Add queued email notifications for collaboration events

apps/server/internal/email/templates.go

@@ -0,0 +1,149 @@
+package email
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+// TemplateData carries the context required to render any notification email.
+// Fields are optional per template; callers should populate what they have.
+type TemplateData struct {
+	ActorName    string
+	ActorEmail   string
+	DocumentPath string
+	DocumentTitle string
+	CommentBody  string
+	MentionText  string
+	ConflictDesc string
+	ViewURL      string
+	UnsubURL     string
+	InstanceName string
+}
+
+// Render returns a plain-text subject and body for the given notification
+// type. Subjects are short and prefixed with the document path so email
+// clients thread per-document.
+func Render(kind string, data TemplateData) (subject, body string, err error) {
+	if data.InstanceName == "" {
+		data.InstanceName = "Cairnquire"
+	}
+	switch kind {
+	case "file_changed":
+		return renderFileChanged(data)
+	case "comment":
+		return renderComment(data)
+	case "mention":
+		return renderMention(data)
+	case "conflict":
+		return renderConflict(data)
+	default:
+		return "", "", fmt.Errorf("unknown email template kind %q", kind)
+	}
+}
+
+func subjectPrefix(data TemplateData) string {
+	if data.DocumentPath != "" {
+		return "[" + data.DocumentPath + "]"
+	}
+	return "[" + data.InstanceName + "]"
+}
+
+func footer(data TemplateData) string {
+	var b strings.Builder
+	b.WriteString("\n--\n")
+	if data.ViewURL != "" {
+		fmt.Fprintf(&b, "View online: %s\n", data.ViewURL)
+	}
+	if data.UnsubURL != "" {
+		fmt.Fprintf(&b, "Unsubscribe: %s\n", data.UnsubURL)
+	}
+	fmt.Fprintf(&b, "You receive this because you watch this document on %s.\n", data.InstanceName)
+	return b.String()
+}
+
+func renderFileChanged(data TemplateData) (string, string, error) {
+	title := data.DocumentTitle
+	if title == "" {
+		title = data.DocumentPath
+	}
+	actor := data.ActorName
+	if actor == "" {
+		actor = "Someone"
+	}
+	subject := fmt.Sprintf("%s Updated by %s", subjectPrefix(data), actor)
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "%s updated %q at %s UTC.\n", actor, title, time.Now().UTC().Format("2006-01-02 15:04"))
+	if data.DocumentPath != "" {
+		fmt.Fprintf(&b, "Path: %s\n", data.DocumentPath)
+	}
+	b.WriteString("\nView the changes online to see what is new.\n")
+	b.WriteString(footer(data))
+	return subject, b.String(), nil
+}
+
+func renderComment(data TemplateData) (string, string, error) {
+	actor := data.ActorName
+	if actor == "" {
+		actor = "Someone"
+	}
+	subject := fmt.Sprintf("%s Comment from %s", subjectPrefix(data), actor)
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "%s commented on %q:\n", actor, docLabel(data))
+	b.WriteString("\n")
+	if data.CommentBody != "" {
+		// Quote the comment body, line by line, as plain text.
+		for _, line := range strings.Split(data.CommentBody, "\n") {
+			fmt.Fprintf(&b, "> %s\n", line)
+		}
+	} else {
+		b.WriteString("> (no body)\n")
+	}
+	b.WriteString("\nReply to this email to respond.\n")
+	b.WriteString(footer(data))
+	return subject, b.String(), nil
+}
+
+func renderMention(data TemplateData) (string, string, error) {
+	actor := data.ActorName
+	if actor == "" {
+		actor = "Someone"
+	}
+	subject := fmt.Sprintf("%s Mention from %s", subjectPrefix(data), actor)
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "%s mentioned you on %q.\n", actor, docLabel(data))
+	if data.MentionText != "" {
+		b.WriteString("\n")
+		for _, line := range strings.Split(data.MentionText, "\n") {
+			fmt.Fprintf(&b, "> %s\n", line)
+		}
+	}
+	b.WriteString(footer(data))
+	return subject, b.String(), nil
+}
+
+func renderConflict(data TemplateData) (string, string, error) {
+	subject := fmt.Sprintf("%s Sync conflict", subjectPrefix(data))
+
+	var b strings.Builder
+	fmt.Fprintf(&b, "A sync conflict was detected on %q.\n", docLabel(data))
+	if data.ConflictDesc != "" {
+		fmt.Fprintf(&b, "\nDetails: %s\n", data.ConflictDesc)
+	}
+	b.WriteString("\nOpen the document to review and resolve the conflict.\n")
+	b.WriteString(footer(data))
+	return subject, b.String(), nil
+}
+
+func docLabel(data TemplateData) string {
+	if data.DocumentTitle != "" {
+		return data.DocumentTitle
+	}
+	if data.DocumentPath != "" {
+		return data.DocumentPath
+	}
+	return "a document"
+}