package org.hwo.pulscounter.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.hwo.pulscounter.SnapShot;

import static org.hwo.logging.Logging.*;
import static org.hwo.logging.LogLevel.*;

public class PulsCounterDatabase {

	private Connection	dbConnection;
	
	public PulsCounterDatabase(){
		
		try {
			getClass().getClassLoader().loadClass("org.hsqldb.jdbcDriver");
			dbConnection = DriverManager.getConnection("jdbc:hsqldb:file:synololog-hsql", "SA", "");
			
			
			
		} catch (SQLException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			log(ERROR,"HyperSQL Driver could not be loaded. [%s]",e.toString());
		}
		
	}
	
	public void close(){
		try {
			dbConnection.close();
		} catch (SQLException e) {
			log(ERROR,"Exception while closing database: %s",e.toString());
		}
	}
	
	private ResultSet executeSimpleSQL(String query,Object... args){
		
		try {
			PreparedStatement stmt = dbConnection.prepareStatement(query);
			
			for (int i=0;i<args.length;i++){
				stmt.setObject(i+1, args[i]);
			}
			
			stmt.execute();
			
			ResultSet result = stmt.getResultSet();
			
			stmt.closeOnCompletion();
			
			return result;
			
		} catch (SQLException e) {
			log(ERROR,"SQL Statement failed: %s",query);
			log(ERROR,"Exception: %s", e.toString());
		}
		
		return null;
	}
	
	private String executeVerySimpleQuery(String query,Object... args){
		ResultSet result = executeSimpleSQL(query,args);
		if (result != null){
			try {
				if (result.next()){
					return result.getString(1);
				}
			} catch (SQLException e) {
				log(ERROR,"SQL Statement failed: %s",query);
				log(ERROR,"Exception: %s", e.toString());
			}
		}
		return null;
	}
	
	public String getProperty(String name){
		return executeVerySimpleQuery("SELECT value FROM properties WHERE name=?", name);
	}
	public void setProperty(String name,String value){
		executeSimpleSQL("MERGE INTO properties USING (VALUES(?,?)) as p(name,value) ON properties.name = p.name WHEN MATCHED THEN UPDATE SET properties.value = p.value WHEN NOT MATCHED THEN INSERT VALUES uuid(), p.name, p.value", name,value);
	}
	public void removeProperty(String name){
		executeSimpleSQL("DELETE FROM properties WHERE properties.name = ?", name);
	}
	
	public String getSchemaVersion(){
		return getProperty("db.schema.version");
	}
	
	public void storeSnapshots(SnapShot[] snapShots){
		
	}
	
	
}