# Read locked GeViDB.mdb using Windows Volume Shadow Copy
# This allows reading the database even when GeViServer has it locked

param(
    [string]$Action = "test"
)

$ErrorActionPreference = "Stop"

Write-Host "========================================" -ForegroundColor Cyan
Write-Host "Volume Shadow Copy Database Reader" -ForegroundColor Cyan
Write-Host "========================================" -ForegroundColor Cyan
Write-Host ""

$dbPath = "C:\GEVISOFT\DATABASE\GeViDB.mdb"
$drive = "C:"

function Create-ShadowCopy {
    Write-Host "Creating shadow copy of $drive..." -ForegroundColor Yellow

    # Create shadow copy using WMI
    $class = [WMICLASS]"root\cimv2:Win32_ShadowCopy"
    $result = $class.Create($drive + "\", "ClientAccessible")

    if ($result.ReturnValue -ne 0) {
        throw "Failed to create shadow copy. Return value: $($result.ReturnValue)"
    }

    $shadowID = $result.ShadowID
    Write-Host "  [OK] Shadow copy created: $shadowID" -ForegroundColor Green

    # Get the shadow copy
    $shadow = Get-WmiObject -Class Win32_ShadowCopy | Where-Object { $_.ID -eq $shadowID }

    if (-not $shadow) {
        throw "Failed to retrieve shadow copy"
    }

    $deviceObject = $shadow.DeviceObject
    Write-Host "  Device: $deviceObject" -ForegroundColor Gray

    return @{
        ID = $shadowID
        DeviceObject = $deviceObject
        Shadow = $shadow
    }
}

function Remove-ShadowCopy {
    param($ShadowInfo)

    Write-Host "Removing shadow copy..." -ForegroundColor Yellow
    try {
        $ShadowInfo.Shadow.Delete()
        Write-Host "  [OK] Shadow copy removed" -ForegroundColor Green
    } catch {
        Write-Host "  [WARN] Failed to remove shadow copy: $($_.Exception.Message)" -ForegroundColor Yellow
    }
}

function Test-DatabaseAccess {
    param($ShadowDevicePath)

    Write-Host "Testing database access from shadow copy..." -ForegroundColor Yellow

    # Create a symbolic link to access the shadow copy
    $linkPath = "C:\ShadowLink"

    # Remove existing link if present
    if (Test-Path $linkPath) {
        cmd /c "rmdir $linkPath"
    }

    Write-Host "  Creating symbolic link to shadow copy..." -ForegroundColor Gray
    $linkCmd = "mklink /d `"$linkPath`" `"$ShadowDevicePath\`""
    $linkResult = cmd /c $linkCmd 2>&1

    if (-not (Test-Path $linkPath)) {
        throw "Failed to create symbolic link: $linkResult"
    }

    Write-Host "  [OK] Symbolic link created" -ForegroundColor Green

    try {
        # List what's in the shadow link root
        Write-Host "  Listing shadow copy root..." -ForegroundColor Gray
        $rootItems = Get-ChildItem $linkPath -ErrorAction SilentlyContinue | Select-Object -First 10 -ExpandProperty Name
        if ($rootItems) {
            foreach ($item in $rootItems) {
                Write-Host "    - $item" -ForegroundColor DarkGray
            }
        } else {
            Write-Host "    [WARN] No items found in shadow root" -ForegroundColor Yellow
        }

        # The relative path from the drive root
        $relativePath = $dbPath.Substring(3) # Remove "C:\" to get "GEVISOFT\DATABASE\GeViDB.mdb"
        $shadowDbPath = Join-Path $linkPath $relativePath

        Write-Host "  Shadow DB path: $shadowDbPath" -ForegroundColor Gray

        # Check if GEVISOFT folder exists
        $gevisoftPath = Join-Path $linkPath "GEVISOFT"
        if (Test-Path $gevisoftPath) {
            Write-Host "  [OK] GEVISOFT folder found in shadow" -ForegroundColor Green

