# Transfer Oracle RMAN Backup towards DR Server
# Rulează după backup RMAN (03:00 AM)
# Copiază backup-uri de pe PRIMARY (10.0.20.36) către DR (10.0.20.37)

param(
    [string]$SourceFRA = "C:\Users\Oracle\recovery_area\ROA",
    [string]$DRHost = "10.0.20.37",
    [int]$DRPort = 22122,
    [string]$DRUser = "romfast",
    [string]$DRPath = "D:/oracle/backups/primary",
    [string]$SSHKeyPath = "$env:USERPROFILE\.ssh\id_rsa",
    [int]$RetentionDays = 2,
    [string]$LogFile = "D:\rman_backup\logs\transfer_$(Get-Date -Format 'yyyyMMdd').log"
)

$ErrorActionPreference = "Continue"

function Write-Log {
    param([string]$Message, [string]$Level = "INFO")
    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
    $logLine = "[$timestamp] [$Level] $Message"
    Write-Host $logLine
    Add-Content -Path $LogFile -Value $logLine -Encoding UTF8 -ErrorAction SilentlyContinue
}

function Test-SSHConnection {
    Write-Log "Testing SSH connection to $DRHost`:$DRPort..."

    try {
        # Folosește -n pentru a nu citi din stdin (fix pentru blocare)
        $null = & ssh -n -p $DRPort -i $SSHKeyPath -o StrictHostKeyChecking=no -o ConnectTimeout=10 "${DRUser}@${DRHost}" "exit 0" 2>&1

        if ($LASTEXITCODE -eq 0) {
            Write-Log "SSH connection successful" "SUCCESS"
            return $true
        } else {
            Write-Log "SSH connection failed with exit code: $LASTEXITCODE" "ERROR"
            return $false
        }
    } catch {
        Write-Log "SSH connection error: $_" "ERROR"
        return $false
    }
}

function Get-TodaysBackups {
    Write-Log "Searching for today's backup files..."

    $today = Get-Date
    $cutoffDate = $today.Date  # Only today (after midnight)
    $backupFiles = @()

    $searchPaths = @(
        "$SourceFRA\BACKUPSET",
        "$SourceFRA\AUTOBACKUP"
    )

    foreach ($path in $searchPaths) {
        if (Test-Path $path) {
            # Get files created TODAY only (exclude old backups)
            $files = Get-ChildItem -Path $path -Recurse -File -ErrorAction SilentlyContinue |
                Where-Object {
                    $_.LastWriteTime -gt $cutoffDate -and
                    $_.Name -notlike "*__TAG_*"  # Exclude old uncompressed backups
                } |
                Sort-Object LastWriteTime -Descending

            $backupFiles += $files
        }
    }

    if ($backupFiles.Count -eq 0) {
        Write-Log "No backup files found for today!" "WARNING"
        return @()
    }

    $totalSizeGB = ($backupFiles | Measure-Object -Property Length -Sum).Sum / 1GB
    Write-Log "Found $($backupFiles.Count) files, total size: $([math]::Round($totalSizeGB, 2)) GB"

    return $backupFiles
}

function Transfer-FileToDR {
    param([System.IO.FileInfo]$File, [string]$DestPath)

    $fileName = $File.Name
    $fileSizeMB = [math]::Round($File.Length / 1MB, 2)

    try {
        # Check dacă fișierul există deja pe DR (skip duplicates) - Windows PowerShell command
        $checkCmd = "powershell -Command `"Test-Path '$DestPath/$fileName'`""
        $checkResult = & ssh -n -p $DRPort -i $SSHKeyPath "${DRUser}@${DRHost}" $checkCmd 2>&1

        if ($checkResult -match "True") {
            Write-Log "Skipping (already on DR): $fileName" "INFO"
            return $true
        }

        Write-Log "Transferring: $fileName ($fileSizeMB MB)"

