<#
    .SYNOPSIS
        Displays the modal progress window while selected changes are applied.

    .PARAMETER Owner
        The optional window that owns the modal and its overlay.

    .PARAMETER InvokeRestartExplorer
        Indicates whether the modal should run the Explorer-restart flow after applying changes.
#>
function Show-ApplyModal {
    param (
        [Parameter(Mandatory=$false)]
        [System.Windows.Window]$Owner = $null,
        [Parameter(Mandatory=$false)]
        [bool]$InvokeRestartExplorer = $false
    )
    
    Add-Type -AssemblyName PresentationFramework,PresentationCore,WindowsBase | Out-Null
    
    $usesDarkMode = Get-SystemUsesDarkMode
    
    # Determine owner window
    $ownerWindow = if ($Owner) { $Owner } else { $script:GuiWindow }
    
    # Show overlay if owner window exists
    $overlay = $null
    if ($ownerWindow) {
        try {
            $overlay = $ownerWindow.FindName('ModalOverlay')
            if ($overlay) {
                $ownerWindow.Dispatcher.Invoke([action]{ $overlay.Visibility = 'Visible' })
            }
        }
        catch { }
    }
    
    # Load XAML from file
    $xaml = Get-Content -Path $script:ApplyChangesWindowSchema -Raw
    $reader = [System.Xml.XmlReader]::Create([System.IO.StringReader]::new($xaml))
    try {
        $applyWindow = [System.Windows.Markup.XamlReader]::Load($reader)
    }
    finally {
        $reader.Close()
    }
    
    # Set owner to owner window if it exists
    if ($ownerWindow) {
        try {
            $applyWindow.Owner = $ownerWindow
        }
        catch { }
    }
    
    # Apply theme resources
    Set-WindowThemeResources -window $applyWindow -usesDarkMode $usesDarkMode
    
    # Get UI elements
    $script:ApplyInProgressPanel = $applyWindow.FindName('ApplyInProgressPanel')
    $script:ApplyCompletionPanel = $applyWindow.FindName('ApplyCompletionPanel')
    $script:ApplyStepNameEl = $applyWindow.FindName('ApplyStepName')
    $script:ApplyStepCounterEl = $applyWindow.FindName('ApplyStepCounter')
    $script:ApplyProgressBarEl = $applyWindow.FindName('ApplyProgressBar')
    $script:ApplyCompletionTitleEl = $applyWindow.FindName('ApplyCompletionTitle')
    $script:ApplyCompletionMessageEl = $applyWindow.FindName('ApplyCompletionMessage')
    $script:ApplyCompletionIconEl = $applyWindow.FindName('ApplyCompletionIcon')
    $applyRebootPanel = $applyWindow.FindName('ApplyRebootPanel')
    $applyRebootList = $applyWindow.FindName('ApplyRebootList')
    $applyCloseBtn = $applyWindow.FindName('ApplyCloseBtn')
    $applyKofiBtn = $applyWindow.FindName('ApplyKofiBtn')
    $applyCancelBtn = $applyWindow.FindName('ApplyCancelBtn')
    
    # Initialize in-progress state
    $script:ApplyInProgressPanel.Visibility = 'Visible'
    $script:ApplyCompletionPanel.Visibility = 'Collapsed'
    $script:ApplyStepNameEl.Text = "Preparing..."
    $script:ApplyStepCounterEl.Text = "Preparing..."
    $script:ApplyProgressBarEl.Value = 0
    $script:ApplyModalInErrorState = $false
    
    # Set up progress callback for Invoke-AllChanges
    $script:ApplyProgressCallback = {
        param($currentStep, $totalSteps, $stepName)
        $script:ApplyStepNameEl.Text = $stepName
        $script:ApplyStepCounterEl.Text = "Step $currentStep of $totalSteps"
        # Store current step/total in Tag properties for sub-step interpolation
        $script:ApplyStepCounterEl.Tag = $currentStep
        $script:ApplyProgressBarEl.Tag = $totalSteps
        # Show progress at the start of each step (empty at step 1, full after last step completes)
        $pct = if ($totalSteps -gt 0) { [math]::Round((($currentStep - 1) / $totalSteps) * 100) } else { 0 }
        $script:ApplyProgressBarEl.Value = $pct
        # Process pending window messages to keep UI responsive
        Invoke-DoEvents
    }