            # Check DATABASE subfolder
            $databasePath = Join-Path $gevisoftPath "DATABASE"
            if (Test-Path $databasePath) {
                Write-Host "  [OK] DATABASE folder found" -ForegroundColor Green

                # List database files - try different methods
                Write-Host "  Attempting to list database files..." -ForegroundColor Gray

                try {
                    $dbFiles = Get-ChildItem $databasePath -Force -ErrorAction Stop
                    Write-Host "  Found $($dbFiles.Count) files:" -ForegroundColor Gray
                    foreach ($file in $dbFiles) {
                        Write-Host "    - $($file.Name) ($([math]::Round($file.Length / 1MB, 2)) MB)" -ForegroundColor DarkGray
                    }
                } catch {
                    Write-Host "  [WARN] Get-ChildItem failed: $($_.Exception.Message)" -ForegroundColor Yellow

                    # Try dir command instead
                    Write-Host "  Trying dir command..." -ForegroundColor Gray
                    $dirOutput = cmd /c "dir `"$databasePath`" /b" 2>&1
                    Write-Host "  Dir output: $dirOutput" -ForegroundColor DarkGray
                }
            } else {
                Write-Host "  [WARN] DATABASE folder not found at: $databasePath" -ForegroundColor Yellow
            }
        } else {
            Write-Host "  [WARN] GEVISOFT folder not found in shadow copy" -ForegroundColor Yellow
        }

        Write-Host ""
        Write-Host "  Preparing to copy database..." -ForegroundColor Yellow

        # Copy from shadow to temp location for testing
        $tempDb = "$env:TEMP\GeViDB_shadow_copy.mdb"

        if (Test-Path $tempDb) {
            Remove-Item $tempDb -Force
        }

        Write-Host "  Copying database from shadow..." -ForegroundColor Gray
        Write-Host "  Target: $tempDb" -ForegroundColor Gray

        # Try .NET file I/O which may handle shadow copies better
        Write-Host "  Attempting .NET File.Copy..." -ForegroundColor Yellow

        try {
            # Use .NET FileStream to read from shadow copy
            Write-Host "  Opening source file..." -ForegroundColor Gray
            $sourceStream = [System.IO.File]::Open(
                $shadowDbPath,
                [System.IO.FileMode]::Open,
                [System.IO.FileAccess]::Read,
                [System.IO.FileShare]::ReadWrite
            )

            Write-Host "  Source opened, size: $([math]::Round($sourceStream.Length / 1MB, 2)) MB" -ForegroundColor Green

            # Create destination file
            Write-Host "  Creating destination file..." -ForegroundColor Gray
            $destStream = [System.IO.File]::Create($tempDb)

            # Copy data
            Write-Host "  Copying data..." -ForegroundColor Gray
            $sourceStream.CopyTo($destStream)

            # Close streams
            $destStream.Close()
            $sourceStream.Close()

            Write-Host "  [OK] .NET copy completed" -ForegroundColor Green
        } catch {
            Write-Host "  [ERROR] .NET copy failed: $($_.Exception.Message)" -ForegroundColor Red

            # Clean up if open
            if ($null -ne $destStream) { $destStream.Dispose() }
            if ($null -ne $sourceStream) { $sourceStream.Dispose() }

            # Try direct .NET File.Copy as last resort
            Write-Host "  Trying System.IO.File.Copy..." -ForegroundColor Yellow
            try {
                [System.IO.File]::Copy($shadowDbPath, $tempDb, $true)
                Write-Host "  [OK] System.IO.File.Copy succeeded" -ForegroundColor Green
            } catch {
                Write-Host "  [ERROR] All copy methods failed: $($_.Exception.Message)" -ForegroundColor Red
            }
        }

