package packages

import (
	"brunel/config"
	"brunel/deb"
	"brunel/domain"
	"brunel/fastmap"
	"brunel/helpers"
	"compress/bzip2"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"slices"
	"strings"
	"time"

	"pault.ag/go/debian/version"

	"github.com/klauspost/compress/gzip"
	"github.com/ulikunitz/xz"
)

var LastUpdateTime time.Time
var currentPackagesFastMap = fastmap.New[string, domain.SourcePackage]()

func ProcessPackages() error {
	var internalPackages = fastmap.New[string, domain.SourcePackage]()
	var externalPackages = fastmap.New[string, domain.SourcePackage]()
	err := LoadInternalPackages(internalPackages)
	if err != nil {
		return err
	}
	err = LoadExternalPackages(externalPackages)
	if err != nil {
		return err
	}
	ProcessStalePackages(internalPackages, externalPackages)
	ProcessMissingPackages(internalPackages, externalPackages)

	currentPackagesFastMap.Clear()
	internalPackages.Iter(func(k string, v domain.SourcePackage) bool {
		currentPackagesFastMap.Set(k, v)
		return true
	})
	currentPackagesFastMap.StableSortByKey()

	LastUpdateTime = time.Now()
	helpers.ReloadCache()
	err = SaveToDb()
	if err != nil {
		return err
	}

	return nil
}

func GetPackages() *fastmap.Fastmap[string, domain.SourcePackage] {
	return currentPackagesFastMap
}

func UpdatePackage(pkg domain.PackageInfo) error {
	curr, ok := currentPackagesFastMap.Get(pkg.Source)
	if !ok {
		return fmt.Errorf("package %s not found", pkg.Source)
	}
	curr.Packages.Set(pkg.PackageName, pkg)
	currentPackagesFastMap.Set(pkg.Source, curr)
	return saveSingleToDb(curr)
}

func UpdateSourcePackage(pkg domain.SourcePackage) error {
	currentPackagesFastMap.Set(pkg.Name, pkg)
	return saveSingleToDb(pkg)
}

func IsBuilt(pkg domain.PackageInfo) bool {
	curr, ok := currentPackagesFastMap.Get(pkg.Source)
	if !ok {
		return false
	}
	pk, ok := curr.Packages.Get(pkg.PackageName)
	if !ok {
		return false
	}
	return pk.Status == domain.Built || pk.Status == domain.Current
}

func saveSingleToDb(pkg domain.SourcePackage) error {
	err := helpers.DBInst.UpdatePackage(pkg)
	if err != nil {
		return err
	}
	LastUpdateTime = time.Now()
	helpers.ReloadCache()
	err = helpers.DBInst.UpdateLastUpdateTime(LastUpdateTime)
	if err != nil {
		return err
	}
	return nil
}

func SaveToDb() error {
	err := helpers.DBInst.SavePackages(currentPackagesFastMap)
	if err != nil {
		slog.Error(err.Error())
		return err
	}
	LastUpdateTime = time.Now()
	helpers.ReloadCache()
	return helpers.DBInst.UpdateLastUpdateTime(LastUpdateTime)
}

func LoadFromDb() error {
	packages, err := helpers.DBInst.GetPackages()
	if err != nil {
		slog.Error(err.Error())
		return nil
	}
	slices.SortStableFunc(packages, func(a, b domain.SourcePackage) int {
		if a.Name == b.Name {
			return 0
		}
		if a.Name > b.Name {
			return 1
		}
		return -1
	})
	currentPackagesFastMap.Clear()
	for _, pkg := range packages {
		currentPackagesFastMap.Set(pkg.Name, pkg)
	}
	currentPackagesFastMap.StableSortByKey()
	return nil
}

func LoadInternalPackages(internalPackages *fastmap.Fastmap[string, domain.SourcePackage]) error {
	localPackageFile := config.Configs.LocalPackageFiles
	slices.SortStableFunc(localPackageFile, func(a, b config.PackageFile) int {
		if a.Priority == b.Priority {
			return 0
		}
		if a.Priority < b.Priority {
			return 1
		}
		return -1
	})

