<?php

namespace App\Services\Abo;

use App\Models\UserAbo;
use App\Services\Backoffice\BackofficeDashboardService;
use App\User;
use Carbon\Carbon;
use Illuminate\Support\Collection;

/**
 * Abo-fokussierte Team-Übersicht (für alle aktiven Berater, nicht nur VIP).
 *
 * Gruppiert die Downline nach Linien/Ebenen und liefert pro Ebene die Abo-Kennzahlen:
 * wer hat selbst ein Abo, wie viele Kundenabos, sowie die im gewählten Monat neu
 * hinzugekommenen Abos. Wiederverwendet die Linien-Logik aus
 * {@see BackofficeDashboardService} (keine Duplizierung der Baum-Traversierung).
 */
class TeamAboOverviewService
{
    public function __construct(private BackofficeDashboardService $dashboardService) {}

    /**
     * @return array{
     *     month: int,
     *     year: int,
     *     lines: array<int, array<string, mixed>>,
     *     totals: array<string, mixed>
     * }
     */
    public function linesOverview(User $user, int $month, int $year): array
    {
        $lineBuckets = $this->dashboardService->lineBuckets($user->id);

        $lines = [];
        $totals = $this->emptyLine(0);
        $totals['label'] = __('abo.team_total');

        foreach ($lineBuckets as $line => $users) {
            $row = $this->buildLineRow((int) $line, $users, $month, $year);
            $lines[$line] = $row;
            $totals = $this->addToTotals($totals, $row);
        }

        return [
            'month' => $month,
            'year' => $year,
            'lines' => $lines,
            'totals' => $totals,
        ];
    }

    /**
     * Leichtgewichtige Kennzahlen für das Dashboard (ohne Punkte-/Mitglieder-Details).
     *
     * @return array{team_total_abos: int, team_partner_abos: int, team_customer_abos: int, shop_1000: int}
     */
    public function teamKpis(User $user, int $month, int $year): array
    {
        $teamUserIds = $this->dashboardService->teamUserIds($user->id);

        if ($teamUserIds === []) {
            return [
                'team_total_abos' => 0,
                'team_partner_abos' => 0,
                'team_customer_abos' => 0,
                'shop_1000' => 0,
            ];
        }

        $partnerAbos = UserAbo::query()->activeAbo()->where('is_for', 'me')->whereIn('user_id', $teamUserIds)->count();
        $customerAbos = UserAbo::query()->activeAbo()->where('is_for', 'ot')->whereIn('member_id', $teamUserIds)->count();

        return [
            'team_total_abos' => $partnerAbos + $customerAbos,
            'team_partner_abos' => $partnerAbos,
            'team_customer_abos' => $customerAbos,
            'shop_1000' => $this->dashboardService->shop1000Count($teamUserIds, $month, $year),
        ];
    }

    /**
     * Monatliches Abo-Wachstum des Teams für ein Jahr: je Monat die Anzahl neu
     * hinzugekommener (aktiver) Eigen- und Kunden-Abos anhand des Eingangsmonats
     * (start_date). Dient der separaten Wachstums-Tabelle unter der Bestandsübersicht.
     *
     * @return array{
     *     year: int,
     *     months: array<int, array{month: int, label: string, own_new: int, customer_new: int, total_new: int}>,
     *     totals: array{own_new: int, customer_new: int, total_new: int}
     * }
     */
    public function monthlyGrowth(User $user, int $year): array
    {
        $teamUserIds = $this->dashboardService->teamUserIds($user->id);
        $monthNames = \App\Services\HTMLHelper::getTransMonths();

        $ownByMonth = $teamUserIds === [] ? [] : $this->newAbosByMonth($teamUserIds, 'user_id', 'me', $year);
        $customerByMonth = $teamUserIds === [] ? [] : $this->newAbosByMonth($teamUserIds, 'member_id', 'ot', $year);

        $months = [];
        $totals = ['own_new' => 0, 'customer_new' => 0, 'total_new' => 0];

        for ($month = 1; $month <= 12; $month++) {
            $own = $ownByMonth[$month] ?? 0;
            $customer = $customerByMonth[$month] ?? 0;

            $months[] = [
                'month' => $month,
                'label' => $monthNames[$month] ?? (string) $month,
                'own_new' => $own,
                'customer_new' => $customer,
                'total_new' => $own + $customer,
            ];

            $totals['own_new'] += $own;
            $totals['customer_new'] += $customer;
            $totals['total_new'] += $own + $customer;
        }

        return [
            'year' => $year,
            'months' => $months,
            'totals' => $totals,
        ];
    }

