package tree

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

func Generate(root string) (string, error) {

	ig, _ := Load(root)

	var builder strings.Builder

	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		if path == root {
			builder.WriteString(".\n")
			return nil
		}

		rel, _ := filepath.Rel(root, path)

		// gitignore filter
		if ig != nil && ig.MatchesPath(rel) {
			if info.IsDir() {
				return filepath.SkipDir
			}
			return nil
		}

		level := strings.Count(rel, string(os.PathSeparator))
		prefix := strings.Repeat("│   ", level)

		builder.WriteString(fmt.Sprintf("%s├── %s\n", prefix, info.Name()))
		return nil
	})

	return builder.String(), err
}