package models

import (
	"encoding/json"
	"fmt"
)

// ParseSnapshotStages parses a version snapshot into a slice of
// WorkflowStage.  It handles both the wrapped format
// {"stages": [...], "workflow": {...}} and the legacy flat array [...].
func ParseSnapshotStages(raw json.RawMessage) ([]WorkflowStage, error) {
	// Try wrapped format first
	var wrapped struct {
		Stages []WorkflowStage `json:"stages"`
	}
	if err := json.Unmarshal(raw, &wrapped); err == nil && len(wrapped.Stages) > 0 {
		return wrapped.Stages, nil
	}
	// Fallback to flat array
	var stages []WorkflowStage
	if err := json.Unmarshal(raw, &stages); err != nil {
		return nil, fmt.Errorf("corrupt version snapshot: %w", err)
	}
	return stages, nil
}