# Define the IP addresses to monitor
$addresses = @()
$addressDefinitions = @(
    "1.1.1.1",
    "1.0.0.1",
    "8.8.8.8-9"  # Using range notation for cleaner definition
)

# Set up logging configuration - Use absolute path to avoid system32 issues
$scriptPath = Split-Path -Parent $MyInvocation.MyCommand.Path
$logFolder = Join-Path $scriptPath "LogsPing"
$logFile = Join-Path $logFolder "network_monitor.log"
$statLogFile = Join-Path $logFolder "statistics.log"
$csvLogFile = Join-Path $logFolder "ping_data.csv"
$errorLogFile = Join-Path $logFolder "errors.log"

# Create log directory if it doesn't exist
if (-not (Test-Path $logFolder)) {
    try {
        New-Item -Path $logFolder -ItemType Directory -Force | Out-Null
        Write-Host "Created log directory: $logFolder" -ForegroundColor Green
    } catch {
        Write-Host "Error creating log directory: $_" -ForegroundColor Red
        exit 1
    }
}

# Initialize log files with headers - Use streamwriter for lower memory footprint
try {
    if (-not (Test-Path $csvLogFile)) {
        # Ensure directory exists
        $csvDir = Split-Path -Parent $csvLogFile
        if (-not (Test-Path $csvDir)) {
            New-Item -Path $csvDir -ItemType Directory -Force | Out-Null
        }
        
        $csvStream = [System.IO.StreamWriter]::new($csvLogFile)
        $csvStream.WriteLine("Timestamp,IPAddress,Status,ResponseTime,SuccessRate")
        $csvStream.Close()
        $csvStream.Dispose()
        Write-Host "Created CSV log file: $csvLogFile" -ForegroundColor Green
    }
} catch {
    Write-Host "Error creating CSV log file: $_" -ForegroundColor Red
}

# Prepare log streamwriters - more memory efficient than Out-File
$logStream = $null
$statLogStream = $null
$errorLogStream = $null
$csvLogStream = $null

# Function to write to log file with timestamp - using streamwriter for efficiency
function Write-Log {
    param(
        [Parameter(Mandatory=$true)]
        [string]$Message,
        [string]$LogPath = $logFile,
        [switch]$NoConsole
    )
    
    $timestamp = Get-Date -Format 'yyyy-MM-dd HH:mm:ss'
    $logLine = "$timestamp - $Message"
    
    # Use streamwriter instead of Out-File with error handling
    try {
        # Ensure directory exists
        $logDir = Split-Path -Parent $LogPath
        if (-not (Test-Path $logDir)) {
            New-Item -Path $logDir -ItemType Directory -Force | Out-Null
        }
        
        $stream = [System.IO.StreamWriter]::new($LogPath, $true)
        $stream.WriteLine($logLine)
        $stream.Close()
        $stream.Dispose()
    } catch {
        # Fall back to console output if file writing fails
        Write-Host "Failed to write to log file $LogPath. Error: $_" -ForegroundColor Red
    }
    
    if (-not $NoConsole) {
        Write-Host $logLine
    }
}

# Log script start
Write-Log "Network monitoring script started"

# Set script end time (24 hours from now)
$endTime = (Get-Date).AddHours(24)
Write-Log "Script will automatically stop at $($endTime.ToString('yyyy-MM-dd HH:mm:ss'))"

# Process IP address definitions more efficiently
foreach ($addr in $addressDefinitions) {
    if ($addr -match "(\d+\.\d+\.\d+\.)(\d+)-(\d+)") {
        $prefix = $matches[1]
        $start = [int]$matches[2]
        $end = [int]$matches[3]
        for ($i = $start; $i -le $end; $i++) {
            $addresses += "$prefix$i"
        }
    } else {
        $addresses += $addr
    }
}

