<?php

namespace App\Services\Incentive;

use App\Models\Incentive;
use App\Models\IncentiveNewAbo;
use App\Models\IncentiveNewPartner;
use App\Models\IncentiveParticipant;
use App\Models\IncentivePointsLog;
use App\Models\ShoppingOrder;
use App\Models\UserAbo;
use App\Models\UserAboOrder;
use App\Models\UserSalesVolume;
use App\User;
use Carbon\Carbon;
use Illuminate\Support\Facades\Log;

class IncentiveTracker
{
    /**
     * Track a new partner registration (Starterpaket bezahlt).
     * Fuegt Partner in Tracking-Tabelle ein + Log-Eintrag + Neuberechnung.
     */
    public static function trackNewPartner(ShoppingOrder $shopping_order): void
    {
        try {
            if (! $shopping_order->qualifiesForIncentiveTrackedPartner()) {
                return;
            }

            $new_user = User::find($shopping_order->auth_user_id);
            if (! $new_user || ! $new_user->m_sponsor) {
                return;
            }

            $sponsor_id = $new_user->m_sponsor;
            // Neupartner zaehlen im Moment der ersten Kontozahlung, nicht der Bestellung
            // (Kundenentscheid 16.09.2026, wie in der Statistik): wer Ende September
            // bestellt und am 1. Oktober bezahlt, zaehlt ab Oktober.
            $registration_date = self::newPartnerCountedAt($new_user);

            $incentives = Incentive::query()
                ->active()
                ->qualificationWindowContains($registration_date)
                ->get();

            foreach ($incentives as $incentive) {
                $participant = IncentiveParticipant::ensureForIncentiveUser($incentive, $sponsor_id);

                // Tracking-Tabelle: Partner erfassen (keine Duplikate)
                $newPartner = IncentiveNewPartner::firstOrCreate(
                    ['participant_id' => $participant->id, 'user_id' => $new_user->id],
                    ['registered_at' => $registration_date]
                );

                // Log-Eintrag (Audit-Trail, keine Duplikate)
                self::writeLog($participant, 'partner', User::class, $new_user->id, $new_user->getFullName() ?: $new_user->email ?: ('User #'.$new_user->id), $registration_date, $incentive->points_partner_onetime, $newPartner->id);

                // Neuberechnung aus Tracking-Tabellen
                $participant->recalculateFromTrackingTables()->save();

                self::updateRanking($incentive);
            }
        } catch (\Throwable $e) {
            Log::error('IncentiveTracker::trackNewPartner error: '.$e->getMessage(), [
                'shopping_order_id' => $shopping_order->id,
            ]);
        }
    }

    /**
     * Zeitpunkt, zu dem ein Neupartner fuer ein Incentive zaehlt: seine erste
     * Kontozahlung (`users.partner_paid_at`, {@see User::scopeNewPartnerIn()}). Im
     * Zahlungspfad ist der Wert schon gesetzt; fehlt er ausnahmsweise, ist jetzt der
     * Zahlungsmoment.
     */
    public static function newPartnerCountedAt(User $partner): Carbon
    {
        return $partner->partner_paid_at ? Carbon::parse($partner->partner_paid_at) : Carbon::now();
    }

    /**
     * Track an abo activation (Kundenabo is_for=ot oder Berater-Eigenabo is_for=me, bezahlt + aktiv).
     * Fuegt Abo in Tracking-Tabelle ein + Log-Eintrag + Neuberechnung.
     */
    /**
     * Berater-ID für Incentive-Zuordnung: Bei Kundenabos (ot) sitzt der Berater in member_id,
     * bei Berater-Eigenabo (me) in user_id (vgl. AboHelper::createNewAbo).
     */
    public static function consultantUserIdForAboIncentive(UserAbo $user_abo): ?int
    {
        if ($user_abo->is_for === 'ot') {
            return $user_abo->member_id ? (int) $user_abo->member_id : null;
        }

        return $user_abo->user_id ? (int) $user_abo->user_id : null;
    }

    public static function trackAboActivated(ShoppingOrder $shopping_order): void
    {
        try {
            $user_abo = $shopping_order->getUserAbo();
            if (! $user_abo) {
                return;
            }

            if ($user_abo->is_for === 'ot') {
                $consultant_id = self::consultantUserIdForAboIncentive($user_abo);
            } elseif ($user_abo->is_for === 'me') {
                $consultant_id = $user_abo->user_id ? (int) $user_abo->user_id : null;
            } else {
                return;
            }

            if (! $consultant_id) {
                return;
            }

            $activation_date = $shopping_order->created_at ?? Carbon::now();

