Interwiki: Fix some bugs

* Actually, you could not edit interwiki entries before
* Fix faulty template in English locale

interwiki/interwiki.go

@@ -29,6 +29,32 @@ func Init() {
 	log.Printf("Loaded %d interwiki entries\n", len(listOfEntries))
 }
 
+func dropEmptyStrings(ss []string) (clean []string) {
+	for _, s := range ss {
+		if s != "" {
+			clean = append(clean, s)
+		}
+	}
+	return clean
+}
+
+// difference returns the elements in `a` that aren't in `b`.
+// Taken from https://stackoverflow.com/a/45428032
+// CC BY-SA 4.0, no changes made
+func difference(a, b []string) []string {
+	mb := make(map[string]struct{}, len(b))
+	for _, x := range b {
+		mb[x] = struct{}{}
+	}
+	var diff []string
+	for _, x := range a {
+		if _, found := mb[x]; !found {
+			diff = append(diff, x)
+		}
+	}
+	return diff
+}
+
 func areNamesFree(names []string) (bool, string) {
 	for _, name := range names {
 		if _, found := entriesByName[name]; found {
@@ -40,21 +66,59 @@ func areNamesFree(names []string) (bool, string) {
 
 var mutex sync.Mutex
 
-func addEntry(wiki *Wiki) error {
+func replaceEntry(oldWiki *Wiki, newWiki *Wiki) error {
+	diff := difference(
+		append(newWiki.Aliases, newWiki.Name),
+		append(oldWiki.Aliases, oldWiki.Name),
+	)
+	if ok, name := areNamesFree(diff); !ok {
+		return errors.New(name)
+	}
+	deleteEntry(oldWiki)
+	return addEntry(newWiki)
+}
+
+func deleteEntry(wiki *Wiki) {
 	mutex.Lock()
 	defer mutex.Unlock()
 
-	var (
-		// non-empty names only
-		names = func(names []string) []string {
-			var result []string
+	// I'm being fancy here. Come on, the code here is already a mess.
+	// Let me have some fun.
+	var wg sync.WaitGroup
+
+	wg.Add(2)
+	go func() {
+		names := append(wiki.Aliases, wiki.Name)
 		for _, name := range names {
-				if name != "" {
-					result = append(result, name)
+			name := name // I guess we need that
+			delete(entriesByName, name)
+		}
+		wg.Done()
+	}()
+
+	go func() {
+		for i, w := range listOfEntries {
+			i, w := i, w
+			if w.Name == wiki.Name {
+				log.Println("It came to delete")
+				// Drop ith element.
+				listOfEntries[i] = listOfEntries[len(listOfEntries)-1]
+				listOfEntries = listOfEntries[:len(listOfEntries)-1]
+				break
 			}
 		}
-			return result
-		}(append(wiki.Aliases, wiki.Name))
+		wg.Done()
+	}()
+
+	wg.Wait()
+}
+
+func addEntry(wiki *Wiki) error {
+	mutex.Lock()
+	defer mutex.Unlock()
+	wiki.Aliases = dropEmptyStrings(wiki.Aliases)
+	var (
+		names    = append(wiki.Aliases, wiki.Name)
 		ok, name = areNamesFree(names)
 	)
 	if !ok {

interwiki/view_interwiki.html

@@ -5,6 +5,8 @@
 {{define "aliases (,)"}}Aliases (separated by commas):{{end}}
 {{define "engine"}}Engine:{{end}}
 	{{define "engine/mycorrhiza"}}Mycorrhiza{{end}}
+	{{define "engine/betula"}}Betula{{end}}
+	{{define "engine/agora"}}Agora{{end}}
 	{{define "engine/generic"}}Generic (any website){{end}}
 {{define "url"}}URL{{end}}
 {{define "link href format"}}Link href attribute format string:{{end}}
@@ -53,7 +55,7 @@
 			<form method="post" action="/interwiki/modify-entry/{{.Name}}">
 				<p>
 					<label for="name{{$i}}" class="required-field">{{template "name"}}</label>
-					<input type="text" id="name" name="name{{$i}}" required
+					<input type="text" id="name{{$i}}" name="name" required
 					       value="{{.Name}}">
 				</p>
 				<p>
@@ -125,7 +127,7 @@
 			<input type="url" id="img-src-format" name="img-src-format"
 			       placeholder="https://wiki.example.org/media/{NAME}">
 		</p>
-		<input type="submit" class="btn">
+		<input type="submit" class="btn" value="Add entry">
 	</form>
 {{end}}
 

