package util

import (
	"path/filepath"
	"strings"
)

// CleanRelative validates and cleans a workspace-relative path.
// It rejects absolute paths and paths that escape the workspace root via "..".
// Empty path and "." return ".".
func CleanRelative(path string) (string, error) {
	if path == "" || path == "." {
		return ".", nil
	}

	// Reject absolute paths.
	if filepath.IsAbs(path) {
		return "", New(CodeBadRequest, "absolute paths are not allowed")
	}

	cleaned := filepath.Clean(path)

	// Reject paths that escape the workspace root.
	if cleaned == ".." || strings.HasPrefix(cleaned, ".."+string(filepath.Separator)) {
		return "", New(CodeBadRequest, "path escapes workspace root")
	}

	return cleaned, nil
}

// JoinClean joins base and elem after cleaning, returning a cleaned path.
func JoinClean(base, elem string) string {
	return filepath.Clean(filepath.Join(base, elem))
}