From d22ff9adf0f3a647edfc9fffb845e1abf1616d8e Mon Sep 17 00:00:00 2001
From: Jesse Duffield <jessedduffield@gmail.com>
Date: Sat, 22 Jul 2023 13:04:39 +1000
Subject: [PATCH] Use fuzzy search when filtering a view

This adds fuzzy filtering instead of exact match filtering, which is more forgiving of typos
and allows more efficiency.
---
 pkg/gui/context/filtered_list.go | 39 ++++++++++++++++++++++----------
 1 file changed, 27 insertions(+), 12 deletions(-)

diff --git a/pkg/gui/context/filtered_list.go b/pkg/gui/context/filtered_list.go
index 298d3d615d0..d2361ad53f9 100644
--- a/pkg/gui/context/filtered_list.go
+++ b/pkg/gui/context/filtered_list.go
@@ -1,7 +1,11 @@
 package context
 
 import (
+	"strings"
+
 	"github.com/jesseduffield/lazygit/pkg/utils"
+	"github.com/sahilm/fuzzy"
+	"github.com/samber/lo"
 	"github.com/sasha-s/go-deadlock"
 )
 
@@ -53,6 +57,21 @@ func (self *FilteredList[T]) UnfilteredLen() int {
 	return len(self.getList())
 }
 
+type fuzzySource[T any] struct {
+	list            []T
+	getFilterFields func(T) []string
+}
+
+var _ fuzzy.Source = &fuzzySource[string]{}
+
+func (self *fuzzySource[T]) String(i int) string {
+	return strings.Join(self.getFilterFields(self.list[i]), " ")
+}
+
+func (self *fuzzySource[T]) Len() int {
+	return len(self.list)
+}
+
 func (self *FilteredList[T]) applyFilter() {
 	self.mutex.Lock()
 	defer self.mutex.Unlock()
@@ -60,20 +79,16 @@ func (self *FilteredList[T]) applyFilter() {
 	if self.filter == "" {
 		self.filteredIndices = nil
 	} else {
-		self.filteredIndices = []int{}
-		for i, item := range self.getList() {
-			for _, field := range self.getFilterFields(item) {
-				if self.match(field, self.filter) {
-					self.filteredIndices = append(self.filteredIndices, i)
-					break
-				}
-			}
+		source := &fuzzySource[T]{
+			list:            self.getList(),
+			getFilterFields: self.getFilterFields,
 		}
-	}
-}
 
-func (self *FilteredList[T]) match(haystack string, needle string) bool {
-	return utils.CaseAwareContains(haystack, needle)
+		matches := fuzzy.FindFrom(self.filter, source)
+		self.filteredIndices = lo.Map(matches, func(match fuzzy.Match, _ int) int {
+			return match.Index
+		})
+	}
 }
 
 func (self *FilteredList[T]) UnfilteredIndex(index int) int {