    /**
     * Zählt neue (aktive) Abos je Monat eines Jahres anhand start_date.
     * DB-agnostisch (kein MONTH()/strftime): rohe Datumswerte werden in PHP gruppiert.
     *
     * @param  int[]  $userIds
     * @return array<int, int>
     */
    private function newAbosByMonth(array $userIds, string $userColumn, string $isFor, int $year): array
    {
        $dates = UserAbo::query()
            ->activeAbo()
            ->where('is_for', $isFor)
            ->whereIn($userColumn, $userIds)
            ->whereYear('start_date', $year)
            ->toBase()
            ->pluck('start_date');

        $byMonth = [];
        foreach ($dates as $date) {
            if (! $date) {
                continue;
            }
            $month = (int) Carbon::parse($date)->month;
            $byMonth[$month] = ($byMonth[$month] ?? 0) + 1;
        }

        return $byMonth;
    }

    /**
     * Abo-Zusammenfassung eines einzelnen Team-Mitglieds für das Detail-Modal.
     * Liefert null, wenn das Mitglied nicht in der Downline des Owners liegt.
     *
     * @return array{
     *     name: string,
     *     email: string,
     *     own_abo: array<string, mixed>|null,
     *     customer_abos: array{count: int, total_points: float, items: array<int, array<string, mixed>>}
     * }|null
     */
    public function memberAboSummary(User $owner, int $memberId): ?array
    {
        if (! \App\Services\AboHelper::isUserInTeam($owner->id, $memberId)) {
            return null;
        }

        $member = User::with('account')->find($memberId);

        if (! $member) {
            return null;
        }

        $ownAbo = UserAbo::query()
            ->activeAbo()
            ->where('is_for', 'me')
            ->where('user_id', $memberId)
            ->with(['user_abo_items.product', 'user_abo_orders'])
            ->orderByDesc('id')
            ->first();

        $customerAbos = UserAbo::query()
            ->activeAbo()
            ->where('is_for', 'ot')
            ->where('member_id', $memberId)
            ->with(['user_abo_items.product', 'user_abo_orders'])
            ->orderBy('start_date')
            ->get();

        return [
            'name' => $this->memberName($member),
            'email' => $member->email ?? '',
            'own_abo' => $ownAbo ? $this->aboSummary($ownAbo) : null,
            'customer_abos' => [
                'count' => $customerAbos->count(),
                'total_points' => (float) $customerAbos->sum(fn (UserAbo $abo) => $abo->getTotalPoints()),
                'items' => $customerAbos->map(fn (UserAbo $abo) => $this->aboSummary($abo))->all(),
            ],
        ];
    }

    /**
     * @return array{points: float, start_date: string, next_date: string, executions: int, amount: string, interval: int}
     */
    private function aboSummary(UserAbo $abo): array
    {
        return [
            'points' => (float) $abo->getTotalPoints(),
            'start_date' => $abo->start_date,
            'next_date' => $abo->next_date,
            'executions' => $abo->getCountPaidOrders(),
            'amount' => $abo->getFormattedAmount(),
            'interval' => (int) $abo->abo_interval,
        ];
    }

    /**
     * @param  \Illuminate\Support\Collection<int, \App\User>  $users
     * @return array<string, mixed>
     */
    private function buildLineRow(int $line, Collection $users, int $month, int $year): array
    {
        $userIds = $users->pluck('id')->map(fn ($id) => (int) $id)->all();

        if ($userIds === []) {
            return $this->emptyLine($line);
        }

        $users->loadMissing('user_level');

        $ownAbos = $this->ownAbosByUser($userIds);
        $customerAbos = $this->customerAbosByMember($userIds);

        $members = [];
        $membersWithOwnAbo = 0;
        $ownAbosCount = 0;
        $ownAboPoints = 0.0;
        $customerAbosCount = 0;
        $customerAboPoints = 0.0;

        foreach ($users as $teamUser) {
            $uid = (int) $teamUser->id;
            $ownAbo = $ownAbos->get($uid);
            $custList = $customerAbos->get($uid, collect());

            $hasOwnAbo = $ownAbo !== null;
            $memberOwnPoints = $hasOwnAbo ? (float) $ownAbo->getTotalPoints() : 0.0;
            $memberCustomerCount = $custList->count();
            $memberCustomerPoints = (float) $custList->sum(fn (UserAbo $abo) => $abo->getTotalPoints());

            if ($hasOwnAbo) {
                $membersWithOwnAbo++;
                $ownAbosCount++;
                $ownAboPoints += $memberOwnPoints;
            }
            $customerAbosCount += $memberCustomerCount;
            $customerAboPoints += $memberCustomerPoints;

