feat: mail service

mail/internal/domain/template/model.go

@@ -0,0 +1,65 @@
+// Package template defines the logical template entity used by the
+// filesystem-backed Mail Service template catalog.
+package template
+
+import (
+	"fmt"
+	"strings"
+
+	"galaxy/mail/internal/domain/common"
+)
+
+// Template stores one locale-specific template bundle.
+type Template struct {
+	// TemplateID identifies the template family.
+	TemplateID common.TemplateID
+
+	// Locale stores the canonical locale of the template variant.
+	Locale common.Locale
+
+	// SubjectTemplate stores the subject template source.
+	SubjectTemplate string
+
+	// TextTemplate stores the plaintext body template source.
+	TextTemplate string
+
+	// HTMLTemplate stores the optional HTML body template source.
+	HTMLTemplate string
+
+	// Version stores the template version marker projected into the domain
+	// model.
+	Version string
+}
+
+// Validate reports whether Template satisfies the frozen Stage 2 structural
+// invariants.
+func (record Template) Validate() error {
+	if err := record.TemplateID.Validate(); err != nil {
+		return fmt.Errorf("template id: %w", err)
+	}
+	if err := record.Locale.Validate(); err != nil {
+		return fmt.Errorf("template locale: %w", err)
+	}
+	if record.SubjectTemplate == "" {
+		return fmt.Errorf("template subject template must not be empty")
+	}
+	if record.TextTemplate == "" {
+		return fmt.Errorf("template text template must not be empty")
+	}
+	if err := validateToken("template version", record.Version); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func validateToken(name string, value string) error {
+	switch {
+	case strings.TrimSpace(value) == "":
+		return fmt.Errorf("%s must not be empty", name)
+	case strings.TrimSpace(value) != value:
+		return fmt.Errorf("%s must not contain surrounding whitespace", name)
+	default:
+		return nil
+	}
+}

mail/internal/domain/template/model_test.go

@@ -0,0 +1,71 @@
+package template
+
+import (
+	"testing"
+
+	"galaxy/mail/internal/domain/common"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestTemplateValidate(t *testing.T) {
+	t.Parallel()
+
+	locale, err := common.ParseLocale("en-us")
+	require.NoError(t, err)
+
+	tests := []struct {
+		name    string
+		record  Template
+		wantErr bool
+	}{
+		{
+			name: "valid",
+			record: Template{
+				TemplateID:      common.TemplateID("auth.login_code"),
+				Locale:          locale,
+				SubjectTemplate: "Your code",
+				TextTemplate:    "Code: {{.Code}}",
+				HTMLTemplate:    "<p>Code: {{.Code}}</p>",
+				Version:         "sha256:abcd",
+			},
+		},
+		{
+			name: "non canonical locale rejected",
+			record: Template{
+				TemplateID:      common.TemplateID("auth.login_code"),
+				Locale:          common.Locale("en-us"),
+				SubjectTemplate: "Your code",
+				TextTemplate:    "Code: {{.Code}}",
+				Version:         "sha256:abcd",
+			},
+			wantErr: true,
+		},
+		{
+			name: "missing subject template",
+			record: Template{
+				TemplateID:   common.TemplateID("auth.login_code"),
+				Locale:       locale,
+				TextTemplate: "Code: {{.Code}}",
+				Version:      "sha256:abcd",
+			},
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			err := tt.record.Validate()
+			if tt.wantErr {
+				require.Error(t, err)
+				return
+			}
+
+			require.NoError(t, err)
+		})
+	}
+}