package fastmirror

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
)

func cliEntry() {
	if runtime.GOOS != "linux" {
		log.Fatal("This program is only for Linux")
	}
	if !isUbuntu() {
		log.Fatal("This program is only for Ubuntu")
	}

	fp := identifySourcesFile()

	fmt.Printf("Found sources file: %s\n", fp)

	architecture := runtime.GOARCH
	switch architecture {
	case "amd64", "386":
		fmt.Println("Use archive.ubuntu.com for packages")
	default:
		fmt.Println("Use ports.ubuntu.com for packages")
	}
}

func getUbuntuCodename() string {
	cmd := exec.Command("lsb_release", "-cs")
	output, err := cmd.Output()
	if err != nil {
		log.Fatal("Failed to run lsb_release: %v\n", err)
	}
	codename := strings.TrimSpace(string(output))
	return codename
}

func isUbuntu() bool {
	cmd := exec.Command("lsb_release", "-is")
	output, err := cmd.Output()
	if err != nil {
		log.Fatal("Failed to run lsb_release: %v\n", err)
	}

	distro := strings.TrimSpace(string(output))
	if distro == "Ubuntu" {
		return true
	} else {
		return false
	}
}

func identifySourcesFile() string {
	const sourcesList = "/etc/apt/sources.list"
	const sourcesListD = "/etc/apt/sources.list.d/"
	if checkFileForUbuntu(sourcesList) {
		fmt.Printf("Found Ubuntu sources file: %s\n", sourcesList)
		return sourcesList
	}
	files, err := ioutil.ReadDir(sourcesListD)
	if err != nil {
		fmt.Printf("Failed to read directory %s: %v\n", sourcesListD, err)
		os.Exit(1)
	}

	for _, file := range files {
		if file.IsDir() {
			continue
		}

		filePath := filepath.Join(sourcesListD, file.Name())
		if checkFileForUbuntu(filePath) {
			fmt.Printf("Found Ubuntu sources file: %s\n", filePath)
			return filePath
		}
	}
	return ""
}

func checkFileForUbuntu(filePath string) bool {
	content, err := ioutil.ReadFile(filePath)
	if err != nil {
		fmt.Printf("Failed to read file %s: %v\n", filePath, err)
		return false
	}

	if strings.Contains(strings.ToLower(string(content)), "ubuntu.com") {
		return true
	}

	return false
}