<?php
// app/Services/MetricCalculators/AverageBedDaysCalculator.php

namespace App\Services\MetricCalculators;

use App\Services\Base\BaseMetricService;
use App\Contracts\MetricCalculatorInterface;
use Illuminate\Support\Facades\DB;

class AverageBedDaysCalculator extends BaseMetricService implements MetricCalculatorInterface
{
    public function getMetricId(): int
    {
        return 18;
    }

    public function calculate(array $departmentIds, string $startDate, string $endDate): array
    {
        if (empty($departmentIds)) {
            return [];
        }

        $results = DB::table('reports as r')
            ->join('metrika_results as mr', 'r.report_id', '=', 'mr.rf_report_id')
            ->whereIn('r.rf_department_id', $departmentIds)
            ->where('mr.rf_metrika_item_id', 18)
            ->where('r.period_start', '>=', $startDate)
            ->where('r.period_end', '<', $endDate)
            ->select(
                'r.rf_department_id',
                DB::raw('AVG(CAST(mr.value AS DECIMAL)) as avg_value')
            )
            ->groupBy('r.rf_department_id')
            ->get()
            ->keyBy('rf_department_id');

        $averages = [];
        foreach ($departmentIds as $deptId) {
            $averages[$deptId] = isset($results[$deptId])
                ? round((float)$results[$deptId]->avg_value, 1)
                : 0;
        }

        return $averages;
    }
}