<?php

namespace Modules\EcommerceFinance\Services;

/**
 * 厂家对账单 vs 我方结算数据：
 * - 行键 = 采购单号 + 日期 + 我方商品编码（对应厂家条码去掉厂家编号/版本后缀）；
 * - 同一行键的多行先合并数量与金额，再比较双方数量和金额；
 * - 厂家未填采购单号时，仅在同日期+商品编码能唯一对应我方一条数据时兜底匹配。
 */
class SupplierStatementMatcher
{
    public const TYPE_MATCH = '一致';

    public const TYPE_SUPPLIER_EXTRA = '厂家多';

    public const TYPE_MISMATCH = '数量/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  我方数据（purchaseNo/date/productCode/unitPrice/qty/amount；productCode 为空才回退货号）
     * @param  list<array<string,mixed>>  $theirs  厂家数据（purchaseNo/createdAt/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, ['productCode', 'skuCode'], 'purchaseNo', 'date');
        $theirsGrouped = $this->group($theirs, ['barcode'], 'purchaseNo', 'createdAt');

        // 已有采购单号时严格按三元组匹配；缺失采购单号时，仅在日期+商品编码唯一时兜底。
        $fallbackIndex = [];
        foreach ($mineGrouped as $key => $row) {
            $fallbackIndex[$row['date'] . "\0" . $row['barcodeKey']][] = $key;
        }
        $theirsGrouped = $this->resolveMissingPurchaseNumbers($theirsGrouped, $fallbackIndex);

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

            $purchaseNo = (string) ($mineRow['purchaseNo'] ?? $theirsRow['purchaseNo'] ?? '');
            $date = (string) ($mineRow['date'] ?? $theirsRow['date'] ?? '');
            $barcode = (string) ($mineRow['barcode'] ?? $theirsRow['barcode'] ?? '');
            $supplierBarcode = (string) ($theirsRow['supplierBarcode'] ?? '');
            $mineUnitPrice = (float) ($mineRow['unitPrice'] ?? 0);
            $theirsUnitPrice = (float) ($theirsRow['unitPrice'] ?? 0);
            $unitPrice = $mineUnitPrice > 0 ? $mineUnitPrice : $theirsUnitPrice;
            $mineQty = (float) ($mineRow['qty'] ?? 0);
            $mineAmount = (float) ($mineRow['amount'] ?? 0);
            $theirsQty = (float) ($theirsRow['qty'] ?? 0);
            $theirsAmount = (float) ($theirsRow['amount'] ?? 0);
            $qtyDifference = $theirsQty - $mineQty;
            $amountDifference = $theirsAmount - $mineAmount;
            $quantityDifference = $this->describeDifference($qtyDifference, $amountDifference);
            $fallbackNote = '';
            if (($theirsRow['matchedByFallback'] ?? false) === true) {
                $fallbackNote = '厂家未填采购单号，已按日期+商品编码唯一匹配；';
            } elseif (($theirsRow['fallbackAmbiguous'] ?? false) === true) {
                $fallbackNote = '厂家未填采购单号，且同日期+商品编码有多条我方数据，无法唯一匹配；';
            }

            if ($mineRow === null) {
                $type = self::TYPE_SUPPLIER_EXTRA;
                $settle = 0.0;
                $note = $fallbackNote . '厂家整条多报：' . $quantityDifference . '；我方没有该采购单号+日期+商品编码，不结算';
                $summary['supplierExtra']++;
            } elseif ($theirsRow === null) {
                $type = self::TYPE_SUPPLIER_MISSING;
                $settle = 0.0;
                $note = '厂家漏报：我方数量 ' . $this->number($mineQty)
                    . '，单价 ￥' . number_format($mineUnitPrice, 2)
                    . '，金额 ￥' . number_format($mineAmount, 2)
                    . '；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 = $fallbackNote . '采购单号、日期、商品编码、数量和金额一致，正常结算';
                $summary['match']++;
            } else {
                $type = self::TYPE_MISMATCH;
                $settle = min($mineAmount, $theirsAmount);
                $note = $fallbackNote . $quantityDifference . '；按金额低的一方结算，请厂家修改';
                $summary['mismatch']++;
            }

