package main

import (
	"fmt"
	"log"
	"os"
	"os/exec"
	"strings"
)

type OS struct {
	ID             string
	Name           string
	Version        string
	PackageManager string
	InstallCommand string
}

func parseOsRelease(osRelease string) *OS {
	var result OS
	result.ID = "Unknown"
	result.Name = "Unknown"
	result.Version = "Unknown"
	result.PackageManager = "Unkown"
	result.InstallCommand = "Unkown"

	lines := strings.Split(osRelease, "\n")

	for _, line := range lines {
		splitLine := strings.SplitN(line, "=", 2)
		if len(splitLine) != 2 {
			continue
		}
		switch splitLine[0] {
		case "ID":
			result.ID = strings.ToLower(strings.Trim(splitLine[1], "\""))
		case "NAME":
			result.Name = strings.Trim(splitLine[1], "\"")
		case "VERSION_ID":
			result.Version = strings.Trim(splitLine[1], "\"")
		}
	}
	err := result.getPackageManager()
	if err != nil {
		log.Fatal(err)
	}
	err = result.getInstallCommand()
	if err != nil {
		log.Fatal(err)
	}
	return &result
}

func getLinuxDistribution() (*OS, error) {
	_, err := os.Stat("/etc/os-release")
	if os.IsNotExist(err) {
		return nil, fmt.Errorf("unable to read system information")
	}

	osRelease, _ := os.ReadFile("/etc/os-release")
	return parseOsRelease(string(osRelease)), nil
}

func (os *OS) getPackageManager() error {
	switch os.ID {
	case "debian", "ubuntu":
		os.PackageManager = "apt"
		return nil
	case "arch":
		os.PackageManager = "pacman"
		return nil
	case "fedora":
		os.PackageManager = "dnf"
		return nil
	default:
		pmcommands := []string{
			"apt",
			"dnf",
			"pacman",
		}
		for _, pmname := range pmcommands {
			_, err := exec.LookPath(pmname)
			if err == nil {
				os.PackageManager = pmname
				return nil
			}
		}
		return fmt.Errorf("no packagemanager found for os: %s", os)
	}
}

func (os *OS) getInstallCommand() error {
	switch os.PackageManager {
	case "apt":
		os.InstallCommand = "apt install -y"
		return nil
	case "pacman":
		os.InstallCommand = "pacman -S --noconfirm --needed"
		return nil
	case "dnf":
		os.InstallCommand = "dnf install -y --best"
		return nil
	default:
		return fmt.Errorf("no install command found for package manager: %s", os.ID)
	}
}

func installBuildEssentials(os *OS, sudoPassword string) error {
	var command string
	switch os.PackageManager {
	case "pacman":
		command = "pacman -S --noconfirm --needed base-devel"
	case "apt":
		command = "apt install -y build-essential"
	case "dnf":
		command = "dnf install -y @development-tools"
	default:
		return fmt.Errorf("keine Build Essentials für OS %s definiert", os.ID)
	}

	fmt.Printf("Installiere Build Essentials für %s...\n", os.Name)
	if err := installPackage(command, "", sudoPassword); err != nil {
		return fmt.Errorf("fehler bei der Installation der Build Essentials: %v", err)
	}
	return nil
}