package com.walker.di.excel;

import com.alibaba.excel.EasyExcel;
import com.walker.di.BatchLoadListener;
import com.walker.di.BusinessImportException;
import com.walker.di.Constants;
import com.walker.di.DataImportException;
import com.walker.di.ErrorWriter;
import com.walker.di.support.InputStreamDataImportor;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;
import java.util.Map;

/**
 * 基于阿里 <code>EasyExcel</code> 实现的数据导入器。
 * @author 时克英
 * @date 2023-02-03
 */
public abstract class ExcelDataImportor extends InputStreamDataImportor {

    private String batchError = null;
    private LoadListener loadListener = new InternalLoadListener();

    @Override
    public void setBatchEnabled() {
        this.setBatchSize(MAX_BATCH_SIZE);
    }

    @Override
    public void setBatchSize(long batchSize) {
        super.setBatchSize(batchSize);
        // 2023-02-03 因为该对象用户到: BatchLoadListener，所以创建一个默认的。
        this.setBatchLoadListener(new BatchLoadListener() {
            @Override
            public List<Object[]> onBatchLoad(Map<String, List<String>> columnsByName, String[] fieldNames, int dataSize) {
                throw new UnsupportedOperationException("不会使用到该对象");
            }
        });
    }

    @Override
    protected List<Object[]> acquireImportDataList(Object source) throws DataImportException {
        this.checkSource(source);
        try {
            DefaultDataListener dataListener = new DefaultDataListener(null);
            dataListener.setHeadRowNumber(this.getHeadRowNumber());

            EasyExcel.read((InputStream) source, dataListener)
                    .sheet(0).headRowNumber(this.getHeadRowNumber()).doRead();
            // 设置表头(这里只返回标识行，如果存在多行表头，只是最后一行表头)
            this.setFieldNames(dataListener.getHeaders());
            return dataListener.getRows();
        } catch (Exception ex){
            throw new DataImportException("EasyExcel解析异常:" + ex.getMessage(), ex);
        } finally {
            this.releaseSource(source);
        }
    }

    @Override
    protected void acquireImportBatch(BatchLoadListener batchLoadListener, Object source) throws DataImportException {
        BatchDataListener dataListener = new BatchDataListener(this.loadListener);
        dataListener.setHeadRowNumber(this.getHeadRowNumber());
        dataListener.setSaveSizeOnce(this.getSaveSizeOnce());
        dataListener.setSleepMillSeconds(this.getSleepMillSeconds());

        try {
            EasyExcel.read((InputStream) source, dataListener)
                    .sheet(0).headRowNumber(this.getHeadRowNumber()).doRead();
        } catch (Exception ex){
            throw new DataImportException("EasyExcel批量解析异常:" + ex.getMessage(), ex);
        } finally {
            this.releaseSource(source);
        }
    }

    @Override
    protected ErrorWriter acquireErrorWriter(String id, List<String> fieldNames) {
        File errorFile = null;
        OutputStream errorFileStream = null;
        errorFile = new File(this.getErrorFile());
        try {
            errorFileStream = new BufferedOutputStream(new FileOutputStream(errorFile));
            ErrorWriter errorWriter = new ExcelErrorWriter(errorFileStream, fieldNames);
            if(this.loadListener != null){
                this.loadListener.setErrorWriter(errorWriter);
            }
            return errorWriter;
//            return new ExcelErrorWriter(errorFileStream, fieldNames);

        } catch (FileNotFoundException e) {
            logger.error("未找到'错误文件':" + errorFile.getAbsolutePath(), e);
            return null;
        }
    }

    @Override
    public String getBatchError(){
        return this.batchError;
    }

    @Override
    public String getImportFileSuffix(){
        return Constants.IMPORT_ERROR_SUFFIX_XLSX;
    }

    private class InternalLoadListener implements LoadListener{
        @Override
        public void onSave(List<Object[]> rows, List<String> fieldNames) throws BusinessImportException {
            try {
                // 这里必须设置表头
                ExcelDataImportor.this.setFieldNames(fieldNames);
                ExcelDataImportor.this.doExecuteImport(rows, getFieldNames());
            } catch (DataImportException e) {
                batchError = e.getMessage();
                if(e instanceof BusinessImportException){
                    BusinessImportException bex = (BusinessImportException)e;
                    throw bex;
                } else {
                    throw new BusinessImportException("批量导入监听错误:" + e.getMessage(), e);
                }
            }
        }

        @Override
        public void setErrorWriter(ErrorWriter errorWriter) {
            this.errorWriter = errorWriter;
        }

        @Override
        public ErrorWriter getErrorWriter() {
            return this.errorWriter;
        }

        private ErrorWriter errorWriter = null;
    }
}