package search

import (
	"sort"
	"strings"
)

var ignoreWords = []string{`a`, `of`, `in`, `the`, `wa`, `ga`, `no`, `ni`, `wo`, `he`, `o`, `ka`}
var replaceCharacters = strings.Split(`〜☆♪・〈〉「」！『』²Ⅱ＋[](),.!?\/{}+-_=~"'@#$%^&*|;:<>`, ``)

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

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

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

// IndexSearch ...
func (DB *Search) IndexSearch(id interface{}, st [][]string) {
	if DB.Titles == nil {
		DB.Titles = make(map[interface{}][][]string)
	}
	for _, t := range st {
		DB.Titles[id] = append(DB.Titles[id], t)
	}

}

// Match ...
func (DB *Search) Match(Title string) []interface{} {
	IDS := []ID{}
	title := CleanSearch(strings.ToLower(Title))
mainLoop:
	for i := range DB.Titles {
		for _, t := range DB.Titles[i] {
			if len(t) == 0 {
				continue
			}

			sim := similarity(t, title)
			if sim > 0 {
				IDS = append(IDS, ID{ID: i.(int), Score: sim, Title: t})
				continue mainLoop
			}
		}
	}
	sort.Slice(IDS, func(i, j int) bool {
		return IDS[i].Score > IDS[j].Score
	})

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

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 {
				s = s - 0.125
			}
		}
	}
	return s
}

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