# Directory mappings
$directories = @('01', '02', '03', '04', '05', '06', '07', '08', '09', '10', 
                '11', '12', '13', '15', '16', '17', '18', '19', '21', '22', 
                '23', '24', '25', '27', '28', '31', '32', '33')

# SFTP Configuration - Replace with your actual values
$sftpConfig = @{
    Server = "ftp.domain.com"
    Port = 22
    Username = "user"
    Password = "password"
    RemotePath = "/folder/PDF"
    SshHostKeyFingerprint = "ssh-rsa 2048 number"
}

# Log directory
$logDir = "D:\LOCAL-FOLDER\Log"
if (-not (Test-Path $logDir)) {
    New-Item -ItemType Directory -Path $logDir -Force
}

# Function to write to log file
function Write-ToLog {
    param(
        [string]$Message,
        [string]$LogFile
    )
    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
    "$timestamp - $Message" | Out-File -FilePath $LogFile -Append
}
# Function to list all files in SFTP directory
function List-SftpFiles {
    param(
        [WinSCP.Session]$Session,
        [string]$LogFile
    )
    try {
        Write-ToLog "Listing all files in remote directory:" $LogFile
        $allFiles = $Session.EnumerateRemoteFiles(
            $sftpConfig.RemotePath,
            "*.*",
            [WinSCP.EnumerationOptions]::None
        )
        foreach ($file in $allFiles) {
            Write-ToLog "Found file in SFTP: $($file.Name)" $LogFile
        }
    }
    catch {
        Write-ToLog "Error listing SFTP directory: $_" $LogFile
    }
}

# Function to process files
function Process-Files {
    param(
        [WinSCP.Session]$Session,
        [string]$Pattern,
        [bool]$DeleteAfterDownload
    )
    
    $date = Get-Date
    $logFile = Join-Path $logDir ("FileTransfer_" + $date.ToString("yyyyMMdd_HHmmss") + "_" + $Pattern.Replace("*", "all") + ".log")
    Write-ToLog "Starting file transfer process for pattern: $Pattern" $logFile
    
    # List all files in SFTP directory for debugging
    List-SftpFiles -Session $Session -LogFile $logFile
    
    try {
        # First try to list all PDF files
        Write-ToLog "Attempting to list all PDF files..." $LogFile
        $allPdfFiles = $Session.EnumerateRemoteFiles(
            $sftpConfig.RemotePath,
            "*.pdf",
            [WinSCP.EnumerationOptions]::None
        )
        
        # Filter files based on pattern
        $files = $allPdfFiles | Where-Object { 
            $_.Name -like $Pattern.Replace("*", "*") -or 
            ($Pattern -eq "705pdfnd_*.pdf" -and $_.Name -match "705pdfnd_\d+\.pdf")
        }
        
        $filesFound = $false
        foreach ($file in $files) {
            $filesFound = $true
            Write-ToLog "Processing file: $($file.Name)" $logFile
            
            # Extract SNIF number using more flexible pattern matching
            $snif = $null
            if ($file.Name -match '705pdf(?:nd)?_20(\d{2})') {
                $snif = $matches[1]
                Write-ToLog "Extracted SNIF number: $snif" $logFile
            }
            else {
                Write-ToLog "Could not extract SNIF number from filename: $($file.Name)" $logFile
                continue
            }
            
            if ($directories -contains $snif) {
                $year = $date.ToString("yyyy")
                $month = $date.ToString("MM")
                $unique = $date.ToString("yyyyMMdd")
                
                $basePath = "D:\LOCAL-FOLDER\FROM\"
                $targetPath = Join-Path -Path $basePath -ChildPath "$snif\$year\$month\$unique"
                
                Write-ToLog "Processing file $($file.Name) for SNIF: $snif" $logFile
                Write-ToLog "Target path: $targetPath" $logFile
                
                if (-not (Test-Path $targetPath)) {
                    New-Item -ItemType Directory -Path $targetPath -Force
                    Write-ToLog "Created directory: $targetPath" $logFile
                }
                
                try {
                    $transferResult = $Session.GetFiles(
                        "$($sftpConfig.RemotePath)/$($file.Name)",
                        "$targetPath\$($file.Name)"
                    )
                    
                    if ($transferResult.IsSuccess) {
                        Write-ToLog "Successfully downloaded: $($file.Name) to $targetPath" $logFile
                        
                        if ($DeleteAfterDownload) {
                            try {
                                $Session.RemoveFiles("$($sftpConfig.RemotePath)/$($file.Name)")
                                Write-ToLog "Removed $($file.Name) from SFTP server" $logFile
                            }
                            catch {
                                Write-ToLog "Error removing $($file.Name) from SFTP server: $_" $logFile
                            }
                        }
                    }
                    else {
                        Write-ToLog "Failed to download $($file.Name): $($transferResult.Failures)" $logFile
                    }
                }
                catch {
                    Write-ToLog "Error transferring file $($file.Name): $_" $logFile
                }
            }
            else {
                Write-ToLog "SNIF $snif not in allowed directories list" $logFile
            }
        }
        
        if (-not $filesFound) {
            Write-ToLog "No files found matching pattern: $Pattern" $logFile
            Write-ToLog "Note: This could mean either no files exist or pattern matching failed" $logFile
        }
    }
    catch {
        Write-ToLog "Error processing files: $_" $logFile
        throw $_
    }
}

try {
    # delete option 
    $shouldDelete =  $true
    
    # Load WinSCP .NET assembly
    Add-Type -Path "C:\Program Files (x86)\WinSCP\WinSCPnet.dll"
    
    # Setup session options
    $sessionOptions = New-Object WinSCP.SessionOptions -Property @{
        Protocol = [WinSCP.Protocol]::Sftp
        HostName = $sftpConfig.Server
        PortNumber = $sftpConfig.Port
        UserName = $sftpConfig.Username
        Password = $sftpConfig.Password
        SshHostKeyFingerprint = $sftpConfig.SshHostKeyFingerprint
    }
    
    # Create session
    $session = New-Object WinSCP.Session
    
    try {
        # Connect to SFTP
        $session.Open($sessionOptions)
        
        # Process both file patterns
        Process-Files -Session $session -Pattern "705pdf_*.pdf" -DeleteAfterDownload $shouldDelete
        Process-Files -Session $session -Pattern "705pdfnd_*.pdf" -DeleteAfterDownload $shouldDelete
    }
    finally {
        # Cleanup
        $session.Dispose()
    }
    
    # Change to LOCAL-FOLDER directory
    Set-Location -Path "D:\LOCAL-FOLDER"
    Write-Host "Process completed successfully"
}
catch {
    Write-Error "Error in main process: $_"
    exit 1
}