<?php
declare(strict_types=1);
namespace plugin\saiadmin\app\service\alerts;

/** One persisted platform policy snapshot per query service. */
final class ReplenishmentPolicy
{
    private readonly array $settings;
    public function __construct() { $this->settings=(new AlertSettings())->current(); }
    public function settings(): array { return $this->settings; }

    public function daysExpression(): string
    {
        return '(CASE WHEN e.employee_count > 0 THEN a.full_qty * '.(int)$this->settings['days_per_barrel'].'.0 / NULLIF(e.employee_count,0) ELSE NULL END)';
    }

    public function alertExpression(): string
    {
        return '(a.full_qty < '.(int)$this->settings['alert_qty'].')';
    }

    public function urgentExpression(): string
    {
        return '(a.full_qty <= '.(int)$this->settings['urgent_qty'].')';
    }

    public function evaluate(array $row): array
    {
        $full = (int)$row['full_qty'];
        $people = (int)($row['employee_count'] ?? 0);
        $daily = $people > 0 ? (float)$row['liters'] * $people / $this->settings['days_per_barrel'] : null;
        $days = $people > 0 ? $full * $this->settings['days_per_barrel'] / $people : null;
        $alert = $full < $this->settings['alert_qty'];
        return ['available_entitlement' => (int)$row['entitlement'] - (int)$row['frozen'],
            'employee_count' => $people > 0 ? $people : null,
            'estimated_daily_liters' => $daily === null ? null : round($daily, 2),
            'estimated_daily_barrels' => $people > 0 ? round($people / $this->settings['days_per_barrel'], 2) : null,
            'days_left' => $days === null ? null : round($days, 1), 'raw_days_left' => $days,
            'is_alert' => $alert, 'severity' => !$alert ? 'healthy' : ($full <= $this->settings['urgent_qty'] ? 'urgent' : 'normal'),
            'reasons' => [($alert ? '现场满桶少于' : '现场满桶不少于').$this->settings['alert_qty'].'桶']];
    }
}