//go:build linux

package utils

import (
	"git.jmbit.de/jmb/patchman/common"
	"log"
	"os"
	"os/exec"
	"runtime"
	"strings"
)

var OSInfoCache common.OSInfo

// GetOSInfo() parses /etc/os-release and uname for OS information
func GetOSInfo() common.OSInfo {
	if OSInfoCache.OS != "" {
		return OSInfoCache
	}
	var distribution string
	var version string
	var distributionLike []string
	var kernelRelease string
	var packageManager string

	data, err := os.ReadFile("/etc/os-release")
	if err != nil {
		log.Fatalf("Could not read /etc/os-release: %w", err)
	}
	lines := strings.Split(string(data), "\n")

	for _, line := range lines {
		if strings.HasPrefix(line, "ID=") {
			// Extract distribution ID
			distribution = strings.Trim(strings.SplitN(line, "=", 2)[1], "\"")
		}
		if strings.HasPrefix(line, "ID_LIKE=") {
			// Extract ID_Like
			distributionLike = strings.Split(strings.Trim(strings.SplitN(line, "=", 2)[1], "\""), " ")
		}
		if strings.HasPrefix(line, "VERSION_ID=") {
			// Extract Version string
			version = strings.Trim(strings.SplitN(line, "=", 2)[1], "\"")

		}
	}

	unameRelease := exec.Command("/usr/bin/uname", "-r")
	unameReleaseOutput, err := unameRelease.Output()
	if err != nil {
		log.Printf("Could not determine Kernel release: %w", err)
	} else {
		kernelRelease = strings.TrimRight(string(unameReleaseOutput), "\n")
	}

	//determine package manager
	packageManager = getPackageManager(distribution, distributionLike)

	return common.OSInfo{
		OS:               runtime.GOOS,
		Distribution:     distribution,
		DistributionLike: distributionLike,
		Version:          version,
		KernelRelease:    kernelRelease,
		Architecture:     runtime.GOARCH,
		PackageManager:   packageManager,
	}
}

// getPackageManager determines the Package Manager used by the system.
// TODO support multiple Package Managers at once.
func getPackageManager(distribution string, distributionLike []string) string {
	distroLike := append(distributionLike, distribution)
	if IsStringInSlice("debian", distroLike) {
		return "apt"
	}
	if IsStringInSlice("suse", distroLike) {
		return "zypper"
	}
	if IsStringInSlice("fedora", distroLike) {
		return "dnf"
	} else {
		return ""
	}

}