package cn.iocoder.yudao.framework.excel.core.handler;

import cn.idev.excel.metadata.Head;
import cn.idev.excel.write.handler.CellWriteHandler;
import cn.idev.excel.write.handler.context.CellWriteHandlerContext;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.Workbook;

import java.lang.reflect.Field;

/**
 * 必填表头处理器
 *
 * <p>导出模板时，把标注了 {@link ExcelRequired} 的字段对应的表头文字标红，并在前面加一个星号，
 * 让用户一眼看出哪些列必须填写。
 *
 * @author 超级管理员
 */
public class RequiredHeaderWriteHandler implements CellWriteHandler {

    private static final String REQUIRED_MARK = "*";

    @Override
    public void afterCellDispose(CellWriteHandlerContext context) {
        // 1. 只处理表头单元格
        if (!Boolean.TRUE.equals(context.getHead())) {
            return;
        }
        Head head = context.getHeadData();
        Cell cell = context.getCell();
        if (head == null || head.getField() == null || cell == null) {
            return;
        }
        // 2. 只处理标注了 @ExcelRequired 的字段
        Field field = head.getField();
        if (!field.isAnnotationPresent(ExcelRequired.class)) {
            return;
        }
        // 3. 多级表头时只标记最后一行，避免父级表头重复加星号
        int lastHeadRowIndex = head.getHeadNameList() == null ? 0 : head.getHeadNameList().size() - 1;
        if (context.getRelativeRowIndex() != null && context.getRelativeRowIndex() < lastHeadRowIndex) {
            return;
        }

        // 4. 表头加星号
        String text = cell.getStringCellValue();
        if (text != null && !text.startsWith(REQUIRED_MARK)) {
            cell.setCellValue(REQUIRED_MARK + text);
        }
        // 5. 字体标红，并保留原有表头样式的其它属性
        Workbook workbook = cell.getSheet().getWorkbook();
        CellStyle oldStyle = cell.getCellStyle();
        CellStyle style = workbook.createCellStyle();
        style.cloneStyleFrom(oldStyle);
        Font oldFont = workbook.getFontAt(oldStyle.getFontIndex());
        Font font = workbook.createFont();
        font.setFontName(oldFont.getFontName());
        font.setFontHeightInPoints(oldFont.getFontHeightInPoints());
        font.setBold(oldFont.getBold());
        font.setItalic(oldFont.getItalic());
        font.setColor(IndexedColors.RED.getIndex());
        style.setFont(font);
        cell.setCellStyle(style);
    }

}