    # Sub-step callback updates step name and interpolates progress bar within the current step
    $script:ApplySubStepCallback = {
        param($subStepName, $subIndex, $subCount)
        $script:ApplyStepNameEl.Text = $subStepName
        # Interpolate progress bar between previous step and current step
        $currentStep = [int]($script:ApplyStepCounterEl.Tag)
        $totalSteps = [int]($script:ApplyProgressBarEl.Tag)
        if ($totalSteps -gt 0 -and $subCount -gt 0) {
            $baseProgress = ($currentStep - 1) / $totalSteps
            $stepFraction = ($subIndex / $subCount) / $totalSteps
            $script:ApplyProgressBarEl.Value = [math]::Round(($baseProgress + $stepFraction) * 100)
        }
        Invoke-DoEvents
    }
    
    # Run changes in background to keep UI responsive
    $applyWindow.Dispatcher.BeginInvoke([System.Windows.Threading.DispatcherPriority]::Background, [action]{
        try {
            Invoke-AllChanges

            $registryImportFailureCount = [int]$script:RegistryImportFailures
            $appRemovalFailureCount = [int]$script:AppRemovalFailures
            $failureCount = $registryImportFailureCount + $appRemovalFailureCount
            $appRemovalVerificationUnavailable = [bool]$script:AppRemovalVerificationUnavailable
            
            # Restart explorer if requested
            if ($InvokeRestartExplorer -and -not $script:CancelRequested) {
                Invoke-RestartExplorer
                
                # Wait for Explorer to finish relaunching, then reclaim focus.
                Start-Sleep -Milliseconds 800
                $applyWindow.Dispatcher.Invoke([action]{
                    $applyWindow.Activate()
                })
            }
            
            Write-Host ""
            
            # Show completion state
            $script:ApplyProgressBarEl.Value = 100
            $script:ApplyInProgressPanel.Visibility = 'Collapsed'
            $script:ApplyCompletionPanel.Visibility = 'Visible'
            
            if ($script:CancelRequested) {
                Write-Warning "Script execution was cancelled by the user. Any remaining changes were not applied."

                $script:ApplyCompletionIconEl.Text = [char]0xE7BA
                $script:ApplyCompletionIconEl.Foreground = [System.Windows.Media.SolidColorBrush]::new([System.Windows.Media.ColorConverter]::ConvertFromString("#e8912d"))
                $script:ApplyCompletionTitleEl.Text = "Cancelled"
                $script:ApplyCompletionMessageEl.Text = "Script execution was cancelled by the user."
            } elseif ($failureCount -gt 0 -or $appRemovalVerificationUnavailable) {
                if ($failureCount -gt 0) {
                    Write-Host "Script completed with $failureCount error(s)."
                }

                $script:ApplyCompletionIconEl.Text = [char]0xE7BA
                $script:ApplyCompletionIconEl.Foreground = [System.Windows.Media.SolidColorBrush]::new([System.Windows.Media.ColorConverter]::ConvertFromString("#e8912d"))
                if ($failureCount -eq 0 -and $appRemovalVerificationUnavailable) {
                    $script:ApplyCompletionTitleEl.Text = "Changes Applied"
                    $script:ApplyCompletionMessageEl.Text = "All changes were applied without errors, but Win11Debloat could not confirm that all selected apps were successfully uninstalled."
                }
                else {
                    $script:ApplyCompletionTitleEl.Text = "Changes Applied with Errors"
                    $failureMessages = @()
                    if ($registryImportFailureCount -gt 0) { $failureMessages += "$registryImportFailureCount registry change(s) failed" }
                    if ($appRemovalFailureCount -gt 0) { $failureMessages += "$appRemovalFailureCount app removal(s) failed" }
                    if ($appRemovalVerificationUnavailable) { $failureMessages += "Unable to verify if all apps were uninstalled successfully" }
                    $script:ApplyCompletionMessageEl.Text = "$($failureMessages -join '; '). See console for details."
                }
            } else {
                Write-Host "All changes have been applied successfully!"

