<?php

namespace App\Services;

use App\Mail\SponsorSuspensionNoticeMail;
use App\Mail\SponsorTransferMail;
use App\Models\ConsultantSuspensionTransfer;
use App\Models\Customer;
use App\Models\ShoppingUser;
use App\Models\ShoppingUserMemberLog;
use App\Models\UserAbo;
use App\Models\UserCleanUpLog;
use App\User;
use Carbon\Carbon;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Mail\Mailable;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Mail;

/**
 * Ablauf, wenn ein Berater seine Mitgliedschaft nicht verlängert
 * (Entwicklungsplan dev/_tickets/entwicklungsplan-protokoll-september-2026.md, B2).
 *
 * 1. Pausieren ({@see suspend()}), Ablauf + `mivita.cleanup_suspend_days`: Team, Kunden,
 *    Kundenabos und Portal-Logins gehen an den nächsten aktiven Sponsor, der Berater
 *    fällt aus dem Provisionsbaum. Alles wird protokolliert und ist umkehrbar. Der
 *    Sponsor bekommt eine Kurzinfo ohne Listen.
 * 2. Rückgabe ({@see reinstate()}): Zahlt der Berater vor dem harten Cut, bekommt er
 *    Team und Kunden zurück — nur Datensätze, die noch beim Sponsor liegen. Umsätze
 *    der Zwischenzeit bleiben beim Sponsor, weil Punkte zum Bestellzeitpunkt gebucht
 *    werden.
 * 3. Harter Cut ({@see terminate()}), Ablauf + `mivita.cleanup_delete_days`: der Berater
 *    wird Kunde seines Sponsors und gelöscht; der Sponsor bekommt die Listen.
 *
 * Cron (`user:cleanup`), Zahlungseingang ({@see Payment::paymentStatusPaidAction()})
 * und das Ablaufdatum im Admin laufen über diese Klasse, damit es nur einen Weg gibt.
 */
class ConsultantSuspensionService
{
    public function suspendDays(): int
    {
        return max(0, (int) config('mivita.cleanup_suspend_days', 2));
    }

    public function deleteDays(): int
    {
        return max($this->suspendDays(), (int) config('mivita.cleanup_delete_days', 28));
    }

    /**
     * Tag der Pause: Ablauftag + `cleanup_suspend_days` Kalendertage, im Nachtlauf dieses
     * Tages. Die Fristen zählen in Kalendertagen, nicht ab der Uhrzeit des Ablaufs —
     * sonst läge der Nachtlauf je nach Uhrzeit einen Tag später als das Datum in der Mail.
     */
    public function suspensionDateFor(User $user): ?Carbon
    {
        return $user->payment_account ? Carbon::parse($user->payment_account)->startOfDay()->addDays($this->suspendDays()) : null;
    }

    /**
     * Letzter Tag, an dem der Berater durch Zahlung alles zurückholen kann. Im Nachtlauf
     * des Folgetags (Ablauftag + `cleanup_delete_days`) folgt der harte Cut.
     */
    public function deadlineFor(User $user): ?Carbon
    {
        return $user->payment_account ? Carbon::parse($user->payment_account)->startOfDay()->addDays($this->deleteDays() - 1)->endOfDay() : null;
    }

    /**
     * Wer vor diesem Zeitpunkt abgelaufen ist, ist heute an der Reihe: der Ablauftag
     * liegt mindestens `$days` Kalendertage zurück. Bei 0 Tagen gilt jetzt.
     */
    private function expiredBefore(int $days): Carbon
    {
        return $days > 0 ? now()->startOfDay()->subDays($days - 1) : now();
    }

    /**
     * Aktive Berater, deren Mitgliedschaft seit mehr als `cleanup_suspend_days` abgelaufen ist.
     *
     * @return Collection<int, User>
     */
    public function suspensionCandidates(): Collection
    {
        return User::query()
            ->with('account')
            ->where('active', true)
            ->whereNotNull('m_sponsor')
            ->where('payment_account', '<', $this->expiredBefore($this->suspendDays()))
            ->get();
    }

    /**
     * Berater (keine Admins), deren Mitgliedschaft seit mehr als `cleanup_delete_days` abgelaufen ist.
     *
     * @return Collection<int, User>
     */
    public function terminationCandidates(): Collection
    {
        return User::query()
            ->with('account')
            ->where('admin', 0)
            ->where('payment_account', '<', $this->expiredBefore($this->deleteDays()))
            ->get();
    }

