<#
.SYNOPSIS
Script 12 - Feature Inventory Report

.DESCRIPTION
READ-ONLY.
 WebAppUrlScans SharePoint feature activations across:
Target SharePoint Web Application URL

.PARAMETER OutputCsv
Full path to output CSV

.PARAMETER SiteCollectionUrl
Optional - limit scan to one site collection

.PARAMETER NoPrompt
Skip confirmation prompt
#>

[CmdletBinding()]
param(
    [Parameter(Mandatory = $true)]
    [string]$WebAppUrl,

    [Parameter(Mandatory = $true)]
    [string]$OutputCsv,

    [string]$SiteCollectionUrl,

    [switch]$NoPrompt
)

Set-StrictMode -Version Latest
$ErrorActionPreference = "Stop"

Write-Host ""
Write-Host "SCRIPT 12 - FEATURE INVENTORY REPORT" -ForegroundColor Cyan
Write-Host "READ-ONLY. NO CHANGES ARE MADE." -ForegroundColor Green
Write-Host ""

# ------------------------------------------------------------
# Load SharePoint Snap-in
# ------------------------------------------------------------
try {
    if (-not (Get-PSSnapin "Microsoft.SharePoint.PowerShell" -ErrorAction SilentlyContinue)) {
        Add-PSSnapin "Microsoft.SharePoint.PowerShell"
    }
}
catch {
    throw "Run in SharePoint Management Shell. Error: $($_.Exception.Message)"
}

# ------------------------------------------------------------
# Output Setup
# ------------------------------------------------------------
$outDir = Split-Path -Path $OutputCsv -Parent
if ([string]::IsNullOrWhiteSpace($outDir)) {
    throw "OutputCsv must be full path (e.g., C:\Temp\FeatureInventory.csv)"
}

if (-not (Test-Path $outDir)) {
    New-Item -Path $outDir -ItemType Directory -Force | Out-Null
}

$timestamp   = (Get-Date).ToString("yyyyMMdd_HHmmss")
$baseName    = [System.IO.Path]::GetFileNameWithoutExtension($OutputCsv)
$summaryPath = Join-Path $outDir "$baseName`_$timestamp`_Summary.csv"
$logPath     = Join-Path $outDir "$baseName`_$timestamp`_RunLog.txt"
$errorPath   = Join-Path $outDir "$baseName`_$timestamp`_Errors.csv"

# ------------------------------------------------------------
# Logging Helpers
# ------------------------------------------------------------
$errors = New-Object System.Collections.Generic.List[object]
$log = New-Object System.Collections.Generic.List[string]

function Log {
    param($msg)
    $line = "[{0}] {1}" -f (Get-Date -Format "yyyy-MM-dd HH:mm:ss"), $msg
    $log.Add($line) | Out-Null
    Write-Host $line
}

function Add-Error {
    param($scope, $msg)
    $errors.Add([pscustomobject]@{
        Timestamp = Get-Date
        Scope     = $scope
        Message   = $msg
    }) | Out-Null
}

# ------------------------------------------------------------
# Prompt
# ------------------------------------------------------------
if (-not $NoPrompt) {
    Write-Host "This script scans feature activations only." -ForegroundColor Yellow
    if ((Read-Host "Type YES to continue") -ne "YES") { return }
}

# ------------------------------------------------------------
# Resolve Sites
# ------------------------------------------------------------
function Get-Sites {
    if ($SiteCollectionUrl) {
        return @(Get-SPSite -Identity $SiteCollectionUrl)
    }
    return @(Get-SPSite -WebApplication $WebAppUrl -Limit All)
}