	for _, pkg := range config.Configs.LocalPackageFiles {
		for _, repo := range pkg.Subrepos {
			packages, err := fetchPackageFile(pkg, repo)
			if err != nil {
				return err
			}
			packages.Iter(func(newKey string, newPkg domain.PackageInfo) bool {
				pk, ok := internalPackages.Get(newPkg.Source)
				if !ok {
					newMap := fastmap.New[string, domain.PackageInfo]()
					newMap.Set(newKey, newPkg)
					internalPackages.Set(newPkg.Source, domain.SourcePackage{
						Name:     newPkg.Source,
						Packages: newMap,
					})
					return true
				}
				pkg, ok := pk.Packages.Get(newKey)
				if !ok {
					pk.Packages.Set(newKey, newPkg)
					return true
				}
				mVer, _ := version.Parse(pkg.Version)
				extVer, _ := version.Parse(newPkg.Version)
				cmpVal := version.Compare(extVer, mVer)
				if cmpVal >= 0 {
					pk.Packages.Set(newKey, newPkg)
					return true
				}
				return true
			})
		}
	}

	return nil
}

func LoadExternalPackages(externalPackages *fastmap.Fastmap[string, domain.SourcePackage]) error {
	externalPackageFile := config.Configs.ExternalPackageFiles
	slices.SortStableFunc(externalPackageFile, func(a, b config.PackageFile) int {
		if a.Priority == b.Priority {
			return 0
		}
		if a.Priority < b.Priority {
			return -1
		}
		return 1
	})

	for _, pkg := range config.Configs.ExternalPackageFiles {
		for _, repo := range pkg.Subrepos {
			packages, err := fetchPackageFile(pkg, repo)
			if err != nil {
				return err
			}
			packages.Iter(func(k string, v domain.PackageInfo) bool {
				pk, ok := externalPackages.Get(v.Source)
				if !ok {
					newMap := fastmap.New[string, domain.PackageInfo]()
					newMap.Set(k, v)
					externalPackages.Set(v.Source, domain.SourcePackage{
						Name:     v.Source,
						Packages: newMap,
					})
					return true
				}
				pkg, ok := pk.Packages.Get(k)
				if !ok {
					pk.Packages.Set(k, v)
					return true
				}
				mVer, _ := version.Parse(pkg.Version)
				extVer, _ := version.Parse(v.Version)
				cmpVal := version.Compare(extVer, mVer)
				if cmpVal >= 0 {
					pk.Packages.Set(k, v)
					return true
				}
				return true
			})
		}
	}

	return nil
}

func ProcessMissingPackages(internalPackages *fastmap.Fastmap[string, domain.SourcePackage], externalPackages *fastmap.Fastmap[string, domain.SourcePackage]) {
	externalPackages.Iter(func(k string, src domain.SourcePackage) bool {
		_, ok := internalPackages.Get(k)
		if !ok && src.Packages.Len() > 0 {
			newStatus := domain.Missing
			src.Packages.Iter(func(k string, v domain.PackageInfo) bool {
				v.Status = newStatus
				v.Version = strings.Split(v.Version, "+b")[0]
				src.Packages.Set(k, v)
				return true
			})
			internalPackages.Set(k, src)
		}
		return true
	})
}

