package packages

import (
	"brunel/deb"
	"compress/bzip2"
	"fmt"
	"net/http"
	"strconv"
	"strings"
	"time"
)

const nest64Url = "https://ppa.pika-os.com/dists/pika/nest/binary-amd64/Packages.bz2"
const canary64Url = "https://ppa.pika-os.com/dists/pika/canary/binary-amd64/Packages.bz2"
const nest32Url = "https://ppa.pika-os.com/dists/pika/nest/binary-i386/Packages.bz2"
const canary32Url = "https://ppa.pika-os.com/dists/pika/canary/binary-i386/Packages.bz2"

type freezeItem struct {
	Name string
	Ver  string
}

func GetFreezeItems() ([]freezeItem, []freezeItem, error) {
	freeze64, err := compareRepositories(nest64Url, canary64Url)
	if err != nil {
		return nil, nil, fmt.Errorf("error comparing 64-bit repositories: %w", err)
	}

	freeze32, err := compareRepositories(nest32Url, canary32Url)
	if err != nil {
		return nil, nil, fmt.Errorf("error comparing 32-bit repositories: %w", err)
	}

	return freeze64, freeze32, nil
}

func compareRepositories(nestUrl, canaryUrl string) ([]freezeItem, error) {
	nestPackages, err := getPackages(nestUrl)
	if err != nil {
		return nil, fmt.Errorf("error getting nest packages: %w", err)
	}

	canaryPackages, err := getPackages(canaryUrl)
	if err != nil {
		return nil, fmt.Errorf("error getting canary packages: %w", err)
	}

	nestSet := make(map[string]bool)
	for _, pkg := range nestPackages {
		nestSet[pkg] = true
	}

	var freezeItems []freezeItem
	for _, pkg := range canaryPackages {
		if !nestSet[pkg] {
			parts := strings.SplitN(pkg, ":", 2)
			if len(parts) == 2 {
				freezeItems = append(freezeItems, freezeItem{Name: parts[0], Ver: parts[1]})
			}
		}
	}

	return freezeItems, nil
}

func getPackages(url string) ([]string, error) {
	resp, err := http.Get(url + "?nocache=" + strconv.Itoa(int(time.Now().Unix())))
	if err != nil {
		return nil, fmt.Errorf("fetching package file: %w", err)
	}
	defer resp.Body.Close()

	rdr := bzip2.NewReader(resp.Body)
	sreader := deb.NewControlFileReader(rdr, false, false)

	var packages []string

	for {
		stanza, err := sreader.ReadStanza()
		if err != nil || stanza == nil {
			break
		}

		name := stanza["Package"]
		versionStr := stanza["Version"]

		if name == "" || versionStr == "" {
			continue
		}

		if strings.Contains(name, "-dbgsym") {
			continue
		}

		packages = append(packages, name+":"+versionStr)
	}

	return packages, nil
}