<#
.SYNOPSIS
    Bug-Verursachungs-Analyse (Bulk-Ansatz)
    Holt alle Bugs + Features der letzten 6 Monate in 2 Bulk-Abfragen
    und korreliert lokal.
#>

$JiraUrl = "https://arija.jaas.service.deutschebahn.com"
$ApiBase = "$JiraUrl/rest"
$OutputDir = "project-audit\data\jira-bugs"

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

Write-Host "============================================================"
Write-Host "  Bug-Verursachungs-Analyse (Bulk)"
Write-Host "  2 API-Calls statt 60+"
Write-Host "============================================================"

$Token = $null
$SecretsPath = Join-Path (Split-Path -Parent $MyInvocation.MyCommand.Path) "..\.secrets"
if (Test-Path $SecretsPath) {
    Get-Content $SecretsPath | ForEach-Object {
        if ($_ -match "^JIRA_TOKEN=(.+)$") {
            $val = $Matches[1].Trim()
            if ($val -ne "HIER_TOKEN_EINTRAGEN") { $Token = $val }
        }
    }
}
if (-not $Token) { $Token = Read-Host "Jira PAT" }
$Headers = @{ "Authorization" = "Bearer $Token"; "Content-Type" = "application/json" }

New-Item -ItemType Directory -Path $OutputDir -Force | Out-Null

function Invoke-JiraBulk {
    param([string]$Jql, [int]$MaxTotal = 5000)
    $AllIssues = @()
    $StartAt = 0
    $PageSize = 1000
    do {
        $Uri = "$ApiBase/api/2/search?jql=$([Uri]::EscapeDataString($Jql))&startAt=$StartAt&maxResults=$PageSize&fields=summary,created,resolutiondate,assignee,issuetype,project,reporter"
        Write-Host "  Lade $StartAt..." -NoNewline
        try {
            $R = Invoke-WebRequest -Uri $Uri -Headers $Headers -UseBasicParsing -ErrorAction Stop
            $Data = $R.Content | ConvertFrom-Json
            $AllIssues += $Data.issues
            $Total = $Data.total
            Write-Host " $($AllIssues.Count)/$Total" -ForegroundColor Green
            $StartAt += $PageSize
            Start-Sleep -Seconds 2
        } catch {
            $StatusCode = 0
            if ($_.Exception.Response) { $StatusCode = [int]$_.Exception.Response.StatusCode }
            if ($StatusCode -eq 429) {
                Write-Host " [429 - warte 30s]" -ForegroundColor Yellow
                Start-Sleep -Seconds 30
            } else {
                Write-Host " FEHLER: $($_.Exception.Message)" -ForegroundColor Red
                break
            }
        }
    } while ($AllIssues.Count -lt $Total -and $AllIssues.Count -lt $MaxTotal)
    return $AllIssues
}

$Projects = "O2C404, O2CCIB, O2CZERO"

# Abfrage 1: Alle Bugs (6 Monate)
Write-Host ""
Write-Host ">> Bugs (6 Monate)..." -ForegroundColor Yellow
$BugJql = "project in ($Projects) AND issuetype = Bug AND created >= -180d ORDER BY created DESC"
$Bugs = Invoke-JiraBulk -Jql $BugJql -MaxTotal 2000
Write-Host "  $($Bugs.Count) Bugs geladen"

# Abfrage 2: Abgeschlossene Features/Stories (6 Monate)
Write-Host ""
Write-Host ">> Features/Stories (6 Monate, abgeschlossen)..." -ForegroundColor Yellow
$FeatureJql = "project in ($Projects) AND issuetype in (Feature, Enabler, Story, Aufgabe, Unteraufgabe) AND status in (Fertig, Done, Closed) AND resolved >= -180d ORDER BY resolved DESC"
$Features = Invoke-JiraBulk -Jql $FeatureJql -MaxTotal 3000
Write-Host "  $($Features.Count) Features geladen"