func ProcessStalePackages(internalPackages *fastmap.Fastmap[string, domain.SourcePackage], externalPackages *fastmap.Fastmap[string, domain.SourcePackage]) {
	externalPackages.Iter(func(newPackage string, newSource domain.SourcePackage) bool {
		matchedPackage, ok := internalPackages.Get(newPackage)
		if !ok || matchedPackage.Packages.Len() == 0 {
			return true
		}
		matchedPackage.Packages.Iter(func(currentKey string, currentPackage domain.PackageInfo) bool {
			if currentPackage.Status == domain.Missing {
				return true
			}
			newSource.Packages.Iter(func(newKey string, newPackage domain.PackageInfo) bool {
				if currentKey != newKey {
					return true
				}
				newVersion := strings.Split(newPackage.Version, "+b")[0]
				mVer, _ := version.Parse(currentPackage.Version)
				extVer, _ := version.Parse(newVersion)
				cmpVal := version.Compare(mVer, extVer)
				if cmpVal < 0 {
					currentPackage.Status = domain.Stale
					currentPackage.NewVersion = extVer.String()
					matchedPackage.Packages.Set(currentKey, currentPackage)
				}
				return false
			})
			return true
		})
		wasMissing := false
		newSource.Packages.Iter(func(newKey string, newPackage domain.PackageInfo) bool {
			found := false
			matchedPackage.Packages.Iter(func(currentKey string, currentPackage domain.PackageInfo) bool {
				if currentKey != newKey {
					return true
				}
				found = true
				return false
			})
			if !found {
				wasMissing = true
				newPackage.Status = domain.Missing
				newPackage.NewVersion = newPackage.Version
				matchedPackage.Packages.Set(newKey, newPackage)
			}
			return true
		})
		if wasMissing {
			matchedPackage.Packages.Iter(func(k string, v domain.PackageInfo) bool {
				if v.Status == domain.Missing {
					return true
				}
				v.Status = domain.Missing
				return true
			})
		}
		return true
	})
}

func fetchPackageFile(pkg config.PackageFile, selectedRepo string) (*fastmap.Fastmap[string, domain.PackageInfo], error) {
	resp, err := http.Get(pkg.Url + selectedRepo + "/" + pkg.Packagepath + "." + pkg.Compression)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	rdr := io.Reader(resp.Body)
	if pkg.Compression == "bz2" {
		r := bzip2.NewReader(resp.Body)
		rdr = r
	}
	if pkg.Compression == "xz" {
		r, err := xz.NewReader(resp.Body)
		if err != nil {
			return nil, err
		}
		rdr = r
	}
	if pkg.Compression == "gz" {
		r, err := gzip.NewReader(resp.Body)
		if err != nil {
			return nil, err
		}
		rdr = r
	}

	packages := fastmap.New[string, domain.PackageInfo]()
	sreader := deb.NewControlFileReader(rdr, false, false)
	for {
		stanza, err := sreader.ReadStanza()
		if err != nil || stanza == nil {
			break
		}

		if stanza["Section"] == "debian-installer" {
			continue
		}

		name := stanza["Package"]

		useWhitelist := pkg.UseWhitelist && len(pkg.Whitelist) > 0
		if useWhitelist {
			contained := nameContains(name, pkg.Whitelist)
			if !contained {
				continue
			}
		}

		broken := nameContains(name, pkg.Blacklist)
		if broken {
			continue
		}

		ver, err := version.Parse(stanza["Version"])
		if err != nil {
			return nil, err
		}

		pk, ok := packages.Get(name)
		if ok {
			matchedVer, _ := version.Parse(pk.Version)
			cmpVal := version.Compare(ver, matchedVer)
			if cmpVal < 0 {
				continue
			}
		}

		sourceSplit := strings.Split(stanza["Source"], " ")
		source := sourceSplit[0]
		if source == "" {
			source = name
		}

		packages.Set(name, domain.PackageInfo{
			PackageName:  name,
			Version:      ver.String(),
			Source:       source,
			Architecture: stanza["Architecture"],
			Description:  stanza["Description"],
			Status:       domain.Current,
		})
	}

	return packages, nil
}

func nameContains(name string, match []string) bool {
	for _, m := range match {
		if strings.Contains(name, m) {
			return true
		}
	}
	return false
}

func GetPackagesCount() domain.PackagesCount {
	count := domain.PackagesCount{
		Stale:    0,
		Missing:  0,
		Current:  0,
		Error:    0,
		Queued:   0,
		Building: 0,
	}
	currentPackagesFastMap.Iter(func(k string, v domain.SourcePackage) bool {
		v.Packages.Iter(func(k string, pkg domain.PackageInfo) bool {
			switch pkg.Status {
			case domain.Stale:
				count.Stale++
			case domain.Missing:
				count.Missing++
			case domain.Built:
				count.Current++
			case domain.Current:
				count.Current++
			case domain.Error:
				count.Error++
			}
			return false
		})
		return true
	})

	return count
}