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package org.nlpcn.es4sql.parse;

import com.alibaba.druid.sql.ast.expr.SQLCastExpr;
import com.google.common.base.Joiner;
import org.nlpcn.es4sql.SQLFunctions;
import org.nlpcn.es4sql.Util;
import org.nlpcn.es4sql.exception.SqlParseException;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by leonlu on 2017/9/21.
 */
public class CastParser {

    private enum DataType {
        INT, LONG, FLOAT, DOUBLE, STRING, DATETIME
    }

    private SQLCastExpr castExpr;
    private String alias;
    private String tableAlias;

    private String name;

    public CastParser(SQLCastExpr castExpr, String alias, String tableAlias) {
        this.castExpr = castExpr;
        this.alias = alias;
        this.tableAlias = tableAlias;
        this.name = "field_"+SQLFunctions.random();
    }

    public String getName(){
        return this.name ;
    }
    public String parse(boolean isReturn) throws SqlParseException {
        List result = new ArrayList<>();

        String dataType = castExpr.getDataType().getName().toUpperCase();
        String fileName = String.format("doc['%s'].value",Util.expr2Object(castExpr.getExpr()));


        try {
            if (DataType.valueOf(dataType) == DataType.INT) {
                result.add(String.format("def %s = Double.parseDouble(%s.toString()).intValue()", name, fileName));
            } else if (DataType.valueOf(dataType) == DataType.LONG) {
                result.add(String.format("def %s = Double.parseDouble(%s.toString()).longValue()", name, fileName));
            } else if (DataType.valueOf(dataType) == DataType.FLOAT) {
                result.add(String.format("def %s = Double.parseDouble(%s.toString()).floatValue()", name, fileName));
            } else if (DataType.valueOf(dataType) == DataType.DOUBLE) {
                result.add(String.format("def %s = Double.parseDouble(%s.toString()).doubleValue()", name, fileName));
            } else if (DataType.valueOf(dataType) == DataType.STRING) {
                result.add(String.format("def %s = %s.toString()",name, fileName));
            } else if (DataType.valueOf(dataType) == DataType.DATETIME) {
                result.add(String.format("def %s = new Date(Double.parseDouble(%s.toString()).longValue())", name, fileName));
            } else {
                throw new SqlParseException("not support cast to data type:" + dataType);
            }
            if(isReturn) {
                result.add("return " + name);
            }

            return Joiner.on("; ").join(result);
        } catch (Exception ex) {
            throw new SqlParseException(String.format("field cast to type: %s failed. error:%s",dataType, ex.getMessage()));
        }
    }
}