<?php

namespace App\Services\Finance;

use App\Enums\EmployeeAdvanceStatus;
use App\Enums\PayrollAdjustmentType;
use App\Enums\PayrollPeriodStatus;
use App\Enums\PayrollStatus;
use App\Enums\Role;
use App\Models\Employee;
use App\Models\EmployeeAdvance;
use App\Models\Payroll;
use App\Models\PayrollAdjustment;
use App\Models\PayrollPeriod;
use App\Models\User;
use App\Services\System\PushNotificationService;
use Carbon\Carbon;
use Illuminate\Contracts\Pagination\LengthAwarePaginator;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class PayrollService
{
    public function __construct(
        private readonly CashService $cashService,
        private readonly PushNotificationService $pushNotificationService,
    ) {}

    /**
     * @return Collection<int, PayrollPeriod>
     */
    public function listPeriods(): Collection
    {
        return PayrollPeriod::query()
            ->orderByDesc('year')
            ->orderByDesc('month')
            ->get();
    }

    public function resolvePeriod(?int $periodId): ?PayrollPeriod
    {
        if ($periodId !== null) {
            return PayrollPeriod::query()->find($periodId);
        }

        return PayrollPeriod::query()
            ->where('status', PayrollPeriodStatus::OPEN)
            ->orderByDesc('year')
            ->orderByDesc('month')
            ->first()
            ?? PayrollPeriod::query()
                ->orderByDesc('year')
                ->orderByDesc('month')
                ->first();
    }

    /**
     * @return array{total_amount: int, total_amount_formatted: string, total_count: int, status: string, status_label: string}
     */
    public function periodSummary(PayrollPeriod $period, User $user): array
    {
        $query = Payroll::query()
            ->where('payroll_period_id', $period->id);

        if (! $user->hasAnyRole(['owner', 'developer', 'direktur'])) {
            $employeeId = $user->employee?->id ?? -1;
            $query->where('employee_id', $employeeId);
        }

        $totalAmount = (int) $query->sum('total_amount');

        $totalCount = $query->count();

        return [
            'total_amount' => $totalAmount,
            'total_amount_formatted' => 'Rp '.number_format($totalAmount, 0, ',', '.'),
            'total_count' => $totalCount,
            'status' => $period->status->value,
            'status_label' => $period->status->label(),
        ];
    }

    /**
     * @param  array{search: string, sort: string, direction: 'asc'|'desc'}  $tableQuery
     */
    public function paginateForPeriod(PayrollPeriod $period, array $tableQuery, User $user): LengthAwarePaginator
    {
        $query = Payroll::query()
            ->with(['employee.user.profile', 'payrollPeriod', 'adjustments.createdBy.profile'])
            ->where('payroll_period_id', $period->id)
            ->when(! $user->hasAnyRole(['owner', 'developer', 'direktur']), function (Builder $query) use ($user): void {
                $employeeId = $user->employee?->id ?? -1;
                $query->where('employee_id', $employeeId);
            })
            ->when($tableQuery['search'] !== '', function (Builder $query) use ($tableQuery): void {
                $search = $tableQuery['search'];
                $query->where(function (Builder $query) use ($search): void {
                    $query->whereHas('employee.user.profile', fn (Builder $query) => $query->where('full_name', 'like', "%{$search}%"))
                        ->orWhereHas('employee.user', fn (Builder $query) => $query->where('username', 'like', "%{$search}%"));
                });
            });

        $this->applySorting($query, $tableQuery['sort'], $tableQuery['direction']);

        return $query
            ->paginate(10)
            ->withQueryString();
    }

    public function openCurrentPeriod(?User $closedBy = null): PayrollPeriod
    {
        $user = $closedBy
            ?? auth()->user()
            ?? User::query()->whereHas('roles', fn ($q) => $q->whereIn('name', [Role::DEVELOPER->value, Role::OWNER->value]))->first()
            ?? User::query()->first();

        $period = DB::transaction(function () use ($user): PayrollPeriod {
            $now = now();
            $year = $now->year;
            $month = $now->month;

            $openPeriods = PayrollPeriod::query()
                ->where('status', PayrollPeriodStatus::OPEN)
                ->get();

            foreach ($openPeriods as $oldPeriod) {
                $unpaidPayrolls = Payroll::query()
                    ->where('payroll_period_id', $oldPeriod->id)
                    ->where('status', PayrollStatus::UNPAID)
                    ->get();

                foreach ($unpaidPayrolls as $payroll) {
                    if ($user) {
                        $this->pay($payroll, $user);
                    }
                }