interwiki/view_name_taken.html

@@ -2,7 +2,7 @@
 	<main class="main-width">
 		<h1>{{block "heading" .}}Name taken{{end}}</h1>
 		<p>{{block "tip" .TakenName}}Name <kbd>{{.}}</kbd> is already taken, please choose a different one.{{end}}</p>
-		<form method="post" action="/interwiki/add-entry">
+		<form method="post" action="/interwiki/{{.Action}}">
 			<p>
 				<label for="name" class="required-field">Name:</label>
 				<input type="text" id="name" name="name" required

interwiki/web.go

@@ -4,6 +4,7 @@ import (
 	"embed"
 	"github.com/bouncepaw/mycorrhiza/viewutil"
 	"github.com/gorilla/mux"
+	"log"
 	"net/http"
 	"strings"
 )
@@ -37,9 +38,10 @@ func InitHandlers(rtr *mux.Router) {
 	chainNameTaken = viewutil.CopyEnRuWith(fs, "view_name_taken.html", ruTranslation)
 	rtr.HandleFunc("/interwiki", handlerInterwiki)
 	rtr.HandleFunc("/interwiki/add-entry", handlerAddEntry).Methods(http.MethodPost)
+	rtr.HandleFunc("/interwiki/modify-entry/{target}", handlerModifyEntry).Methods(http.MethodPost)
 }
 
-func handlerAddEntry(w http.ResponseWriter, rq *http.Request) {
+func readInterwikiEntryFromRequest(rq *http.Request) Wiki {
 	wiki := Wiki{
 		Name:           rq.PostFormValue("name"),
 		Aliases:        strings.Split(rq.PostFormValue("aliases"), ","),
@@ -49,8 +51,38 @@ func handlerAddEntry(w http.ResponseWriter, rq *http.Request) {
 		Engine:         WikiEngine(rq.PostFormValue("engine")),
 	}
 	wiki.canonize()
+	return wiki
+}
+
+func handlerModifyEntry(w http.ResponseWriter, rq *http.Request) {
+	var (
+		oldData *Wiki
+		ok      bool
+		name    = mux.Vars(rq)["target"]
+		newData = readInterwikiEntryFromRequest(rq)
+	)
+
+	if oldData, ok = entriesByName[name]; !ok {
+		log.Printf("Could not modify interwiki entry ‘%s’ because it does not exist", name)
+		viewutil.HandlerNotFound(w, rq)
+		return
+	}
+
+	if err := replaceEntry(oldData, &newData); err != nil {
+		log.Printf("Could not modify interwiki entry ‘%s’ because one of the proposed aliases/name is taken\n", name)
+		viewNameTaken(viewutil.MetaFrom(w, rq), oldData, err.Error(), "modify-entry/"+name)
+		return
+	}
+
+	saveInterwikiJson()
+	log.Printf("Modified interwiki entry ‘%s’\n", name)
+	http.Redirect(w, rq, "/interwiki", http.StatusSeeOther)
+}
+
+func handlerAddEntry(w http.ResponseWriter, rq *http.Request) {
+	wiki := readInterwikiEntryFromRequest(rq)
 	if err := addEntry(&wiki); err != nil {
-		viewNameTaken(viewutil.MetaFrom(w, rq), &wiki, err.Error())
+		viewNameTaken(viewutil.MetaFrom(w, rq), &wiki, err.Error(), "add-entry")
 		return
 	}
 	saveInterwikiJson()
@@ -61,13 +93,15 @@ type nameTakenData struct {
 	*viewutil.BaseData
 	*Wiki
 	TakenName string
+	Action    string
 }
 
-func viewNameTaken(meta viewutil.Meta, wiki *Wiki, takenName string) {
+func viewNameTaken(meta viewutil.Meta, wiki *Wiki, takenName, action string) {
 	viewutil.ExecutePage(meta, chainNameTaken, nameTakenData{
 		BaseData:  &viewutil.BaseData{},
 		Wiki:      wiki,
 		TakenName: takenName,
+		Action:    action,
 	})
 }
 

viewutil/err.go

@@ -26,3 +26,9 @@ func HttpErr(meta Meta, status int, name, errMsg string) {
 		),
 	)
 }
+
+// HandlerNotFound prints the simples 404 page. Use in rare places that cannot be achieved normally.
+func HandlerNotFound(w http.ResponseWriter, _ *http.Request) {
+	w.WriteHeader(http.StatusNotFound)
+	w.Write([]byte("404 Page not found"))
+}