# Log monitored addresses
Write-Log "Monitoring IP addresses: $($addresses -join ', ')"

# Initialize statistics storage - Use simpler data structures for memory efficiency
$sampleSize = 60  # Maximum number of samples to keep
$stats = @{}

foreach ($addr in $addresses) {
    # Use fixed-size arrays instead of queue for better memory efficiency
    $stats[$addr] = @{
        MinTime = [int]::MaxValue
        MaxTime = 0
        SampleArray = New-Object 'int[]' $sampleSize  # Fixed-size array
        SamplePosition = 0  # Current position in array
        SampleCount = 0  # Current number of samples (up to sampleSize)
        SuccessCount = 0
        FailCount = 0
        LastStatus = $null
        LastLoggedStats = [DateTime]::MinValue
    }
}

# More efficient mean calculation for fixed array
function Get-ArrayMean {
    param(
        [int[]]$Array,
        [int]$Count,
        [int]$Max
    )
    
    if ($Count -eq 0) { return 0 }
    
    $sum = 0
    $actualCount = [Math]::Min($Count, $Max)
    
    for ($i = 0; $i -lt $actualCount; $i++) {
        $sum += $Array[$i]
    }
    
    return $sum / $actualCount
}

# Function to clear the console and position cursor
function Reset-Display {
    Clear-Host
    $host.UI.RawUI.CursorPosition = @{X=0; Y=0}
}

# Function to format number with fixed width - optimized to reduce string operations
function Format-Number {
    param(
        [Parameter(Mandatory=$true)]
        [double]$Number,
        [int]$Width = 6,
        [int]$Decimals = 1
    )
    
    if ($Number -eq [int]::MaxValue) { 
        return ' ' * $Width 
    }
    
    $formatted = [string]::Format("{0:F$Decimals}", $Number)
    $padding = $Width - $formatted.Length
    
    if ($padding -gt 0) {
        return (' ' * $padding) + $formatted
    }
    return $formatted
}

# Function to log status changes - streamwriter based
function Write-StatusLog {
    param(
        [string]$Address,
        [bool]$OldStatus,
        [bool]$NewStatus
    )
    
    $statusText = if ($NewStatus) { "UP" } else { "DOWN" }
    $oldStatusText = if ($OldStatus) { "UP" } else { "DOWN" }
    $logMessage = "$Address status changed from $oldStatusText to $statusText"
    
    Write-Log $logMessage
    Write-Host "`n$logMessage" -ForegroundColor Yellow
}

# Function to log ping data to CSV - using streamwriter for efficiency
function Write-PingDataLog {
    param(
        [string]$Address,
        [bool]$Status,
        [int]$ResponseTime,
        [double]$SuccessRate
    )
    
    $statusText = if ($Status) { "UP" } else { "DOWN" }
    $timestamp = Get-Date -Format 'yyyy-MM-dd HH:mm:ss'
    
    try {
        $stream = [System.IO.StreamWriter]::new($csvLogFile, $true)
        $stream.WriteLine("$timestamp,$Address,$statusText,$ResponseTime,$SuccessRate")
        $stream.Close()
        $stream.Dispose()
    } catch {
        Write-Host "Error writing to CSV log file: $_" -ForegroundColor Red
    }
}

# Function to log statistics periodically - streamwriter based
function Write-StatisticsLog {
    param(
        [string]$Address,
        [hashtable]$Statistics,
        [int]$IntervalMinutes = 15
    )
    
    $now = Get-Date
    if (($now - $Statistics.LastLoggedStats).TotalMinutes -ge $IntervalMinutes) {
        $totalRequests = $Statistics.SuccessCount + $Statistics.FailCount
        $successRate = if ($totalRequests -gt 0) {
            [math]::Round(($Statistics.SuccessCount / $totalRequests) * 100, 1)
        } else { 0 }
        
        $meanTime = [math]::Round((Get-ArrayMean -Array $Statistics.SampleArray -Count $Statistics.SampleCount -Max $sampleSize), 1)
        
        $statsMessage = "$Address Stats - Min: $($Statistics.MinTime)ms, Max: $($Statistics.MaxTime)ms, " + 
                        "Mean: ${meanTime}ms, Success Rate: ${successRate}%, " +
                        "Success Count: $($Statistics.SuccessCount), Fail Count: $($Statistics.FailCount)"
        
        Write-Log -Message $statsMessage -LogPath $statLogFile -NoConsole
        $Statistics.LastLoggedStats = $now
    }
}