            $incentives = Incentive::query()
                ->active()
                ->qualificationWindowContains($activation_date)
                ->get()
                ->filter(fn (Incentive $incentive) => $incentive->includesAbos());

            foreach ($incentives as $incentive) {
                $participant = IncentiveParticipant::ensureForIncentiveUser($incentive, $consultant_id);

                // Tracking-Tabelle: Abo erfassen (keine Duplikate)
                $newAbo = IncentiveNewAbo::firstOrCreate(
                    ['participant_id' => $participant->id, 'user_abo_id' => $user_abo->id],
                    ['activated_at' => $activation_date]
                );

                // Log-Eintrag (Audit-Trail)
                self::writeLog($participant, 'abo', get_class($user_abo), $user_abo->id, $user_abo->email ?: ('Abo #'.$user_abo->id), $activation_date, $incentive->points_abo_onetime, null, $newAbo->id);

                // Neuberechnung aus Tracking-Tabellen
                $participant->recalculateFromTrackingTables()->save();

                self::updateRanking($incentive);
            }
        } catch (\Throwable $e) {
            Log::error('IncentiveTracker::trackAboActivated error: '.$e->getMessage(), [
                'shopping_order_id' => $shopping_order->id,
            ]);
        }
    }

    /**
     * Track accumulated sales volume points.
     * Punkte werden NUR gezaehlt wenn der Umsatz von einem gettrackten
     * Neupartner oder Neuabo stammt. Incentives mit `include_sales_points = 0`
     * (Recruiting-Challenge) bekommen keine Umsatzpunkte.
     */
    public static function trackSalesVolume(UserSalesVolume $user_sales_volume): void
    {
        try {
            $month = $user_sales_volume->month;
            $year = $user_sales_volume->year;

            if (! $month || ! $year) {
                return;
            }

            $points = (int) abs($user_sales_volume->points ?? 0);
            if ($points <= 0) {
                return;
            }

            // A. Pruefen ob der User ein gettrackter Neupartner ist
            $partner_trackings = IncentiveNewPartner::where('user_id', $user_sales_volume->user_id)
                ->whereHas('participant.incentive', fn ($q) => $q->active()->includingSalesPoints())
                ->with('participant.incentive')
                ->get();

            foreach ($partner_trackings as $tracking) {
                $participant = $tracking->participant;
                $incentive = $participant->incentive;

                if (! $incentive->isDateInScope($month, $year)) {
                    continue;
                }

                $exists = IncentivePointsLog::where('participant_id', $participant->id)
                    ->where('user_sales_volume_id', $user_sales_volume->id)
                    ->where('is_storno', false)
                    ->exists();

                if (! $exists) {
                    IncentivePointsLog::create([
                        'participant_id' => $participant->id,
                        'type' => 'partner',
                        'source_type' => UserSalesVolume::class,
                        'source_id' => $user_sales_volume->id,
                        'source_label' => $user_sales_volume->message ?? ('SV '.$month.'/'.$year),
                        'month' => $month,
                        'year' => $year,
                        'points_onetime' => 0,
                        'points_accumulated' => $points,
                        'user_sales_volume_id' => $user_sales_volume->id,
                        'incentive_new_partner_id' => $tracking->id,
                    ]);
                }

                $participant->recalculateFromTrackingTables()->save();
                self::updateRanking($incentive);
            }

            // B. Pruefen ob die Bestellung zu einem getrackten Neuabo gehoert (Kundenabo ot oder Berater me).
            // Bei Verlaengerung weicht shopping_order.shopping_user_id oft vom Stamm-user_abos.shopping_user_id ab (Replikat).
            if ($user_sales_volume->shopping_order_id) {
                $order = ShoppingOrder::find($user_sales_volume->shopping_order_id);

                if ($order) {
                    // Bewusst inkl. geloeschter Abos: ein bereits getracktes Abo kann
                    // geloescht/ersetzt worden sein, waehrend Umsaetze nachgebucht werden
                    // (z. B. extern erledigte Lieferungen) - die zaehlen weiterhin.
                    $userAboFromOrder = UserAboOrder::where('shopping_order_id', $order->id)
                        ->first()?->user_abo()->withTrashed()->first();
                    if (! $userAboFromOrder || ! in_array($userAboFromOrder->is_for, ['ot', 'me'], true)) {
                        $userAboFromOrder = null;
                    }

