<#
.SYNOPSIS
Script 19 - Service Application Inventory Report

.DESCRIPTION
READ-ONLY script.
Collects SharePoint Service Application configuration:
- Service App Name & Type
- Application Pool & Service Account
- Proxy / Endpoint indicators
- Migration risk classification
#>

[CmdletBinding()]
param (
    [Parameter(Mandatory = $true)]
    [string]$OutputCsv,

    [switch]$NoPrompt
)

Set-StrictMode -Version Latest
$ErrorActionPreference = "Stop"

Write-Host "SCRIPT 18 - SERVICE APPLICATION INVENTORY REPORT" -ForegroundColor Cyan
Write-Host "READ-ONLY - NO CHANGES WILL BE 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 -Path $OutputCsv -Parent
if ([string]::IsNullOrWhiteSpace($outDir)) {
    throw "Provide full OutputCsv path. Example: C:\Temp\ServiceAppInventory.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
$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 inventories service applications (read-only)." -ForegroundColor Yellow
    if ((Read-Host "Type YES to continue") -ne "YES") { return }
}

# Risk Model
function Get-RiskLevel {
    param($TypeName)

    if ($TypeName -match "Search|User Profile|Managed Metadata") { return "High" }
    if ($TypeName -match "Secure Store|Subscription") { 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 "Validate service app compatibility. Plan rebuild or migration." }
        "Medium" { return "Review configuration and confirm requirement post-migration." }
        "Low"    { return "Baseline service application. Suitable for migration." }
    }
}

# Main execution
$results = New-Object System.Collections.Generic.List[object]

try {
    $serviceApps = Get-SPServiceApplication
    Log "Found $($serviceApps.Count) service application(s)"
}
catch {
    Add-Error "ServiceAppDiscovery" $_.Exception.Message
    throw
}

foreach ($app in $serviceApps) {

    try {
        $name       = $app.Name
        $type       = $app.TypeName
        $appPool    = $app.ApplicationPool.Name
        $appPoolId  = $app.ApplicationPool.Id
        $svcAccount = $app.ApplicationPool.ProcessAccountName

        # Endpoint presence (not full detail, just indicator)
        $hasEndpoint = $false
        try {
            $endpoints = Get-SPServiceApplicationEndpoint -ServiceApplication $app -ErrorAction SilentlyContinue
            if ($endpoints) { $hasEndpoint = $true }
        }
        catch { }

        $risk = Get-RiskLevel -TypeName $type

        $results.Add([pscustomobject]@{
            ServiceAppName    = $name
            TypeName          = $type
            ApplicationPool   = $appPool
            IISAppPoolId      = $appPoolId
            ServiceAccount    = $svcAccount
            EndpointPresent   = $hasEndpoint
            RiskLevel         = $risk
            Score             = Get-Score $risk
            Category          = "ServiceApplicationInventory"
            ActionRecommendation = Get-Recommendation $risk
        }) | Out-Null

    }
    catch {
        Add-Error $app.Name $_.Exception.Message
    }
}

# Export detail
$results | Export-Csv -Path $OutputCsv -NoTypeInformation -Encoding UTF8

# Export summary
$results |
Group-Object RiskLevel |
ForEach-Object {
    [pscustomobject]@{
        RiskLevel = $_.Name
        Count     = $_.Count
    }
} | Export-Csv -Path $summaryPath -NoTypeInformation -Encoding UTF8

# Logs
$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 "DETAIL REPORT: $OutputCsv" -ForegroundColor Green
Write-Host "SUMMARY REPORT: $summaryPath" -ForegroundColor Green
Write-Host "RUN LOG: $logPath" -ForegroundColor Green
Write-Host "Complete." -ForegroundColor Green