# Function to handle errors - streamwriter based
function Write-ErrorLog {
    param(
        [Parameter(Mandatory=$true)]
        [System.Management.Automation.ErrorRecord]$ErrorRecord,
        [string]$Context = "General"
    )
    
    $errorMessage = "[$Context] $($ErrorRecord.Exception.GetType().Name): $($ErrorRecord.Exception.Message)"
    
    # More memory efficient than Format-List
    $errorDetails = "Exception: $($ErrorRecord.Exception)"
    
    Write-Log -Message $errorMessage -LogPath $errorLogFile -NoConsole
    Write-Log -Message "Details: $errorDetails" -LogPath $errorLogFile -NoConsole
    Write-Host "Error: $errorMessage" -ForegroundColor Red
}

# Function to display time remaining
function Format-TimeRemaining {
    param([TimeSpan]$TimeSpan)
    return "{0:D2}:{1:D2}:{2:D2}" -f $TimeSpan.Hours, $TimeSpan.Minutes, $TimeSpan.Seconds
}

# Memory cleanup function - call periodically
function Invoke-MemoryCleanup {
    [System.GC]::Collect()
    [System.GC]::WaitForPendingFinalizers()
    [System.GC]::Collect()
}

# Display script information
Write-Host "Network Monitoring Tool" -ForegroundColor Cyan
Write-Host "======================" -ForegroundColor Cyan
Write-Host "Log Directory: $logFolder" -ForegroundColor Yellow
Write-Host "Monitoring these IPs: $($addresses -join ', ')" -ForegroundColor Yellow
Write-Host "Press Enter to continue or Ctrl+C to exit..." -ForegroundColor Green
$null = Read-Host

# Main monitoring loop
try {
    $pingInterval = 1  # seconds between pings
    $statsLogInterval = 15  # minutes between logging statistics
    $csvLogFrequency = 5  # log every Nth ping to CSV to avoid huge files
    $memoryCleanupInterval = 100  # Garbage collect every N pings
    $pingCounter = 0
    
    # Create ping object once, outside the loop
    $ping = New-Object System.Net.NetworkInformation.Ping
    
    Write-Log "Monitoring started with ping interval of ${pingInterval}s and stats logging every ${statsLogInterval} minutes"
    
    while ($true) {
        # Check if 24 hours have elapsed
        $currentTime = Get-Date
        if ($currentTime -ge $endTime) {
            Write-Log "24-hour monitoring period completed. Stopping the script."
            break
        }
        
        $timeRemaining = $endTime - $currentTime
        
        Reset-Display
        $currentTimeFormatted = $currentTime.ToString("HH:mm:ss")
        Write-Host "Network Monitor - Last Updated: $currentTimeFormatted" -ForegroundColor Cyan
        Write-Host "Time remaining: $(Format-TimeRemaining -TimeSpan $timeRemaining)" -ForegroundColor Cyan
        Write-Host "Press Ctrl+C to exit`n" -ForegroundColor DarkGray
        
        # Header with fixed widths
        Write-Host "IP Address      Status    Min   Max   Mean  Success%  Fails   Trend" -ForegroundColor Yellow
        Write-Host "--------------- -------- ----- ----- ----- -------- ------ -------" -ForegroundColor Yellow
        
        $pingCounter++
        
        # Force garbage collection periodically
        if ($pingCounter % $memoryCleanupInterval -eq 0) {
            Invoke-MemoryCleanup
        }
        
        foreach ($addr in $addresses) {
            try {
                $result = $ping.Send($addr, 1000)  # 1 second timeout
                $status = $result.Status -eq 'Success'
                $responseTime = if ($status) { $result.RoundtripTime } else { 0 }
            } catch {
                $status = $false
                $responseTime = 0
                Write-ErrorLog -ErrorRecord $_ -Context "Ping to $addr"
            }
            
            if ($status) {
                $stats[$addr].SuccessCount++
                
                # Update sample array using fixed position tracking
                $position = $stats[$addr].SamplePosition
                $stats[$addr].SampleArray[$position] = $responseTime
                $stats[$addr].SamplePosition = ($position + 1) % $sampleSize
                if ($stats[$addr].SampleCount -lt $sampleSize) {
                    $stats[$addr].SampleCount++
                }
                