                $script:ApplyCompletionTitleEl.Text = "Changes Applied"

                # Show completion message with reboot instructions if any applied features require reboot
                if ($InvokeRestartExplorer) {
                    $rebootFeatures = Get-RebootFeatureLabels

                    if ($rebootFeatures.Count -gt 0) {
                        foreach ($featureName in $rebootFeatures) {
                            $tb = [System.Windows.Controls.TextBlock]::new()
                            $tb.Text = "$([char]0x2022) $featureName"
                            $tb.FontSize = 12
                            $tb.SetResourceReference([System.Windows.Controls.TextBlock]::ForegroundProperty, "AppFgColor")
                            $tb.Opacity = 0.85
                            $tb.Margin = [System.Windows.Thickness]::new(0, 2, 0, 0)
                            $applyRebootList.Children.Add($tb) | Out-Null
                        }
                        $applyRebootPanel.Visibility = 'Visible'
                    }
                    else {
                        $script:ApplyCompletionMessageEl.Text = "Your system is ready. Thanks for using Win11Debloat!"
                    }
                }
            }
            $applyWindow.Dispatcher.Invoke([System.Windows.Threading.DispatcherPriority]::Render, [action]{})
        }
        catch {
            Write-Host "Error: $($_.Exception.Message)"
            $script:ApplyInProgressPanel.Visibility = 'Collapsed'
            $script:ApplyCompletionPanel.Visibility = 'Visible'
            $script:ApplyCompletionIconEl.Text = [char]0xEA39
            $script:ApplyCompletionIconEl.Foreground = [System.Windows.Media.SolidColorBrush]::new([System.Windows.Media.ColorConverter]::ConvertFromString("#c42b1c"))
            $script:ApplyCompletionTitleEl.Text = "Error"
            $script:ApplyCompletionMessageEl.Text = "An error occurred while applying changes: $($_.Exception.Message)"
            
            # Set error state to change Kofi button to report link
            $script:ApplyModalInErrorState = $true

            # Update Kofi button to be a report issue button
            $applyKofiBtn.Content = $null
            
            $reportText = [System.Windows.Controls.TextBlock]::new()
            $reportText.Text = 'Report a bug'
            $reportText.VerticalAlignment = 'Center'
            $reportText.FontSize = 14
            $reportText.Margin = [System.Windows.Thickness]::new(0, 0, 0, 1)

            $applyKofiBtn.Content = $reportText
            
            [System.Windows.Automation.AutomationProperties]::SetName($applyKofiBtn, 'Report a bug')
            
            $applyWindow.Dispatcher.Invoke([System.Windows.Threading.DispatcherPriority]::Render, [action]{})
        }
        finally {
            $script:ApplyProgressCallback = $null
            $script:ApplySubStepCallback = $null
        }
    }) | Out-Null
    
    # Button handlers
    $applyCloseBtn.Add_Click({
        $applyWindow.Close()
    })

    $applyKofiBtn.Add_Click({
        if ($script:ApplyModalInErrorState) {
            Start-Process "https://github.com/Raphire/Win11Debloat/issues/new"
        } else {
            Start-Process "https://ko-fi.com/raphire"
        }
    })

    $applyCancelBtn.Add_Click({
        if ($script:ApplyCompletionPanel.Visibility -eq 'Visible') {
            # Completion state - just close
            $applyWindow.Close()
        } else {
            # In-progress state - request cancellation
            $script:CancelRequested = $true
        }
    })
    
    # Show dialog
    try {
        $applyWindow.ShowDialog() | Out-Null
    }
    finally {
        # Hide overlay after dialog closes
        if ($overlay) {
            try {
                $ownerWindow.Dispatcher.Invoke([action]{ $overlay.Visibility = 'Collapsed' })
            }
            catch { }
        }
    }
}