package distros

import (
	"bufio"
	"errors"
	"fmt"
	"net/http"
	"regexp"

	"github.com/rs/zerolog/log"
	"libguestfs.org/guestfs"

	"git.csclub.uwaterloo.ca/cloud/cloudbuild/pkg/config"
)

type DebianTemplateManager struct {
	TemplateManager
}

// NewDebianTemplateManager returns a DebianTemplateManager with the given
// config values.
func NewDebianTemplateManager(cfg *config.Config) *DebianTemplateManager {
	logger := log.With().Str("distro", "debian").Logger()
	debianTemplateManager := DebianTemplateManager{
		TemplateManager{
			cfg:    cfg,
			logger: &logger,
			impl:   nil,
		},
	}
	debianTemplateManager.TemplateManager.impl = &debianTemplateManager
	return &debianTemplateManager
}

func (mgr *DebianTemplateManager) GetLatestVersion() (version string, codename string, err error) {
	// We're only interested in the major version (integer part)
	versionPattern := regexp.MustCompile("^Version: (\\d+)(?:\\.\\d)?$")
	codenamePattern := regexp.MustCompile("^Codename: ([a-z-]+)$")
	resp, err := http.Get("https://mirror.csclub.uwaterloo.ca/debian/dists/stable/InRelease")
	if err != nil {
		return
	}
	defer resp.Body.Close()
	scanner := bufio.NewScanner(resp.Body)
	for scanner.Scan() {
		if version == "" {
			submatches := versionPattern.FindStringSubmatch(scanner.Text())
			if submatches != nil {
				version = submatches[1]
			}
		}
		if codename == "" {
			submatches := codenamePattern.FindStringSubmatch(scanner.Text())
			if submatches != nil {
				codename = submatches[1]
			}
		}
		if version != "" && codename != "" {
			break
		}
	}
	if version == "" {
		err = errors.New("Could not determine latest version of Debian")
	}
	return
}

func (mgr *DebianTemplateManager) DownloadTemplate(version, codename string) (path string, err error) {
	filename := fmt.Sprintf("debian-%s-genericcloud-amd64.qcow2", version)
	url := fmt.Sprintf("https://cloud.debian.org/images/cloud/%s/latest/%s", codename, filename)
	return mgr.DownloadTemplateGeneric(filename, url)
}

func (mgr *DebianTemplateManager) HasSELinuxEnabled() bool {
	return false
}

func (mgr *DebianTemplateManager) UsesNetworkManager() bool {
	// Debian uses /etc/network/interfaces instead
	return false
}

func (mgr *DebianTemplateManager) CommandToUpdatePackageCache() []string {
	return debianCommandToUpdatePackageCache()
}

func (mgr *DebianTemplateManager) PerformDistroSpecificModifications(handle *guestfs.Guestfs) (err error) {
	if err = mgr.setChronyOptions(handle, "/etc/chrony/chrony.conf"); err != nil {
		return
	}
	if err = mgr.setDhclientOptions(handle); err != nil {
		return
	}
	if err = mgr.replaceDebianMirrorUrls(handle); err != nil {
		return
	}
	return
}