        type: 'system'
      }
    })
  } catch (error: any) {
    return NextResponse.json({
      success: false,
      error: `Failed to get system logs: ${error.message}`
    }, { status: 500 })
  }
}

async function getBlockedIPs(limit: number) {
  try {
    // Get current blocked IPs from iptables
    const { stdout } = await execAsync('/usr/local/csf/bin/csf --status | grep DROP | head -' + limit)
    const blockedIPs = parseBlockedIPs(stdout)
    
    return NextResponse.json({
      success: true,
      data: {
        blocked_ips: blockedIPs,
        total: blockedIPs.length,
        type: 'blocked'
      }
    })
  } catch (error: any) {
    return NextResponse.json({
      success: false,
      error: `Failed to get blocked IPs: ${error.message}`
    }, { status: 500 })
  }
}

async function getActiveConnections() {
  try {
    // Get active network connections
    const { stdout } = await execAsync('netstat -tn | grep ESTABLISHED | wc -l')
    const activeConnections = parseInt(stdout.trim()) || 0
    
    // Get connection details
    const { stdout: connections } = await execAsync('netstat -tn | grep ESTABLISHED | head -20')
    const connectionList = parseConnections(connections)
    
    return NextResponse.json({
      success: true,
      data: {
        active_connections: activeConnections,
        connections: connectionList,
        type: 'connections'
      }
    })
  } catch (error: any) {
    return NextResponse.json({
      success: false,
      error: `Failed to get active connections: ${error.message}`
    }, { status: 500 })
  }
}

async function getAllLogs(limit: number, since?: string) {
  try {
    const [firewallResult, lfdResult, systemResult] = await Promise.allSettled([
      getFirewallLogs(Math.floor(limit / 3), since),
      getLfdLogs(Math.floor(limit / 3), since),
      getSystemLogs(Math.floor(limit / 3), since)
    ])
    
    const allLogs = []
    
    if (firewallResult.status === 'fulfilled') {
      const response = await firewallResult.value.json()
      if (response.success) allLogs.push(...response.data.logs)
    }
    
    if (lfdResult.status === 'fulfilled') {
      const response = await lfdResult.value.json()
      if (response.success) allLogs.push(...response.data.logs)
    }
    
    if (systemResult.status === 'fulfilled') {
      const response = await systemResult.value.json()
      if (response.success) allLogs.push(...response.data.logs)
    }
    
    // Sort by timestamp
    allLogs.sort((a, b) => new Date(b.timestamp).getTime() - new Date(a.timestamp).getTime())
    
    return NextResponse.json({
      success: true,
      data: {
        logs: allLogs.slice(0, limit),
        total: allLogs.length,
        type: 'all'
      }
    })
  } catch (error: any) {
    return NextResponse.json({
      success: false,
      error: `Failed to get all logs: ${error.message}`
    }, { status: 500 })
  }
}

// Parsing functions
function parseFirewallLogs(output: string) {
  const logs = []
  const lines = output.split('\\n').filter(line => line.trim())
  
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i]
    const logEntry = parseLogLine(line, 'firewall')
    if (logEntry) logs.push(logEntry)
  }
  
  return logs
}

function parseLfdLogs(output: string) {
  const logs = []
  const lines = output.split('\\n').filter(line => line.trim())
  
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i]
    const logEntry = parseLogLine(line, 'lfd')
    if (logEntry) logs.push(logEntry)
  }
  
  return logs
}

function parseSystemLogs(output: string) {
  const logs = []
  const lines = output.split('\\n').filter(line => line.trim())
  
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i]
    const logEntry = parseLogLine(line, 'system')
    if (logEntry) logs.push(logEntry)
  }
  
  return logs
}

function parseLogLine(line: string, type: string) {
  // Basic log parsing - adjust regex patterns based on actual log format
  const patterns = {
    timestamp: /^(\\w{3}\\s+\\d{1,2}\\s+\\d{2}:\\d{2}:\\d{2})/,
    ip: /(\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3})/,
    port: /DPT=(\\d+)/,
    protocol: /(TCP|UDP|ICMP)/i,
    action: /(BLOCK|DROP|ACCEPT|ALLOW|DENY)/i
  }
  
  const timestampMatch = line.match(patterns.timestamp)
  const ipMatch = line.match(patterns.ip)
  const portMatch = line.match(patterns.port)
  const protocolMatch = line.match(patterns.protocol)
  const actionMatch = line.match(patterns.action)
  
  if (!timestampMatch) return null
  
  const currentYear = new Date().getFullYear()
  const timestamp = new Date(`${currentYear} ${timestampMatch[1]}`).toISOString()
  
  return {
    id: `${type}-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
    timestamp,
    level: actionMatch && (actionMatch[1].toLowerCase() === 'block' || actionMatch[1].toLowerCase() === 'drop') ? 'block' : 'info',
    message: line,
    ip: ipMatch ? ipMatch[1] : undefined,
    port: portMatch ? portMatch[1] : undefined,
    protocol: protocolMatch ? protocolMatch[1].toUpperCase() : undefined,
    action: actionMatch ? actionMatch[1].toUpperCase() : undefined,
    type
  }
}

function parseBlockedIPs(output: string) {
  const blockedIPs = []
  const lines = output.split('\\n').filter(line => line.trim())
  
  for (const line of lines) {
    const ipMatch = line.match(/(\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3})/)
    if (ipMatch) {
      blockedIPs.push({
        ip: ipMatch[1],
        reason: 'Firewall rule',
        timestamp: new Date().toISOString()
      })
    }
  }
  
  return blockedIPs
}

function parseConnections(output: string) {
  const connections = []
  const lines = output.split('\\n').filter(line => line.trim())
  
  for (const line of lines) {
    const parts = line.trim().split(/\\s+/)
    if (parts.length >= 4) {
      const [protocol, , , localAddress, foreignAddress] = parts
      connections.push({
        protocol,
        local_address: localAddress,
        foreign_address: foreignAddress,
        state: 'ESTABLISHED'
      })
    }
  }
  
  return connections
}