package com.ruoyi.ai.service;

import com.ruoyi.common.utils.StringUtils;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.DataFormatter;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.apache.poi.xwpf.extractor.XWPFWordExtractor;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
import org.springframework.stereotype.Component;
import org.springframework.web.multipart.MultipartFile;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;

@Component
public class AiFileTextExtractor {

    private static final long MAX_FILE_SIZE = 10L * 1024 * 1024;

    public String extractText(MultipartFile file) throws IOException {
        if (file == null || file.isEmpty()) {
            throw new IllegalArgumentException("文件不能为空");
        }
        if (file.getSize() > MAX_FILE_SIZE) {
            throw new IllegalArgumentException("文件过大，请控制在10MB以内");
        }

        String filename = file.getOriginalFilename();
        String ext = getExtension(filename);
        byte[] bytes = file.getBytes();

        if (isPlainText(ext)) {
            return decodeText(bytes);
        }
        if ("docx".equals(ext)) {
            return extractDocx(bytes);
        }
        if ("xlsx".equals(ext)) {
            return extractXlsx(bytes);
        }
        if ("xls".equals(ext)) {
            return extractXls(bytes);
        }
        if (isImage(ext)) {
            return "图片文件：" + filename + "，已上传，请结合图片内容识别采购单据、表格和产品明细。";
        }
        throw new IllegalArgumentException("暂不支持该文件类型: " + ext);
    }

    public boolean isImageFile(MultipartFile file) {
        if (file == null) {
            return false;
        }
        return isImage(getExtension(file.getOriginalFilename()));
    }

    private String extractDocx(byte[] bytes) throws IOException {
        try (ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
             XWPFDocument document = new XWPFDocument(inputStream);
             XWPFWordExtractor extractor = new XWPFWordExtractor(document)) {
            return extractor.getText();
        }
    }

    private String extractXlsx(byte[] bytes) throws IOException {
        try (ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
             XSSFWorkbook workbook = new XSSFWorkbook(inputStream)) {
            return extractWorkbook(workbook);
        }
    }

    private String extractXls(byte[] bytes) throws IOException {
        try (ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
             HSSFWorkbook workbook = new HSSFWorkbook(inputStream)) {
            return extractWorkbook(workbook);
        }
    }

    private String extractWorkbook(org.apache.poi.ss.usermodel.Workbook workbook) {
        StringBuilder text = new StringBuilder();
        DataFormatter formatter = new DataFormatter();
        for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
            Sheet sheet = workbook.getSheetAt(i);
            text.append("Sheet: ").append(sheet.getSheetName()).append("\n");
            for (Row row : sheet) {
                short lastCellNum = row.getLastCellNum();
                if (lastCellNum <= 0) {
                    text.append("\n");
                    continue;
                }
                for (int c = 0; c < lastCellNum; c++) {
                    String cellText = formatter.formatCellValue(row.getCell(c));
                    text.append(cellText);
                    if (c < lastCellNum - 1) {
                        text.append('\t');
                    }
                }
                text.append('\n');
            }
        }
        return text.toString();
    }

    private String decodeText(byte[] bytes) {
        String utf8 = new String(bytes, StandardCharsets.UTF_8);
        if (utf8.contains("�")) {
            return new String(bytes, java.nio.charset.Charset.forName("GBK"));
        }
        return utf8;
    }

    private String getExtension(String filename) {
        if (!StringUtils.hasText(filename) || !filename.contains(".")) {
            return "";
        }
        return filename.substring(filename.lastIndexOf('.') + 1).toLowerCase();
    }

    private boolean isPlainText(String ext) {
        return StringUtils.inStringIgnoreCase(ext,
                "txt", "md", "markdown", "json", "xml", "yaml", "yml", "csv", "log", "properties",
                "java", "js", "ts", "vue", "html", "css", "sql", "py", "go", "sh", "bat");
    }

    private boolean isImage(String ext) {
        return StringUtils.inStringIgnoreCase(ext, "png", "jpg", "jpeg", "webp", "bmp");
    }
}