feat: message parser with json/regex/text modes

internal/parser/json.go

@@ -0,0 +1,37 @@
+package parser
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type JSONParser struct{}
+
+func (p *JSONParser) Parse(body []byte) (*ParsedMessage, error) {
+	var raw map[string]interface{}
+	if err := json.Unmarshal(body, &raw); err != nil {
+		return nil, fmt.Errorf("json parse: %w", err)
+	}
+
+	event, ok := raw["event"].(string)
+	if !ok {
+		return nil, fmt.Errorf("json: missing 'event' field")
+	}
+
+	data, _ := raw["data"].(map[string]interface{})
+	if data == nil {
+		// If no "data" key, use the entire JSON as data (minus event)
+		data = make(map[string]interface{})
+		for k, v := range raw {
+			if k != "event" {
+				data[k] = v
+			}
+		}
+	}
+
+	return &ParsedMessage{
+		Event: event,
+		Data:  data,
+		Body:  string(body),
+	}, nil
+}