<#
.SYNOPSIS
SharePoint Production Toolkit - Script 09 - Workflow Inventory Report

.DES.DESCRIPTION
Optional. Limit to one site collection

.PARAMETER NoPrompt
Skip confirmation

#>

[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 09 - WORKFLOW 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 $OutputCsv -Parent
if ([string]::IsNullOrWhiteSpace($outDir)) {
    throw "Provide full OutputCsv path. Example: C:\Temp\WorkflowInventory.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 ("{0}_{1}_Summary_ByType.csv" -f $baseName,$timestamp)
$logPath      = Join-Path $outDir ("{0}_{1}_RunLog.txt" -f $baseName,$timestamp)
$errorPath    = Join-Path $outDir ("{0}_{1}_Errors.csv" -f $baseName,$timestamp)

# --------------------------------------------------
# Logging + Errors
# --------------------------------------------------
$errors = New-Object System.Collections.Generic.List[object]
$log    = @()

function Log {
    param($msg)
    $line = "[{0}] {1}" -f (Get-Date -Format "yyyy-MM-dd HH:mm:ss"), $msg
    $log += $line
    Write-Host $line
}

function Add-Error {
    param($scope,$msg)
    $errors.Add([pscustomobject]@{
        Timestamp = Get-Date
        Scope     = $scope
        Message   = $msg
    }) | Out-Null
}

if (-not $NoPrompt) {
    Write-Host "This script inventories workflows. No changes are made." -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 (Migration impact)
# --------------------------------------------------
function Get-RiskLevel {
    param($RunningInstances, $WorkflowType)

    if ($RunningInstances -gt 0) { return "High" }
    if ($WorkflowType -eq "SiteWorkflow") { return "Medium" }
    return "Low"
}

function Get-Score {
    param($risk)
    switch ($risk) {
        "High"   {30}
        "Medium" {60}
        "Low"    {90}
        default  {50}
    }
}

function Get-Recommendation {
    param($risk)

    switch ($risk) {
        "High"   { "Active workflow. Validate migration strategy or rebuild in Power Automate." }
        "Medium" { "Review workflow design. Confirm if still required post-migration." }
        "Low"    { "Legacy workflow. Consider retirement or modernization." }
    }
}

# --------------------------------------------------
# Main Scan
# --------------------------------------------------
$results = New-Object System.Collections.Generic.List[object]

try {
    $sites = Get-Sites
    Log "Resolved $($sites.Count) site collections."
}
catch {
    Add-Error $WebAppUrl $_.Exception.Message
    throw
}

foreach ($site in $sites) {
    try {
        Log "Scanning site: $($site.Url)"

        foreach ($web in $site.AllWebs) {
            try {

                # -------------------------
                # SITE WORKFLOWS
                # -------------------------
                foreach ($wf in $web.WorkflowAssociations) {

                    $risk = Get-RiskLevel -RunningInstances $wf.RunningInstances -WorkflowType "SiteWorkflow"

                    $results.Add([pscustomobject]@{
                        SiteCollectionUrl = $site.Url
                        WebUrl            = $web.Url
                        ScopeType         = "SiteWorkflow"
                        ListTitle         = ""
                        WorkflowName      = $wf.Name
                        RunningInstances  = $wf.RunningInstances
                        Created           = $wf.Created
                        Modified          = $wf.Modified
                        TaskList          = $wf.TaskListTitle
                        HistoryList       = $wf.HistoryListTitle
                        RiskLevel         = $risk
                        Score             = Get-Score $risk
                        Category          = "WorkflowInventory"
                        ActionRecommendation = Get-Recommendation $risk
                    }) | Out-Null
                }

                # -------------------------
                # LIST WORKFLOWS
                # -------------------------
                foreach ($list in $web.Lists) {
                    foreach ($wf in $list.WorkflowAssociations) {

                        $risk = Get-RiskLevel -RunningInstances $wf.RunningInstances -WorkflowType "ListWorkflow"

                        $results.Add([pscustomobject]@{
                            SiteCollectionUrl = $site.Url
                            WebUrl            = $web.Url
                            ScopeType         = "ListWorkflow"
                            ListTitle         = $list.Title
                            WorkflowName      = $wf.Name
                            RunningInstances  = $wf.RunningInstances
                            Created           = $wf.Created
                            Modified          = $wf.Modified
                            TaskList          = $wf.TaskListTitle
                            HistoryList       = $wf.HistoryListTitle
                            RiskLevel         = $risk
                            Score             = Get-Score $risk
                            Category          = "WorkflowInventory"
                            ActionRecommendation = Get-Recommendation $risk
                        }) | 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 ScopeType |
    ForEach-Object {
        [pscustomobject]@{
            WorkflowType = $_.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 "Complete." -ForegroundColor Green
READ-ONLY.
Scans workflows across:
- Lists / Libraries (List workflows)
- Site (Site workflows)

Used for:
- Migration planning (SP 2019 -> SE)
- Workflow modernization (Power Automate readiness)
- Governance and cleanup

.PARAMETER WebAppUrl
Target SharePoint Web Application URL

.PARAMETER OutputCsv
Full path to output CSV