<?php

namespace app\cunkebao\controller;

class RFMController extends BaseController
{
    /**
     * 计算 RFM 评分（默认规则）
     * @param int|null $recencyDays 最近购买天数
     * @param int $frequency 购买次数
     * @param float $monetary 购买金额
     * @return array{R:int,F:int,M:int}
     */
    public static function calcRfmScores($recencyDays = 30, $frequency, $monetary)
    {
        $recencyDays = is_numeric($recencyDays) ? (int)$recencyDays : 9999;
        $frequency = max(0, (int)$frequency);
        $monetary = max(0, (float)$monetary);
        return [
            'R' => self::scoreR_Default($recencyDays),
            'F' => self::scoreF_Default($frequency),
            'M' => self::scoreM_Default($monetary),
        ];
    }

    // 默认规则
    protected static function scoreR_Default(int $days): int
    {
        if ($days <= 30) return 5;
        if ($days <= 60) return 4;
        if ($days <= 90) return 3;
        if ($days <= 120) return 2;
        return 1;
    }
    protected static function scoreF_Default(int $times): int
    {
        if ($times >= 10) return 5;
        if ($times >= 6) return 4;
        if ($times >= 3) return 3;
        if ($times >= 2) return 2;
        if ($times >= 1) return 1;
        return 0;
    }
    protected static function scoreM_Default(float $amount): int
    {
        if ($amount >= 2000) return 5;
        if ($amount >= 1000) return 4;
        if ($amount >= 500) return 3;
        if ($amount >= 200) return 2;
        if ($amount > 0) return 1;
        return 0;
    }
}