//  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 cjk

import (
	"reflect"
	"testing"

	"github.com/blevesearch/bleve/v2/analysis"
)

func TestCJKBigramFilter(t *testing.T) {

	tests := []struct {
		outputUnigram bool
		input         analysis.TokenStream
		output        analysis.TokenStream
	}{
		// first test that non-adjacent terms are not combined
		{
			outputUnigram: false,
			input: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Ideographic,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Ideographic,
					Position: 2,
					Start:    5,
					End:      8,
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Single,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Single,
					Position: 2,
					Start:    5,
					End:      8,
				},
			},
		},
		{
			outputUnigram: false,
			input: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Ideographic,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Ideographic,
					Position: 2,
					Start:    3,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("に"),
					Type:     analysis.Ideographic,
					Position: 3,
					Start:    6,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("ち"),
					Type:     analysis.Ideographic,
					Position: 4,
					Start:    9,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("は"),
					Type:     analysis.Ideographic,
					Position: 5,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("世"),
					Type:     analysis.Ideographic,
					Position: 6,
					Start:    15,
					End:      18,
				},
				&analysis.Token{
					Term:     []byte("界"),
					Type:     analysis.Ideographic,
					Position: 7,
					Start:    18,
					End:      21,
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こん"),
					Type:     analysis.Double,
					Position: 1,
					Start:    0,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("んに"),
					Type:     analysis.Double,
					Position: 2,
					Start:    3,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("にち"),
					Type:     analysis.Double,
					Position: 3,
					Start:    6,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("ちは"),
					Type:     analysis.Double,
					Position: 4,
					Start:    9,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("は世"),
					Type:     analysis.Double,
					Position: 5,
					Start:    12,
					End:      18,
				},
				&analysis.Token{
					Term:     []byte("世界"),
					Type:     analysis.Double,
					Position: 6,
					Start:    15,
					End:      21,
				},
			},
		},
		{
			outputUnigram: true,
			input: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Ideographic,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Ideographic,
					Position: 2,
					Start:    3,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("に"),
					Type:     analysis.Ideographic,
					Position: 3,
					Start:    6,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("ち"),
					Type:     analysis.Ideographic,
					Position: 4,
					Start:    9,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("は"),
					Type:     analysis.Ideographic,
					Position: 5,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("世"),
					Type:     analysis.Ideographic,
					Position: 6,
					Start:    15,
					End:      18,
				},
				&analysis.Token{
					Term:     []byte("界"),
					Type:     analysis.Ideographic,
					Position: 7,
					Start:    18,
					End:      21,
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Single,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("こん"),
					Type:     analysis.Double,
					Position: 1,
					Start:    0,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Single,
					Position: 2,
					Start:    3,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("んに"),
					Type:     analysis.Double,
					Position: 2,
					Start:    3,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("に"),
					Type:     analysis.Single,
					Position: 3,
					Start:    6,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("にち"),
					Type:     analysis.Double,
					Position: 3,
					Start:    6,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("ち"),
					Type:     analysis.Single,
					Position: 4,
					Start:    9,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("ちは"),
					Type:     analysis.Double,
					Position: 4,
					Start:    9,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("は"),
					Type:     analysis.Single,
					Position: 5,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("は世"),
					Type:     analysis.Double,
					Position: 5,
					Start:    12,
					End:      18,
				},
				&analysis.Token{
					Term:     []byte("世"),
					Type:     analysis.Single,
					Position: 6,
					Start:    15,
					End:      18,
				},
				&analysis.Token{
					Term:     []byte("世界"),
					Type:     analysis.Double,
					Position: 6,
					Start:    15,
					End:      21,
				},
				&analysis.Token{
					Term:     []byte("界"),
					Type:     analysis.Single,
					Position: 7,
					Start:    18,
					End:      21,
				},
			},
		},
		{
			// Assuming that `、` is removed by unicode tokenizer from `こんにちは、世界`
			outputUnigram: true,
			input: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Ideographic,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Ideographic,