    /**
     * Was ein Lauf für diesen Berater bewegen würde (Trockenlauf).
     *
     * @return array{team: int, customers: int, abos: int, portal_customers: int, parked: int}
     */
    public function preview(User $user): array
    {
        return [
            'team' => User::where('m_sponsor', $user->id)->count(),
            'customers' => ShoppingUser::withTrashed()->where('member_id', $user->id)->count(),
            'abos' => UserAbo::withTrashed()->where('member_id', $user->id)->count(),
            'portal_customers' => Customer::where('member_id', $user->id)->count(),
            'parked' => ConsultantSuspensionTransfer::openFor($user->id)->count(),
        ];
    }

    /**
     * Stufe 1: Berater pausieren, Team und Kundendaten umkehrbar an den Sponsor.
     *
     * @return array{sponsor_id: int, team: int, customers: int, abos: int, portal_customers: int}|null null, wenn kein Sponsor gefunden wurde
     */
    public function suspend(User $user, string $info = ''): ?array
    {
        $user = User::with('account')->find($user->id);
        if (! $user) {
            return null;
        }

        $sponsor = $user->m_sponsor ? UserUtil::findNextActiveSponsor($user->m_sponsor) : null;
        if (! $sponsor || (int) $sponsor->id === (int) $user->id) {
            Log::channel('cleanup')->error('ConsultantSuspension::suspend kein aktiver Sponsor fuer user_id '.$user->id.' '.$info);

            return null;
        }

        $summary = DB::transaction(function () use ($user, $sponsor): array {
            $team = User::where('m_sponsor', $user->id)->count();
            UserUtil::setNewSponsorToChilds($user->id, $sponsor->id);
            $moved = $this->moveCustomerData($user, $sponsor);
            UserUtil::deactiveUser($user);

            return ['sponsor_id' => (int) $sponsor->id, 'team' => $team] + $moved;
        });

        Log::channel('cleanup')->info('ConsultantSuspension::suspend '.$info.' : '.json_encode(['user_id' => $user->id, 'email' => $user->email] + $summary));

        $this->mailSponsor($sponsor, new SponsorSuspensionNoticeMail($sponsor, $user, $this->deadlineFor($user)));

        return $summary;
    }

    /**
     * Rückgabe nach Zahlung: Berater aktivieren, Team und Kundendaten zurückholen.
     *
     * @return array{customers: int, abos: int, portal_customers: int, kept: int}
     */
    public function reinstate(User $user, string $info = ''): array
    {
        $user = User::find($user->id);
        if (! $user) {
            return ['customers' => 0, 'abos' => 0, 'portal_customers' => 0, 'kept' => 0];
        }

        $summary = DB::transaction(function () use ($user): array {
            UserUtil::reactiveUser($user);
            UserUtil::resetChildsToSponsor($user->id);

            return $this->returnCustomerData($user);
        });

        Log::channel('cleanup')->info('ConsultantSuspension::reinstate '.$info.' : '.json_encode(['user_id' => $user->id, 'email' => $user->email] + $summary));

        return $summary;
    }

    /**
     * Stufe 2: harter Cut. Was noch am Berater hängt, geht endgültig an den Sponsor,
     * der Berater wird dessen Kunde und gelöscht. Danach gehen die Listen an jeden
     * Sponsor, der Team oder Kunden dieses Beraters hält.
     *
     * @return array{sponsor_id: int, team: int, customers: int, abos: int, portal_customers: int}|null
     */
    public function terminate(User $user): ?array
    {
        $user = User::with('account')->find($user->id);
        if (! $user) {
            return null;
        }

        $sponsor = UserUtil::findNextActiveSponsor($user->id);
        if (! $sponsor || (int) $sponsor->id === (int) $user->id) {
            Log::channel('cleanup')->error('ConsultantSuspension::terminate kein aktiver Sponsor fuer user_id '.$user->id);

            return null;
        }

        if (! $user->account) {
            Log::channel('cleanup')->error('ConsultantSuspension::terminate ohne Account-Daten, uebersprungen: user_id '.$user->id);

            return null;
        }

        $summary = DB::transaction(function () use ($user, $sponsor): array {
            $team = User::where('m_sponsor', $user->id)->count();
            UserUtil::setNewSponsorToChilds($user->id, $sponsor->id);
            $moved = $this->moveCustomerData($user, $sponsor);
            $this->convertToCustomer($user, $sponsor);
            UserUtil::deleteUser($user);

            return ['sponsor_id' => (int) $sponsor->id, 'team' => $team] + $moved;
        });

