Render help through command aliases

help_view.go

@@ -0,0 +1,98 @@
+package commandkit
+
+import (
+	"sort"
+
+	commandmeta "gitea.maximumdirect.net/eric/CommandKit/internal/commandmeta"
+	"gitea.maximumdirect.net/eric/CommandKit/internal/commandpath"
+)
+
+func (a *App) helpView(route routeResult, snapshot *routingSnapshot) commandmeta.HelpView {
+	view := commandmeta.HelpView{
+		EnteredPath:   clonePath(route.enteredPath),
+		CanonicalPath: clonePath(route.canonicalPath),
+		Discovery:     route.kind == routeDiscovery,
+	}
+	if snapshot == nil {
+		return view
+	}
+	if view.Discovery {
+		view.CommandAliases = discoveryHelpAliases(snapshot.commandAliases, route.discoveryPath)
+		view.FlagAliases = snapshot.discoveryFlags[route.discoveryPath.Key()].neutralRecords()
+		return view
+	}
+	view.FlagAliases = snapshot.flagAliases[route.canonicalPath.Key()].neutralRecords()
+	view.CommandAliases = routeHelpAliases(snapshot, route)
+	return view
+}
+
+func clonePath(path commandpath.Path) []string {
+	return append([]string(nil), path...)
+}
+
+func discoveryHelpAliases(aliases []commandmeta.CommandAlias, prefix commandpath.Path) []commandmeta.CommandAlias {
+	var result []commandmeta.CommandAlias
+	for _, alias := range aliases {
+		source := commandpath.FromTokens(alias.Source)
+		if len(source) <= len(prefix) || !source.HasPrefix(prefix) {
+			continue
+		}
+		result = append(result, commandmeta.CommandAlias{
+			Source: clonePath(source[len(prefix):]),
+			Target: append([]string(nil), alias.Target...),
+		})
+	}
+	return result
+}
+
+func routeHelpAliases(snapshot *routingSnapshot, route routeResult) []commandmeta.CommandAlias {
+	if len(route.canonicalPath) == 0 {
+		return append([]commandmeta.CommandAlias(nil), snapshot.commandAliases...)
+	}
+	node := traceCanonicalPath(snapshot.canonical, route.canonicalPath).exact
+	if node == nil || len(node.children) == 0 {
+		return nil
+	}
+
+	entered := route.enteredPath
+	canonical := route.canonicalPath
+	bySource := make(map[string]commandmeta.CommandAlias)
+	add := func(base commandpath.Path, includeOnlyWhenReached bool) {
+		for _, alias := range snapshot.commandAliases {
+			source := commandpath.FromTokens(alias.Source)
+			if len(source) <= len(base) || !source.HasPrefix(base) {
+				continue
+			}
+			suffix := source[len(base):]
+			if includeOnlyWhenReached {
+				enteredSource := append(entered.Clone(), suffix...)
+				if !snapshot.aliases.Resolve(enteredSource).Equal(commandpath.FromTokens(alias.Target)) {
+					continue
+				}
+			}
+			key := commandpath.FromTokens(suffix).Key()
+			if _, exists := bySource[key]; exists {
+				continue
+			}
+			bySource[key] = commandmeta.CommandAlias{
+				Source: clonePath(suffix),
+				Target: append([]string(nil), alias.Target...),
+			}
+		}
+	}
+	add(entered, false)
+	if !entered.Equal(canonical) {
+		add(canonical, true)
+	}
+
+	keys := make([]string, 0, len(bySource))
+	for key := range bySource {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	result := make([]commandmeta.CommandAlias, 0, len(keys))
+	for _, key := range keys {
+		result = append(result, bySource[key])
+	}
+	return result
+}