# GSP Windows Agent Rollback - PowerShell Script
# This script lets an admin restore a previous agent version from backup

#Requires -RunAsAdministrator

param(
    [string]$InstallPath = "C:\GSP"
)

$Script:AgentDir = Join-Path $InstallPath "Agent"
$Script:BackupDir = Join-Path $InstallPath "backups\agent"
$Script:LogsDir = Join-Path $InstallPath "logs"
$Script:RollbackLogFile = Join-Path $Script:LogsDir "rollback.log"

function Log-Message {
    param([string]$Message, [switch]$IsError = $false)
    
    $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
    $logLine = "[$timestamp] $Message"
    
    if ($IsError) {
        Write-Host $logLine -ForegroundColor Red
    } else {
        Write-Host $logLine
    }
    
    Add-Content -Path $Script:RollbackLogFile -Value $logLine -Force
}

function Test-Administrator {
    $currentUser = [Security.Principal.WindowsIdentity]::GetCurrent()
    $principal = New-Object Security.Principal.WindowsPrincipal($currentUser)
    return $principal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
}

function List-Backups {
    Log-Message "Listing available backups..."
    
    if (-not (Test-Path $Script:BackupDir)) {
        Write-Host "No backups directory found"
        return @()
    }
    
    $backups = Get-ChildItem -Path $Script:BackupDir -Directory | Sort-Object Name -Descending
    
    if ($backups.Count -eq 0) {
        Write-Host "No backups available"
        return @()
    }
    
    Write-Host ""
    Write-Host "Available backups:" -ForegroundColor Green
    
    $backupList = @()
    $index = 1
    foreach ($backup in $backups) {
        $path = $backup.FullName
        $created = $backup.CreationTime
        $size = (Get-ChildItem -Path $path -Recurse | Measure-Object -Property Length -Sum).Sum / 1MB
        
        Write-Host "  [$index] $($backup.Name) (created: $created, size: $([math]::Round($size, 2)) MB)"
        $backupList += $backup.FullName
        $index++
    }
    
    return $backupList
}

function Select-Backup {
    param([array]$BackupList)
    
    if ($BackupList.Count -eq 0) {
        Write-Host "ERROR: No backups available"
        return $null
    }
    
    if ($BackupList.Count -eq 1) {
        Write-Host ""
        $response = Read-Host "Only one backup available. Restore it? (Y/N)"
        if ($response -eq "Y" -or $response -eq "y") {
            return $BackupList[0]
        } else {
            return $null
        }
    }
    
    Write-Host ""
    $choice = Read-Host "Select backup number (1-$($BackupList.Count)) or 'Q' to quit"
    
    if ($choice -eq "Q" -or $choice -eq "q") {
        return $null
    }
    
    if ($choice -match '^\d+$' -and [int]$choice -ge 1 -and [int]$choice -le $BackupList.Count) {
        return $BackupList[[int]$choice - 1]
    } else {
        Write-Host "Invalid selection"
        return $null
    }
}

function Stop-Agent {
    Log-Message "Stopping agent..."
    
    try {
        Stop-ScheduledTask -TaskName "GSP Windows Agent" -ErrorAction SilentlyContinue
        Log-Message "Scheduled task stopped"
        
        Start-Sleep -Seconds 2
        
        Get-Process bash,perl -ErrorAction SilentlyContinue | ForEach-Object {
            try {
                Stop-Process -Id $_.Id -Force
                Log-Message "Killed: $($_.Name) (PID: $($_.Id))"
            } catch {
                # Already gone
            }
        }
        
        return $true
    } catch {
        Log-Message "WARNING stopping agent: $_" -IsError $true
        return $false
    }
}

function Restore-Backup {
    param([string]$BackupPath)
    
    Log-Message "Restoring from backup: $BackupPath"
    
    try {
        # Stop agent
        Stop-Agent
        
        # Preserve current Cfg if user wants
        $preserveCfg = $false
        Write-Host ""
        $response = Read-Host "Preserve current Cfg folder? (Y/N, default: Y)"
        if ($response -ne "N" -and $response -ne "n") {
            $preserveCfg = $true
        }
        
