<?php

namespace App\Services;

use App\Models\Sales\SalesCommission;
use App\Models\Sales\SalesCommissionDetail;
use App\Models\Sales\SalesContractProduct;
use App\Models\Sales\SalesPartner;
use App\Models\Sales\SalesTenantManagement;
use Carbon\Carbon;
use Illuminate\Contracts\Pagination\LengthAwarePaginator;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;

class SalesCommissionService
{
    /**
     * 기본 수당률
     */
    const DEFAULT_PARTNER_RATE = 20.00;
    const DEFAULT_MANAGER_RATE = 5.00;

    // =========================================================================
    // 정산 목록 조회
    // =========================================================================

    /**
     * 정산 목록 조회 (페이지네이션)
     */
    public function getCommissions(array $filters = [], int $perPage = 20): LengthAwarePaginator
    {
        $query = SalesCommission::query()
            ->with(['tenant', 'partner.user', 'manager', 'management']);

        // 상태 필터
        if (!empty($filters['status'])) {
            $query->where('status', $filters['status']);
        }

        // 입금구분 필터
        if (!empty($filters['payment_type'])) {
            $query->where('payment_type', $filters['payment_type']);
        }

        // 영업파트너 필터
        if (!empty($filters['partner_id'])) {
            $query->where('partner_id', $filters['partner_id']);
        }

        // 매니저 필터
        if (!empty($filters['manager_user_id'])) {
            $query->where('manager_user_id', $filters['manager_user_id']);
        }

        // 지급예정 년/월 필터
        if (!empty($filters['scheduled_year']) && !empty($filters['scheduled_month'])) {
            $query->forScheduledMonth((int) $filters['scheduled_year'], (int) $filters['scheduled_month']);
        }

        // 입금일 기간 필터
        if (!empty($filters['payment_start_date']) && !empty($filters['payment_end_date'])) {
            $query->paymentDateBetween($filters['payment_start_date'], $filters['payment_end_date']);
        }

        // 테넌트 검색
        if (!empty($filters['search'])) {
            $search = $filters['search'];
            $query->whereHas('tenant', function ($q) use ($search) {
                $q->where('name', 'like', "%{$search}%")
                    ->orWhere('company_name', 'like', "%{$search}%");
            });
        }

        return $query
            ->orderBy('scheduled_payment_date', 'desc')
            ->orderBy('created_at', 'desc')
            ->paginate($perPage);
    }

    /**
     * 정산 상세 조회
     */
    public function getCommissionById(int $id): ?SalesCommission
    {
        return SalesCommission::with([
            'tenant',
            'partner.user',
            'manager',
            'management',
            'details.contractProduct.product',
            'approver',
        ])->find($id);
    }

    // =========================================================================
    // 수당 생성 (입금 시)
    // =========================================================================

    /**
     * 입금 등록 및 수당 생성
     */
    public function createCommission(int $managementId, string $paymentType, float $paymentAmount, string $paymentDate): SalesCommission
    {
        return DB::transaction(function () use ($managementId, $paymentType, $paymentAmount, $paymentDate) {
            $management = SalesTenantManagement::with(['salesPartner', 'contractProducts.product'])
                ->findOrFail($managementId);

            // 영업파트너 필수 체크
            if (!$management->sales_partner_id) {
                throw new \Exception('영업파트너가 지정되지 않았습니다.');
            }

            $partner = $management->salesPartner;
            $paymentDateCarbon = Carbon::parse($paymentDate);

            // 계약 상품이 없으면 기본 계산
            $contractProducts = $management->contractProducts;
            $totalRegistrationFee = $contractProducts->sum('registration_fee') ?: $paymentAmount * 2;
            $baseAmount = $totalRegistrationFee / 2; // 개발비의 50%

            // 수당률 (영업파트너 설정 또는 기본값)
            $partnerRate = $partner->commission_rate ?? self::DEFAULT_PARTNER_RATE;
            $managerRate = $partner->manager_commission_rate ?? self::DEFAULT_MANAGER_RATE;

            // 수당 계산
            $partnerCommission = $baseAmount * ($partnerRate / 100);
            $managerCommission = $management->manager_user_id
                ? $baseAmount * ($managerRate / 100)
                : 0;

