package providers

import (
	"fmt"
	"os"
	"os/exec"
	"strconv"
	"strings"
	"sync"
)

func pathExists(path string) bool {
	_, err := os.Stat(path)
	return err == nil
}

func getPmPackages(packagerName string, packagerPath string) string {
	if pathExists(packagerPath) {
		pkgs, err := os.ReadDir(packagerPath)
		if err != nil {
			return "error reading " + packagerPath
		}
		if packagerName == "pacman" {
			return strconv.Itoa(len(pkgs)-1) + " (pacman)"
		}
		if packagerName == "apk" {
			out, err := exec.Command("apk", "info").Output()
			if err != nil {
				return "error reading apk package list"
			}
			pkgsRaw := strings.TrimSpace(string(out))

			pkgsList := strings.Split(pkgsRaw, "\n")
			pkgCount := len(pkgsList)

			if pkgsRaw == "" {
				pkgCount = 0
			}

			return fmt.Sprintf("%d (apk)", pkgCount)
		}
		return strconv.Itoa(len(pkgs)) + " (" + packagerName + ")"
	}
	return ""
}

func GetPkgs() string {
	managers := []struct {
		name, path string
	}{
		{"pacman", "/var/lib/pacman/local"},
		{"nix-user", os.Getenv("HOME") + "/.local/state/nix/profiles/profile/bin"},
		{"nix", "/run/current-system/sw/bin"},
		{"apt", "/var/lib/apt"},
		{"dnf", "/var/lib/dnf"},
		{"zypper", "/var/lib/zypp"},
		{"xbps", "/var/db/xbps"},
		{"emerge", "/var/lib/portage"},
		{"apk", "/etc/apk/"},
		{"flatpak", "/var/lib/flatpak/app"},
	}

	results := make([]string, len(managers))
	var wg sync.WaitGroup

	for i, m := range managers {
		wg.Add(1)
		go func(idx int, name, path string) {
			defer wg.Done()
			if p := getPmPackages(name, path); p != "" {
				results[idx] = p
			}
		}(i, m.name, m.path)
	}

	wg.Wait()

	var pkgsList []string
	for _, p := range results {
		if p != "" {
			pkgsList = append(pkgsList, p)
		}
	}

	if len(pkgsList) == 0 {
		return "unknown package manager"
	}

	return strings.Join(pkgsList, ", ")
}