/*
 * Copyright (c) 2002-2020 "Neo4j,"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.exceptions;

import java.util.Optional;

import org.neo4j.kernel.api.exceptions.Status;

import static java.lang.System.lineSeparator;

@SuppressWarnings( "OptionalUsedAsFieldOrParameterType" )
public class SyntaxException extends Neo4jException
{
    private final Optional<Integer> offset;
    private final String query;

    public SyntaxException( String message, String query, Optional<Integer> offset, Throwable cause )
    {
        super( message, cause );
        this.offset = offset;
        this.query = query;
    }

    public SyntaxException( String message, String query, int offset )
    {
        this( message, query, Optional.of( offset ), null );
    }

    public SyntaxException( String message, String query, int offset, Throwable cause )
    {
        this( message, query, Optional.of( offset ), cause );
    }

    public SyntaxException( String message, Throwable cause )
    {
        this( message, "", Optional.empty(), cause );
    }

    public SyntaxException( String message )
    {
        this( message, "", Optional.empty(), null );
    }

    @Override
    public Status status()
    {
        return Status.Statement.SyntaxError;
    }

    public Optional<Integer> getOffset()
    {
        return offset;
    }

    @Override
    public String getMessage()
    {
        if ( offset.isPresent() )
        {
            //split can be empty if query = '\n'
            var split = query.split( "\n" );
            return super.getMessage() + lineSeparator() + findErrorLine( offset.get(), split.length != 0 ? split : new String[]{""} );
        }
        else
        {
            return super.getMessage();
        }
    }

    private String findErrorLine( int offset, String[] message )
    {
        int currentOffset = offset;
        if ( message.length == 0 )
        {
            throw new IllegalArgumentException( "message converted to empty list" );
        }
        else
        {
            StringBuilder builder = new StringBuilder();
            for ( int i = 0; i < message.length; i++ )
            {
                String element = message[i];
                if ( i < message.length - 1 )
                {
                    if ( element.length() >= currentOffset )
                    {
                        buildErrorString( builder, element, currentOffset );
                        break;
                    }
                    else
                    {
                        //The extra minus one is there for the now missing \n
                        currentOffset -= element.length() + 1;
                    }
                }
                else
                {
                    buildErrorString( builder, element, Math.min( element.length(), currentOffset ) );
                }
            }
            return builder.toString();
        }
    }

    private void buildErrorString( StringBuilder builder, String element, int currentOffset )
    {
        builder.append( "\"" )
               .append( element.stripTrailing() ) // removes potential \r at the end
               .append( "\"" )
               .append( lineSeparator() )
               .append( " ".repeat( currentOffset + 1 ) ) // extra space to compensate for an opening quote
               .append( '^' );
    }
}