                    $abo_trackings = $userAboFromOrder
                        ? IncentiveNewAbo::query()
                            ->where('user_abo_id', $userAboFromOrder->id)
                            ->whereHas('participant.incentive', fn ($q) => $q->active()->includingSalesPoints())
                            ->with('participant.incentive')
                            ->get()
                        : collect();
                    foreach ($abo_trackings as $tracking) {
                        $participant = $tracking->participant;
                        $incentive = $participant->incentive;
                        if (! $incentive->isDateInScope($month, $year)) {
                            continue;
                        }

                        $exists = IncentivePointsLog::where('participant_id', $participant->id)
                            ->where('user_sales_volume_id', $user_sales_volume->id)
                            ->where('is_storno', false)
                            ->exists();

                        if (! $exists) {
                            IncentivePointsLog::create([
                                'participant_id' => $participant->id,
                                'type' => 'abo',
                                'source_type' => UserSalesVolume::class,
                                'source_id' => $user_sales_volume->id,
                                'source_label' => $user_sales_volume->message ?? ('SV '.$month.'/'.$year),
                                'month' => $month,
                                'year' => $year,
                                'points_onetime' => 0,
                                'points_accumulated' => $points,
                                'user_sales_volume_id' => $user_sales_volume->id,
                                'incentive_new_abo_id' => $tracking->id,
                            ]);
                        }

                        $participant->recalculateFromTrackingTables()->save();
                        self::updateRanking($incentive);
                    }
                }
            }
        } catch (\Throwable $e) {
            Log::error('IncentiveTracker::trackSalesVolume error: '.$e->getMessage(), [
                'user_sales_volume_id' => $user_sales_volume->id,
            ]);
        }
    }

    /**
     * Track a storno (cancellation) of a sales volume.
     * Storno-Log + Neuberechnung aus Tracking-Tabellen.
     */
    public static function trackStorno(UserSalesVolume $original, UserSalesVolume $cancellation): void
    {
        try {
            // Storno-Log-Eintraege schreiben
            $original_logs = IncentivePointsLog::where('user_sales_volume_id', $original->id)
                ->where('is_storno', false)
                ->get();

            $affected_participants = collect();

            foreach ($original_logs as $original_log) {
                IncentivePointsLog::create([
                    'participant_id' => $original_log->participant_id,
                    'type' => $original_log->type,
                    'source_type' => $original_log->source_type,
                    'source_id' => $original_log->source_id,
                    'source_label' => 'Storno: '.$original_log->source_label,
                    'month' => $cancellation->month ?? $original_log->month,
                    'year' => $cancellation->year ?? $original_log->year,
                    'points_onetime' => -$original_log->points_onetime,
                    'points_accumulated' => -$original_log->points_accumulated,
                    'is_storno' => true,
                    'storno_of_id' => $original_log->id,
                    'user_sales_volume_id' => $cancellation->id,
                    'incentive_new_partner_id' => $original_log->incentive_new_partner_id,
                    'incentive_new_abo_id' => $original_log->incentive_new_abo_id,
                ]);

                $affected_participants->push($original_log->participant_id);
            }

            // Auch ohne Log-Eintraege: alle Teilnehmer dieses Users neu berechnen
            if ($affected_participants->isEmpty() && $original->user_id) {
                $affected_participants = IncentiveParticipant::whereHas('incentive', function ($q) {
                    $q->active();
                })->where('user_id', $original->user_id)->pluck('id');
            }

            // Neuberechnung fuer alle betroffenen Teilnehmer
            foreach ($affected_participants->unique() as $participant_id) {
                $participant = IncentiveParticipant::with('incentive')->find($participant_id);
                if (! $participant) {
                    continue;
                }

                $participant->recalculateFromTrackingTables()->save();

                if ($participant->incentive) {
                    self::updateRanking($participant->incentive);
                }
            }
        } catch (\Throwable $e) {
            Log::error('IncentiveTracker::trackStorno error: '.$e->getMessage(), [
                'original_id' => $original->id,
                'cancellation_id' => $cancellation->id,
            ]);
        }
    }

