/*
 * Copyright 1999-2017 Alibaba Group Holding Ltd.
 *
 * Licensed 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.alibaba.druid.sql.dialect.mysql.parser;

import com.alibaba.druid.sql.ast.SQLExpr;
import com.alibaba.druid.sql.ast.SQLObject;
import com.alibaba.druid.sql.ast.SQLSetQuantifier;
import com.alibaba.druid.sql.ast.expr.SQLIdentifierExpr;
import com.alibaba.druid.sql.ast.expr.SQLLiteralExpr;
import com.alibaba.druid.sql.ast.expr.SQLVariantRefExpr;
import com.alibaba.druid.sql.ast.statement.*;
import com.alibaba.druid.sql.dialect.mysql.ast.*;
import com.alibaba.druid.sql.dialect.mysql.ast.clause.MySqlSelectIntoStatement;
import com.alibaba.druid.sql.dialect.mysql.ast.expr.MySqlOutFileExpr;
import com.alibaba.druid.sql.dialect.mysql.ast.statement.MySqlSelectQueryBlock;
import com.alibaba.druid.sql.parser.ParserException;
import com.alibaba.druid.sql.parser.SQLExprParser;
import com.alibaba.druid.sql.parser.SQLSelectParser;
import com.alibaba.druid.sql.parser.Token;
import com.alibaba.druid.util.FnvHash;

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

/**
 * @author zz [455910092@qq.com]
 */
public class MySqlSelectIntoParser extends SQLSelectParser {
    private List<SQLExpr> argsList;

    public MySqlSelectIntoParser(SQLExprParser exprParser) {
        super(exprParser);
    }

    public MySqlSelectIntoParser(String sql) {
        this(new MySqlExprParser(sql));
    }

    public MySqlSelectIntoStatement parseSelectInto() {
        SQLSelect select = select();
        MySqlSelectIntoStatement stmt = new MySqlSelectIntoStatement();
        stmt.setSelect(select);
        stmt.setVarList(argsList);
        return stmt;

    }

    @Override
    public SQLSelectQuery query(SQLObject parent, boolean acceptUnion) {
        if (lexer.token() == (Token.LPAREN)) {
            lexer.nextToken();

            SQLSelectQuery select = query();
            accept(Token.RPAREN);

            return queryRest(select, acceptUnion);
        }

        MySqlSelectQueryBlock queryBlock = new MySqlSelectQueryBlock();

        if (lexer.token() == Token.SELECT) {
            lexer.nextToken();

            if (lexer.token() == Token.HINT) {
                this.exprParser.parseHints(queryBlock.getHints());
            }

            if (lexer.token() == Token.COMMENT) {
                lexer.nextToken();
            }

            if (lexer.token() == (Token.DISTINCT)) {
                queryBlock.setDistionOption(SQLSetQuantifier.DISTINCT);
                lexer.nextToken();
            } else if (lexer.identifierEquals("DISTINCTROW")) {
                queryBlock.setDistionOption(SQLSetQuantifier.DISTINCTROW);
                lexer.nextToken();
            } else if (lexer.token() == (Token.ALL)) {
                queryBlock.setDistionOption(SQLSetQuantifier.ALL);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("HIGH_PRIORITY")) {
                queryBlock.setHignPriority(true);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("STRAIGHT_JOIN")) {
                queryBlock.setStraightJoin(true);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("SQL_SMALL_RESULT")) {
                queryBlock.setSmallResult(true);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("SQL_BIG_RESULT")) {
                queryBlock.setBigResult(true);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("SQL_BUFFER_RESULT")) {
                queryBlock.setBufferResult(true);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("SQL_CACHE")) {
                queryBlock.setCache(true);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("SQL_NO_CACHE")) {
                queryBlock.setCache(false);
                lexer.nextToken();
            }

            if (lexer.identifierEquals("SQL_CALC_FOUND_ROWS")) {
                queryBlock.setCalcFoundRows(true);
                lexer.nextToken();
            }

            parseSelectList(queryBlock);

            argsList = parseIntoArgs();
        }

        parseFrom(queryBlock);

        parseWhere(queryBlock);

        parseGroupBy(queryBlock);

        queryBlock.setOrderBy(this.exprParser.parseOrderBy());

        if (lexer.token() == Token.LIMIT) {
            queryBlock.setLimit(this.exprParser.parseLimit());
        }

        if (lexer.token() == Token.PROCEDURE) {
            lexer.nextToken();
            throw new ParserException("TODO. " + lexer.info());
        }

        parseInto(queryBlock);

        if (lexer.token() == Token.FOR) {
            lexer.nextToken();
            accept(Token.UPDATE);

            queryBlock.setForUpdate(true);
        }

        if (lexer.token() == Token.LOCK) {
            lexer.nextToken();
            accept(Token.IN);
            acceptIdentifier("SHARE");
            acceptIdentifier("MODE");
            queryBlock.setLockInShareMode(true);
        }