                $oldPeriod->status = PayrollPeriodStatus::CLOSED;
                $oldPeriod->closed_at = now();
                $oldPeriod->closed_by_id = $user?->id;
                $oldPeriod->save();
            }

            $period = PayrollPeriod::query()
                ->where('year', $year)
                ->where('month', $month)
                ->first();

            if ($period === null) {
                $period = PayrollPeriod::create([
                    'year' => $year,
                    'month' => $month,
                    'status' => PayrollPeriodStatus::OPEN,
                ]);
            } elseif ($period->status === PayrollPeriodStatus::CLOSED) {
                $period->status = PayrollPeriodStatus::OPEN;
                $period->closed_at = null;
                $period->closed_by_id = null;
                $period->save();
            }

            $this->generatePayrollsForPeriod($period);

            return $period->fresh();
        });

        return $period;
    }

    public function generatePayrollsForPeriod(PayrollPeriod $period): void
    {
        $employees = $this->payrollEligibleEmployees($period);

        foreach ($employees as $employee) {
            $exists = Payroll::query()
                ->where('payroll_period_id', $period->id)
                ->where('employee_id', $employee->id)
                ->exists();

            if ($exists) {
                continue;
            }

            $payroll = new Payroll([
                'payroll_period_id' => $period->id,
                'employee_id' => $employee->id,
                'base_salary' => $employee->base_salary ?? 0,
                'bonus_amount' => 0,
                'deduction_amount' => 0,
                'total_amount' => 0,
                'status' => PayrollStatus::UNPAID,
            ]);

            $payroll->save();
            $payroll->recalculateAmounts();
            $payroll->save();
        }
    }

    /**
     * @param  array{type: string, amount: int, description: string}  $validated
     */
    public function addAdjustment(Payroll $payroll, array $validated, User $user): void
    {
        $payroll->loadMissing(['payrollPeriod', 'employee.user']);

        if (! $payroll->can_adjust) {
            throw ValidationException::withMessages([
                'payroll' => 'Penyesuaian hanya dapat ditambahkan pada gaji yang belum dibayar di periode terbuka.',
            ]);
        }

        DB::transaction(function () use ($payroll, $validated, $user): void {
            $payroll->adjustments()->create([
                'type' => PayrollAdjustmentType::from($validated['type']),
                'amount' => (int) $validated['amount'],
                'description' => $validated['description'],
                'created_by_id' => $user->id,
            ]);

            $payroll->load('adjustments');
            $payroll->recalculateAmounts();
            $payroll->save();
        });

        if ($payroll->employee?->user_id) {
            $typeLabel = PayrollAdjustmentType::from($validated['type'])->label();
            $formattedAmount = 'Rp '.number_format($validated['amount'], 0, ',', '.');
            $this->pushNotificationService->sendToUser(
                "📊 Penyesuaian Gaji: {$typeLabel}",
                "Gaji periode {$payroll->payrollPeriod->period_label} disesuaikan: {$typeLabel} sebesar {$formattedAmount} ({$validated['description']}).",
                $payroll->employee->user_id,
                '/admin/finance/payrolls',
            );
        }
    }

    public function updateAdjustment(PayrollAdjustment $adjustment, array $validated, User $user): void
    {
        $payroll = $adjustment->payroll;
        $payroll->loadMissing(['payrollPeriod', 'employee.user']);

        if (! $payroll->can_adjust) {
            throw ValidationException::withMessages([
                'payroll' => 'Penyesuaian hanya dapat diubah pada gaji yang belum dibayar di periode terbuka.',
            ]);
        }

        DB::transaction(function () use ($payroll, $adjustment, $validated): void {
            $adjustment->update([
                'type' => PayrollAdjustmentType::from($validated['type']),
                'amount' => (int) $validated['amount'],
                'description' => $validated['description'],
            ]);

            $payroll->load('adjustments');
            $payroll->recalculateAmounts();
            $payroll->save();
        });

        if ($payroll->employee?->user_id) {
            $typeLabel = PayrollAdjustmentType::from($validated['type'])->label();
            $formattedAmount = 'Rp '.number_format($validated['amount'], 0, ',', '.');
            $this->pushNotificationService->sendToUser(
                "📊 Penyesuaian Gaji Diperbarui: {$typeLabel}",
                "Penyesuaian gaji Anda untuk periode {$payroll->payrollPeriod->period_label} diperbarui: {$typeLabel} menjadi {$formattedAmount} ({$validated['description']}).",
                $payroll->employee->user_id,
                '/admin/finance/payrolls',
            );
        }
    }

    public function deleteAdjustment(PayrollAdjustment $adjustment): void
    {
        $payroll = $adjustment->payroll;
        $payroll->loadMissing(['payrollPeriod', 'employee.user']);

        if (! $payroll->can_adjust) {
            throw ValidationException::withMessages([
                'payroll' => 'Penyesuaian hanya dapat dihapus pada gaji yang belum dibayar di periode terbuka.',
            ]);
        }

