package config

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

func parseLibraryRoots(raw string) ([]string, error) {
	var roots []string
	seenRoots := make(map[string]bool)

	for _, entry := range strings.Split(raw, ";") {
		entry = strings.TrimSpace(entry)
		if entry == "" {
			continue
		}

		root, err := resolveRoot(entry)
		if err != nil {
			return nil, err
		}
		if seenRoots[root] {
			continue
		}
		seenRoots[root] = true
		roots = append(roots, root)
	}

	if len(roots) == 0 {
		return nil, errors.New("LIBRARY_ROOTS must list at least one folder")
	}
	return roots, nil
}

func resolveRoot(entry string) (string, error) {
	cleaned := filepath.Clean(entry)
	if !filepath.IsAbs(cleaned) || cleaned == "/" {
		return "", fmt.Errorf("LIBRARY_ROOTS: invalid path %q", entry)
	}

	resolved, err := filepath.EvalSymlinks(cleaned)
	if err != nil {
		return "", fmt.Errorf("LIBRARY_ROOTS: %w", err)
	}
	info, err := os.Stat(resolved)
	if err != nil {
		return "", fmt.Errorf("LIBRARY_ROOTS: %w", err)
	}
	if !info.IsDir() {
		return "", fmt.Errorf("LIBRARY_ROOTS: %q is not a directory", entry)
	}
	return resolved, nil
}