import java.io.*;
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;

public class ExcelReader {
    
    private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd", Locale.CHINA);
    
    public static List<PostInfo> readExcelData(String filePath, int maxRows) {
        List<PostInfo> posts = new ArrayList<>();
        
        try (BufferedReader reader = new BufferedReader(new FileReader(filePath, java.nio.charset.StandardCharsets.UTF_8))) {
            
            String line;
            boolean isFirstLine = true;
            int rowCount = 0;
            
            while ((line = reader.readLine()) != null && rowCount < maxRows) {
                if (isFirstLine) {
                    isFirstLine = false;
                    continue;
                }
                
                String[] parts = parseCSVLine(line);
                if (parts.length >= 9) {
                    PostInfo post = parsePostInfo(parts);
                    if (post != null) {
                        posts.add(post);
                        rowCount++;
                    }
                }
            }
            
            System.out.println("成功读取 " + posts.size() + " 条数据");
            
        } catch (IOException e) {
            System.err.println("读取文件时出错: " + e.getMessage());
        }
        
        return posts;
    }
    
    private static String[] parseCSVLine(String line) {
        List<String> fields = new ArrayList<>();
        StringBuilder currentField = new StringBuilder();
        boolean inQuotes = false;
        
        for (char c : line.toCharArray()) {
            if (c == '"') {
                inQuotes = !inQuotes;
            } else if (c == ',' && !inQuotes) {
                fields.add(currentField.toString().trim());
                currentField.setLength(0);
            } else {
                currentField.append(c);
            }
        }
        
        fields.add(currentField.toString().trim());
        return fields.toArray(new String[0]);
    }
    
    private static PostInfo parsePostInfo(String[] parts) {
        try {
            PostInfo post = new PostInfo();
            
            post.setTitle(parts[0]);
            post.setContent(parts[1]);
            post.setAuthor(parts[2]);
            
            if (!parts[3].isEmpty()) {
                post.setPostDate(LocalDate.parse(parts[3], DATE_FORMATTER));
            }
            
            post.setLikeCount(parseInt(parts[4]));
            post.setCommentCount(parseInt(parts[5]));
            post.setViewCount(parseInt(parts[6]));
            
            post.setTags(parts[7]);
            post.setSentiment(parts[8]);
            
            return post;
        } catch (Exception e) {
            System.err.println("解析数据时出错: " + e.getMessage());
            return null;
        }
    }
    
    private static int parseInt(String value) {
        try {
            if (value == null || value.isEmpty()) {
                return 0;
            }
            return Integer.parseInt(value);
        } catch (NumberFormatException e) {
            return 0;
        }
    }
}