package distros

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

	"github.com/rs/zerolog/log"
	"golang.org/x/net/html"
	"libguestfs.org/guestfs"

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

// TODO: reduce code duplication with FedoraTemplateManager

type AlmaLinuxTemplateManager struct {
	TemplateManager
}

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

func (mgr *AlmaLinuxTemplateManager) GetLatestVersion() (version string, codename string, err error) {
	resp, err := http.Get("https://mirror.csclub.uwaterloo.ca/almalinux/")
	if err != nil {
		return
	}
	defer resp.Body.Close()
	node, err := html.Parse(resp.Body)
	if err != nil {
		return
	}
	var intVersion int64
	getMaxVersionFromHtml(node, &intVersion)
	if intVersion == 0 {
		err = errors.New("Could not determine latest AlmaLinux version from HTML")
	} else {
		version = strconv.FormatInt(intVersion, 10)
		// AlmaLinux doesn't have codenames, only numbered versions
		codename = version
	}
	return
}

func (mgr *AlmaLinuxTemplateManager) DownloadTemplate(version, codename string) (path string, err error) {
	floatVersion, err := strconv.ParseFloat(version, 64)
	if err != nil {
		return
	}
	majorVersion := int(floatVersion)
	filename := fmt.Sprintf("AlmaLinux-%d-GenericCloud-latest.x86_64.qcow2", majorVersion)
	url := fmt.Sprintf("https://mirror.csclub.uwaterloo.ca/almalinux/%s/cloud/x86_64/images/%s", version, filename)
	return mgr.DownloadTemplateGeneric(filename, url)
}

func (mgr *AlmaLinuxTemplateManager) UsesNetworkManager() bool {
	return true
}

func (mgr *AlmaLinuxTemplateManager) addCloudInitSnippet(handle *guestfs.Guestfs) error {
	path := "/etc/cloud/cloud.cfg.d/99_csclub.cfg"
	mgr.logger.Debug().Msg("Writing to " + path)
	return handle.Write(path, getResource("fedora-cloud-init"))
}

func (mgr *AlmaLinuxTemplateManager) HasSELinuxEnabled() bool {
	return true
}

func (mgr *AlmaLinuxTemplateManager) CommandToUpdatePackageCache() []string {
	return fedoraCommandToUpdatePackageCache()
}

var almaLinuxYumRepoBaseUrlPattern *regexp.Regexp = regexp.MustCompile(
	"^(?P<scheme>https?://)[A-Za-z0-9./-]+(?P<path>/almalinux/\\$releasever/[A-Za-z0-9./$-]+)$",
)

func (mgr *AlmaLinuxTemplateManager) transformAlmaLinuxYumRepoBaseUrl(url string) string {
	submatches := almaLinuxYumRepoBaseUrlPattern.FindStringSubmatch(url)
	if submatches != nil {
		scheme, path := submatches[1], submatches[2]
		url = scheme + mgr.cfg.MirrorHost + path
	}
	return url
}

func (mgr *AlmaLinuxTemplateManager) PerformDistroSpecificModifications(handle *guestfs.Guestfs) (err error) {
	if err = mgr.setChronyOptions(handle, "/etc/chrony.conf"); err != nil {
		return
	}
	if err = mgr.setNetworkManagerOptions(handle); err != nil {
		return
	}
	if err = mgr.addCloudInitSnippet(handle); err != nil {
		return
	}
	if err = mgr.replaceYumMirrorUrls(handle, mgr.transformAlmaLinuxYumRepoBaseUrl); err != nil {
		return
	}
	return
}