# ------------------------------------------------------------
# Risk Model
# ------------------------------------------------------------
function Get-RiskLevel {
    param($FeatureId, $DisplayName)

    if ($DisplayName -match "Workflow|Publishing|Custom") { return "High" }
    if ($DisplayName -match "Search|Metadata") { return "Medium" }
    return "Low"
}

function Get-Score {
    param($risk)
    switch ($risk) {
        "High"   { return 30 }
        "Medium" { return 60 }
        "Low"    { return 90 }
        default  { return 50 }
    }
}

function Get-Recommendation {
    param($risk, $DisplayName)

    if ($risk -eq "High") {
        return "Validate feature availability in target farm. Rebuild or replace before migration."
    }

    if ($risk -eq "Medium") {
        return "Validate compatibility and confirm feature usage."
    }

    return "Low-impact feature. Include in baseline validation."
}

# ------------------------------------------------------------
# Main Execution
# ------------------------------------------------------------
$results = New-Object System.Collections.Generic.List[object]

try {
    $sites = Get-Sites
    Log ("Resolved {0} site collections" -f $sites.Count)
}
catch {
    Add-Error $WebAppUrl $_.Exception.Message
    throw
}

foreach ($site in $sites) {
    try {
        Log ("Scanning site collection: {0}" -f $site.Url)

        # --- SITE FEATURES ---
        foreach ($feature in $site.Features) {
            try {
                $displayName = ""
                try { $displayName = $feature.Definition.DisplayName } catch { }

                $risk = Get-RiskLevel -FeatureId $feature.DefinitionId -DisplayName $displayName

                $results.Add([pscustomobject]@{
                    ScopeType            = "SiteCollection"
                    SiteCollectionUrl    = $site.Url
                    WebUrl               = ""
                    FeatureId            = $feature.DefinitionId
                    FeatureName          = $displayName
                    Version              = $feature.Version
                    RiskLevel            = $risk
                    Score                = Get-Score $risk
                    Category             = "FeatureInventory"
                    ActionRecommendation = Get-Recommendation -risk $risk -DisplayName $displayName
                }) | Out-Null
            }
            catch {
                Add-Error $site.Url $_.Exception.Message
            }
        }

        # --- WEB FEATURES ---
        foreach ($web in $site.AllWebs) {
            try {
                foreach ($feature in $web.Features) {
                    try {
                        $displayName = ""
                        try { $displayName = $feature.Definition.DisplayName } catch { }

                        $risk = Get-RiskLevel -FeatureId $feature.DefinitionId -DisplayName $displayName

                        $results.Add([pscustomobject]@{
                            ScopeType            = "Web"
                            SiteCollectionUrl    = $site.Url
                            WebUrl               = $web.Url
                            FeatureId            = $feature.DefinitionId
                            FeatureName          = $displayName
                            Version              = $feature.Version
                            RiskLevel            = $risk
                            Score                = Get-Score $risk
                            Category             = "FeatureInventory"
                            ActionRecommendation = Get-Recommendation -risk $risk -DisplayName $displayName
                        }) | Out-Null
                    }
                    catch {
                        Add-Error $web.Url $_.Exception.Message
                    }
                }
            }
            finally {
                try { $web.Dispose() } catch {}
            }
        }

        $site.Dispose()
    }
    catch {
        Add-Error $site.Url $_.Exception.Message
    }
}

# ------------------------------------------------------------
# Export Reports
# ------------------------------------------------------------
$results | Export-Csv -Path $OutputCsv -NoTypeInformation -Encoding UTF8

$results |
    Group-Object RiskLevel |
    ForEach-Object {
        [pscustomobject]@{
            RiskLevel = $_.Name
            Count     = $_.Count
        }
    } |
    Export-Csv -Path $summaryPath -NoTypeInformation -Encoding UTF8

$log | Set-Content $logPath

if ($errors.Count -gt 0) {
    $errors | Export-Csv -Path $errorPath -NoTypeInformation -Encoding UTF8
    Write-Host "ERROR REPORT: $errorPath" -ForegroundColor Yellow
}

Write-Host ""
Write-Host "DETAIL REPORT:  $OutputCsv" -ForegroundColor Green
Write-Host "SUMMARY REPORT: $summaryPath" -ForegroundColor Green
Write-Host "RUN LOG:        $logPath" -ForegroundColor Green
Write-Host ""
Write-Host "Complete." -ForegroundColor Green
- Site collections
- Webs

Used for:
- Migration planning
- Test-SPContentDatabase remediation
- Feature dependency analysis