Improve issue & code search (#33860)

Each "indexer" should provide the "search modes" they support by
themselves. And we need to remove the "fuzzy" search for code.

routers/common/codesearch.go

@@ -4,36 +4,30 @@
 package common
 
 import (
+	"code.gitea.io/gitea/modules/indexer"
+	code_indexer "code.gitea.io/gitea/modules/indexer/code"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/services/context"
 )
 
 func PrepareCodeSearch(ctx *context.Context) (ret struct {
-	Keyword  string
-	Language string
-	IsFuzzy  bool
+	Keyword    string
+	Language   string
+	SearchMode indexer.SearchModeType
 },
 ) {
 	ret.Language = ctx.FormTrim("l")
 	ret.Keyword = ctx.FormTrim("q")
+	ret.SearchMode = indexer.SearchModeType(ctx.FormTrim("search_mode"))
 
-	fuzzyDefault := setting.Indexer.RepoIndexerEnabled
-	fuzzyAllow := true
-	if setting.Indexer.RepoType == "bleve" && setting.Indexer.TypeBleveMaxFuzzniess == 0 {
-		fuzzyDefault = false
-		fuzzyAllow = false
-	}
-	isFuzzy := ctx.FormOptionalBool("fuzzy").ValueOrDefault(fuzzyDefault)
-	if isFuzzy && !fuzzyAllow {
-		ctx.Flash.Info("Fuzzy search is disabled by default due to performance reasons", true)
-		isFuzzy = false
-	}
-
-	ctx.Data["IsBleveFuzzyDisabled"] = true
 	ctx.Data["Keyword"] = ret.Keyword
 	ctx.Data["Language"] = ret.Language
-	ctx.Data["IsFuzzy"] = isFuzzy
-
+	ctx.Data["SelectedSearchMode"] = string(ret.SearchMode)
+	if setting.Indexer.RepoIndexerEnabled {
+		ctx.Data["SearchModes"] = code_indexer.SupportedSearchModes()
+	} else {
+		ctx.Data["SearchModes"] = indexer.GitGrepSupportedSearchModes()
+	}
 	ctx.Data["IsRepoIndexerEnabled"] = setting.Indexer.RepoIndexerEnabled
 	return ret
 }