Initial Commit

cmd/search/search.go

@@ -0,0 +1,215 @@
+package search
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"sap-cds-search/cmd/model"
+	"sap-cds-search/cmd/ui"
+	"slices"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/lithammer/fuzzysearch/fuzzy"
+)
+
+type fuzzyResult struct {
+	CDSViewTechnicalName string
+	hits                 int
+	averageDistance      float32
+	score                float32
+}
+
+type resultBuffer struct {
+	createdAt time.Time
+	hits      int
+	mu        sync.Mutex
+	results   []fuzzyResult
+}
+
+const pageStep = 12
+
+var (
+	ErrNoBuffer  = errors.New("no buffer")
+	ErrNoResults = errors.New("no results")
+)
+
+var searchTargets map[string][]string = make(map[string][]string)
+var resultsBuffer map[string]*resultBuffer = make(map[string]*resultBuffer)
+
+func Load() error {
+	keywords, err := model.GetKeywordsModel()
+	if err != nil {
+		return err
+	}
+	for _, keyword := range *keywords {
+		table := searchTargets[keyword.CDSViewTechnicalName]
+		table = append(table, keyword.Keyword)
+		searchTargets[keyword.CDSViewTechnicalName] = table
+	}
+
+	ticker := time.NewTicker(5 * time.Minute)
+
+	go func() {
+		for {
+			select {
+			case <-ticker.C:
+				ClearOldBuffers()
+			}
+		}
+	}()
+
+	return nil
+}
+
+func GetSearchTerm(r *http.Request) string {
+	return strings.ToLower(r.URL.Query().Get("q"))
+}
+
+func GetPage(r *http.Request) int {
+	page, _ := strconv.Atoi(r.URL.Query().Get("p"))
+	if page < 0 {
+		page = 0
+	}
+	return page
+}
+
+func GetBuffer(searchTerm string) (*resultBuffer, error) {
+	buffer, exists := resultsBuffer[searchTerm]
+
+	if !exists {
+		return nil, ErrNoBuffer
+	}
+
+	return buffer, nil
+}
+
+func BuildBuffer(searchTerm string) error {
+	if searchTerm == "" {
+		return ErrNoResults
+	}
+
+	splitSearchTerms := strings.Split(searchTerm, " ")
+
+	splitSearchTerms = append(splitSearchTerms, searchTerm)
+	splitSearchTerms = append(splitSearchTerms, strings.ReplaceAll(searchTerm, " ", searchTerm))
+
+	var fuzzyResults []fuzzyResult
+
+	for viewName, targets := range searchTargets {
+		totalHits := 0
+		var totalDistance float32
+		for i, splitSearchTerm := range splitSearchTerms {
+			ranks := fuzzy.RankFindFold(splitSearchTerm, targets)
+
+			hits := len(ranks)
+			if hits == 0 {
+				if i < len(splitSearchTerm)-3 {
+					totalDistance += 500
+				}
+				continue
+			}
+
+			totalHits += hits
+
+			var averageDistance float32 = 0
+			for _, rank := range ranks {
+				averageDistance += float32(rank.Distance)
+			}
+
+			totalDistance += averageDistance / float32(hits)
+		}
+
+		if totalHits > 0 {
+			fuzzyResults = append(fuzzyResults, fuzzyResult{
+				CDSViewTechnicalName: viewName,
+				hits:                 totalHits,
+				averageDistance:      totalDistance,
+				score:                totalDistance / float32(totalHits),
+			})
+		}
+	}
+
+	hits := len(fuzzyResults)
+	if hits == 0 {
+		return ErrNoResults
+	}
+
+	slices.SortFunc(fuzzyResults, func(a, b fuzzyResult) int {
+		if a.score > b.score {
+			return 1
+		} else if a.score < b.score {
+			return -1
+		}
+		return 0
+	})
+
+	resultsBuffer[searchTerm] = &resultBuffer{
+		createdAt: time.Now(),
+		hits:      hits,
+		results:   fuzzyResults,
+	}
+
+	return nil
+}
+
+func HandleSearch(w http.ResponseWriter, r *http.Request) {
+	searchTerm := GetSearchTerm(r)
+
+	buffer, err := GetBuffer(searchTerm)
+	if err != nil {
+		err := BuildBuffer(searchTerm)
+		if err != nil {
+			err := ui.Template.ExecuteTemplate(w, "search-placeholder-no-result", nil)
+			if err != nil {
+				fmt.Println(err)
+			}
+			return
+		}
+		buffer, _ = GetBuffer(searchTerm)
+	}
+
+	buffer.mu.Lock()
+	defer buffer.mu.Unlock()
+
+	page := GetPage(r)
+
+	maxPage := (buffer.hits / pageStep) - 1
+	if page+1 > maxPage {
+		page = maxPage
+	}
+
+	resultsModel := model.NewResultsModel()
+	for i := page * pageStep; i < page*pageStep+pageStep; i++ {
+		result := buffer.results[i]
+		cdsView, err := model.GetCDSViewModel(result.CDSViewTechnicalName)
+		if err != nil {
+			fmt.Println(err)
+			continue
+		}
+
+		resultsModel.AppendResultsModelViews(cdsView)
+	}
+
+	resultsModel.SearchTerm = searchTerm
+	resultsModel.CurrentPage = page
+	resultsModel.MaxPage = maxPage
+
+	err = ui.Template.ExecuteTemplate(w, "results", resultsModel)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+}
+
+func ClearOldBuffers() {
+	for key, buffer := range resultsBuffer {
+		if time.Since(buffer.createdAt) >= time.Minute*10 {
+			buffer.mu.Lock()
+			delete(resultsBuffer, key)
+			buffer.mu.Unlock()
+		}
+	}
+}