feat: message parser with json/regex/text modes

internal/parser/parser.go

@@ -0,0 +1,33 @@
+package parser
+
+import (
+	"fmt"
+)
+
+// ParsedMessage is the result of parsing an incoming notification body.
+type ParsedMessage struct {
+	Event string
+	Data  map[string]interface{} // field name → value, passed to template
+	Body  string                 // raw body (for text mode)
+}
+
+// Parser converts a raw HTTP body into a ParsedMessage.
+type Parser interface {
+	Parse(body []byte) (*ParsedMessage, error)
+}
+
+func NewParser(parseMode string, parsePattern string) (Parser, error) {
+	switch parseMode {
+	case "json":
+		return &JSONParser{}, nil
+	case "regex":
+		if parsePattern == "" {
+			return nil, fmt.Errorf("regex parse mode requires parse_pattern")
+		}
+		return NewRegexParser(parsePattern)
+	case "text":
+		return &TextParser{}, nil
+	default:
+		return nil, fmt.Errorf("unknown parse_mode: %s", parseMode)
+	}
+}