//  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 ngram_filter

import (
	"reflect"
	"testing"

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

func TestNgramFilter(t *testing.T) {

	tests := []struct {
		min    int
		max    int
		input  analysis.TokenStream
		output analysis.TokenStream
	}{
		{
			min: 1,
			max: 1,
			input: analysis.TokenStream{
				&analysis.Token{
					Term: []byte("abcde"),
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term: []byte("a"),
				},
				&analysis.Token{
					Term: []byte("b"),
				},
				&analysis.Token{
					Term: []byte("c"),
				},
				&analysis.Token{
					Term: []byte("d"),
				},
				&analysis.Token{
					Term: []byte("e"),
				},
			},
		},
		{
			min: 2,
			max: 2,
			input: analysis.TokenStream{
				&analysis.Token{
					Term: []byte("abcde"),
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term: []byte("ab"),
				},
				&analysis.Token{
					Term: []byte("bc"),
				},
				&analysis.Token{
					Term: []byte("cd"),
				},
				&analysis.Token{
					Term: []byte("de"),
				},
			},
		},
		{
			min: 1,
			max: 3,
			input: analysis.TokenStream{
				&analysis.Token{
					Term: []byte("abcde"),
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term: []byte("a"),
				},
				&analysis.Token{
					Term: []byte("ab"),
				},
				&analysis.Token{
					Term: []byte("abc"),
				},
				&analysis.Token{
					Term: []byte("b"),
				},
				&analysis.Token{
					Term: []byte("bc"),
				},
				&analysis.Token{
					Term: []byte("bcd"),
				},
				&analysis.Token{
					Term: []byte("c"),
				},
				&analysis.Token{
					Term: []byte("cd"),
				},
				&analysis.Token{
					Term: []byte("cde"),
				},
				&analysis.Token{
					Term: []byte("d"),
				},
				&analysis.Token{
					Term: []byte("de"),
				},
				&analysis.Token{
					Term: []byte("e"),
				},
			},
		},
	}

	for _, test := range tests {
		ngramFilter := NewNgramFilter(test.min, test.max)
		actual := ngramFilter.Filter(test.input)
		if !reflect.DeepEqual(actual, test.output) {
			t.Errorf("expected %s, got %s", test.output, actual)
		}
	}
}