import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.*;
import org.apache.hadoop.hbase.client.*;
import org.apache.hadoop.hbase.util.Bytes;
import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.*;

public class HBaseEmpManager {
    private static Configuration configuration;
    private static Connection connection;
    private static Admin admin;

    private static final String TABLE_NAME = "emp1520";
    private static final String CF_EMPNUM = "empnum";
    private static final String CF_INFO = "info";
    private static final String CF_SALARY = "salary";
    private static final String CF_PERFORMANCE = "performance";
    private static final String CF_TRAINING = "training";

    public static void main(String[] args) throws IOException, NoSuchAlgorithmException {
        init(); // 初始化 HBase 连接
        createTable(); // 创建表
        insertData("emp.txt"); // 读取 emp.txt 插入数据
        queryById(); // 查询 ID > 7500 的员工
        queryByPerformance(); // 查询绩效评分 > 4 且入职时间 < 2022 年的员工
        queryRecentPromotion(); // 查找最近晋升的员工
        countTrainingParticipants(); // 统计培训课程的参与人数
        close(); // 关闭连接
    }

    // 初始化 HBase 连接
    private static void init() {
        configuration = HBaseConfiguration.create();
        try {
            connection = ConnectionFactory.createConnection(configuration);
            admin = connection.getAdmin();
            System.out.println("Connected to HBase Successfully!");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // 关闭 HBase 连接
    private static void close() {
        try {
            if (admin != null) {
                admin.close();
            }
            if (connection != null) {
                connection.close();
            }
            System.out.println("HBase Connection Closed.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // 创建 HBase 表
    private static void createTable() throws IOException {
        TableName tableName = TableName.valueOf(TABLE_NAME);
        // 检查表格是否存在
        if (admin.tableExists(tableName)) {
            System.out.println("表 " + TABLE_NAME + " 已经存在，准备禁用并删除...");

            // 禁用表格
            admin.disableTable(tableName);
            System.out.println("表 " + TABLE_NAME + " 已禁用。");

            // 删除表格
            admin.deleteTable(tableName);
            System.out.println("表 " + TABLE_NAME + " 已删除。");
        }

        HTableDescriptor tableDescriptor = new HTableDescriptor(tableName);
        tableDescriptor.addFamily(new HColumnDescriptor(CF_EMPNUM));
        tableDescriptor.addFamily(new HColumnDescriptor(CF_INFO));
        tableDescriptor.addFamily(new HColumnDescriptor(CF_SALARY));
        tableDescriptor.addFamily(new HColumnDescriptor(CF_PERFORMANCE));
        tableDescriptor.addFamily(new HColumnDescriptor(CF_TRAINING));

        admin.createTable(tableDescriptor);
        System.out.println("Table emp1520 created successfully.");
    }

    // 读取并插入数据
    private static void insertData(String filePath) throws IOException, NoSuchAlgorithmException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        BufferedReader br = new BufferedReader(new FileReader(filePath));
        String line;

        while ((line = br.readLine()) != null) {
            String[] emp = line.split(",");

            if (emp.length < 12) continue; // 确保数据完整

            String rowKey = generateRowKey(emp[0]); // 使用哈希前缀

            Put put = new Put(Bytes.toBytes(rowKey));
            put.addColumn(Bytes.toBytes(CF_EMPNUM), Bytes.toBytes("empno"), Bytes.toBytes(emp[0]));
            put.addColumn(Bytes.toBytes(CF_INFO), Bytes.toBytes("ename"), Bytes.toBytes(emp[1]));
            put.addColumn(Bytes.toBytes(CF_INFO), Bytes.toBytes("job"), Bytes.toBytes(emp[2]));
            put.addColumn(Bytes.toBytes(CF_INFO), Bytes.toBytes("mgr"), Bytes.toBytes(emp[3]));
            put.addColumn(Bytes.toBytes(CF_INFO), Bytes.toBytes("hiredate"), Bytes.toBytes(emp[4]));
            put.addColumn(Bytes.toBytes(CF_SALARY), Bytes.toBytes("sal"), Bytes.toBytes(emp[5]));
            put.addColumn(Bytes.toBytes(CF_SALARY), Bytes.toBytes("credit"), Bytes.toBytes(emp[6]));
            put.addColumn(Bytes.toBytes(CF_INFO), Bytes.toBytes("deptno"), Bytes.toBytes(emp[7]));
            put.addColumn(Bytes.toBytes(CF_INFO), Bytes.toBytes("work_hours"), Bytes.toBytes(emp[8]));
            put.addColumn(Bytes.toBytes(CF_PERFORMANCE), Bytes.toBytes("performance_rating"), Bytes.toBytes(emp[9]));
            put.addColumn(Bytes.toBytes(CF_PERFORMANCE), Bytes.toBytes("promotion_date"), Bytes.toBytes(emp[10]));
            put.addColumn(Bytes.toBytes(CF_TRAINING), Bytes.toBytes("training_courses"), Bytes.toBytes(emp[11]));

            table.put(put);
        }

        br.close();
        table.close();
        System.out.println("Data inserted successfully!");
    }