            // 지급예정일 (익월 10일)
            $scheduledPaymentDate = SalesCommission::calculateScheduledPaymentDate($paymentDateCarbon);

            // 정산 생성
            $commission = SalesCommission::create([
                'tenant_id' => $management->tenant_id,
                'management_id' => $managementId,
                'payment_type' => $paymentType,
                'payment_amount' => $paymentAmount,
                'payment_date' => $paymentDate,
                'base_amount' => $baseAmount,
                'partner_rate' => $partnerRate,
                'manager_rate' => $managerRate,
                'partner_commission' => $partnerCommission,
                'manager_commission' => $managerCommission,
                'scheduled_payment_date' => $scheduledPaymentDate,
                'status' => SalesCommission::STATUS_PENDING,
                'partner_id' => $partner->id,
                'manager_user_id' => $management->manager_user_id,
            ]);

            // 상품별 상세 내역 생성
            foreach ($contractProducts as $contractProduct) {
                $productBaseAmount = ($contractProduct->registration_fee ?? 0) / 2;
                $productPartnerRate = $contractProduct->product->partner_commission ?? $partnerRate;
                $productManagerRate = $contractProduct->product->manager_commission ?? $managerRate;

                SalesCommissionDetail::create([
                    'commission_id' => $commission->id,
                    'contract_product_id' => $contractProduct->id,
                    'registration_fee' => $contractProduct->registration_fee ?? 0,
                    'base_amount' => $productBaseAmount,
                    'partner_rate' => $productPartnerRate,
                    'manager_rate' => $productManagerRate,
                    'partner_commission' => $productBaseAmount * ($productPartnerRate / 100),
                    'manager_commission' => $productBaseAmount * ($productManagerRate / 100),
                ]);
            }

            // management 입금 정보 업데이트
            $updateData = [];
            if ($paymentType === SalesCommission::PAYMENT_DEPOSIT) {
                $updateData = [
                    'deposit_amount' => $paymentAmount,
                    'deposit_paid_date' => $paymentDate,
                    'deposit_status' => 'paid',
                ];
            } else {
                $updateData = [
                    'balance_amount' => $paymentAmount,
                    'balance_paid_date' => $paymentDate,
                    'balance_status' => 'paid',
                ];
            }

            // 총 개발비 업데이트
            $updateData['total_registration_fee'] = $totalRegistrationFee;
            $management->update($updateData);

            return $commission->load(['tenant', 'partner.user', 'manager', 'details']);
        });
    }

    // =========================================================================
    // 승인/지급 처리
    // =========================================================================

    /**
     * 승인 처리
     */
    public function approve(int $commissionId, int $approverId): SalesCommission
    {
        $commission = SalesCommission::findOrFail($commissionId);

        if (!$commission->approve($approverId)) {
            throw new \Exception('승인할 수 없는 상태입니다.');
        }

        return $commission->fresh(['tenant', 'partner.user', 'manager']);
    }

    /**
     * 일괄 승인
     */
    public function bulkApprove(array $ids, int $approverId): int
    {
        $count = 0;

        DB::transaction(function () use ($ids, $approverId, &$count) {
            $commissions = SalesCommission::whereIn('id', $ids)
                ->where('status', SalesCommission::STATUS_PENDING)
                ->get();

            foreach ($commissions as $commission) {
                if ($commission->approve($approverId)) {
                    $count++;
                }
            }
        });

        return $count;
    }

    /**
     * 지급완료 처리
     */
    public function markAsPaid(int $commissionId, ?string $bankReference = null): SalesCommission
    {
        $commission = SalesCommission::findOrFail($commissionId);

        if (!$commission->markAsPaid($bankReference)) {
            throw new \Exception('지급완료 처리할 수 없는 상태입니다.');
        }

        // 영업파트너 누적 수당 업데이트
        $this->updatePartnerTotalCommission($commission->partner_id);

        return $commission->fresh(['tenant', 'partner.user', 'manager']);
    }

    /**
     * 일괄 지급완료
     */
    public function bulkMarkAsPaid(array $ids, ?string $bankReference = null): int
    {
        $count = 0;
        $partnerIds = [];