    } finally {
        # Clean up symbolic link
        if (Test-Path $linkPath) {
            Write-Host "  Removing symbolic link..." -ForegroundColor Gray
            cmd /c "rmdir $linkPath" 2>&1 | Out-Null
        }
    }

    if (Test-Path $tempDb) {
        $size = (Get-Item $tempDb).Length / 1MB
        Write-Host "  [OK] Database copied successfully ($([math]::Round($size, 2)) MB)" -ForegroundColor Green

        # Try to read it
        Write-Host ""
        Write-Host "Testing database read..." -ForegroundColor Yellow

        # Try different providers
        $providers = @(
            "Microsoft.Jet.OLEDB.4.0",        # Access 2003 and earlier
            "Microsoft.ACE.OLEDB.12.0",       # Access 2007-2013
            "Microsoft.ACE.OLEDB.16.0"        # Access 2016+
        )

        $connected = $false
        $conn = New-Object -ComObject ADODB.Connection

        foreach ($provider in $providers) {
            $connectionString = "Provider=$provider;Data Source=$tempDb;"
            Write-Host "  Trying provider: $provider" -ForegroundColor Gray

            try {
                $conn.Open($connectionString)
                Write-Host "  [OK] Connected with $provider" -ForegroundColor Green
                $connected = $true
                break
            } catch {
                Write-Host "  [WARN] Failed with $provider : $($_.Exception.Message)" -ForegroundColor Yellow
                if ($conn.State -ne 0) {
                    try { $conn.Close() } catch { }
                }
            }
        }

        if (-not $connected) {
            throw "Failed to connect with any provider"
        }

        try {
            # Test query
            $rs = $conn.Execute("SELECT COUNT(*) FROM MSysObjects WHERE Type=1")
            $tableCount = $rs.Fields.Item(0).Value
            $rs.Close()

            Write-Host "  [OK] Database has $tableCount user tables" -ForegroundColor Green

            $conn.Close()

            return $tempDb
        } catch {
            Write-Host "  [ERROR] Failed to query database: $($_.Exception.Message)" -ForegroundColor Red
            if ($conn.State -ne 0) {
                try { $conn.Close() } catch { }
            }
            throw
        }
    } else {
        throw "Failed to copy database from shadow"
    }
}

# Main execution
try {
    # Check if running as administrator
    $currentPrincipal = New-Object Security.Principal.WindowsPrincipal([Security.Principal.WindowsIdentity]::GetCurrent())
    $isAdmin = $currentPrincipal.IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)

    if (-not $isAdmin) {
        Write-Host "[ERROR] This script requires Administrator privileges" -ForegroundColor Red
        Write-Host "Please run PowerShell as Administrator and try again" -ForegroundColor Yellow
        exit 1
    }

    Write-Host "[OK] Running as Administrator" -ForegroundColor Green
    Write-Host ""

    # Create shadow copy
    $shadowInfo = Create-ShadowCopy

    Write-Host ""

    try {
        # Test access
        $tempDb = Test-DatabaseAccess -ShadowDevicePath $shadowInfo.DeviceObject

        Write-Host ""
        Write-Host "========================================" -ForegroundColor Cyan
        Write-Host "SUCCESS!" -ForegroundColor Green
        Write-Host "========================================" -ForegroundColor Cyan
        Write-Host ""
        Write-Host "Database successfully copied from shadow to:" -ForegroundColor Green
        Write-Host "  $tempDb" -ForegroundColor White
        Write-Host ""
        Write-Host "You can now use this copy for read operations." -ForegroundColor Gray

    } finally {
        Write-Host ""
        Remove-ShadowCopy -ShadowInfo $shadowInfo
    }

} catch {
    Write-Host ""
    Write-Host "[ERROR] $($_.Exception.Message)" -ForegroundColor Red
    Write-Host ""
    Write-Host "Stack trace:" -ForegroundColor Gray
    Write-Host $_.ScriptStackTrace -ForegroundColor Gray
    exit 1
}

Write-Host ""
Write-Host "========================================" -ForegroundColor Cyan