package com.teaching.backend.utils.Chapter;

/**
 * ClassName: ExcelParser
 * Package: com.teaching
 * Description:
 *
 * @Author 姜钧瀚
 * @Create 2024/8/3 14:58
 * @Version 1.0
 */

import com.teaching.backend.mapper.chapter.TemporaryChapterMapper;
import com.teaching.backend.service.chapter.IChapterService;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.xssf.eventusermodel.XSSFReader;
import org.apache.poi.xssf.eventusermodel.XSSFSheetXMLHandler;
import org.apache.poi.xssf.model.SharedStringsTable;
import org.apache.poi.xssf.model.StylesTable;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.XMLReaderFactory;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

/**
 * 自定义Excel解析器
 */
@Component
public class ExcelParser {
    @Autowired
    TemporaryChapterMapper temporaryChapterMapper;
    @Autowired
    IChapterService chapterService;

    public List<String> parse(InputStream inputStream, String courseId) throws Exception {
        OPCPackage pkg = OPCPackage.open(inputStream);
        List<String> validationErrors = new ArrayList<>();
        int totalRows = 0;
        try {
            XSSFReader reader = new XSSFReader(pkg);
            SharedStringsTable sst = reader.getSharedStringsTable();
            StylesTable styles = reader.getStylesTable();
            XMLReader parser = XMLReaderFactory.createXMLReader();

            XSSFReader.SheetIterator sheets = (XSSFReader.SheetIterator) reader.getSheetsData();
            SheetPreScanner preScanner = new SheetPreScanner();
            while (sheets.hasNext()) {
                InputStream sheetstream = sheets.next();
                InputSource sheetSource = new InputSource(sheetstream);
                try {
                    parser.setContentHandler(new XSSFSheetXMLHandler(styles, sst, preScanner, false));
                    parser.parse(sheetSource);
                } finally {
                    sheetstream.close();
                }
            }
            totalRows = preScanner.getRowCount();

            sheets = (XSSFReader.SheetIterator) reader.getSheetsData();
            SheetHandler sheetHandler = null;
            while (sheets.hasNext()) {
                InputStream sheetstream = sheets.next();
                InputSource sheetSource = new InputSource(sheetstream);
                try {
                    sheetHandler = new SheetHandler(temporaryChapterMapper, chapterService, courseId, totalRows);
                    parser.setContentHandler(new XSSFSheetXMLHandler(styles, sst, sheetHandler, false));
                    parser.parse(sheetSource);
                } finally {
                    sheetstream.close();
                }
            }

            validationErrors = sheetHandler.finalizeProcess();
            if (!validationErrors.isEmpty()) {
                for (String error : validationErrors) {
                    System.out.println("导入错误: " + error);
                }
            } else {
                System.out.println("数据导入成功！");
            }

        } finally {
            pkg.close();
        }
        return validationErrors;
    }
}