package config

import (
	"fmt"
	"path/filepath"
	"strings"
)

// DefaultChunkPlanRoot resolves the existing per-user chunk-plan cache root.
func DefaultChunkPlanRoot(userCacheDir func() (string, error)) (string, error) {
	if userCacheDir == nil {
		return "", fmt.Errorf("user cache directory resolver must not be nil")
	}
	root, err := userCacheDir()
	if err != nil {
		return "", fmt.Errorf("resolve user cache directory: %w", err)
	}
	root = strings.TrimSpace(root)
	if root == "" {
		return "", fmt.Errorf("user cache directory must not be empty")
	}
	return filepath.Join(filepath.Clean(root), "notarius", "chunk-plans"), nil
}