            $members[] = [
                'user_id' => $uid,
                'name' => $this->memberName($teamUser),
                'career_level' => $teamUser->user_level?->getLang('name') ?? '',
                'has_own_abo' => $hasOwnAbo,
                'own_abo_points' => $memberOwnPoints,
                'customer_abo_count' => $memberCustomerCount,
                'customer_abo_points' => $memberCustomerPoints,
                'total_abos' => ($hasOwnAbo ? 1 : 0) + $memberCustomerCount,
            ];
        }

        return [
            'line' => $line,
            'label' => __('abo.team_line', ['line' => $line]),
            'consultants' => $users->count(),
            'members_total' => $users->count(),
            'members_with_own_abo' => $membersWithOwnAbo,
            'own_abos' => $ownAbosCount,
            'own_abos_new' => $this->newAboCount($userIds, 'user_id', 'me', $month, $year),
            'own_abo_points' => $ownAboPoints,
            'customer_abos' => $customerAbosCount,
            'customer_abos_new' => $this->newAboCount($userIds, 'member_id', 'ot', $month, $year),
            'customer_abo_points' => $customerAboPoints,
            'total_abos' => $ownAbosCount + $customerAbosCount,
            'members' => $members,
        ];
    }

    /**
     * Eigene (me) aktive Abos je Berater, indiziert nach user_id (ein Abo pro Berater).
     *
     * @param  int[]  $userIds
     * @return \Illuminate\Support\Collection<int, \App\Models\UserAbo>
     */
    private function ownAbosByUser(array $userIds): Collection
    {
        return UserAbo::query()
            ->activeAbo()
            ->where('is_for', 'me')
            ->whereIn('user_id', $userIds)
            ->with('user_abo_items.product')
            ->get()
            ->keyBy(fn (UserAbo $abo) => (int) $abo->user_id);
    }

    /**
     * Kundenabos (ot) je Berater, gruppiert nach member_id.
     *
     * @param  int[]  $userIds
     * @return \Illuminate\Support\Collection<int, \Illuminate\Support\Collection<int, \App\Models\UserAbo>>
     */
    private function customerAbosByMember(array $userIds): Collection
    {
        return UserAbo::query()
            ->activeAbo()
            ->where('is_for', 'ot')
            ->whereIn('member_id', $userIds)
            ->with('user_abo_items.product')
            ->get()
            ->groupBy(fn (UserAbo $abo) => (int) $abo->member_id);
    }

    /**
     * @param  int[]  $userIds
     */
    private function newAboCount(array $userIds, string $userColumn, string $isFor, int $month, int $year): int
    {
        $startDate = Carbon::create($year, $month, 1)->startOfMonth();
        $endDate = Carbon::create($year, $month, 1)->endOfMonth();

        return UserAbo::query()
            ->activeAbo()
            ->whereIn($userColumn, $userIds)
            ->where('is_for', $isFor)
            ->whereBetween('start_date', [$startDate, $endDate])
            ->count();
    }

    private function memberName(User $user): string
    {
        if ($user->account) {
            $name = trim($user->account->first_name.' '.$user->account->last_name);
            if ($name !== '') {
                return $name;
            }
        }

        return $user->email ?? ('#'.$user->id);
    }

    /**
     * @return array<string, mixed>
     */
    private function emptyLine(int $line): array
    {
        return [
            'line' => $line,
            'label' => $line > 0 ? __('abo.team_line', ['line' => $line]) : __('abo.team_total'),
            'consultants' => 0,
            'members_total' => 0,
            'members_with_own_abo' => 0,
            'own_abos' => 0,
            'own_abos_new' => 0,
            'own_abo_points' => 0.0,
            'customer_abos' => 0,
            'customer_abos_new' => 0,
            'customer_abo_points' => 0.0,
            'total_abos' => 0,
            'members' => [],
        ];
    }

    /**
     * @param  array<string, mixed>  $totals
     * @param  array<string, mixed>  $row
     * @return array<string, mixed>
     */
    private function addToTotals(array $totals, array $row): array
    {
        foreach (['consultants', 'members_total', 'members_with_own_abo', 'own_abos', 'own_abos_new', 'own_abo_points', 'customer_abos', 'customer_abos_new', 'customer_abo_points', 'total_abos'] as $key) {
            $totals[$key] += $row[$key];
        }

        return $totals;
    }
}