Add dynamic admin panel for managing entities (#108)

ent/admin/extension.go

@@ -0,0 +1,97 @@
+package admin
+
+import (
+	"embed"
+	"strings"
+	"text/template"
+	"unicode"
+
+	"entgo.io/ent/entc"
+	"entgo.io/ent/entc/gen"
+	"entgo.io/ent/schema/field"
+)
+
+var (
+	//go:embed templates
+	templateDir embed.FS
+)
+
+// Extension is the Ent extension that generates code to support the entity admin panel.
+type Extension struct {
+	entc.DefaultExtension
+}
+
+func (*Extension) Templates() []*gen.Template {
+	return []*gen.Template{
+		gen.MustParse(
+			gen.NewTemplate("admin").
+				Funcs(template.FuncMap{
+					"fieldName":      fieldName,
+					"fieldLabel":     FieldLabel,
+					"fieldIsPointer": fieldIsPointer,
+				}).
+				ParseFS(templateDir, "templates/*tmpl"),
+		),
+	}
+}
+
+// fieldName provides a struct field name from an entity field name (ie, user_id -> UserID).
+func fieldName(name string) string {
+	if len(name) == 0 {
+		return name
+	}
+
+	parts := strings.Split(name, "_")
+	for i := 0; i < len(parts); i++ {
+		if parts[i] == "id" {
+			parts[i] = "ID"
+		} else {
+			parts[i] = upperFirst(parts[i])
+		}
+	}
+
+	return strings.Join(parts, "")
+}
+
+// FieldLabel provides a label for an entity field name (ie, user_id -> User ID).
+func FieldLabel(name string) string {
+	if len(name) == 0 {
+		return name
+	}
+
+	parts := strings.Split(name, "_")
+	for i := 0; i < len(parts); i++ {
+		if parts[i] == "id" {
+			parts[i] = "ID"
+		}
+		if i == 0 {
+			parts[i] = upperFirst(parts[i])
+		}
+	}
+
+	return strings.Join(parts, " ")
+}
+
+// fieldIsPointer determines if a given entity field should be a pointer on the struct.
+func fieldIsPointer(f *gen.Field) bool {
+	switch {
+	case f.Type.Type == field.TypeBool:
+		return false
+	case f.Optional,
+		f.Default,
+		f.Sensitive(),
+		f.Nillable:
+		return true
+	}
+	return false
+}
+
+// upperFirst uppercases the first character of a given string.
+func upperFirst(s string) string {
+	if len(s) == 0 {
+		return s
+	}
+	out := []rune(s)
+	out[0] = unicode.ToUpper(out[0])
+	return string(out)
+}