        Log::channel('cleanup')->info('ConsultantSuspension::terminate : '.json_encode(['user_id' => $user->id, 'email' => $user->email] + $summary));

        foreach ($this->transferListsBySponsor($user, $sponsor) as $sponsorId => $lists) {
            $receiver = User::with('account')->find($sponsorId);
            if ($receiver) {
                $this->mailSponsor($receiver, new SponsorTransferMail(
                    $receiver,
                    $user,
                    $lists['customers'],
                    $lists['team'],
                    (int) $sponsorId === (int) $sponsor->id,
                ));
            }
        }

        return $summary;
    }

    /**
     * Kunden, Kundenabos und Portal-Logins des Beraters an den Sponsor, je Datensatz protokolliert.
     *
     * @return array{customers: int, abos: int, portal_customers: int}
     */
    private function moveCustomerData(User $user, User $sponsor): array
    {
        $customers = 0;
        foreach (ShoppingUser::withTrashed()->where('member_id', $user->id)->get() as $customer) {
            $this->logTransfer($user, $sponsor, ConsultantSuspensionTransfer::TYPE_SHOPPING_USER, $customer->id);
            ShoppingUserMemberLog::create([
                'pre_member_id' => $user->id,
                'shopping_user_id' => $customer->id,
                'new_member_id' => $sponsor->id,
            ]);
            $customer->member_id = $sponsor->id;
            $customer->save();
            $customers++;
        }

        $abos = 0;
        foreach (UserAbo::withTrashed()->where('member_id', $user->id)->pluck('id') as $aboId) {
            $this->logTransfer($user, $sponsor, ConsultantSuspensionTransfer::TYPE_USER_ABO, (int) $aboId);
            $abos++;
        }
        UserAbo::withTrashed()->where('member_id', $user->id)->update(['member_id' => $sponsor->id]);

        $portal = 0;
        foreach (Customer::where('member_id', $user->id)->pluck('id') as $customerId) {
            $this->logTransfer($user, $sponsor, ConsultantSuspensionTransfer::TYPE_CUSTOMER, (int) $customerId);
            $portal++;
        }
        Customer::where('member_id', $user->id)->update(['member_id' => $sponsor->id]);

        return ['customers' => $customers, 'abos' => $abos, 'portal_customers' => $portal];
    }

    /**
     * Gibt alle offenen Umhängungen zurück — aber nur Datensätze, die noch bei dem
     * Sponsor liegen, der sie bekommen hat. Wurde ein Kunde inzwischen von Hand
     * woanders hin übertragen, bleibt er dort.
     *
     * @return array{customers: int, abos: int, portal_customers: int, kept: int}
     */
    private function returnCustomerData(User $user): array
    {
        $summary = ['customers' => 0, 'abos' => 0, 'portal_customers' => 0, 'kept' => 0];

        foreach (ConsultantSuspensionTransfer::openFor($user->id)->get() as $transfer) {
            $record = match ($transfer->record_type) {
                ConsultantSuspensionTransfer::TYPE_SHOPPING_USER => ShoppingUser::withTrashed()->find($transfer->record_id),
                ConsultantSuspensionTransfer::TYPE_USER_ABO => UserAbo::withTrashed()->find($transfer->record_id),
                ConsultantSuspensionTransfer::TYPE_CUSTOMER => Customer::find($transfer->record_id),
                default => null,
            };

            if ($record && (int) $record->member_id === $transfer->sponsor_id) {
                if ($record instanceof ShoppingUser) {
                    ShoppingUserMemberLog::create([
                        'pre_member_id' => $transfer->sponsor_id,
                        'shopping_user_id' => $record->id,
                        'new_member_id' => $user->id,
                    ]);
                }
                // Ohne Model-Events: an Abo und Portal-Login haengt sonst Status-/Audit-Logik,
                // die hier nichts zu suchen hat — es aendert sich nur die Zuordnung.
                $record->newQuery()->withoutGlobalScopes()->whereKey($record->getKey())->update(['member_id' => $user->id]);
                $summary[match ($transfer->record_type) {
                    ConsultantSuspensionTransfer::TYPE_SHOPPING_USER => 'customers',
                    ConsultantSuspensionTransfer::TYPE_USER_ABO => 'abos',
                    default => 'portal_customers',
                }]++;
            } else {
                $summary['kept']++;
            }