        $currentCfg = Join-Path $Script:AgentDir "OGP64\OGP\Cfg"
        $tempCfg = Join-Path $env:TEMP "gsp_preserve_cfg"
        
        if ($preserveCfg -and (Test-Path $currentCfg)) {
            Log-Message "Preserving current Cfg folder"
            if (Test-Path $tempCfg) {
                Remove-Item $tempCfg -Recurse -Force
            }
            Copy-Item -Path $currentCfg -Destination $tempCfg -Recurse -Force
        }
        
        # Remove current installation
        Log-Message "Removing current agent directory"
        if (Test-Path $Script:AgentDir) {
            Remove-Item -Path $Script:AgentDir -Recurse -Force
        }
        
        # Restore backup
        Log-Message "Copying backup to $Script:AgentDir"
        Copy-Item -Path $BackupPath -Destination $Script:AgentDir -Recurse -Force
        
        # Restore preserved Cfg
        if ($preserveCfg -and (Test-Path $tempCfg)) {
            Log-Message "Restoring preserved Cfg folder"
            $targetCfg = Join-Path $Script:AgentDir "OGP64\OGP\Cfg"
            if (Test-Path $targetCfg) {
                Remove-Item -Path $targetCfg -Recurse -Force
            }
            Copy-Item -Path $tempCfg -Destination $targetCfg -Recurse -Force
            Remove-Item -Path $tempCfg -Recurse -Force
        }
        
        # Start the task
        Log-Message "Starting agent"
        try {
            Start-ScheduledTask -TaskName "GSP Windows Agent" -ErrorAction SilentlyContinue
        } catch {
            Log-Message "WARNING: Could not start scheduled task"
        }
        
        Log-Message "Rollback completed successfully"
        return $true
    } catch {
        Log-Message "ERROR during rollback: $_" -IsError $true
        return $false
    }
}

function Main {
    Log-Message "========================================="
    Log-Message "GSP Windows Agent Rollback"
    Log-Message "========================================="
    Log-Message "Install Path: $InstallPath"
    Log-Message "Backup Directory: $Script:BackupDir"
    Log-Message ""
    
    if (-not (Test-Administrator)) {
        Log-Message "ERROR: This script must be run as Administrator" -IsError $true
        exit 1
    }
    
    if (-not (Test-Path $Script:LogsDir)) {
        New-Item -ItemType Directory -Path $Script:LogsDir -Force | Out-Null
    }
    
    # List available backups
    $backupList = List-Backups
    
    if ($backupList.Count -eq 0) {
        Write-Host ""
        Write-Host "No backups available for rollback" -ForegroundColor Yellow
        Read-Host "Press Enter to close this window"
        exit 0
    }
    
    # Select a backup
    $selectedBackup = Select-Backup $backupList
    
    if (-not $selectedBackup) {
        Write-Host "Rollback cancelled"
        exit 0
    }
    
    # Confirm restore
    Write-Host ""
    Write-Host "Selected: $selectedBackup" -ForegroundColor Yellow
    $confirm = Read-Host "Restore this backup? (Y/N)"
    
    if ($confirm -ne "Y" -and $confirm -ne "y") {
        Write-Host "Rollback cancelled"
        exit 0
    }
    
    # Perform rollback
    if (Restore-Backup $selectedBackup) {
        Log-Message ""
        Log-Message "========================================="
        Log-Message "Rollback Complete!"
        Log-Message "========================================="
        Write-Host ""
        Write-Host "Rollback successful. Agent has been restored." -ForegroundColor Green
        Write-Host "Log file: $Script:RollbackLogFile"
    } else {
        Log-Message ""
        Log-Message "========================================="
        Log-Message "Rollback Failed!"
        Log-Message "========================================="
        Write-Host ""
        Write-Host "Rollback failed. Check the log for details." -ForegroundColor Red
        Write-Host "Log file: $Script:RollbackLogFile"
    }
    
    Write-Host ""
    Read-Host "Press Enter to close this window"
}

Main