<?php

namespace App\Services;

use App\Models\Consultant;
use App\Models\DataCentre;
use App\Models\DataCentreConsultantAssignment;
use App\Models\User;
use Illuminate\Support\Carbon;
use Illuminate\Support\Facades\DB;

class AssignmentService
{
    /**
     * Tugaskan perunding kepada pusat data.
     *
     * Peraturan: satu pusat data hanya boleh ada SATU perunding aktif pada satu masa.
     * Penugasan terdahulu ditamatkan (end_date diisi, is_active=false) dan disimpan
     * dalam sejarah penugasan.
     */
    public function assign(DataCentre $dataCentre, Consultant $consultant, User $officer, ?string $startDate = null, ?string $reason = null): DataCentreConsultantAssignment
    {
        return DB::transaction(function () use ($dataCentre, $consultant, $officer, $startDate, $reason) {
            $start = $startDate ? Carbon::parse($startDate) : now();

            // Tamatkan semua penugasan aktif sedia ada untuk pusat data ini.
            $dataCentre->assignments()
                ->where('is_active', true)
                ->get()
                ->each(function (DataCentreConsultantAssignment $existing) use ($start) {
                    $existing->update([
                        'is_active' => false,
                        'end_date' => $existing->end_date ?? $start->copy()->subDay(),
                    ]);
                });

            $assignment = $dataCentre->assignments()->create([
                'consultant_id' => $consultant->id,
                'start_date' => $start,
                'reason' => $reason,
                'assigned_by' => $officer->id,
                'is_active' => true,
            ]);

            $dataCentre->update(['current_consultant_id' => $consultant->id]);

            activity('penugasan')
                ->performedOn($dataCentre)
                ->causedBy($officer)
                ->withProperties([
                    'consultant_id' => $consultant->id,
                    'consultant' => $consultant->nama_perunding,
                    'reason' => $reason,
                ])
                ->log('Perunding ditugaskan kepada pusat data');

            return $assignment;
        });
    }

    /**
     * Tamatkan penugasan aktif tanpa menggantikan dengan perunding baharu.
     */
    public function endActive(DataCentre $dataCentre, User $officer, ?string $reason = null): void
    {
        DB::transaction(function () use ($dataCentre, $officer, $reason) {
            $dataCentre->assignments()->where('is_active', true)->update([
                'is_active' => false,
                'end_date' => now(),
                'reason' => $reason,
            ]);
            $dataCentre->update(['current_consultant_id' => null]);

            activity('penugasan')
                ->performedOn($dataCentre)
                ->causedBy($officer)
                ->log('Penugasan perunding ditamatkan');
        });
    }
}