            $transfer->returned_at = now();
            $transfer->save();
        }

        return $summary;
    }

    /**
     * Der Berater wird Kunde des Sponsors. Liegt schon ein Kundendatensatz mit seiner
     * E-Mail oder seinem Login beim Sponsor (z. B. aus seinen eigenen Bestellungen, der
     * eben mit umgezogen ist), wird kein zweiter angelegt.
     */
    private function convertToCustomer(User $user, User $sponsor): void
    {
        $exists = ShoppingUser::query()
            ->where('member_id', $sponsor->id)
            ->where(function ($query) use ($user): void {
                $query->where('auth_user_id', $user->id)
                    ->orWhere('billing_email', $user->email);
            })
            ->exists();

        if (! $exists) {
            UserUtil::setUserToClient($user->id, $sponsor->id);
        }
    }

    /**
     * Listen für die Sponsor-Mail beim harten Cut, gruppiert nach dem Sponsor, der die
     * Datensätze heute hält. Der Berater selbst steht beim Sponsor des harten Cuts.
     *
     * @return array<int, array{customers: list<array{first_name: string, last_name: string, phone: string, email: string}>, team: list<array{first_name: string, last_name: string, phone: string, email: string}>}>
     */
    private function transferListsBySponsor(User $user, User $sponsor): array
    {
        $lists = [(int) $sponsor->id => ['customers' => [], 'team' => []]];

        // Nur Datensaetze, die noch bei dem Sponsor liegen, der sie ueber diesen Ablauf
        // bekommen hat — von Hand weiter uebertragene Kunden gehoeren nicht in seine Liste.
        $sponsorByCustomer = ConsultantSuspensionTransfer::openFor($user->id)
            ->where('record_type', ConsultantSuspensionTransfer::TYPE_SHOPPING_USER)
            ->pluck('sponsor_id', 'record_id');

        $customers = ShoppingUser::query()->whereIn('id', $sponsorByCustomer->keys())->orderBy('billing_lastname')->get();
        foreach ($customers as $customer) {
            $holder = (int) $customer->member_id;
            if ($holder !== (int) $sponsorByCustomer->get($customer->id)) {
                continue;
            }
            $lists[$holder] ??= ['customers' => [], 'team' => []];
            $lists[$holder]['customers'][] = [
                'first_name' => (string) $customer->billing_firstname,
                'last_name' => (string) $customer->billing_lastname,
                'phone' => (string) $customer->billing_phone,
                'email' => (string) $customer->billing_email,
            ];
        }

        $sponsorByMember = UserCleanUpLog::where('inactive_sponsor_id', $user->id)->pluck('new_sponsor_id', 'child_user_id');
        $team = User::query()->with('account')->whereIn('id', $sponsorByMember->keys())->get();
        foreach ($team as $member) {
            $holder = (int) ($member->m_sponsor ?: $member->pre_sponsor);
            if (! $holder || $holder !== (int) $sponsorByMember->get($member->id)) {
                continue;
            }
            $lists[$holder] ??= ['customers' => [], 'team' => []];
            $lists[$holder]['team'][] = [
                'first_name' => (string) $member->account?->first_name,
                'last_name' => (string) $member->account?->last_name,
                'phone' => trim((string) $member->account?->getPhoneNumber()),
                'email' => (string) $member->email,
            ];
        }

        return $lists;
    }

    private function logTransfer(User $user, User $sponsor, string $type, int $recordId): void
    {
        ConsultantSuspensionTransfer::create([
            'consultant_id' => $user->id,
            'sponsor_id' => $sponsor->id,
            'record_type' => $type,
            'record_id' => $recordId,
        ]);
    }

    /**
     * Keine Mail an das Firmenkonto; ein Mailfehler darf den Lauf nicht abbrechen.
     */
    private function mailSponsor(User $sponsor, Mailable $mail): void
    {
        if ((int) $sponsor->id === (int) config('mivita.company_user_id') || ! $sponsor->email) {
            return;
        }

        try {
            Mail::to($sponsor->email)->locale($sponsor->getLocale())->send($mail);
        } catch (\Throwable $e) {
            Log::channel('cleanup')->error('ConsultantSuspension Sponsor-Mail fehlgeschlagen fuer sponsor_id '.$sponsor->id.': '.$e->getMessage());
        }
    }
}