        DB::transaction(function () use ($ids, $bankReference, &$count, &$partnerIds) {
            $commissions = SalesCommission::whereIn('id', $ids)
                ->where('status', SalesCommission::STATUS_APPROVED)
                ->get();

            foreach ($commissions as $commission) {
                if ($commission->markAsPaid($bankReference)) {
                    $count++;
                    $partnerIds[] = $commission->partner_id;
                }
            }
        });

        // 영업파트너 누적 수당 일괄 업데이트
        foreach (array_unique($partnerIds) as $partnerId) {
            $this->updatePartnerTotalCommission($partnerId);
        }

        return $count;
    }

    /**
     * 취소 처리
     */
    public function cancel(int $commissionId): SalesCommission
    {
        $commission = SalesCommission::findOrFail($commissionId);

        if (!$commission->cancel()) {
            throw new \Exception('취소할 수 없는 상태입니다.');
        }

        return $commission->fresh(['tenant', 'partner.user', 'manager']);
    }

    // =========================================================================
    // 영업파트너/매니저 대시보드용
    // =========================================================================

    /**
     * 영업파트너 수당 요약
     */
    public function getPartnerCommissionSummary(int $partnerId): array
    {
        $commissions = SalesCommission::forPartner($partnerId)->get();

        $thisMonth = now()->format('Y-m');
        $thisMonthStart = now()->startOfMonth()->format('Y-m-d');
        $thisMonthEnd = now()->endOfMonth()->format('Y-m-d');

        // 1차/2차 수당 상세 계산
        $firstCommissionDetails = $this->calculateStageCommission($commissions, 'first');
        $secondCommissionDetails = $this->calculateStageCommission($commissions, 'second');

        return [
            // 이번 달 지급예정 (승인 완료된 건)
            'scheduled_this_month' => $commissions
                ->where('status', SalesCommission::STATUS_APPROVED)
                ->filter(fn($c) => $c->scheduled_payment_date->format('Y-m') === $thisMonth)
                ->sum('partner_commission'),

            // 누적 수령 수당
            'total_received' => $commissions
                ->where('status', SalesCommission::STATUS_PAID)
                ->sum('partner_commission'),

            // 대기중 수당
            'pending_amount' => $commissions
                ->where('status', SalesCommission::STATUS_PENDING)
                ->sum('partner_commission'),

            // 이번 달 신규 계약 건수
            'contracts_this_month' => $commissions
                ->filter(fn($c) => $c->payment_date >= $thisMonthStart && $c->payment_date <= $thisMonthEnd)
                ->count(),

            // 1차 수당 상세
            'first_commission' => $firstCommissionDetails,

            // 2차 수당 상세
            'second_commission' => $secondCommissionDetails,

            // 총 수당 금액 (1차 + 2차)
            'total_commission' => $commissions->sum('partner_commission'),
        ];
    }

    /**
     * 단계별 수당 계산 (1차/2차)
     * 파트너 수당의 50%씩 1차/2차로 분할
     */
    private function calculateStageCommission($commissions, string $stage): array
    {
        $paymentAtField = $stage === 'first' ? 'first_payment_at' : 'second_payment_at';
        $paidAtField = $stage === 'first' ? 'first_partner_paid_at' : 'second_partner_paid_at';

        $total = 0;
        $pending = 0;   // 납입 대기 (입금 전)
        $scheduled = 0; // 지급예정 (입금 완료, 수당 미지급)
        $paid = 0;      // 지급완료

        foreach ($commissions as $commission) {
            // 파트너 수당의 50%가 각 단계별 금액
            $stageAmount = $commission->partner_commission / 2;
            $total += $stageAmount;

            $paymentAt = $commission->{$paymentAtField};
            $paidAt = $commission->{$paidAtField};

            if ($paidAt) {
                // 지급완료
                $paid += $stageAmount;
            } elseif ($paymentAt) {
                // 납입완료, 수당 지급예정
                $scheduled += $stageAmount;
            } else {
                // 납입 대기
                $pending += $stageAmount;
            }
        }

        return [
            'total' => $total,
            'pending' => $pending,     // 납입 대기
            'scheduled' => $scheduled, // 지급예정
            'paid' => $paid,           // 지급완료
        ];
    }