                # Update min/max
                if ($stats[$addr].MinTime -eq [int]::MaxValue -or $responseTime -lt $stats[$addr].MinTime) {
                    $stats[$addr].MinTime = $responseTime
                }
                if ($responseTime -gt $stats[$addr].MaxTime) {
                    $stats[$addr].MaxTime = $responseTime
                }
                
                $statusText = "UP"
                $color = "Green"
            } else {
                $stats[$addr].FailCount++
                $statusText = "DOWN"
                $color = "Red"
            }
            
            # Calculate statistics
            $totalRequests = $stats[$addr].SuccessCount + $stats[$addr].FailCount
            $successRate = if ($totalRequests -gt 0) {
                [math]::Round(($stats[$addr].SuccessCount / $totalRequests) * 100, 1)
            } else { 0 }
            
            $meanTime = [math]::Round((Get-ArrayMean -Array $stats[$addr].SampleArray -Count $stats[$addr].SampleCount -Max $sampleSize), 1)
            
            # Check for status changes and log them
            if ($null -ne $stats[$addr].LastStatus -and $stats[$addr].LastStatus -ne $status) {
                Write-StatusLog -Address $addr -OldStatus $stats[$addr].LastStatus -NewStatus $status
            }
            $stats[$addr].LastStatus = $status
            
            # Log statistics periodically
            Write-StatisticsLog -Address $addr -Statistics $stats[$addr] -IntervalMinutes $statsLogInterval
            
            # Log to CSV (but not every ping to avoid huge files)
            if ($pingCounter % $csvLogFrequency -eq 0) {
                Write-PingDataLog -Address $addr -Status $status -ResponseTime $responseTime -SuccessRate $successRate
            }
            
            # Calculate trend more efficiently - FIXED: Using ASCII characters instead of Unicode
            $trend = "-"  # Default to neutral (horizontal line)
            if ($stats[$addr].SampleCount -ge 5) {
                $samples = $stats[$addr].SampleArray
                $count = $stats[$addr].SampleCount
                $position = $stats[$addr].SamplePosition
                
                # Get first sample (oldest of last 5)
                $firstIndex = ($position - 5 + $sampleSize) % $sampleSize
                $first = $samples[$firstIndex]
                
                # Get last sample (newest)
                $lastIndex = ($position - 1 + $sampleSize) % $sampleSize
                $last = $samples[$lastIndex]
                
                $slope = $last - $first
                if ([Math]::Abs($slope) -lt 5) {
                    $trend = "-"  # Neutral
                } elseif ($slope -lt 0) {
                    $trend = "v"  # Down arrow
                } else {
                    $trend = "^"  # Up arrow
                }
            }
            
            # Format output fields - efficient string formatting
            $ipField = $addr.PadRight(15)
            $statusField = $statusText.PadRight(8)
            $minField = Format-Number -Number $stats[$addr].MinTime -Width 5 -Decimals 0
            $maxField = Format-Number -Number $stats[$addr].MaxTime -Width 5 -Decimals 0
            $meanField = Format-Number -Number $meanTime -Width 5 -Decimals 1
            $successField = Format-Number -Number $successRate -Width 8 -Decimals 1
            $failsField = $stats[$addr].FailCount.ToString().PadLeft(6)
            
            # Display the line
            Write-Host $ipField -NoNewline
            Write-Host $statusField -NoNewline -ForegroundColor $color
            Write-Host "$minField $maxField $meanField $successField $failsField   $trend"
        }
        
        Start-Sleep -Seconds $pingInterval
    }
} catch {
    # Log any unhandled exceptions
    Write-ErrorLog -ErrorRecord $_ -Context "Main monitoring loop"
} finally {
    # Final garbage collection and cleanup
    Invoke-MemoryCleanup
    
    # Cleanup when script is interrupted
    $endMessage = "Monitoring stopped at $(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')"
    Write-Log $endMessage
    Write-Host "`n$endMessage" -ForegroundColor Cyan
    
    # Dispose of ping object
    if ($ping -ne $null) {
        $ping.Dispose()
    }
}