        # SCP transfer - NO compression (files already compressed by RMAN)
        # Use cipher aes128-gcm for better performance
        $null = & scp -P $DRPort -i $SSHKeyPath -o StrictHostKeyChecking=no -o Compression=no -o Cipher=aes128-gcm@openssh.com $File.FullName "${DRUser}@${DRHost}:${DestPath}/" 2>&1

        if ($LASTEXITCODE -eq 0) {
            Write-Log "Transferred: $fileName" "SUCCESS"
            return $true
        } else {
            Write-Log "Failed to transfer: $fileName (exit code: $LASTEXITCODE)" "ERROR"
            return $false
        }
    } catch {
        Write-Log "Transfer error for $fileName : $_" "ERROR"
        return $false
    }
}

function Cleanup-OldBackupsOnDR {
    Write-Log "Cleaning up old backups on DR (keeping last $RetentionDays days)..."

    try {
        # Cleanup: șterge fișiere mai vechi de $RetentionDays zile - Windows PowerShell command
        $retentionDate = (Get-Date).AddDays(-$RetentionDays).ToString("yyyy-MM-dd")
        $cleanupCmd = "powershell -Command `"Get-ChildItem -Path '$DRPath' -Recurse -File | Where-Object { `$_.LastWriteTime -lt '$retentionDate' } | Remove-Item -Force -ErrorAction SilentlyContinue`""
        $result = & ssh -n -p $DRPort -i $SSHKeyPath "${DRUser}@${DRHost}" $cleanupCmd 2>&1

        Write-Log "Cleanup completed on DR (removed files older than $retentionDate)"
    } catch {
        Write-Log "Cleanup warning: $_" "WARNING"
    }
}

# ==================== MAIN ====================

try {
    Write-Log "========================================="
    Write-Log "Oracle DR Backup Transfer Started"
    Write-Log "========================================="
    Write-Log "Source FRA: $SourceFRA"
    Write-Log "DR Server: $DRHost"
    Write-Log "DR Path: $DRPath"

    # Verificare prerequisite
    if (-not (Test-Path $SourceFRA)) {
        throw "Source FRA path not found: $SourceFRA"
    }

    if (-not (Test-Path $SSHKeyPath)) {
        throw "SSH key not found: $SSHKeyPath"
    }

    # Test SSH connection
    if (-not (Test-SSHConnection)) {
        throw "Cannot connect to DR server via SSH"
    }

    # Creare director pe DR - Windows PowerShell command
    Write-Log "Ensuring DR directory exists..."
    $null = & ssh -n -p $DRPort -i $SSHKeyPath "${DRUser}@${DRHost}" "powershell -Command `"New-Item -ItemType Directory -Path '$DRPath' -Force | Out-Null`"" 2>&1

    # Găsește backup-uri
    $backupFiles = Get-TodaysBackups

    if ($backupFiles.Count -eq 0) {
        throw "No backup files to transfer!"
    }

    # Transfer fișiere
    Write-Log "Starting file transfer..."
    $successCount = 0
    $failCount = 0

    foreach ($file in $backupFiles) {
        if (Transfer-FileToDR -File $file -DestPath $DRPath) {
            $successCount++
        } else {
            $failCount++
        }
    }

    Write-Log "Transfer summary: $successCount succeeded, $failCount failed"

    if ($failCount -gt 0) {
        Write-Log "Some transfers failed!" "WARNING"
    }

    # Cleanup old backups pe DR
    Cleanup-OldBackupsOnDR

    Write-Log "========================================="
    Write-Log "DR Backup Transfer Completed Successfully"
    Write-Log "========================================="
    Write-Log "Files transferred: $successCount/$($backupFiles.Count)"
    Write-Log "DR Server: ${DRHost}:${DRPath}"

    exit 0

} catch {
    Write-Log "CRITICAL ERROR: $($_.Exception.Message)" "ERROR"
    Write-Log "Stack trace: $($_.ScriptStackTrace)" "ERROR"
    exit 1
}