<?php

namespace Modules\EcommerceFinance\Services;

use Illuminate\Validation\ValidationException;

class AccessoryReshipRateCalculator
{
    /** 界面及文本导入均以百分数为单位；数据库保存万分比整数。 */
    public static function basisPoints(string $percent): int
    {
        $percent = trim(str_replace(['%', '％'], '', $percent));
        if (!preg_match('/^\d{1,3}(?:\.\d{1,2})?$/', $percent)) {
            throw ValidationException::withMessages(['rate_percent' => '扣款比例须为0至100的数字，最多两位小数。']);
        }
        [$whole, $decimal] = array_pad(explode('.', $percent, 2), 2, '');
        $points = (int) $whole * 100 + (int) str_pad($decimal, 2, '0');
        if ($points > 10000) {
            throw ValidationException::withMessages(['rate_percent' => '扣款比例不能超过100%。']);
        }
        return $points;
    }

    public static function amount(int $freightCents, int $basisPoints): int
    {
        return intdiv($freightCents * $basisPoints + 5000, 10000);
    }

    /** 名称精确匹配；不默认比例，不对多候选累计运费。 */
    public function apply(array $row, array $configs, ?string $selectedCourier = null): array
    {
        // 同名快递只保留一个首发包裹；不同名称必须由业务选择，不能按比例猜归属。
        $candidates = [];
        foreach ($row['matches'] as $match) {
            $name = trim((string) $match['courier']);
            $candidates[$name] ??= array_replace($match, ['courier' => $name]);
        }
        $row['courier_candidates'] = array_values($candidates);
        $selected = $selectedCourier !== null ? ($candidates[$selectedCourier] ?? null) : null;
        if (count($candidates) === 1) $selected = reset($candidates);
        $row['selected_courier'] = $selected['courier'] ?? null;
        $row['matches'] = $selected === null ? array_values($candidates) : [$selected];
        $row['deduction_cents'] = $row['status'] === 'unmatched' ? 0 : null;
        $row['deduction_rate_basis_points'] = null;
        $row['deduction_state'] = 'unmatched';
        $row['deduction_note'] = '三个月内未匹配首发快递单号';
        $reshipCourier = trim((string) (($row['express_name1'] ?? '') ?: ($row['express_name2'] ?? '')));
        if (in_array($reshipCourier, ['外采快递', '线下快递'], true)) {
            $row['deduction_cents'] = 0;
            $row['deduction_state'] = 'excluded_courier';
            $row['deduction_note'] = '补发快递为' . $reshipCourier . '，不参与扣款';
            return $row;
        }
        if ($row['status'] === 'unmatched') {
            return $row;
        }
        if ($selected === null) {
            $row['deduction_state'] = 'selection_required';
            $row['deduction_note'] = '请选择需要扣款的首发快递，补发运费仅计一次';
            return $row;
        }
        $rates = [];
        $missing = false;
        foreach ($row['matches'] as &$match) {
            $config = $configs[trim((string) $match['courier'])] ?? null;
            $match['rate_basis_points'] = $config['rate_basis_points'] ?? null;
            $match['courier_code'] = $config['courier_code'] ?? null;
            $match['deduction_cents'] = $config !== null && $row['freight_cents'] !== null
                ? self::amount($row['freight_cents'], (int) $config['rate_basis_points']) : null;
            if ($config === null) {
                $missing = true;
            } else {
                $rates[] = (int) $config['rate_basis_points'];
            }
        }
        unset($match);
        if ($missing) {
            $row['deduction_state'] = 'missing_config';
            $row['deduction_note'] = '首发快递未配置扣款比例，暂不计入扣款合计';
        } elseif ($row['freight_cents'] === null) {
            $row['deduction_state'] = 'invalid_amount';
            $row['deduction_note'] = '补发运费缺失或异常，待核实';
        } else {
            $rate = $rates[0];
            $row['deduction_rate_basis_points'] = $rate;
            $row['deduction_cents'] = self::amount($row['freight_cents'], $rate);
            $row['deduction_state'] = $rate === 0 ? 'zero_rate' : 'ready';
            $row['deduction_note'] = $rate === 0 ? '扣款比例0%，不扣款' : '按所选首发快递配置比例核算，仅计一次';
            if ($rate > 0 && $row['deduction_cents'] === 0) {
                $row['deduction_state'] = 'zero_amount';
                $row['deduction_note'] = '扣款金额为0，不扣款';
            }
        }
        return $row;
    }
}