search using levenshtein distance

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cointop/navigation.go

@@ -1,14 +1,18 @@
 package cointop
 
-func (ct *Cointop) getCurrentPage() int {
+func (ct *Cointop) currentPage() int {
 	return ct.page + 1
 }
 
-func (ct *Cointop) getTotalPages() int {
+func (ct *Cointop) currentDisplayPage() int {
+	return ct.page + 1
+}
+
+func (ct *Cointop) totalPages() int {
 	return (ct.getListCount() / ct.perpage) + 1
 }
 
-func (ct *Cointop) getTotalPerPage() int {
+func (ct *Cointop) totalPerPage() int {
 	return ct.perpage
 }
 
@@ -29,7 +33,7 @@ func (ct *Cointop) highlightRow(idx int) error {
 	ox, _ := ct.tableview.Origin()
 	cx, _ := ct.tableview.Cursor()
 	_, sy := ct.tableview.Size()
-	perpage := ct.getTotalPerPage()
+	perpage := ct.totalPerPage()
 	p := idx % perpage
 	oy := (p / sy) * sy
 	cy := p % sy

cointop/search.go

@@ -3,6 +3,8 @@ package cointop
 import (
 	"regexp"
 	"strings"
+
+	"github.com/miguelmota/cointop/pkg/levenshtein"
 )
 
 func (ct *Cointop) openSearch() error {
@@ -38,25 +40,34 @@ func (ct *Cointop) doSearch() error {
 
 func (ct *Cointop) search(q string) error {
 	q = strings.TrimSpace(strings.ToLower(q))
+	idx := -1
+	min := -1
 	for i := range ct.allcoins {
 		coin := ct.allcoins[i]
-		if strings.ToLower(coin.Name) == q {
-			ct.goToGlobalIndex(i)
-			return nil
+		name := strings.ToLower(coin.Name)
+		symbol := strings.ToLower(coin.Symbol)
+		if symbol == q {
+			idx = i
+			break
 		}
-	}
-	for i := range ct.allcoins {
-		coin := ct.allcoins[i]
-		if strings.ToLower(coin.Symbol) == q {
-			ct.goToGlobalIndex(i)
-			return nil
+		dist := levenshtein.Distance(name, q)
+		if min == -1 {
+			min = dist
 		}
+		if dist <= min {
+			idx = i
+			min = dist
+		}
+	}
+
+	if idx > -1 && min <= 6 {
+		ct.goToGlobalIndex(idx)
 	}
 	return nil
 }
 
 func (ct *Cointop) goToGlobalIndex(idx int) error {
-	perpage := ct.getTotalPerPage()
+	perpage := ct.totalPerPage()
 	atpage := idx / perpage
 	ct.setPage(atpage)
 	rowIndex := (idx % perpage)

cointop/statusbar.go

@@ -9,8 +9,8 @@ import (
 func (ct *Cointop) updateStatusbar(s string) {
 	ct.update(func() {
 		ct.statusbarview.Clear()
-		currpage := ct.getCurrentPage()
-		totalpages := ct.getTotalPages()
+		currpage := ct.currentDisplayPage()
+		totalpages := ct.totalPages()
 		base := "[q]uit [?]help [c]hart [/]search"
 		fmt.Fprintln(ct.statusbarview, pad.Right(fmt.Sprintf("%v [← →]page %v/%v %s", base, currpage, totalpages, s), ct.maxtablewidth, " "))
 	})

pkg/levenshtein/levenshtein.go

@@ -0,0 +1,57 @@
+package levenshtein
+
+// Distance Levenshtein distance
+// The Levenshtein distance between two strings is defined as the minimum
+// number of edits needed to transform one string into the other, with the
+// allowable edit operations being insertion, deletion, or substitution of
+// a single character
+// http://en.wikipedia.org/wiki/Levenshtein_distance
+//
+// This implemention is optimized to use O(min(m,n)) space.
+// It is based on the optimized C version found here:
+// http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Levenshtein_distance#C
+func Distance(str1, str2 string) int {
+	var cost, lastdiag, olddiag int
+	s1 := []rune(str1)
+	s2 := []rune(str2)
+
+	lenS1 := len(s1)
+	lenS2 := len(s2)
+
+	column := make([]int, lenS1+1)
+
+	for y := 1; y <= lenS1; y++ {
+		column[y] = y
+	}
+
+	for x := 1; x <= lenS2; x++ {
+		column[0] = x
+		lastdiag = x - 1
+		for y := 1; y <= lenS1; y++ {
+			olddiag = column[y]
+			cost = 0
+			if s1[y-1] != s2[x-1] {
+				cost = 1
+			}
+			column[y] = min(
+				column[y]+1,
+				column[y-1]+1,
+				lastdiag+cost)
+			lastdiag = olddiag
+		}
+	}
+	return column[lenS1]
+}
+
+func min(a, b, c int) int {
+	if a < b {
+		if a < c {
+			return a
+		}
+	} else {
+		if b < c {
+			return b
+		}
+	}
+	return c
+}