            $summary['mineAmount'] += $mineAmount;
            $summary['theirsAmount'] += $theirsAmount;
            $summary['supplierOverQty'] += max($qtyDifference, 0);
            $summary['supplierOverAmount'] += max($amountDifference, 0);
            $summary['settleAmount'] += $settle;

            $rows[] = [
                'purchaseNo' => $purchaseNo,
                'date' => $date,
                'barcode' => $barcode,
                'supplierBarcode' => $supplierBarcode !== '' && $supplierBarcode !== $barcode ? $supplierBarcode : '',
                'unitPrice' => $unitPrice,
                'mineUnitPrice' => $mineUnitPrice,
                'theirsUnitPrice' => $theirsUnitPrice,
                'mineQty' => $mineQty,
                'mineAmount' => $mineAmount,
                'theirsQty' => $theirsQty,
                'theirsAmount' => $theirsAmount,
                'qtyDifference' => round($qtyDifference, 4),
                'amountDifference' => round($amountDifference, 2),
                'supplierOverQty' => round(max($qtyDifference, 0), 4),
                'supplierOverAmount' => round(max($amountDifference, 0), 2),
                'type' => $type,
                'settleAmount' => $settle,
                'note' => $note,
            ];
        }

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

        $summary['mineAmount'] = round($summary['mineAmount'], 2);
        $summary['theirsAmount'] = round($summary['theirsAmount'], 2);
        $summary['supplierOverQty'] = round($summary['supplierOverQty'], 4);
        $summary['supplierOverAmount'] = round($summary['supplierOverAmount'], 2);
        $summary['settleAmount'] = round($summary['settleAmount'], 2);
        $summary['differenceAmount'] = round($summary['mineAmount'] - $summary['settleAmount'], 2);

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

    /**
     * 按「采购单号 + 日期 + 商品编码」归组，数量与金额相加。
     *
     * @param  list<array<string,mixed>>  $rows
     * @param  list<string>  $barcodeFields
     * @return array<string,array<string,mixed>>
     */
    private function group(array $rows, array $barcodeFields, string $purchaseField, string $dateField): array
    {
        $grouped = [];
        foreach ($rows as $row) {
            $barcode = $this->barcodeValue($row, $barcodeFields);
            if ($barcode === '') {
                continue;
            }

            $barcodeKey = $this->normalizeBarcode($barcode);
            $purchaseNo = $this->normalizePurchaseNo($row[$purchaseField] ?? '');
            $date = $this->normalizeDate($row[$dateField] ?? '');
            $unitPrice = (float) ($row['unitPrice'] ?? 0);
            $key = $this->matchKey($purchaseNo, $date, $barcodeKey);

            $grouped[$key] ??= [
                'purchaseNo' => $purchaseNo,
                'date' => $date,
                'barcode' => $barcode,
                'barcodeKey' => $barcodeKey,
                'supplierBarcode' => in_array('barcode', $barcodeFields, true) ? $barcode : '',
                'unitPrice' => $unitPrice,
                'unitPrices' => [],
                'qty' => 0.0,
                'amount' => 0.0,
                'matchedByFallback' => false,
                'fallbackAmbiguous' => false,
            ];
            if ($unitPrice > 0) {
                $grouped[$key]['unitPrices'][number_format($unitPrice, 4, '.', '')] = true;
            }
            $grouped[$key]['qty'] += (float) ($row['qty'] ?? 0);
            $grouped[$key]['amount'] += (float) ($row['amount'] ?? 0);
        }

        foreach ($grouped as &$group) {
            $group = $this->finalizeGroup($group);
        }
        unset($group);

        return $grouped;
    }

    /** @param array<string,mixed> $row @param list<string> $fields */
    private function barcodeValue(array $row, array $fields): string
    {
        foreach ($fields as $field) {
            $value = trim((string) ($row[$field] ?? ''));
            if ($value !== '') {
                return $value;
            }
        }

