<?php

namespace App\Services\SearchConsole;

use App\Enums\IndexState;
use App\Enums\Portal;
use App\Models\PressRelease;
use App\Models\PressReleaseIndexCheck;
use App\Scopes\PortalScope;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Carbon;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;

/**
 * Admin-Auswertung des Indexierungsstatus (Roadmap 1c.4/1c.5): Verteilung
 * der jüngsten Befunde je Portal, getrennt nach Direkteinreichung und
 * Syndikation über die API. Erst diese Verteilung entscheidet, ob und wie
 * der Status in die Kundenansicht kommt (E8).
 */
class IndexStatusReport
{
    /**
     * Ausdruck, der eine Meldung der Herkunft „api" oder „direct" zuordnet:
     * Marker ist ein Status-Log-Eintrag mit Quelle „api" (wie beim
     * Mail-Versand — der Kontotyp ist nicht verlässlich).
     */
    private const string ORIGIN_SQL = "case when exists (select 1 from press_release_status_logs l where l.press_release_id = press_releases.id and l.source = 'api') then 'api' else 'direct' end";

    /**
     * Anzahl der Meldungen je Portal, Herkunft und Befund — Stand der jeweils
     * jüngsten Prüfung. Meldungen ohne Prüfung erscheinen unter `unchecked`.
     *
     * @return array<string, array<string, array<string, int>>> portal => origin => state|unchecked|total => count
     */
    public function distribution(): array
    {
        $rows = [];

        foreach ([Portal::Presseecho, Portal::Businessportal24] as $portal) {
            // Herkunft je Meldung erst in einer abgeleiteten Tabelle bestimmen,
            // dann darüber gruppieren — MySQL (only_full_group_by) lehnt den
            // korrelierten Ausdruck direkt im GROUP BY ab.
            $visible = DB::query()
                ->fromSub(
                    PressRelease::query()
                        ->withoutGlobalScope(PortalScope::class)
                        ->visibleInArchive()
                        ->forPortalValues([$portal->value, Portal::Both->value])
                        ->selectRaw('press_releases.id, '.self::ORIGIN_SQL.' as origin'),
                    'r'
                )
                ->selectRaw('origin, count(*) as total')
                ->groupBy('origin')
                ->get();

            $checked = DB::query()
                ->fromSub(
                    $this->latestChecks($portal)
                        ->join('press_releases', 'press_releases.id', '=', 'press_release_index_checks.press_release_id')
                        ->whereNull('press_releases.deleted_at')
                        ->selectRaw('press_release_index_checks.id, press_release_index_checks.state, '.self::ORIGIN_SQL.' as origin'),
                    'c'
                )
                ->selectRaw('origin, state, count(*) as total')
                ->groupBy('origin', 'state')
                ->get();

            foreach (['direct', 'api'] as $origin) {
                $bucket = ['total' => 0, 'unchecked' => 0];

                foreach (IndexState::cases() as $state) {
                    $bucket[$state->value] = 0;
                }

                $bucket['total'] = (int) ($visible->firstWhere('origin', $origin)->total ?? 0);

                $checkedTotal = 0;

                foreach ($checked->where('origin', $origin) as $row) {
                    $bucket[(string) $row->state] = (int) $row->total;
                    $checkedTotal += (int) $row->total;
                }

                $bucket['unchecked'] = max(0, $bucket['total'] - $checkedTotal);
                $rows[$portal->value][$origin] = $bucket;
            }
        }

        return $rows;
    }

    /**
     * Jüngste Prüfungen, neueste zuerst.
     *
     * @return Collection<int, PressReleaseIndexCheck>
     */
    public function latest(int $limit = 100): Collection
    {
        return PressReleaseIndexCheck::query()
            ->with(['pressRelease' => fn ($query) => $query->withoutGlobalScopes()->select(['id', 'title', 'slug', 'published_at'])])
            ->orderByDesc('checked_at')
            ->orderByDesc('id')
            ->limit($limit)
            ->get();
    }

    public function lastCheckedAt(): ?Carbon
    {
        $value = PressReleaseIndexCheck::query()->max('checked_at');

        return $value ? Carbon::parse((string) $value) : null;
    }

    /**
     * Jeweils jüngste Prüfung je Meldung auf einem Portal.
     *
     * @return Builder<PressReleaseIndexCheck>
     */
    private function latestChecks(Portal $portal): Builder
    {
        $latest = PressReleaseIndexCheck::query()
            ->select('press_release_id', DB::raw('max(checked_at) as last_checked_at'))
            ->where('portal', $portal->value)
            ->groupBy('press_release_id');

        return PressReleaseIndexCheck::query()
            ->joinSub($latest, 'latest', fn ($join) => $join
                ->on('latest.press_release_id', '=', 'press_release_index_checks.press_release_id')
                ->on('latest.last_checked_at', '=', 'press_release_index_checks.checked_at'))
            ->where('press_release_index_checks.portal', $portal->value);
    }
}