        DB::transaction(function () use ($payroll, $adjustment): void {
            $adjustment->delete();

            $payroll->load('adjustments');
            $payroll->recalculateAmounts();
            $payroll->save();
        });
    }

    public function pay(Payroll $payroll, User $user): void
    {
        $payroll->loadMissing(['payrollPeriod', 'employee.user.profile']);

        if ($payroll->status !== PayrollStatus::UNPAID) {
            throw ValidationException::withMessages([
                'payroll' => 'Gaji ini sudah dibayar.',
            ]);
        }

        if (! $payroll->payrollPeriod?->isOpen()) {
            throw ValidationException::withMessages([
                'payroll' => 'Periode gaji sudah ditutup.',
            ]);
        }

        if ($payroll->total_amount <= 0) {
            DB::transaction(function () use ($payroll, $user): void {
                $payroll->status = PayrollStatus::PAID;
                $payroll->paid_at = now();
                $payroll->paid_by_id = $user->id;
                $payroll->save();

                $this->settleKasbonFromPayroll($payroll, $user);
            });

            return;
        }

        DB::transaction(function () use ($payroll, $user): void {
            $description = sprintf(
                'Pembayaran gaji: %s (%s)',
                $payroll->employeeName,
                $payroll->payrollPeriod->period_label,
            );

            $cashTransaction = $this->cashService->recordOutgoing(
                $payroll,
                $payroll->total_amount,
                $description,
                $user,
            );

            $payroll->cash_transaction_id = $cashTransaction->id;
            $payroll->status = PayrollStatus::PAID;
            $payroll->paid_at = now();
            $payroll->paid_by_id = $user->id;
            $payroll->save();

            $this->settleKasbonFromPayroll($payroll, $user);
        });

        if ($payroll->employee?->user_id) {
            $this->pushNotificationService->sendToUser(
                '💸 Gaji Dibayarkan',
                "Gaji Anda untuk periode {$payroll->payrollPeriod->period_label} senilai {$payroll->total_amount_formatted} telah dibayarkan.",
                $payroll->employee->user_id,
                '/admin/finance/payrolls',
            );
        }
    }

    /**
     * @return Collection<int, Employee>
     */
    private function payrollEligibleEmployees(PayrollPeriod $period): Collection
    {
        $periodStart = Carbon::create($period->year, $period->month, 1)->startOfMonth();

        return Employee::query()
            ->with('user.roles')
            ->whereHas('user', function (Builder $query): void {
                $query->where('is_active', true)
                    ->whereDoesntHave('roles', fn (Builder $query) => $query->whereIn('name', [
                        Role::DEVELOPER->value,
                        Role::OWNER->value,
                    ]));
            })
            ->where(function (Builder $query) use ($periodStart): void {
                $query->whereNull('resign_date')
                    ->orWhere('resign_date', '>=', $periodStart);
            })
            ->get();
    }

    private function settleKasbonFromPayroll(Payroll $payroll, User $user): void
    {
        $remaining = (int) $payroll->deduction_amount;

        if ($remaining <= 0) {
            return;
        }

        $advances = EmployeeAdvance::query()
            ->where('employee_id', $payroll->employee_id)
            ->where('status', EmployeeAdvanceStatus::APPROVED)
            ->orderBy('created_at')
            ->get();

        foreach ($advances as $advance) {
            if ($remaining <= 0) {
                break;
            }

            $advance->paid_at = now();
            $advance->paid_by_id = $user->id;
            $advance->status = EmployeeAdvanceStatus::PAID;
            $advance->save();

            $remaining -= $advance->amount;
        }
    }

    private function applySorting(Builder $query, string $sort, string $direction): void
    {
        if (in_array($sort, ['base_salary', 'bonus_amount', 'deduction_amount', 'total_amount', 'status', 'created_at'], true)) {
            $query->orderBy($sort, $direction);

            return;
        }

        $query->orderBy('employee_id');
    }
}