        return '';
    }

    /**
     * @param  array<string,array<string,mixed>>  $groups
     * @param  array<string,list<string>>  $fallbackIndex
     * @return array<string,array<string,mixed>>
     */
    private function resolveMissingPurchaseNumbers(array $groups, array $fallbackIndex): array
    {
        $resolved = [];
        foreach ($groups as $key => $group) {
            $targetKey = $key;
            if ($group['purchaseNo'] === '') {
                $candidates = $fallbackIndex[$group['date'] . "\0" . $group['barcodeKey']] ?? [];
                if (count($candidates) === 1) {
                    $targetKey = $candidates[0];
                    $group['matchedByFallback'] = true;
                } elseif (count($candidates) > 1) {
                    $group['fallbackAmbiguous'] = true;
                }
            }

            if (isset($resolved[$targetKey])) {
                $resolved[$targetKey] = $this->mergeGroup($resolved[$targetKey], $group);
            } else {
                $resolved[$targetKey] = $group;
            }
        }

        return $resolved;
    }

    /** @param array<string,mixed> $left @param array<string,mixed> $right */
    private function mergeGroup(array $left, array $right): array
    {
        $left['qty'] += (float) $right['qty'];
        $left['amount'] += (float) $right['amount'];
        $left['unitPrices'] += (array) $right['unitPrices'];
        $left['matchedByFallback'] = (bool) $left['matchedByFallback'] || (bool) $right['matchedByFallback'];
        $left['fallbackAmbiguous'] = (bool) $left['fallbackAmbiguous'] || (bool) $right['fallbackAmbiguous'];
        if ($left['supplierBarcode'] === '' && $right['supplierBarcode'] !== '') {
            $left['supplierBarcode'] = $right['supplierBarcode'];
        }

        return $this->finalizeGroup($left);
    }

    /** @param array<string,mixed> $group @return array<string,mixed> */
    private function finalizeGroup(array $group): array
    {
        $prices = array_keys((array) ($group['unitPrices'] ?? []));
        if (count($prices) === 1) {
            $group['unitPrice'] = (float) $prices[0];
        } elseif ((float) $group['qty'] != 0.0) {
            $group['unitPrice'] = round((float) $group['amount'] / (float) $group['qty'], 4);
        }

        return $group;
    }

    private function matchKey(string $purchaseNo, string $date, string $barcode): string
    {
        return $purchaseNo . "\0" . $date . "\0" . $barcode;
    }

    private function normalizePurchaseNo(mixed $value): string
    {
        $purchaseNo = ltrim(trim((string) $value), "'");

        return preg_match('/^(\d+)\.0+$/', $purchaseNo, $matches) === 1 ? $matches[1] : $purchaseNo;
    }

    private function normalizeDate(mixed $value): string
    {
        $raw = trim((string) $value);
        if (preg_match('/^(\d{4})[-\/.](\d{1,2})[-\/.](\d{1,2})/', $raw, $matches) === 1) {
            $year = (int) $matches[1];
            $month = (int) $matches[2];
            $day = (int) $matches[3];
            if (checkdate($month, $day, $year)) {
                return sprintf('%04d-%02d-%02d', $year, $month, $day);
            }
        }

        return $raw;
    }

    private function describeDifference(float $qtyDifference, float $amountDifference): string
    {
        $parts = [];
        if (abs($qtyDifference) >= 0.005) {
            $parts[] = '厂家数量' . ($qtyDifference > 0 ? '多 ' : '少 ') . $this->number(abs($qtyDifference));
        }
        if (abs($amountDifference) >= 0.005) {
            $parts[] = '厂家金额' . ($amountDifference > 0 ? '多 ￥' : '少 ￥') . number_format(abs($amountDifference), 2);
        }

        return $parts === [] ? '数量、金额一致' : implode('，', $parts);
    }

    private function number(float $value): string
    {
        return rtrim(rtrim(number_format($value, 2, '.', ''), '0'), '.');
    }

    /** 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 strtoupper($normalized === null || $normalized === '' ? $barcode : $normalized);
    }
}