<#
.SYNOPSIS
SharePoint Production Toolkit - Script 10 - Version URL.SharePoint Production Toolkit - Script 10 - Versioning Audit Report

.PARAMETER OutputCsv
Full path to output CSV.

.PARAMETER SiteCollectionUrl
Optional. Limit 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 10 - VERSIONING AUDIT REPORT" -ForegroundColor Cyan
Write-Host "READ-ONLY. NO CHANGES ARE MADE." -ForegroundColor Green
Write-Host ""

# Load 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 $OutputCsv -Parent
if ([string]::IsNullOrWhiteSpace($outDir)) {
    throw "OutputCsv must be full path (e.g. C:\Temp\VersioningAudit.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
$log    = New-Object System.Collections.Generic.List[string]
$errors = New-Object System.Collections.Generic.List[object]

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 audits versioning settings 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 (storage + migration impact)
function Get-RiskLevel {
    param(
        $EnableVersioning,
        $MajorLimit,
        $MinorLimit,
        $ItemCount
    )

    if (-not $EnableVersioning) { return "Low" }

    if ($MajorLimit -gt 500 -or $ItemCount -gt 5000) {
        return "High"
    }

    if ($MajorLimit -gt 100 -or $MinorLimit -gt 20) {
        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($risk)
    switch ($risk) {
        "High" {
            return "Reduce version limits. Large version history increases storage and migration time."
        }
        "Medium" {
            return "Review version limits and confirm retention policy requirements."
        }
        "Low" {
            return "Versioning configuration acceptable for migration."
        }
    }
}

# Main execution
$results = New-Object System.Collections.Generic.List[object]

try {
    $sites = Get-Sites
    Log ("Resolved {0} site collection(s)." -f $sites.Count)
}
catch {
    Add-Error $WebAppUrl $_.Exception.Message
    throw
}

foreach ($site in $sites) {
    try {
        Log ("Scanning site collection: {0}" -f $site.Url)

        foreach ($web in $site.AllWebs) {
            try {
                foreach ($list in $web.Lists) {

                    try {
                        $enableVersioning = $list.EnableVersioning
                        $enableMinor      = $list.EnableMinorVersions
                        $majorLimit       = $list.MajorVersionLimit
                        $minorLimit       = $list.MajorWithMinorVersionsLimit
                        $enableApproval   = $list.EnableModeration
                        $draftVisibility  = $list.DraftVersionVisibility
                        $itemCount        = $list.ItemCount

                        $risk = Get-RiskLevel $enableVersioning $majorLimit $minorLimit $itemCount

                        $results.Add([pscustomobject]@{
                            SiteCollectionUrl = $site.Url
                            WebUrl            = $web.Url
                            ListTitle         = $list.Title
                            ListType          = $list.BaseType
                            ItemCount         = $itemCount
                            EnableVersioning  = $enableVersioning
                            EnableMinor       = $enableMinor
                            MajorLimit        = $majorLimit
                            MinorLimit        = $minorLimit
                            ContentApproval   = $enableApproval
                            DraftVisibility   = $draftVisibility
                            RiskLevel         = $risk
                            Score             = Get-Score $risk
                            Category          = "VersioningAudit"
                            ActionRecommendation = Get-Recommendation $risk
                        }) | Out-Null
                    }
                    catch {
                        Add-Error $web.Url $_.Exception.Message
                    }
                }
            }
            finally {
                $web.Dispose()
            }
        }

        $site.Dispose()
    }
    catch {
        Add-Error $site.Url $_.Exception.Message
    }
}

# Export detail
$results | Export-Csv $OutputCsv -NoTypeInformation -Encoding UTF8

# Export summary
$results |
    Group-Object RiskLevel |
    ForEach-Object {
        [pscustomobject]@{
            RiskLevel = $_.Name
            Count     = $_.Count
        }
    } |
    Export-Csv $summaryPath -NoTypeInformation -Encoding UTF8

# Logs
$log | Set-Content $logPath

if ($errors.Count -gt 0) {
    $errors | Export-Csv $errorPath -NoTypeInformation
    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 "Complete." -ForegroundColor Green

.DESCRIPTION
READ-ONLY.
Audits versioning settings across SharePoint lists and libraries.

Captures:
- Versioning enabled
- Major version limits
- Minor (draft) versions
- Approval settings
- Checkout requirements

Used for:
- Migration planning
- Storage optimization
- Governance reviews

.PARAMETER WebAppUrl