<?php

namespace App\Services;

use App\Models\Member;
use App\Models\MembershipPayment;

class MembershipFeeCalculator
{
    protected SettingsService $settings;

    public function __construct(SettingsService $settings)
    {
        $this->settings = $settings;
    }

    /**
     * 計算會費金額
     *
     * @param Member $member 會員
     * @param string $feeType 會費類型 (entrance_fee | annual_fee)
     * @return array{base_amount: float, discount_amount: float, final_amount: float, disability_discount: bool, fee_type: string}
     */
    public function calculate(Member $member, string $feeType): array
    {
        $baseAmount = $this->getBaseAmount($feeType);
        $discountRate = $member->hasApprovedDisability()
            ? $this->getDisabilityDiscountRate()
            : 0;

        $discountAmount = round($baseAmount * $discountRate, 2);
        $finalAmount = round($baseAmount - $discountAmount, 2);

        return [
            'fee_type' => $feeType,
            'base_amount' => $baseAmount,
            'discount_amount' => $discountAmount,
            'final_amount' => $finalAmount,
            'disability_discount' => $discountRate > 0,
        ];
    }

    /**
     * 為會員計算下一次應繳的會費
     *
     * @param Member $member
     * @return array{base_amount: float, discount_amount: float, final_amount: float, disability_discount: bool, fee_type: string}
     */
    public function calculateNextFee(Member $member): array
    {
        $feeType = $member->getNextFeeType();
        return $this->calculate($member, $feeType);
    }

    /**
     * 取得基本會費金額
     *
     * @param string $feeType
     * @return float
     */
    public function getBaseAmount(string $feeType): float
    {
        return match($feeType) {
            MembershipPayment::FEE_TYPE_ENTRANCE => $this->getEntranceFee(),
            MembershipPayment::FEE_TYPE_ANNUAL => $this->getAnnualFee(),
            default => 0,
        };
    }

    /**
     * 取得入會會費金額
     *
     * @return float
     */
    public function getEntranceFee(): float
    {
        return (float) $this->settings->get('membership_fee.entrance_fee', 1000);
    }

    /**
     * 取得常年會費金額
     *
     * @return float
     */
    public function getAnnualFee(): float
    {
        return (float) $this->settings->get('membership_fee.annual_fee', 1000);
    }

    /**
     * 取得身心障礙折扣比例
     *
     * @return float 折扣比例 (0-1)
     */
    public function getDisabilityDiscountRate(): float
    {
        return (float) $this->settings->get('membership_fee.disability_discount_rate', 0.5);
    }

    /**
     * 取得身心障礙折扣百分比 (用於顯示)
     *
     * @return int 百分比 (0-100)
     */
    public function getDisabilityDiscountPercentage(): int
    {
        return (int) ($this->getDisabilityDiscountRate() * 100);
    }

    /**
     * 驗證繳費金額是否正確
     *
     * @param MembershipPayment $payment
     * @return bool
     */
    public function validatePaymentAmount(MembershipPayment $payment): bool
    {
        $member = $payment->member;
        $expected = $this->calculate($member, $payment->fee_type);

        // 繳費金額應等於或大於應繳金額
        return $payment->amount >= $expected['final_amount'];
    }

    /**
     * 取得會費類型的標籤
     *
     * @param string $feeType
     * @return string
     */
    public function getFeeTypeLabel(string $feeType): string
    {
        return match($feeType) {
            MembershipPayment::FEE_TYPE_ENTRANCE => '入會會費',
            MembershipPayment::FEE_TYPE_ANNUAL => '常年會費',
            default => $feeType,
        };
    }

    /**
     * 取得所有會費設定（用於管理界面）
     *
     * @return array
     */
    public function getFeeSettings(): array
    {
        return [
            'entrance_fee' => $this->getEntranceFee(),
            'annual_fee' => $this->getAnnualFee(),
            'disability_discount_rate' => $this->getDisabilityDiscountRate(),
            'disability_discount_percentage' => $this->getDisabilityDiscountPercentage(),
        ];
    }
}