package org.aegee.runanddine.advertisement;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;

import org.aegee.runanddine.util.data.ModelNotExistingException;
import org.aegee.runanddine.util.model.MySQLModelManager;

/**
 * Manages persistent AdvertisementMailTemplateManager models
 */
public class AdvertisementMailTemplateManager extends MySQLModelManager<AdvertisementMailTemplate> {
    /**
     * Singleton instance of AdvertisementMailTemplateManager
     */
    private static AdvertisementMailTemplateManager instance = null;
    
    /**
     * Init AdvertisementMailTemplateManager
     * (private because of singleton pattern)
     */
    private AdvertisementMailTemplateManager() {
        super();
        this.table = "single_classes";
    }
    
    /**
     * Return singleton instance of AdvertisementMailTemplateManager
     * @return Singleton instance of AdvertisementMailTemplateManager
     */
    public static AdvertisementMailTemplateManager getInstance() {
        // create singleton instance if it does not exist
        if (AdvertisementMailTemplateManager.instance == null) {
            AdvertisementMailTemplateManager.instance = new AdvertisementMailTemplateManager();
        }
        
        return AdvertisementMailTemplateManager.instance;
    }
    
    /**
     * Get persistent AdvertisementMailTemplate
     * @return AdvertisementMailTemplate Persistent AdvertisementMailTemplate
     * @throws ModelNotExistingException Gets thrown if the template is not persistent yet
     */
    public AdvertisementMailTemplate get() throws ModelNotExistingException {
        try {
            PreparedStatement stmt = this.con.prepareStatement("SELECT id, serialized_object FROM " + this.table + " WHERE class_name=?");
            // bind name
            stmt.setString(1, AdvertisementMailTemplate.class.getName());
            // search for model
            ResultSet rs = stmt.executeQuery();
            // check if model exists
            if (rs.next()) {
                // deserialize model
                AdvertisementMailTemplate model = this.readObject(rs.getBytes("serialized_object"));
                model.setId(rs.getInt("id"));
                rs.close();
                stmt.close();

                return model;
            } else {
                throw new ModelNotExistingException();
            }
        } catch (SQLException e) {
            e.printStackTrace(System.err);
            return null;
        }
    }
    
    /**
     * Not supported because there can only be one AdvertisementMailTemplate
     */
    @Override
    public List<AdvertisementMailTemplate> getAll() {
        throw new UnsupportedOperationException();
    }
    
    /**
     * Stores new model or updates existing one
     * @param model Model to be saved/updated
     */
    @Override
    public void save(AdvertisementMailTemplate model) {
        try {
            // update model
            if (this.hasModel(model.getId())) {
                PreparedStatement stmt = this.con.prepareStatement("UPDATE " + this.table + " SET serialized_object=?, class_name=? WHERE id=?");
                // bind values
                stmt.setObject(1, model);
                stmt.setString(2, model.getClass().getName());
                stmt.setInt(3, model.getId());
                // execute update
                stmt.executeUpdate();    
                stmt.close();
            // save new model
            } else {
                PreparedStatement stmt = this.con.prepareStatement("INSERT INTO " + this.table + " (serialized_object, class_name) VALUES (?, ?)");
                // bind values to statement
                stmt.setObject(1, model);
                stmt.setString(2, model.getClass().getName());
                // execute insert
                stmt.executeUpdate();
                // retrieve auto increment id
                ResultSet rs = stmt.getGeneratedKeys();
                rs.next();
                model.setId(rs.getInt(1));
                rs.close();
                stmt.close();
            }
        } catch (SQLException e) {
            e.printStackTrace(System.err);
        }
    }
    
    /**
     * Create empty AdvertisementMailTemplate
     * @return Empty AdvertisementMailTemplate
     */
    public AdvertisementMailTemplate newObject() {
        AdvertisementMailTemplate model = new AdvertisementMailTemplate();
        
        return model;
    }
}