        return queryRest(queryBlock, acceptUnion);
    }

    /**
     * Parses the arguments for the INTO clause and returns a list of SQL expressions.
     *
     * @return a list of SQL expressions representing the arguments passed to the INTO clause
     */
    protected List<SQLExpr> parseIntoArgs() {
        List<SQLExpr> args = new ArrayList<SQLExpr>();
        if (lexer.token() == (Token.INTO)) {
            accept(Token.INTO);
            //lexer.nextToken();
            for (; ; ) {
                SQLExpr var = exprParser.primary();
                if (var instanceof SQLIdentifierExpr) {
                    var = new SQLVariantRefExpr(
                            ((SQLIdentifierExpr) var).getName());
                }
                args.add(var);
                if (lexer.token() == Token.COMMA) {
                    accept(Token.COMMA);
                    continue;
                } else {
                    break;
                }
            }
        }
        return args;
    }

    protected void parseInto(SQLSelectQueryBlock queryBlock) {
        if (lexer.token() == (Token.INTO)) {
            lexer.nextToken();

            if (lexer.identifierEquals("OUTFILE")) {
                lexer.nextToken();

                MySqlOutFileExpr outFile = new MySqlOutFileExpr();
                outFile.setFile(expr());

                queryBlock.setInto(outFile);

                if (lexer.identifierEquals("FIELDS") || lexer.identifierEquals("COLUMNS")) {
                    lexer.nextToken();

                    if (lexer.identifierEquals("TERMINATED")) {
                        lexer.nextToken();
                        accept(Token.BY);
                    }
                    outFile.setColumnsTerminatedBy((SQLLiteralExpr) expr());

                    if (lexer.identifierEquals("OPTIONALLY")) {
                        lexer.nextToken();
                        outFile.setColumnsEnclosedOptionally(true);
                    }

                    if (lexer.identifierEquals("ENCLOSED")) {
                        lexer.nextToken();
                        accept(Token.BY);
                        outFile.setColumnsEnclosedBy((SQLLiteralExpr) expr());
                    }

                    if (lexer.identifierEquals("ESCAPED")) {
                        lexer.nextToken();
                        accept(Token.BY);
                        outFile.setColumnsEscaped((SQLLiteralExpr) expr());
                    }
                }

                if (lexer.identifierEquals("LINES")) {
                    lexer.nextToken();

                    if (lexer.identifierEquals("STARTING")) {
                        lexer.nextToken();
                        accept(Token.BY);
                        outFile.setLinesStartingBy((SQLLiteralExpr) expr());
                    } else {
                        lexer.identifierEquals("TERMINATED");
                        lexer.nextToken();
                        accept(Token.BY);
                        outFile.setLinesTerminatedBy((SQLLiteralExpr) expr());
                    }
                }
            } else {
                queryBlock.setInto(this.exprParser.name());
            }
        }
    }

    public SQLTableSource parseTableSourceRest(SQLTableSource tableSource) {
        if (lexer.identifierEquals("USING")) {
            return tableSource;
        }

        parseIndexHintList(tableSource);

        return super.parseTableSourceRest(tableSource);
    }

    private void parseIndexHintList(SQLTableSource tableSource) {
        if (lexer.token() == Token.USE) {
            lexer.nextToken();
            MySqlUseIndexHint hint = new MySqlUseIndexHint();
            parseIndexHint(hint);
            tableSource.getHints().add(hint);
            parseIndexHintList(tableSource);
        }

        if (lexer.identifierEquals("IGNORE")) {
            lexer.nextToken();
            MySqlIgnoreIndexHint hint = new MySqlIgnoreIndexHint();
            parseIndexHint(hint);
            tableSource.getHints().add(hint);
            parseIndexHintList(tableSource);
        }

        if (lexer.identifierEquals(FnvHash.Constants.FORCE)) {
            lexer.nextToken();
            MySqlForceIndexHint hint = new MySqlForceIndexHint();
            parseIndexHint(hint);
            tableSource.getHints().add(hint);
            parseIndexHintList(tableSource);
        }
    }

    private void parseIndexHint(MySqlIndexHintImpl hint) {
        if (lexer.token() == Token.INDEX) {
            lexer.nextToken();
        } else {
            accept(Token.KEY);
        }

        if (lexer.token() == Token.FOR) {
            lexer.nextToken();

            if (lexer.token() == Token.JOIN) {
                lexer.nextToken();
                hint.setOption(MySqlIndexHint.Option.JOIN);
            } else if (lexer.token() == Token.ORDER) {
                lexer.nextToken();
                accept(Token.BY);
                hint.setOption(MySqlIndexHint.Option.ORDER_BY);
            } else {
                accept(Token.GROUP);
                accept(Token.BY);
                hint.setOption(MySqlIndexHint.Option.GROUP_BY);
            }
        }

        accept(Token.LPAREN);
        if (lexer.token() == Token.PRIMARY) {
            lexer.nextToken();
            hint.getIndexList().add(new SQLIdentifierExpr("PRIMARY"));
        } else {
            this.exprParser.names(hint.getIndexList());
        }
        accept(Token.RPAREN);
    }

    public SQLUnionQuery unionRest(SQLUnionQuery union) {
        if (lexer.token() == Token.LIMIT) {
            union.setLimit(this.exprParser.parseLimit());
        }
        return super.unionRest(union);
    }

    public MySqlExprParser getExprParser() {
        return (MySqlExprParser) exprParser;
    }
}