    // 生成 RowKey，避免 Region 热点
    private static String generateRowKey(String empno) throws NoSuchAlgorithmException {
        String prefix = empno.substring(0, 3);
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        byte[] digest = md5.digest(prefix.getBytes());
        StringBuilder hexString = new StringBuilder();
        for (byte b : digest) {
            hexString.append(String.format("%02x", b));
        }
        return hexString.substring(0, 4) + empno;
    }

    // 查询 ID > 7500 的员工
    private static void queryById() throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Scan scan = new Scan();
        scan.addColumn(Bytes.toBytes(CF_EMPNUM), Bytes.toBytes("empno"));

        ResultScanner scanner = table.getScanner(scan);
        for (Result result : scanner) {
            String empno = Bytes.toString(result.getValue(Bytes.toBytes(CF_EMPNUM), Bytes.toBytes("empno")));
            if (empno != null && Integer.parseInt(empno) > 7500) {
                System.out.println("ID > 7500 Employee: " + empno);
            }
        }
        table.close();
    }

    // 查询绩效评分 > 4 且入职时间 < 2022 年
    private static void queryByPerformance() throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Scan scan = new Scan();
        scan.addColumn(Bytes.toBytes(CF_INFO), Bytes.toBytes("hiredate"));
        scan.addColumn(Bytes.toBytes(CF_PERFORMANCE), Bytes.toBytes("performance_rating"));

        ResultScanner scanner = table.getScanner(scan);
        for (Result result : scanner) {
            String hiredate = Bytes.toString(result.getValue(Bytes.toBytes(CF_INFO), Bytes.toBytes("hiredate")));
            String rating = Bytes.toString(result.getValue(Bytes.toBytes(CF_PERFORMANCE), Bytes.toBytes("performance_rating")));

            if (hiredate.compareTo("2022-01-01") < 0 && Integer.parseInt(rating) > 4) {
                System.out.println("Qualified Employee: Hire Date " + hiredate + ", Rating " + rating);
            }
        }
        table.close();
    }

    // 查找最近晋升的员工
    private static void queryRecentPromotion() throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Scan scan = new Scan();
        scan.addColumn(Bytes.toBytes(CF_PERFORMANCE), Bytes.toBytes("promotion_date"));

        ResultScanner scanner = table.getScanner(scan);
        String latestDate = "";
        String latestEmp = "";

        for (Result result : scanner) {
            String promotionDate = Bytes.toString(result.getValue(Bytes.toBytes(CF_PERFORMANCE), Bytes.toBytes("promotion_date")));
            if (promotionDate != null && promotionDate.compareTo(latestDate) > 0) {
                latestDate = promotionDate;
                latestEmp = Bytes.toString(result.getRow());
            }
        }
        System.out.println("Most Recently Promoted Employee: " + latestEmp + ", Promotion Date: " + latestDate);
        table.close();
    }

    // 统计培训课程的参与人数
    private static void countTrainingParticipants() throws IOException {
        Table table = connection.getTable(TableName.valueOf(TABLE_NAME));
        Scan scan = new Scan();
        scan.addColumn(Bytes.toBytes(CF_TRAINING), Bytes.toBytes("training_courses"));

        ResultScanner scanner = table.getScanner(scan);
        Map<String, Integer> countMap = new HashMap<>();

        for (Result result : scanner) {
            String courses = Bytes.toString(result.getValue(Bytes.toBytes(CF_TRAINING), Bytes.toBytes("training_courses")));
            for (String course : courses.split(", ")) {
                countMap.put(course, countMap.getOrDefault(course, 0) + 1);
            }
        }

        System.out.println("培训课程统计:");
        for (Map.Entry<String, Integer> entry : countMap.entrySet()) {
            System.out.println(entry.getKey() + ": " + entry.getValue() + " 人");
        }

        table.close();
    }
}