<?php

namespace App\Services\Hr;

use App\Enums\LeaveRequestStatus;
use App\Models\LeaveRequest;
use Carbon\Carbon;
use Illuminate\Contracts\Pagination\LengthAwarePaginator;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Facades\DB;
use Illuminate\Validation\ValidationException;

class LeaveRequestService
{
    /**
     * @param  array{search: string, sort: string, direction: 'asc'|'desc'}  $tableQuery
     */
    public function paginateForIndex(array $tableQuery): LengthAwarePaginator
    {
        $query = LeaveRequest::query()
            ->with(['employee.user.profile', 'rejection'])
            ->when($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}%"))
                        ->orWhereHas('rejection', fn (Builder $query) => $query->where('reason', 'like', "%{$search}%"));
                });
            });

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

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

    /**
     * @param  array{start_date: string, end_date: string}  $validated
     */
    public function create(array $validated): void
    {
        $employee = auth()->user()?->employee;

        if ($employee === null) {
            throw ValidationException::withMessages([
                'employee' => 'Akun Anda tidak terhubung ke data pegawai.',
            ]);
        }

        $startDate = Carbon::parse($validated['start_date'])->startOfDay();
        $endDate = Carbon::parse($validated['end_date'])->startOfDay();

        $this->ensureMinimumLeadTime($startDate);
        $this->ensureValidDateRange($startDate, $endDate);

        LeaveRequest::create([
            'employee_id' => $employee->id,
            'start_date' => $startDate,
            'end_date' => $endDate,
            'total_days' => $this->calculateTotalDays($startDate, $endDate),
            'status' => LeaveRequestStatus::PENDING,
        ]);
    }

    /**
     * @param  array{start_date: string, end_date: string}  $validated
     */
    public function update(LeaveRequest $leaveRequest, array $validated): void
    {
        $this->ensureOwnedBySubmitter($leaveRequest);
        $this->ensurePending($leaveRequest, 'Pengajuan cuti hanya dapat diubah saat status menunggu.');

        $startDate = Carbon::parse($validated['start_date'])->startOfDay();
        $endDate = Carbon::parse($validated['end_date'])->startOfDay();

        $this->ensureMinimumLeadTime($startDate);
        $this->ensureValidDateRange($startDate, $endDate);

        $leaveRequest->start_date = $startDate;
        $leaveRequest->end_date = $endDate;
        $leaveRequest->total_days = $this->calculateTotalDays($startDate, $endDate);
        $leaveRequest->save();
    }

    public function delete(LeaveRequest $leaveRequest): void
    {
        $this->ensureOwnedBySubmitter($leaveRequest);
        $this->ensurePending($leaveRequest, 'Pengajuan cuti hanya dapat dihapus saat status menunggu.');

        $leaveRequest->delete();
    }

    public function approve(LeaveRequest $leaveRequest): void
    {
        $this->ensurePending($leaveRequest, 'Pengajuan cuti ini sudah diverifikasi.');

        $user = auth()->user();

        DB::transaction(function () use ($leaveRequest, $user): void {
            $leaveRequest->status = LeaveRequestStatus::APPROVED;
            $leaveRequest->verified_at = now();
            $leaveRequest->verified_by_id = $user->id;
            $leaveRequest->save();
        });
    }

    public function reject(LeaveRequest $leaveRequest, string $reason): void
    {
        $this->ensurePending($leaveRequest, 'Pengajuan cuti ini sudah diverifikasi.');

        $user = auth()->user();

        DB::transaction(function () use ($leaveRequest, $user, $reason): void {
            $leaveRequest->status = LeaveRequestStatus::REJECTED;
            $leaveRequest->verified_at = now();
            $leaveRequest->verified_by_id = $user->id;
            $leaveRequest->save();

            $leaveRequest->rejection()->create([
                'reason' => $reason,
                'rejected_by_id' => $user->id,
            ]);
        });
    }

    private function calculateTotalDays(Carbon $startDate, Carbon $endDate): int
    {
        return (int) $startDate->diffInDays($endDate) + 1;
    }

    private function ensureMinimumLeadTime(Carbon $startDate): void
    {
        $minimumStartDate = now()->startOfDay()->addDay();

        if ($startDate->lt($minimumStartDate)) {
            throw ValidationException::withMessages([
                'start_date' => 'Pengajuan cuti harus diajukan minimal H-1 (tanggal mulai paling cepat besok).',
            ]);
        }
    }

    private function ensureValidDateRange(Carbon $startDate, Carbon $endDate): void
    {
        if ($endDate->lt($startDate)) {
            throw ValidationException::withMessages([
                'end_date' => 'Tanggal selesai tidak boleh sebelum tanggal mulai.',
            ]);
        }
    }

    private function ensureOwnedBySubmitter(LeaveRequest $leaveRequest): void
    {
        if (auth()->user()?->employee?->id !== $leaveRequest->employee_id) {
            throw ValidationException::withMessages([
                'leave_request' => 'Anda tidak memiliki akses untuk mengubah pengajuan cuti ini.',
            ]);
        }
    }

    private function ensurePending(LeaveRequest $leaveRequest, string $message): void
    {
        if ($leaveRequest->status !== LeaveRequestStatus::PENDING) {
            throw ValidationException::withMessages([
                'leave_request' => $message,
            ]);
        }
    }

    private function applySorting(Builder $query, string $sort, string $direction): void
    {
        if (in_array($sort, ['created_at', 'start_date', 'end_date', 'total_days', 'status'], true)) {
            $query->orderBy($sort, $direction);

            return;
        }

        $query->latest();
    }
}