package foundation.data.object;

import java.util.HashSet;
import java.util.Set;

import foundation.persist.NamedSQL;
import foundation.persist.source.NamedDataSource;
import foundation.server.config.DBaseType;
import foundation.variant.provider.DataEvent;
import foundation.variant.provider.IVariantsProvider;
import foundation.variant.provider.VariantProviderType;

public class BatchCounter implements IVariantsProvider {
	
	public static String ProviderName = "BatchCounter";
	public static Set<String> VariantNames;
	private NamedDataSource dataSource;
	private int total;
	private int begin;
	private int batch;
	
	
    static {
    	VariantNames = new HashSet<String>();
    	VariantNames.add("pagesize");
    	VariantNames.add("recordcount");
    	VariantNames.add("beginno");   
    	VariantNames.add(NamedSQL.Param_Page_limit);
    	VariantNames.add(NamedSQL.Param_Page_RowNo);
    }
    
    public BatchCounter(int total, int batch) {
    	this(NamedDataSource.getInstance(), total, batch);
    }
    
	public BatchCounter(NamedDataSource dataSource, int total, int batch) {
		this.total = total;
		this.begin = 0;
		this.batch = batch;
		this.dataSource = dataSource;
	}
	
	public void step(int step) {
		begin = begin + step;
	}
	
	public String getLimitSQL() {
		DBaseType type = dataSource.getDBaseType();
		
		//1. MYSQL
		if (type.isMySQL()) {
			return " limit " + begin + ", " + batch;
		}
		
		//2. SQLServer
		if (type.isSQLServer()) {
			return " offset " + begin + " rows fetch next " + batch + " rows only";
		}
		
//		//3. Oracle
//		if (type.isOracle()) {
//			return " rowno >" + begin + " and rowno <= " + (begin + batch);
//		}
		
		return "";
	}

	public int getBatch() {
		return batch;
	}

	@Override
	public String getProviderName() {
		return ProviderName;
	}

	@Override
	public VariantProviderType getProviderType() {
		return VariantProviderType.Transiant;
	}
	
	@Override
	public Set<String> getVariantNames() {
		return VariantNames;
	}

	@Override
	public boolean containsVariant(String name) {
		if (name == null) {
			return false;
		}
		
		name = name.toLowerCase();
		return VariantNames.contains(name);
	}

	@Override
	public Object getVariantValue(DataEvent dataEvent, String name) {
		if ("pageSize".equalsIgnoreCase(name)) {
			return batch;
		}
		else if ("recordCount".equalsIgnoreCase(name)) {
			return total;
		}
		else if ("beginNo".equalsIgnoreCase(name)) {
			return begin;
		}
		else if ("endNo".equalsIgnoreCase(name)) {
			return begin + batch;
		}
		else if (NamedSQL.Param_Page_limit.equalsIgnoreCase(name)) {
			return getLimitSQL();
		}
		else if (NamedSQL.Param_Page_RowNo.equalsIgnoreCase(name)) {
			return getLimitSQL();
		}
		
		return null;
	}
}