import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;

public class BookDelete
    extends JFrame
    implements ActionListener {
  DataBaseManager db = new DataBaseManager();
  ResultSet rs;
  Container c;
  JLabel TipLabel = new JLabel("請輸入要刪除的書名：", JLabel.CENTER);
  JTextField bookDeleteTextField = new JTextField(15);
  JButton yesBtn, exitBtn;
  JPanel panel1 = new JPanel();
  public BookDelete() {
    super("刪除書籍信息");
    c = getContentPane();
    c.setLayout(new BorderLayout());
    c.add(TipLabel, BorderLayout.NORTH);
    c.add(bookDeleteTextField, BorderLayout.CENTER);
    yesBtn = new JButton("確定");
    exitBtn = new JButton("退出");
    yesBtn.addActionListener(this);
    exitBtn.addActionListener(this);
    panel1.add(yesBtn);
    panel1.add(exitBtn);
    c.add(panel1, BorderLayout.SOUTH);
  }

  public void actionPerformed(ActionEvent e) {
    if (e.getSource() == exitBtn) {
      this.dispose();
    }
    else if (e.getSource() == yesBtn) {
      try {
        String strSQL = "select borrowed_count from books where bookName='" +
            bookDeleteTextField.getText().trim() + "'";
        rs = db.getResult(strSQL);
        if (!rs.first()) {
          JOptionPane.showMessageDialog(null, "書庫里沒有你要刪除的書！");
        }
        else {
          String strSql = "delete books where bookName='" +
              bookDeleteTextField.getText().trim() + "'and borrowed_count=0";
          rs.first();
          int count = rs.getInt(1);
          if (! (count == 0)) {
            JOptionPane.showMessageDialog(null, "此書還有學生沒有還！\n現在還不能從書庫中刪除。。。");
            this.dispose();
          }
          else if (db.updateSql(strSql)>0) {
            JOptionPane.showMessageDialog(null, "刪除成功！");
            db.closeConnection();
            this.dispose();
          }
          else {
            JOptionPane.showMessageDialog(null, "刪除失敗！");
            db.closeConnection();
            this.dispose();
          }
        }
      }
      catch (SQLException sqle) {
        System.out.println(sqle.toString());
      }
      catch (Exception ex) {
        System.out.println(ex.toString());
      }
    }
  }
}