<?php

namespace App\Services;

use Illuminate\Support\Facades\DB;
use Illuminate\Support\Collection;
use App\Models\Park;

/**
 * 利用率状況サービス
 * - 旧 UsingStatusHelper の機能をサービスとして集約
 * - 画面やAPIから本サービスを経由して取得する
 */
class UsingStatusService
{
    /**
     * 駐輪場別利用率統計を取得
     *
     * @param int|null $parkId 駐輪場ID（null の場合は全て）
     * @return Collection 統計データのコレクション
     */
    public function getUtilizationStats(?int $parkId = null): Collection
    {
        // 暫定的な収容台数（実DBに無いカラムのため）
        $defaultCapacity = [
            1 => 100, // 自転車
            2 => 50,  // 原付
            3 => 30,  // その他
        ];

        $query = DB::table('park as p')
            ->leftJoin('price_a as pr', 'p.park_id', '=', 'pr.park_id')
            ->leftJoin('ptype as pt', 'pr.price_ptypeid', '=', 'pt.ptype_id')
            ->leftJoin('regular_contract as rc', function ($join) {
                $join->on('pr.price_parkplaceid', '=', 'rc.price_parkplaceid')
                     ->where('rc.contract_cancel_flag', '=', 0);
            })
            ->select([
                'p.park_id',
                'p.park_name',
                'pt.ptype_id',
                'pt.ptype_subject',
                DB::raw('COUNT(rc.contract_id) as current_count'),
            ])
            ->whereNotNull('pr.price_parkplaceid')
            ->whereNotNull('pt.ptype_id')
            ->where('p.park_close_flag', '!=', 1);

        if ($parkId) {
            $query->where('p.park_id', $parkId);
        }

        $results = $query
            ->groupBy(['p.park_id', 'p.park_name', 'pt.ptype_id', 'pt.ptype_subject'])
            ->orderBy('p.park_name')
            ->orderBy('pt.ptype_subject')
            ->get();

        // 後計算で容量・空き・利用率を付与
        foreach ($results as $result) {
            $capacity = $defaultCapacity[$result->ptype_id] ?? 50;
            $result->park_limit = $capacity;
            $result->available = $capacity - $result->current_count;
            $result->usage_rate = $capacity > 0 ? round(($result->current_count / $capacity * 100), 1) : 0;
        }

        return $results;
    }

    /**
     * 駐輪場一覧を取得（選択用）
     */
    public function getParkList(): Collection
    {
        return Park::select('park_id', 'park_name')
            ->where('park_close_flag', '!=', 1)
            ->orderBy('park_name')
            ->get();
    }

    /**
     * 合計行の計算
     *
     * @param Collection $stats
     * @return array{total_limit:int,total_current:int,total_available:int,total_usage_rate:float}
     */
    public function calculateTotals(Collection $stats): array
    {
        $totalLimit = (int) $stats->sum('park_limit');
        $totalCurrent = (int) $stats->sum('current_count');
        $totalAvailable = $totalLimit - $totalCurrent;
        $totalUsageRate = $totalLimit > 0 ? round(($totalCurrent / $totalLimit * 100), 1) : 0.0;

        return [
            'total_limit' => $totalLimit,
            'total_current' => $totalCurrent,
            'total_available' => $totalAvailable,
            'total_usage_rate' => $totalUsageRate,
        ];
    }
}