package treepath

import "encoding/json"

// IsSummaryMessage checks if a PathMessage has summary metadata
// (metadata.type == "summary").
func IsSummaryMessage(m *PathMessage) bool {
	if m.Metadata == nil {
		return false
	}
	meta := ParseMetadata(m)
	return meta["type"] == "summary"
}

// ParseMetadata unmarshals the JSONB metadata on a PathMessage.
// Returns an empty map on any error.
func ParseMetadata(m *PathMessage) map[string]interface{} {
	if m.Metadata == nil {
		return map[string]interface{}{}
	}
	var meta map[string]interface{}
	if err := json.Unmarshal(*m.Metadata, &meta); err != nil {
		return map[string]interface{}{}
	}
	return meta
}

// FindSummaryBoundary returns the index of the most recent summary node
// in a path, or -1 if no summary exists.
func FindSummaryBoundary(path []PathMessage) int {
	idx := -1
	for i := range path {
		if IsSummaryMessage(&path[i]) {
			idx = i
		}
	}
	return idx
}