					Position: 2,
					Start:    3,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("に"),
					Type:     analysis.Ideographic,
					Position: 3,
					Start:    6,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("ち"),
					Type:     analysis.Ideographic,
					Position: 4,
					Start:    9,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("は"),
					Type:     analysis.Ideographic,
					Position: 5,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("世"),
					Type:     analysis.Ideographic,
					Position: 7,
					Start:    18,
					End:      21,
				},
				&analysis.Token{
					Term:     []byte("界"),
					Type:     analysis.Ideographic,
					Position: 8,
					Start:    21,
					End:      24,
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Single,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("こん"),
					Type:     analysis.Double,
					Position: 1,
					Start:    0,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Single,
					Position: 2,
					Start:    3,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("んに"),
					Type:     analysis.Double,
					Position: 2,
					Start:    3,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("に"),
					Type:     analysis.Single,
					Position: 3,
					Start:    6,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("にち"),
					Type:     analysis.Double,
					Position: 3,
					Start:    6,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("ち"),
					Type:     analysis.Single,
					Position: 4,
					Start:    9,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("ちは"),
					Type:     analysis.Double,
					Position: 4,
					Start:    9,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("は"),
					Type:     analysis.Single,
					Position: 5,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("世"),
					Type:     analysis.Single,
					Position: 6,
					Start:    18,
					End:      21,
				},
				&analysis.Token{
					Term:     []byte("世界"),
					Type:     analysis.Double,
					Position: 6,
					Start:    18,
					End:      24,
				},
				&analysis.Token{
					Term:     []byte("界"),
					Type:     analysis.Single,
					Position: 7,
					Start:    21,
					End:      24,
				},
			},
		},
		{
			outputUnigram: false,
			input: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こ"),
					Type:     analysis.Ideographic,
					Position: 1,
					Start:    0,
					End:      3,
				},
				&analysis.Token{
					Term:     []byte("ん"),
					Type:     analysis.Ideographic,
					Position: 2,
					Start:    3,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("に"),
					Type:     analysis.Ideographic,
					Position: 3,
					Start:    6,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("ち"),
					Type:     analysis.Ideographic,
					Position: 4,
					Start:    9,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("は"),
					Type:     analysis.Ideographic,
					Position: 5,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("cat"),
					Type:     analysis.AlphaNumeric,
					Position: 6,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("世"),
					Type:     analysis.Ideographic,
					Position: 7,
					Start:    18,
					End:      21,
				},
				&analysis.Token{
					Term:     []byte("界"),
					Type:     analysis.Ideographic,
					Position: 8,
					Start:    21,
					End:      24,
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("こん"),
					Type:     analysis.Double,
					Position: 1,
					Start:    0,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("んに"),
					Type:     analysis.Double,
					Position: 2,
					Start:    3,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("にち"),
					Type:     analysis.Double,
					Position: 3,
					Start:    6,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("ちは"),
					Type:     analysis.Double,
					Position: 4,
					Start:    9,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("cat"),
					Type:     analysis.AlphaNumeric,
					Position: 5,
					Start:    12,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("世界"),
					Type:     analysis.Double,
					Position: 6,
					Start:    18,
					End:      24,
				},
			},
		},
		{
			outputUnigram: false,
			input: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("パイプライン"),
					Type:     analysis.Ideographic,
					Position: 1,
					Start:    0,
					End:      18,
				},
			},
			output: analysis.TokenStream{
				&analysis.Token{
					Term:     []byte("パイ"),
					Type:     analysis.Double,
					Position: 1,
					Start:    0,
					End:      6,
				},
				&analysis.Token{
					Term:     []byte("イプ"),
					Type:     analysis.Double,
					Position: 2,
					Start:    3,
					End:      9,
				},
				&analysis.Token{
					Term:     []byte("プラ"),
					Type:     analysis.Double,
					Position: 3,
					Start:    6,
					End:      12,
				},
				&analysis.Token{
					Term:     []byte("ライ"),
					Type:     analysis.Double,
					Position: 4,
					Start:    9,
					End:      15,
				},
				&analysis.Token{
					Term:     []byte("イン"),
					Type:     analysis.Double,
					Position: 5,
					Start:    12,
					End:      18,
				},
			},
		},
	}

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