<?php

namespace Modules\EcommerceFinance\Services;

/**
 * 厂家对账单 vs 我方结算数据：
 * - 行键 = 条码（去掉厂家编号/版本后缀，如 CJ019312N1097V01 → CJ019312）+ 单价
 *   （同一把钥匙的多行先合并：数量、金额相加）；
 * - 四类结果：一致 / 厂家多（不结算、退回）/ 金额不一致（按金额低的一方结算）/ 厂家少（按厂家数据结算，即不付款）。
 */
class SupplierStatementMatcher
{
    public const TYPE_MATCH = '一致';

    public const TYPE_SUPPLIER_EXTRA = '厂家多';

    public const TYPE_MISMATCH = '金额不一致';

    public const TYPE_SUPPLIER_MISSING = '厂家少';

    /** 厂家条码后缀：供应商编号 + 版本，如 N1097V01、N1269V01。 */
    private const SUPPLIER_SUFFIX = '/[A-Z]{1,3}\d{3,6}V\d{1,3}$/i';

    /**
     * @param  list<array<string,mixed>>  $mine  我方结算数据（货款对账：skuCode/unitPrice/qty/amount）
     * @param  list<array<string,mixed>>  $theirs  厂家对账单（barcode/unitPrice/qty/amount）
     * @return array{rows:list<array<string,mixed>>,summary:array<string,mixed>}
     */
    public function compare(array $mine, array $theirs): array
    {
        $mineGrouped = $this->group($mine, 'skuCode');
        $theirsGrouped = $this->group($theirs, 'barcode');

        $rows = [];
        $summary = ['match' => 0, 'supplierExtra' => 0, 'mismatch' => 0, 'supplierMissing' => 0,
            'mineAmount' => 0.0, 'settleAmount' => 0.0];

        foreach (array_unique(array_merge(array_keys($mineGrouped), array_keys($theirsGrouped))) as $key) {
            $mineRow = $mineGrouped[$key] ?? null;
            $theirsRow = $theirsGrouped[$key] ?? null;

            $barcode = (string) ($mineRow['barcode'] ?? $theirsRow['barcode']);
            $supplierBarcode = (string) ($theirsRow['barcode'] ?? '');
            $unitPrice = (float) ($mineRow['unitPrice'] ?? $theirsRow['unitPrice']);
            $mineQty = (float) ($mineRow['qty'] ?? 0);
            $mineAmount = (float) ($mineRow['amount'] ?? 0);
            $theirsQty = (float) ($theirsRow['qty'] ?? 0);
            $theirsAmount = (float) ($theirsRow['amount'] ?? 0);

            if ($mineRow === null) {
                $type = self::TYPE_SUPPLIER_EXTRA;
                $settle = 0.0;
                $note = '我方没有这条数据：不结算，退回厂家修改账单';
                $summary['supplierExtra']++;
            } elseif ($theirsRow === null) {
                $type = self::TYPE_SUPPLIER_MISSING;
                $settle = 0.0;
                $note = '厂家少报了这条数据：按厂家数据结算（不付款）';
                $summary['supplierMissing']++;
            } elseif (abs($mineAmount - $theirsAmount) < 0.005 && abs($mineQty - $theirsQty) < 0.005) {
                $type = self::TYPE_MATCH;
                $settle = $mineAmount;
                $note = '正常结算';
                $summary['match']++;
            } else {
                $type = self::TYPE_MISMATCH;
                $settle = min($mineAmount, $theirsAmount);
                $note = '金额/数量不一致：按金额低的一方结算';
                $summary['mismatch']++;
            }

            $summary['mineAmount'] += $mineAmount;
            $summary['settleAmount'] += $settle;

            $rows[] = [
                'barcode' => $barcode,
                'supplierBarcode' => $supplierBarcode === $barcode ? '' : $supplierBarcode,
                'unitPrice' => $unitPrice,
                'mineQty' => $mineQty,
                'mineAmount' => $mineAmount,
                'theirsQty' => $theirsQty,
                'theirsAmount' => $theirsAmount,
                'type' => $type,
                'settleAmount' => $settle,
                'note' => $note,
            ];
        }

        usort($rows, static fn (array $a, array $b): int => [$a['type'] === self::TYPE_MATCH ? 1 : 0, $a['barcode']]
            <=> [$b['type'] === self::TYPE_MATCH ? 1 : 0, $b['barcode']]);

        $summary['mineAmount'] = round($summary['mineAmount'], 2);
        $summary['settleAmount'] = round($summary['settleAmount'], 2);
        $summary['differenceAmount'] = round($summary['mineAmount'] - $summary['settleAmount'], 2);

        return ['rows' => $rows, 'summary' => $summary];
    }

    /**
     * 按「条码 + 单价」归组，数量与金额相加。
     *
     * @param  list<array<string,mixed>>  $rows
     * @return array<string,array{barcode:string,unitPrice:float,qty:float,amount:float}>
     */
    private function group(array $rows, string $barcodeField): array
    {
        $grouped = [];
        foreach ($rows as $row) {
            $barcode = trim((string) ($row[$barcodeField] ?? ''));
            if ($barcode === '') {
                continue;
            }

            $unitPrice = (float) ($row['unitPrice'] ?? 0);
            $key = $this->normalizeBarcode($barcode) . '|' . number_format($unitPrice, 4, '.', '');

            $grouped[$key] ??= ['barcode' => $barcode, 'unitPrice' => $unitPrice, 'qty' => 0.0, 'amount' => 0.0];
            $grouped[$key]['qty'] += (float) ($row['qty'] ?? 0);
            $grouped[$key]['amount'] += (float) ($row['amount'] ?? 0);
        }

        return $grouped;
    }

    /** 去掉条码末尾的「厂家编号 + 版本」后缀，双方口径统一后再匹配。 */
    private function normalizeBarcode(string $barcode): string
    {
        $normalized = preg_replace(self::SUPPLIER_SUFFIX, '', $barcode);

        return $normalized === null || $normalized === '' ? $barcode : $normalized;
    }
}