<#
.SYNOPSIS
SharePoint Production Toolkit - Script 18 - Content Database Inventory Report

.DES confirmation prompt..DESCRIPTION
#>

[CmdletBinding()]
param(
    [Parameter(Mandatory = $true)]
    [string]$WebAppUrl,

    [Parameter(Mandatory = $true)]
    [string]$OutputCsv,

    [switch]$NoPrompt
)

Set-StrictMode -Version Latest
$ErrorActionPreference = "Stop"

Write-Host ""
Write-Host "SCRIPT 18 - CONTENT DATABASE INVENTORY" -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 "OutputCsv must be full path (example: C:\Temp\DBInventory.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_ByRisk.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 + error 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
}

if (-not $NoPrompt) {
    Write-Host "This script scans content databases and writes reports only." -ForegroundColor Yellow
    if ((Read-Host "Type YES to continue") -ne "YES") { return }
}

# ------------------------------------------------------------
# Risk Classification
# ------------------------------------------------------------
function Get-RiskLevel {
    param($SizeGB, $SiteCount)

    if ($SizeGB -gt 500 -or $SiteCount -gt 5000) { return "High" }
    if ($SizeGB -gt 200 -or $SiteCount -gt 2000) { return "Medium" }
    return "Low"
}

function Get-Score {
    param($risk)
    switch ($risk) {
        "High"   { return 30 }
        "Medium" { return 60 }
        "Low"    { return 90 }
    }
}

function Get-Recommendation {
    param($risk)

    switch ($risk) {
        "High"   { return "Split database, reduce size before migration, validate attach strategy." }
        "Medium" { return "Review sizing and plan migration batches carefully." }
        "Low"    { return "Suitable for standard migration wave." }
    }
}

# ------------------------------------------------------------
# Main execution
# ------------------------------------------------------------
$results = New-Object System.Collections.Generic.List[object]

try {
    $contentDBs = Get-SPContentDatabase -WebApplication $WebAppUrl
    Log ("Found {0} content databases." -f $contentDBs.Count)
}
catch {
    Add-Error $WebAppUrl $_.Exception.Message
    throw
}

foreach ($db in $contentDBs) {
    try {
        Log ("Analyzing DB: {0}" -f $db.Name)

        $sizeGB = 0
        try {
            if ($db.disksizerequired) {
                $sizeGB = [Math]::Round($db.disksizerequired / 1GB, 2)
            }
        } catch {}

        $siteCount = 0
        try {
            $siteCount = $db.CurrentSiteCount
        } catch {}

        $risk = Get-RiskLevel -SizeGB $sizeGB -SiteCount $siteCount

        $results.Add([pscustomobject]@{
            DatabaseName        = $db.Name
            WebApplication      = $WebAppUrl
            DatabaseServer      = $db.Server
            SizeGB              = $sizeGB
            CurrentSiteCount    = $siteCount
            WarningSiteCount    = $db.WarningSiteCount
            MaximumSiteCount    = $db.MaximumSiteCount
            Status              = $db.Status
            RiskLevel           = $risk
            Score               = Get-Score $risk
            Category            = "ContentDatabaseInventory"
            ActionRecommendation= Get-Recommendation $risk
        }) | Out-Null
    }
    catch {
        Add-Error $db.Name $_.Exception.Message
    }
}

# ------------------------------------------------------------
# Export Results
# ------------------------------------------------------------
$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 "Complete." -ForegroundColor Green
READ-ONLY.
Enumerates SharePoint content databases and exports an inventory report.
Used for:
- Migration planning
- Capacity planning
- Database attach readiness validation

.PARAMETER WebAppUrl
Target SharePoint Web Application URL.

.PARAMETER OutputCsv
Full path to output CSV report.

.PARAMETER NoPrompt