    /**
     * Update ranking for all participants of an incentive.
     * Der Rang entspricht der Anzeigereihenfolge des Leaderboards: Qualifizierte zuerst (1..n),
     * dahinter Nicht-Qualifizierte, jeweils nach Punkten absteigend.
     *
     * Einen Rang bekommen nur Teilnehmer mit bestaetigter Teilnahme. Bei Punktgleichstand
     * liegt vorn, wer den Stand zuerst erreicht hat (Teilnahmebedingungen Recruiting-Challenge, Punkt 6), zuletzt die
     * Teilnehmer-ID, damit die Reihenfolge nie von der Datenbank abhaengt.
     */
    public static function updateRanking(Incentive $incentive): void
    {
        // Nur Teilnehmer mit Punkten und bestaetigter Teilnahme bekommen einen Rang
        // (Kundenentscheid 25.09.2026: Unbestaetigte zaehlen im Hintergrund mit, stehen
        // aber nicht in der Rangliste und belegen keinen Gewinnerplatz).
        $with_points = IncentiveParticipant::where('incentive_id', $incentive->id)
            ->where('total_points', '>', 0)
            ->whereNotNull('accepted_terms_at')
            ->get();

        $reached_at = self::pointsReachedAtByParticipant($incentive, $with_points->pluck('id')->all());

        $with_points = $with_points->sort(function (IncentiveParticipant $a, IncentiveParticipant $b) use ($reached_at): int {
            return [(int) $b->is_qualified, (int) $b->total_points, $reached_at[$a->id] ?? PHP_INT_MAX, $a->id]
                <=> [(int) $a->is_qualified, (int) $a->total_points, $reached_at[$b->id] ?? PHP_INT_MAX, $b->id];
        });

        $rank = 1;
        foreach ($with_points as $participant) {
            $participant->rank = $rank;
            $participant->save();
            $rank++;
        }

        // Teilnehmer ohne Punkte oder ohne Bestaetigung: Rang entfernen
        IncentiveParticipant::where('incentive_id', $incentive->id)
            ->where(fn ($query) => $query->where('total_points', '<=', 0)->orWhereNull('accepted_terms_at'))
            ->whereNotNull('rank')
            ->update(['rank' => null]);
    }

    /**
     * Zeitpunkt, zu dem ein Teilnehmer seinen heutigen Stand erreicht hat: der letzte
     * zaehlende Neupartner bzw. das letzte zaehlende Neuabo. Grundlage sind die fachlichen
     * Zeitpunkte der Tracking-Tabellen (registered_at / activated_at), nicht die
     * Log-Zeitstempel — ein Neuaufbau (rebuildFromSourceTables) schreibt die Logs neu.
     *
     * @param  list<int>  $participantIds
     * @return array<int, int> Teilnehmer-ID => Unix-Zeitstempel
     */
    private static function pointsReachedAtByParticipant(Incentive $incentive, array $participantIds): array
    {
        if ($participantIds === []) {
            return [];
        }

        $reached = [];
        $sources = [
            [IncentiveNewPartner::class, 'registered_at', (int) $incentive->points_partner_onetime],
            [IncentiveNewAbo::class, 'activated_at', (int) $incentive->points_abo_onetime],
        ];

        foreach ($sources as [$model, $column, $points]) {
            if ($points <= 0) {
                continue;
            }

            $latest = $model::query()
                ->whereIn('participant_id', $participantIds)
                ->when($model === IncentiveNewPartner::class, fn ($query) => $query->whereNull('cancelled_at'))
                ->groupBy('participant_id')
                ->selectRaw("participant_id, MAX({$column}) as reached_at")
                ->pluck('reached_at', 'participant_id');

            foreach ($latest as $participantId => $timestamp) {
                $reached[$participantId] = max($reached[$participantId] ?? 0, Carbon::parse($timestamp)->getTimestamp());
            }
        }

        return $reached;
    }

    /**
     * Log-Eintrag schreiben (Audit-Trail, keine Duplikate).
     */
    private static function writeLog(IncentiveParticipant $participant, string $type, string $source_type, int $source_id, string $source_label, Carbon $date, int $points_onetime, ?int $incentive_new_partner_id = null, ?int $incentive_new_abo_id = null): void
    {
        $exists = IncentivePointsLog::where('participant_id', $participant->id)
            ->where('type', $type)
            ->where('source_type', $source_type)
            ->where('source_id', $source_id)
            ->where('is_storno', false)
            ->exists();

        if ($exists) {
            return;
        }

        IncentivePointsLog::create([
            'participant_id' => $participant->id,
            'type' => $type,
            'source_type' => $source_type,
            'source_id' => $source_id,
            'source_label' => $source_label,
            'month' => $date->month,
            'year' => $date->year,
            'points_onetime' => $points_onetime,
            'points_accumulated' => 0,
            'incentive_new_partner_id' => $incentive_new_partner_id,
            'incentive_new_abo_id' => $incentive_new_abo_id,
        ]);
    }
}