<?php

namespace Modules\EcommerceFinance\Services;

use Illuminate\Http\UploadedFile;
use Illuminate\Validation\ValidationException;
use PhpOffice\PhpSpreadsheet\IOFactory;
use Throwable;

/**
 * 「终版」目录按表导入：数据独立存放，可以从空表开始导入，
 * 不要求基础页面那种“先导出再改”的记录标识列。
 */
class PayablesFinalImporter
{
    private const MAX_ROWS = 10000;

    public function __construct(
        private readonly PayablesFieldNormalizer $normalizer,
        private readonly SupplierPayableOverrideStore $store,
    ) {
    }

    /**
     * @param  array<string,array{label:string,type:string}>  $fields  该表的字段定义（决定表头）
     * @param  string  $storeDataset  「终版」目录实际保存记录用的数据集键
     * @return array{created:int,updated:int,rows:int}
     */
    public function import(array $fields, string $storeDataset, UploadedFile $file, int $companyId, ?int $userId): array
    {
        $lookup = ['记录标识' => '_action_key', 'recordkey' => '_action_key', '_action_key' => '_action_key'];
        foreach ($fields as $field => $definition) {
            $lookup[$this->header($field)] = $field;
            $lookup[$this->header($definition['label'])] = $field;
        }

        try {
            $readerType = match (mb_strtolower($file->getClientOriginalExtension())) {
                'xlsx' => 'Xlsx',
                'xls' => 'Xls',
                'csv' => 'Csv',
                default => throw new \RuntimeException('Unsupported workbook format.'),
            };
            $spreadsheet = IOFactory::createReader($readerType)->load($file->getRealPath());
            [$rows, $headerRow, $columns] = $this->bestSheet($spreadsheet, $lookup);
        } catch (Throwable) {
            throw ValidationException::withMessages([
                'import' => '无法读取导入文件，请确认文件未损坏且格式为 xlsx、xls 或 csv。',
            ]);
        } finally {
            if (isset($spreadsheet)) {
                $spreadsheet->disconnectWorksheets();
            }
        }

        if ($rows === null || $columns === []) {
            throw ValidationException::withMessages([
                'import' => '没有识别到表头，请先下载本页面的导入模板，按模板列填写后重试。',
            ]);
        }

        $store = $this->store;
        $records = [];
        foreach (array_slice($rows, $headerRow + 1, null, true) as $rowIndex => $row) {
            $line = $rowIndex + 1;
            $key = '';
            $rawValues = [];
            foreach ($columns as $columnIndex => $field) {
                if ($field === '_action_key') {
                    $key = trim((string) ($row[$columnIndex] ?? ''));
                } else {
                    $rawValues[$field] = $row[$columnIndex] ?? null;
                }
            }

            if (collect($rawValues)->every(static fn (mixed $value): bool => trim((string) $value) === '')) {
                continue;
            }

            try {
                $values = $this->normalizer->normalize($fields, $rawValues);
            } catch (ValidationException $exception) {
                throw ValidationException::withMessages([
                    'import' => "第 {$line} 行：" . collect($exception->errors())->flatten()->first(),
                ]);
            }

            if ($key === '') {
                $key = $store->key($storeDataset, $values);
            }

            if (isset($records[$key])) {
                throw ValidationException::withMessages(['import' => "第 {$line} 行与前一行内容重复。"]);
            }

            $records[$key] = $values;

            if (count($records) > self::MAX_ROWS) {
                throw ValidationException::withMessages(['import' => '单次最多导入 10,000 条记录，请拆分文件后重试。']);
            }
        }

        if ($records === []) {
            throw ValidationException::withMessages(['import' => '表格中没有可导入的数据行。']);
        }

        $counts = ['created' => 0, 'updated' => 0];
        $store->transaction(function () use ($store, $records, $storeDataset, $companyId, $userId, &$counts): void {
            foreach ($records as $key => $values) {
                $result = $store->save($storeDataset, $key, $values, $companyId, $userId, 'import');
                $counts['created'] += $result['created'];
                $counts['updated'] += $result['updated'];
            }
        });

        return $counts + ['rows' => count($records)];
    }

    private function bestSheet(mixed $spreadsheet, array $lookup): array
    {
        $best = [null, null, []];
        $score = 0;
        foreach ($spreadsheet->getWorksheetIterator() as $worksheet) {
            $rows = $worksheet->toArray(null, false, false, false);
            foreach (array_slice($rows, 0, 20, true) as $rowIndex => $row) {
                $columns = [];
                foreach ($row as $columnIndex => $heading) {
                    $key = $this->header($heading);
                    if ($key !== '' && isset($lookup[$key])) {
                        $columns[$columnIndex] = $lookup[$key];
                    }
                }
                if (count($columns) > $score) {
                    $best = [$rows, $rowIndex, $columns];
                    $score = count($columns);
                }
            }
        }

        return $best;
    }

    private function header(mixed $value): string
    {
        return mb_strtolower(preg_replace('/[\s\x{FEFF}_\-（）()]+/u', '', trim((string) $value)));
    }
}