//  Copyright (c) 2013 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 search

import (
	"math"
	"reflect"
	"testing"

	"github.com/couchbaselabs/bleve/index"
)

func TestTermScorer(t *testing.T) {

	query := TermQuery{
		Term:     "beer",
		Field:    "desc",
		BoostVal: 1.0,
		Explain:  true,
	}

	var docTotal uint64 = 100
	var docTerm uint64 = 9
	scorer := NewTermQueryScorer(&query, docTotal, docTerm, false)
	idf := 1.0 + math.Log(float64(docTotal)/float64(docTerm+1.0))

	tests := []struct {
		termMatch *index.TermFieldDoc
		result    *DocumentMatch
	}{
		// test some simple math
		{
			termMatch: &index.TermFieldDoc{
				ID:   "one",
				Freq: 1,
				Norm: 1.0,
			},
			result: &DocumentMatch{
				ID:    "one",
				Score: math.Sqrt(1.0) * idf,
			},
		},
		// test the same thing again (score should be cached this time)
		{
			termMatch: &index.TermFieldDoc{
				ID:   "one",
				Freq: 1,
				Norm: 1.0,
			},
			result: &DocumentMatch{
				ID:    "one",
				Score: math.Sqrt(1.0) * idf,
			},
		},
		// test a case where the sqrt isn't precalculated
		{
			termMatch: &index.TermFieldDoc{
				ID:   "one",
				Freq: 65,
				Norm: 1.0,
			},
			result: &DocumentMatch{
				ID:    "one",
				Score: math.Sqrt(65) * idf,
			},
		},
	}

	for _, test := range tests {
		actual := scorer.Score(test.termMatch)

		if !reflect.DeepEqual(actual, test.result) {
			t.Errorf("expected %#v got %#v for %#v", test.result, actual, test.termMatch)
		}
	}

}