    /**
     * 매니저 수당 요약
     */
    public function getManagerCommissionSummary(int $managerUserId): array
    {
        $commissions = SalesCommission::forManager($managerUserId)->get();

        $thisMonth = now()->format('Y-m');

        return [
            // 이번 달 지급예정 (승인 완료된 건)
            'scheduled_this_month' => $commissions
                ->where('status', SalesCommission::STATUS_APPROVED)
                ->filter(fn($c) => $c->scheduled_payment_date->format('Y-m') === $thisMonth)
                ->sum('manager_commission'),

            // 누적 수령 수당
            'total_received' => $commissions
                ->where('status', SalesCommission::STATUS_PAID)
                ->sum('manager_commission'),

            // 대기중 수당
            'pending_amount' => $commissions
                ->where('status', SalesCommission::STATUS_PENDING)
                ->sum('manager_commission'),
        ];
    }

    /**
     * 최근 수당 내역 (대시보드용)
     */
    public function getRecentCommissions(int $partnerId, int $limit = 5): Collection
    {
        return SalesCommission::forPartner($partnerId)
            ->with(['tenant', 'management'])
            ->orderBy('created_at', 'desc')
            ->limit($limit)
            ->get();
    }

    // =========================================================================
    // 통계
    // =========================================================================

    /**
     * 정산 통계 (본사 대시보드용)
     */
    public function getSettlementStats(int $year, int $month): array
    {
        $commissions = SalesCommission::forScheduledMonth($year, $month)->get();

        return [
            // 상태별 건수 및 금액
            'pending' => [
                'count' => $commissions->where('status', SalesCommission::STATUS_PENDING)->count(),
                'partner_total' => $commissions->where('status', SalesCommission::STATUS_PENDING)->sum('partner_commission'),
                'manager_total' => $commissions->where('status', SalesCommission::STATUS_PENDING)->sum('manager_commission'),
            ],
            'approved' => [
                'count' => $commissions->where('status', SalesCommission::STATUS_APPROVED)->count(),
                'partner_total' => $commissions->where('status', SalesCommission::STATUS_APPROVED)->sum('partner_commission'),
                'manager_total' => $commissions->where('status', SalesCommission::STATUS_APPROVED)->sum('manager_commission'),
            ],
            'paid' => [
                'count' => $commissions->where('status', SalesCommission::STATUS_PAID)->count(),
                'partner_total' => $commissions->where('status', SalesCommission::STATUS_PAID)->sum('partner_commission'),
                'manager_total' => $commissions->where('status', SalesCommission::STATUS_PAID)->sum('manager_commission'),
            ],

            // 전체 합계
            'total' => [
                'count' => $commissions->count(),
                'base_amount' => $commissions->sum('base_amount'),
                'partner_commission' => $commissions->sum('partner_commission'),
                'manager_commission' => $commissions->sum('manager_commission'),
            ],
        ];
    }

    /**
     * 입금 대기 중인 테넌트 목록
     */
    public function getPendingPaymentTenants(): Collection
    {
        return SalesTenantManagement::with(['tenant', 'salesPartner.user', 'manager'])
            ->contracted()
            ->where(function ($query) {
                $query->where('deposit_status', 'pending')
                    ->orWhere('balance_status', 'pending');
            })
            ->orderBy('contracted_at', 'desc')
            ->get();
    }

    // =========================================================================
    // 내부 메서드
    // =========================================================================

    /**
     * 영업파트너 누적 수당 업데이트
     */
    private function updatePartnerTotalCommission(int $partnerId): void
    {
        $totalPaid = SalesCommission::forPartner($partnerId)
            ->paid()
            ->sum('partner_commission');

        $contractCount = SalesCommission::forPartner($partnerId)
            ->paid()
            ->count();

        SalesPartner::where('id', $partnerId)->update([
            'total_commission' => $totalPaid,
            'total_contracts' => $contractCount,
        ]);
    }
}