package utils

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

func ExpandGlob(patterns []string) ([]string, error) {
	var result []string
	seen := make(map[string]struct{})

	for _, pattern := range patterns {

		if pattern == "*" {
			filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
				if err != nil {
					return nil
				}
				if info.IsDir() {
					return nil
				}
				add(path, seen, &result)
				return nil
			})
			continue
		}

		isRecursive := strings.Contains(pattern, "**")

		if isRecursive {
			root := strings.Split(pattern, "**")[0]
			if root == "" {
				root = "."
			}

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

				matched, _ := filepath.Match(
					strings.Replace(pattern, "**", "*", 1),
					path,
				)

				if matched {
					add(path, seen, &result)
				}
				return nil
			})
			continue
		}

		matches, err := filepath.Glob(pattern)
		if err != nil {
			return nil, err
		}

		for _, m := range matches {
			info, err := os.Stat(m)
			if err != nil || info.IsDir() {
				continue
			}
			add(m, seen, &result)
		}
	}

	return result, nil
}

func add(path string, seen map[string]struct{}, result *[]string) {
	if _, ok := seen[path]; ok {
		return
	}
	seen[path] = struct{}{}
	*result = append(*result, path)
}