search/search.go

package search

import (
	"sort"
	"strings"
)

// ID ...
type ID struct {
	Key   interface{}
	Score float64
	Title []string
}

// Search ...
type Search struct {
	Words            map[interface{}][][]string
	IgnoreWords      []string
	RemoveCharacters []string
}

// CleanSearch ...
func (DB *Search) CleanSearch(title string) []string {
	s := []string{}
	for _, c := range DB.RemoveCharacters {
		title = strings.Replace(title, c, ` `, -1)
	}
	for _, v := range strings.Split(title, ` `) {
		matched := false
		if v == `` || v == ` ` {
			continue
		}
		for _, w := range DB.IgnoreWords {
			if v == w {
				matched = true
			}
		}
		if !matched {
			s = append(s, strings.ToLower(v))
		}
	}
	return s
}

// Add ...
func (DB *Search) Add(key interface{}, st [][]string) {
	if DB.Words == nil {
		DB.Words = make(map[interface{}][][]string)
	}
	DB.Words[key] = append(DB.Words[key], st...)

}

// Ignore ...
func (DB *Search) Ignore(list []string) {
	DB.IgnoreWords = list
}

// Replace ...
func (DB *Search) Replace(list []string) {
	DB.RemoveCharacters = list
}

// Match ...
func (DB *Search) Match(Title string) []interface{} {
	IDS := []ID{}
	title := DB.CleanSearch(strings.ToLower(Title))
	for k, v := range DB.Words {
		tempKeys := []ID{}
		for _, t := range v {
			sim := similarity(t, title)
			if sim > 0 {
				tempKeys = append(tempKeys, ID{Key: k, Score: sim, Title: t})
			}
		}
		if len(tempKeys) > 0 {
			sort.Slice(tempKeys, func(i, j int) bool {
				return tempKeys[i].Score > tempKeys[j].Score
			})
			IDS = append(IDS, tempKeys[0])
		}
	}
	sort.Slice(IDS, func(i, j int) bool {
		return IDS[i].Score > IDS[j].Score
	})

	keys := []interface{}{}
	for _, v := range IDS {
		keys = append(keys, v.Key)
	}
	return keys
}

func similarity(a, b []string) float64 {
	var s float64
	var matched []int
loop:
	for _, i := range a {
		for f, l := range b {
			if i == l && !intInSlice(f, matched) {
				s++
				matched = append(matched, f)
				continue loop
			} else if i != l {
				s = s - ((float64(len(i)) * 0.1) * (0.125 / 2))
			}
		}
	}
	return s
}

func intInSlice(a int, list []int) bool {
	for _, b := range list {
		if b == a {
			return true
		}
	}
	return false
}