<#
.SYNOPSIS
    Automates USB drive synchronization using CSV-defined mappings with event-driven monitoring.
    To install as a service, use the following commands:
    nssm install "AutomatedFlashDriveSync" "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -File "C:\Users\J2897\Code\PowerShell\DriveSync\AutomatedFlashDriveSync.ps1"
    nssm set "AutomatedFlashDriveSync" Description "Automates the synchronization of USB drives with specified directories using a CSV-defined mapping."

.DESCRIPTION
    This script:
    1. Runs as a service monitoring USB insertion events via WMI
    2. Performs automatic/manual syncs using device mappings from DeviceMapping.csv
    3. Uses Robocopy for file synchronization with detailed logging
    4. Supports multiple partitions per device

.OPERATION MODES
    - Automatic: Triggers on USB insertion (Win32_DiskDrive creation event)
    - Manual: Press 'S' to force sync, 'Q' to quit

.SYNC FEATURES
    - Automatic drive letter detection
    - Path validation (source/target)
    - Logging with timestamps
    - Error handling with exit codes
    - Safe retries (R:3/W:5)

.REQUIREMENTS
    - DeviceMapping.csv from mapping script (USB_Drive_Mapper_CSV.ps1)
    - Robocopy available in PATH
    - Admin privileges for WMI events

.NOTES
    CSV must contain: DeviceID,SourceDirectory,TargetDirectory
    Safe exit code range: Robocopy codes < 8
#>

# Path to CSV file (global variable)
$global:csvPath = "C:\Users\J2897\Code\PowerShell\DriveSync\DeviceMapping.csv"

function global:Scan-Devices {
    param (
        [Parameter(Mandatory=$true)]
        [string]$csvFile
    )
    try {
        Write-Host "`n[SCAN STARTED] Loading CSV from: $csvFile"
        $devices = Import-Csv -Path $csvFile
        Write-Host "Loaded $($devices.Count) device mappings"

        # Wait for drive initialization
        Write-Host "Waiting 5 seconds for drive preparation..."
        1..5 | ForEach-Object { 
            Write-Host "  - Second $_/5"
            Start-Sleep -Seconds 1 
        }

        # Get fresh device lists
        $diskDrives = Get-WmiObject -Class Win32_DiskDrive | Where-Object { $_.PNPDeviceID -like "USBSTOR*" }
        Write-Host "Detected USB disk drives: $($diskDrives.Count)"

        foreach ($device in $devices) {
            $trimmedFriendlyName = $device.FriendlyName.Trim()
            Write-Host "`nProcessing device: $trimmedFriendlyName ($($device.DeviceID))"
            
            # Find matching disk drive
            $matchingDisk = $diskDrives | Where-Object { $_.PNPDeviceID -eq $device.DeviceID }
            if (-not $matchingDisk) {
                Write-Host "  No matching disk found!"
                continue
            }

            Write-Host "  Found matching disk: $($matchingDisk.Model)"
            
            # Get drive letters
            $driveLetters = $matchingDisk.GetRelated("Win32_DiskPartition") | 
                          ForEach-Object { $_.GetRelated("Win32_LogicalDisk") } | 
                          Select-Object -ExpandProperty DeviceID

            if (-not $driveLetters) {
                Write-Host "  No drive letters found!"
                continue
            }

            Write-Host "  Drive letters: $($driveLetters -join ', ')"
						
			foreach ($letter in $driveLetters) {
				# Ensure correct source path handling
				$sourcePath = if ($device.SourceDirectory -and $device.SourceDirectory.Trim() -ne "") {
					"$letter\$($device.SourceDirectory)"
				} else {
					"$letter\"
				}

				Write-Host "`n  Attempting sync from: $sourcePath"
				
				if (Test-Path $sourcePath) {
					Write-Host "  Source path verified - starting sync..."
					
					# Ensure the target directory exists
					if (-not (Test-Path $device.TargetDirectory)) {
						Write-Host "  Target directory does not exist. Creating: $($device.TargetDirectory)"
						New-Item -ItemType Directory -Path $device.TargetDirectory -Force | Out-Null
					}

					$logPath = Join-Path $device.TargetDirectory "SyncLog_$(Get-Date -Format 'yyyyMMdd-HHmmss').txt"

					# Ensure correct formatting for source and target paths
					$robocopyParams = @(
						$sourcePath,
						$device.TargetDirectory,
						"/E", "/COPY:DAT", "/R:3", "/W:5", "/LOG:$logPath",
						"/NP", "/V"
					)

					Write-Host "  Starting sync with Robocopy..."
					try {
						& robocopy @robocopyParams | ForEach-Object { Write-Host $_ }
						if ($LASTEXITCODE -lt 8) {
							Write-Host "  Sync completed successfully (Exit Code: $LASTEXITCODE)"
						} else {
							Write-Host "  Sync completed with warnings (Exit Code: $LASTEXITCODE)"
						}
					} catch {
						Write-Host "  Sync failed: $_"
					}
				}
				else {
					Write-Host "  Source path not found!"
				}
			}

        }
    }
    catch {
        Write-Host "[CRITICAL ERROR] $_"
    }
    Write-Host "`n[SCAN COMPLETED]"
}

# Event registration
$null = Register-WmiEvent -Query @"
SELECT * FROM __InstanceCreationEvent WITHIN 2 
WHERE TargetInstance ISA 'Win32_DiskDrive' 
AND TargetInstance.InterfaceType = 'USB'
"@ -SourceIdentifier "USBInserted" -Action {
    Write-Host "`n[EVENT TRIGGERED] Starting scan sequence..."
    Scan-Devices -csvFile $global:csvPath
}

# Monitoring loop
Write-Host "Monitoring USB devices. Press 'S' to scan manually, 'Q' to quit."

try {
    while ($true) {
        if ([Console]::KeyAvailable) {
            $key = [Console]::ReadKey($true).Key
            if ($key -eq [ConsoleKey]::S) {
                Write-Host "`n[MANUAL SCAN]"
                Scan-Devices -csvFile $global:csvPath
            }
            elseif ($key -eq [ConsoleKey]::Q) {
                break
            }
        }
        Start-Sleep -Milliseconds 100
    }
}
finally {
    Write-Host "Exiting..."
    Get-EventSubscriber -SourceIdentifier "USBInserted" | Unregister-Event -ErrorAction SilentlyContinue
}