1 files changed, 110 insertions, 0 deletions
diff --git a/modules/templates/mailer.go b/modules/templates/mailer.go
new file mode 100644
index 00000000..ee79755d
--- /dev/null
+++ b/modules/templates/mailer.go
@@ -0,0 +1,110 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package templates
+
+import (
+	"context"
+	"fmt"
+	"html/template"
+	"regexp"
+	"strings"
+	texttmpl "text/template"
+
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+var mailSubjectSplit = regexp.MustCompile(`(?m)^-{3,}\s*$`)
+
+// mailSubjectTextFuncMap returns functions for injecting to text templates, it's only used for mail subject
+func mailSubjectTextFuncMap() texttmpl.FuncMap {
+	return texttmpl.FuncMap{
+		"dict": dict,
+		"Eval": Eval,
+
+		"EllipsisString": base.EllipsisString,
+		"AppName": func() string {
+			return setting.AppName
+		},
+		"AppSlogan": func() string {
+			return setting.AppSlogan
+		},
+		"AppDisplayName": func() string {
+			return setting.AppDisplayName
+		},
+		"AppDomain": func() string { // documented in mail-templates.md
+			return setting.Domain
+		},
+	}
+}
+
+func buildSubjectBodyTemplate(stpl *texttmpl.Template, btpl *template.Template, name string, content []byte) error {
+	// Split template into subject and body
+	var subjectContent []byte
+	bodyContent := content
+	loc := mailSubjectSplit.FindIndex(content)
+	if loc != nil {
+		subjectContent = content[0:loc[0]]
+		bodyContent = content[loc[1]:]
+	}
+	if _, err := stpl.New(name).Parse(string(subjectContent)); err != nil {
+		return fmt.Errorf("failed to parse template [%s/subject]: %w", name, err)
+	}
+	if _, err := btpl.New(name).Parse(string(bodyContent)); err != nil {
+		return fmt.Errorf("failed to parse template [%s/body]: %w", name, err)
+	}
+	return nil
+}
+
+// Mailer provides the templates required for sending notification mails.
+func Mailer(ctx context.Context) (*texttmpl.Template, *template.Template) {
+	subjectTemplates := texttmpl.New("")
+	bodyTemplates := template.New("")
+
+	subjectTemplates.Funcs(mailSubjectTextFuncMap())
+	bodyTemplates.Funcs(NewFuncMap())
+
+	assetFS := AssetFS()
+	refreshTemplates := func(firstRun bool) {
+		if !firstRun {
+			log.Trace("Reloading mail templates")
+		}
+		assetPaths, err := ListMailTemplateAssetNames(assetFS)
+		if err != nil {
+			log.Error("Failed to list mail templates: %v", err)
+			return
+		}
+
+		for _, assetPath := range assetPaths {
+			content, layerName, err := assetFS.ReadLayeredFile(assetPath)
+			if err != nil {
+				log.Warn("Failed to read mail template %s by %s: %v", assetPath, layerName, err)
+				continue
+			}
+			tmplName := strings.TrimPrefix(strings.TrimSuffix(assetPath, ".tmpl"), "mail/")
+			if firstRun {
+				log.Trace("Adding mail template %s: %s by %s", tmplName, assetPath, layerName)
+			}
+			if err = buildSubjectBodyTemplate(subjectTemplates, bodyTemplates, tmplName, content); err != nil {
+				if firstRun {
+					log.Fatal("Failed to parse mail template, err: %v", err)
+				}
+				log.Error("Failed to parse mail template, err: %v", err)
+			}
+		}
+	}
+
+	refreshTemplates(true)
+
+	if !setting.IsProd {
+		// Now subjectTemplates and bodyTemplates are both synchronized
+		// thus it is safe to call refresh from a different goroutine
+		go assetFS.WatchLocalChanges(ctx, func() {
+			refreshTemplates(false)
+		})
+	}
+
+	return subjectTemplates, bodyTemplates
+}