/**
 * Alipay.com Inc.
 * Copyright (c) 2004-2012 All Rights Reserved.
 */
package com.alipay.zdal.client.jdbc.resultset;

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

import com.alipay.zdal.client.jdbc.ZdalStatement;

public class CountTResultSet extends AbstractTResultSet {
    private long value;
    private int  cursor;

    public CountTResultSet(ZdalStatement statementProxy, List<ResultSet> resultSets)
                                                                                    throws SQLException {
        super(statementProxy, resultSets);
    }

    @Override
    public boolean next() throws SQLException {
        if (cursor > 0) {
            return false;
        }
        reducer();
        cursor++;
        return true;
    }

    protected ResultSet reducer() throws SQLException {
        long sum = 0;
        for (ResultSet resultSet : actualResultSets) {
            resultSet.next();
            sum += resultSet.getLong(1);
        }
        this.value = sum;
        return null;
    }

    private void checkCursor() throws SQLException {
        if (cursor != 1) {
            throw new SQLException();
        }
    }

    private void checkIndex(int columnIndex) throws SQLException {
        checkCursor();
        if (columnIndex < 1) {
            throw new SQLException("Column index out of range, " + columnIndex + " < 1");
        } else if (columnIndex > 1) {
            throw new SQLException("Column index out of range, " + columnIndex + " > 1");
        }
    }

    @Override
    public int getInt(int columnIndex) throws SQLException {
        checkIndex(columnIndex);
        return (int) value;
    }

    @Override
    public long getLong(int columnIndex) throws SQLException {
        checkIndex(columnIndex);
        return value;
    }

    @Override
    public int findColumn(String columnName) throws SQLException {
        if (!columnName.equalsIgnoreCase(actualResultSets.get(0).getMetaData().getColumnName(1))) {
            throw new SQLException("Column '" + columnName + "' not found");
        }
        checkCursor();
        return 1;
    }

    @Override
    public int getInt(String columnName) throws SQLException {
        return getInt(findColumn(columnName));
    }

    @Override
    public long getLong(String columnName) throws SQLException {
        return getLong(findColumn(columnName));
    }

    @Override
    public Object getObject(int columnIndex) throws SQLException {
        return Long.valueOf(getLong(columnIndex));
    }

    @Override
    public Object getObject(String columnName) throws SQLException {
        return Long.valueOf(getLong(columnName));
    }

    @Override
    public ResultSetMetaData getMetaData() throws SQLException {
        return actualResultSets.get(0).getMetaData();
    }

    @Override
    public boolean wasNull() throws SQLException {
        return false;
    }
}