# Lokale Analyse pro Team
Write-Host ""
Write-Host ">> Korrelationsanalyse..." -ForegroundColor Yellow

foreach ($ProjectKey in @("O2C404", "O2CCIB", "O2CZERO")) {
    $TeamName = switch ($ProjectKey) { "O2C404" { "Team 404" }; "O2CCIB" { "Team CIB" }; "O2CZERO" { "Team Zero" } }
    Write-Host ""
    Write-Host "  === $TeamName ===" -ForegroundColor Cyan

    $TeamBugs = $Bugs | Where-Object { $_.fields.project.key -eq $ProjectKey }
    $TeamFeatures = $Features | Where-Object { $_.fields.project.key -eq $ProjectKey }

    Write-Host "    $($TeamBugs.Count) Bugs, $($TeamFeatures.Count) Features"

    # Korrelation: Wer hat in 14 Tagen vor Bug-Erstellung Features abgeschlossen?
    $Causation = @{}
    foreach ($Bug in $TeamBugs) {
        $BugCreated = [DateTime]::Parse($Bug.fields.created)
        $WindowStart = $BugCreated.AddDays(-14)

        $RecentFeatures = $TeamFeatures | Where-Object {
            $_.fields.resolutiondate -and
            [DateTime]::Parse($_.fields.resolutiondate) -ge $WindowStart -and
            [DateTime]::Parse($_.fields.resolutiondate) -le $BugCreated
        }

        foreach ($F in $RecentFeatures) {
            if ($F.fields.assignee) {
                $Dev = $F.fields.assignee.displayName
                if (-not $Causation[$Dev]) { $Causation[$Dev] = @{ Features = 0; BugKeys = @() } }
                if ($Causation[$Dev].BugKeys -notcontains $Bug.key) {
                    $Causation[$Dev].BugKeys += $Bug.key
                }
            }
        }
    }

    # Feature-Count pro Dev
    foreach ($F in $TeamFeatures) {
        if ($F.fields.assignee) {
            $Dev = $F.fields.assignee.displayName
            if (-not $Causation[$Dev]) { $Causation[$Dev] = @{ Features = 0; BugKeys = @() } }
            $Causation[$Dev].Features++
        }
    }

    # Ausgabe Top 10
    Write-Host "    --- Potenzielle Bug-Verursachung (14-Tage-Fenster) ---"
    $Sorted = $Causation.GetEnumerator() | Sort-Object { $_.Value.BugKeys.Count } -Descending
    foreach ($E in ($Sorted | Select-Object -First 10)) {
        $UniqueBugs = $E.Value.BugKeys.Count
        $Feats = $E.Value.Features
        $Rate = if ($Feats -gt 0) { [Math]::Round($UniqueBugs / $Feats * 100, 0) } else { 0 }
        Write-Host ("      {0,-30} Features:{1,4} | Bugs:{2,4} | Rate:{3,3}%" -f $E.Key, $Feats, $UniqueBugs, $Rate)
    }

    # CSV
    $CsvData = $Sorted | ForEach-Object {
        [PSCustomObject]@{
            Team = $TeamName
            Developer = $_.Key
            Features = $_.Value.Features
            CorrelatedBugs = $_.Value.BugKeys.Count
            BugRate = if ($_.Value.Features -gt 0) { [Math]::Round($_.Value.BugKeys.Count / $_.Value.Features * 100, 0) } else { 0 }
        }
    }
    $CsvData | Export-Csv "$OutputDir\$ProjectKey-causation.csv" -Delimiter ";" -Encoding UTF8 -NoTypeInformation
}

Write-Host ""
Write-Host "============================================================" -ForegroundColor Green
Write-Host "  FERTIG! API-Calls: ~$([Math]::Ceiling(($Bugs.Count + $Features.Count) / 1000) + 2)" -ForegroundColor Green
Write-Host "  Ergebnisse in $OutputDir" -ForegroundColor Green
Write-Host "============================================================" -ForegroundColor Green