<#
.SYNOPSIS
    Apply audit policies from parsed Security Baseline JSON
    
.DESCRIPTION
    Uses native auditpol.exe to configure Advanced Audit Policies.
    Applies settings from AuditPolicies.json generated by Parse-SecurityBaseline.
    
.PARAMETER AuditPoliciesPath
    Path to AuditPolicies.json
    
.PARAMETER DryRun
    Preview changes without applying
    
.OUTPUTS
    PSCustomObject with applied count and errors
    
.NOTES
    Requires Administrator privileges
    Uses auditpol.exe (built into Windows since Vista)
#>

function Set-AuditPolicies {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory = $true)]
        [string]$AuditPoliciesPath,
        
        [Parameter(Mandatory = $false)]
        [switch]$DryRun
    )
    
    $result = [PSCustomObject]@{
        Applied = 0
        Errors = @()
    }
    
    if (-not (Test-Path $AuditPoliciesPath)) {
        $result.Errors += "Audit policies file not found: $AuditPoliciesPath"
        return $result
    }
    
    try {
        $auditPolicies = Get-Content -Path $AuditPoliciesPath -Raw | ConvertFrom-Json
        
        if ($auditPolicies.Count -eq 0) {
            Write-Log -Level DEBUG -Message "No audit policies to apply" -Module "SecurityBaseline"
            return $result
        }
        
        Write-Log -Level DEBUG -Message "Applying $($auditPolicies.Count) audit policies..." -Module "SecurityBaseline"
        Write-Host "    Applying $($auditPolicies.Count) audit policies..." -ForegroundColor Cyan
        
        $currentPolicy = 0
        foreach ($policy in $auditPolicies) {
            $currentPolicy++
            try {
                # Convert SettingValue to auditpol format
                # SettingValue is numeric: 0=No Auditing, 1=Success, 2=Failure, 3=Success and Failure
                # auditpol format: "enable" or "disable" with /success or /failure flags
                
                $settingValue = [int]$policy.SettingValue
                
                # Build auditpol command using GUID (language-independent!)
                $auditpolArgs = @("/set")
                $auditpolArgs += "/subcategory:$($policy.SubcategoryGUID)"
                
                switch ($settingValue) {
                    3 {
                        # Success and Failure
                        $auditpolArgs += "/success:enable"
                        $auditpolArgs += "/failure:enable"
                    }
                    1 {
                        # Success only
                        $auditpolArgs += "/success:enable"
                        $auditpolArgs += "/failure:disable"
                    }
                    2 {
                        # Failure only
                        $auditpolArgs += "/success:disable"
                        $auditpolArgs += "/failure:enable"
                    }
                    default {
                        # No Auditing (0 or any other value)
                        $auditpolArgs += "/success:disable"
                        $auditpolArgs += "/failure:disable"
                    }
                }
                
                if ($DryRun) {
                    Write-Log -Level DEBUG -Message "[DRYRUN] Would run: auditpol.exe $($auditpolArgs -join ' ')" -Module "SecurityBaseline"
                    Write-Host "      [$currentPolicy/$($auditPolicies.Count)] $($policy.Subcategory) [DRYRUN]" -ForegroundColor DarkGray
                    $result.Applied++
                    continue
                }
                
                # Show progress (every 5th policy or first/last)
                if ($currentPolicy % 5 -eq 0 -or $currentPolicy -eq 1 -or $currentPolicy -eq $auditPolicies.Count) {
                    # Remove "Audit " prefix if present for cleaner output
                    $displayName = $policy.Subcategory -replace '^Audit\s+', ''
                    Write-Host "      [$currentPolicy/$($auditPolicies.Count)] $displayName..." -ForegroundColor Gray -NoNewline
                }
                
                # Execute auditpol
                $process = Start-Process -FilePath "auditpol.exe" `
                                         -ArgumentList $auditpolArgs `
                                         -Wait `
                                         -NoNewWindow `
                                         -PassThru `
                                         -RedirectStandardOutput (Join-Path $env:TEMP "auditpol_stdout.txt") `
                                         -RedirectStandardError (Join-Path $env:TEMP "auditpol_stderr.txt")
                
                if ($process.ExitCode -eq 0) {
                    $result.Applied++
                    # Show success for displayed policies
                    if ($currentPolicy % 5 -eq 0 -or $currentPolicy -eq 1 -or $currentPolicy -eq $auditPolicies.Count) {
                        Write-Host " OK" -ForegroundColor Green
                    }
                }
                else {
                    $stderr = Get-Content (Join-Path $env:TEMP "auditpol_stderr.txt") -Raw -ErrorAction SilentlyContinue
                    $result.Errors += "auditpol failed for $($policy.Subcategory): $stderr"
                    Write-Log -Level DEBUG -Message "auditpol failed for $($policy.Subcategory): $stderr" -Module "SecurityBaseline"
                    # Show failure
                    if ($currentPolicy % 5 -eq 0 -or $currentPolicy -eq 1 -or $currentPolicy -eq $auditPolicies.Count) {
                        Write-Host " FAILED" -ForegroundColor Red
                    }
                }
            }
            catch {
                $result.Errors += "Failed to set audit policy $($policy.Subcategory): $($_.Exception.Message)"
                Write-Log -Level DEBUG -Message "Failed to set audit policy $($policy.Subcategory): $_" -Module "SecurityBaseline"
            }
        }
        
        Write-Log -Level DEBUG -Message "Applied $($result.Applied) audit policies" -Module "SecurityBaseline"
        Write-Host "    Completed: $($result.Applied)/$($auditPolicies.Count) audit policies applied" -ForegroundColor Green
    }
    catch {
        $result.Errors += "Audit policy application failed: $($_.Exception.Message)"
        Write-Log -Level DEBUG -Message "Audit policy application failed: $_" -Module "SecurityBaseline"
    }
    
    return $result
}