//  Copyright (c) 2014 Couchbase, Inc.
//  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 apostrophe_filter

import (
	"bytes"

	"github.com/blevesearch/bleve/analysis"
	"github.com/blevesearch/bleve/registry"
)

const Name = "apostrophe"

const RightSingleQoutationMark = "’"
const Apostrophe = "'"
const Apostrophes = Apostrophe + RightSingleQoutationMark

type ApostropheFilter struct{}

func NewApostropheFilter() *ApostropheFilter {
	return &ApostropheFilter{}
}

func (s *ApostropheFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
	rv := make(analysis.TokenStream, 0)

	for _, token := range input {
		firstApostrophe := bytes.IndexAny(token.Term, Apostrophes)
		if firstApostrophe >= 0 {
			// found an apostrophe
			token.Term = token.Term[0:firstApostrophe]
		}
		rv = append(rv, token)
	}

	return rv
}

func ApostropheFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
	return NewApostropheFilter(), nil
}

func init() {
	registry.RegisterTokenFilter(Name, ApostropheFilterConstructor)
}