/*
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

package com.dlink.metadata.parser;

import java.util.Arrays;

import com.alibaba.druid.sql.ast.SQLExpr;
import com.alibaba.druid.sql.ast.expr.SQLArrayExpr;
import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
import com.alibaba.druid.sql.parser.Lexer;
import com.alibaba.druid.sql.parser.SQLExprParser;
import com.alibaba.druid.sql.parser.SQLParserFeature;
import com.alibaba.druid.sql.parser.Token;
import com.alibaba.druid.util.FnvHash;

public class Clickhouse20ExprParser extends SQLExprParser {
    private static final String[] AGGREGATE_FUNCTIONS;
    private static final long[] AGGREGATE_FUNCTIONS_CODES;

    static {
        String[] strings = {"AVG", "COUNT", "MAX", "MIN", "STDDEV", "SUM", "ROW_NUMBER", "ROWNUMBER"};
        AGGREGATE_FUNCTIONS_CODES = FnvHash.fnv1a_64_lower(strings, true);
        AGGREGATE_FUNCTIONS = new String[AGGREGATE_FUNCTIONS_CODES.length];
        for (String str : strings) {
            long hash = FnvHash.fnv1a_64_lower(str);
            int index = Arrays.binarySearch(AGGREGATE_FUNCTIONS_CODES, hash);
            AGGREGATE_FUNCTIONS[index] = str;
        }
    }

    public Clickhouse20ExprParser(String sql) {
        this(new Clickhouse20Lexer(sql));
        this.lexer.nextToken();
    }

    public Clickhouse20ExprParser(String sql, SQLParserFeature... features) {
        this(new Clickhouse20Lexer(sql, features));
        this.lexer.nextToken();
    }

    public Clickhouse20ExprParser(Lexer lexer) {
        super(lexer);
        this.aggregateFunctions = AGGREGATE_FUNCTIONS;
        this.aggregateFunctionHashCodes = AGGREGATE_FUNCTIONS_CODES;
    }

    protected SQLExpr parseAliasExpr(String alias) {
        String chars = alias.substring(1, alias.length() - 1);
        return new SQLCharExpr(chars);
    }

    public SQLExpr primaryRest(SQLExpr expr) {
        if (lexer.token() == Token.LBRACKET) {
            SQLArrayExpr array = new SQLArrayExpr();
            array.setExpr(expr);
            lexer.nextToken();
            this.exprList(array.getValues(), array);
            accept(Token.RBRACKET);
            return primaryRest(array);
        }

        return super.primaryRest(expr);
    }
}
