package main

import (
	"errors"
	"flag"
	"fmt"
	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/session"
	s3 "github.com/fclairamb/afero-s3"
	"github.com/go-ini/ini"
	log "github.com/sirupsen/logrus"
	"github.com/spf13/afero"
	"golang.org/x/crypto/openpgp"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"runtime"
	"strings"
	"sync"
)

var VERSION = "1.4.4"

func packageName(name string) string {
	if index := strings.Index(name, "_"); index != -1 {
		name = name[:index]
	}
	return name
}

type DeleteObj struct {
	Filename   string
	DistroName string
	Arch       string
}

var (
	mutex        sync.RWMutex
	configFile   = flag.String("c", "conf.ini", "config file location")
	flagShowVersion = flag.Bool("version", false, "Show deb-simple version")
	flagDebug = flag.Bool("debug", false, "debug output")
	conf = Conf{}
	pgpEntity *openpgp.Entity
	fs afero.Fs
	tmpFs afero.Fs
)

func main() {
	flag.Parse()

	if *flagDebug {
		log.SetLevel(log.DebugLevel)
	}

	if *flagShowVersion {
		fmt.Printf("deb-simple %s (%s)\n", VERSION, runtime.Version())
		os.Exit(0)
	}

	log.WithFields(log.Fields{
		"version": VERSION,
		"runtimeVersion": runtime.Version(),
	}).Info("Starting deb-simple")

	file, err := ioutil.ReadFile(*configFile)

	if err != nil {
		log.WithError(err).Fatalln("unable to read config file, exiting...")
	}

	if err := ini.MapTo(&conf, file); err != nil {
		log.WithError(err).Fatalln("unable to marshal config file, exiting...", err)
	}

	osFs := afero.NewOsFs()

	switch conf.Fs.Driver {
	case "s3":
		awsConfig := &aws.Config{
			Region: aws.String(conf.Fs.S3.Region),
			Credentials: credentials.NewStaticCredentials(conf.Fs.S3.ID, conf.Fs.S3.Secret, ""),
		}

		if conf.Fs.S3.Endpoint != "" {
			awsConfig.Endpoint = aws.String(conf.Fs.S3.Endpoint)
		}

		sess, err := session.NewSession(awsConfig)

		if err != nil {
			log.Fatalln("Unable to create S3 session:", err)
		}

		fs = s3.NewFs(conf.Fs.S3.Bucket, sess)
	case "local":
		fallthrough
	default:
		fs = afero.NewBasePathFs(osFs, conf.Repo.Root)
	}

	switch conf.Fs.TmpDriver {
	case "memory":
		tmpFs = afero.NewMemMapFs()
	case "local":
		fallthrough
	default:
		baseTempDir := path.Join(os.TempDir(), "deb-simple")

		if _, err := os.Stat(baseTempDir); err != nil {
			if os.IsNotExist(err) {
				if err := os.MkdirAll(baseTempDir, 0755); err != nil {
					log.Fatalln("Unable to create temp dir:", err)
				}
			}
		}

		tmpFs = afero.NewBasePathFs(osFs, baseTempDir)
	}

	if err := createDirs(conf); err != nil {
		log.WithError(err).Fatalln("error creating directory structure, exiting")
	}

	if err := setupPgp(conf); err != nil {
		log.WithError(err).Fatalln("error loading pgp key, exiting")
	}

	log.Info("Indexing packages...")

	for _, dist := range conf.Repo.DistroNames() {
		if err := loadCache(dist); err != nil {
			log.Info("Unable to load cached data for", dist, "- reindexing")
			distro := &Distro{Name: dist, Architectures: make(map[string]map[string]*PackageFile)}

			go scanInitialPackages(conf, distro)

			distros[dist] = distro
		}
	}

	mux := http.NewServeMux()

	httpFs := afero.NewHttpFs(fs)

	mux.Handle("/", http.StripPrefix("/", http.FileServer(httpFs)))
	mux.HandleFunc("/rescan", requireAuth(rescanHandler))
	mux.HandleFunc("/upload", requireAuth(uploadHandler))
	mux.HandleFunc("/delete", requireAuth(deleteHandler))

	bind := fmt.Sprintf(":%d", conf.Http.Port)

	if conf.Http.SSL {
		log.WithFields(log.Fields{
			"bind": bind,
			"certFile": conf.Http.SSLCert,
			"keyFile": conf.Http.SSLKey,
		}).Info("Starting with SSL enabled")

		err = http.ListenAndServeTLS(bind, conf.Http.SSLCert, conf.Http.SSLKey, mux)
	} else {
		log.WithField("bind", bind).Info("Starting without SSL enabled")

		err = http.ListenAndServe(bind, mux)
	}

	if err != nil {
		log.WithError(err).Fatalln("Unable to start or keep running due to error")
	}
}

func scanInitialPackages(config Conf, dist *Distro) {
	for _, arch := range config.Repo.ArchitectureNames() {
		files, err := buildPackageList(config, dist.Name, arch)

		if err != nil {
			log.Fatalln("Unable to load packages:", err)
		}

		dist.Architectures[arch] = files

		log.Info("Generating packages file for", dist.Name, arch)

		err = createPackagesCached(config, dist.Name, arch, files)

		if err != nil {
			log.WithError(err).Fatalln("Unable to generate package list")
		}
	}

	log.Info("Generating Release for", dist.Name)
	err := createRelease(config, dist.Name)

	if err != nil {
		log.WithError(err).Fatalln("Unable to generate release file")
	}

	err = saveCache(dist)

	if err != nil {
		log.WithError(err).Fatalln("Unable to save cache")
	}
}

func setupPgp(config Conf) error {
	if config.PGP.Key == "" {
		return nil
	}

	secretKey, err := os.Open(config.PGP.Key)
	if err != nil {
		return fmt.Errorf("failed to open private key ring file: %s", err)
	}
	defer secretKey.Close()

	entitylist, err := openpgp.ReadKeyRing(secretKey)

	if err != nil {
		return fmt.Errorf("failed to read key ring: %s", err)
	}

	if len(entitylist) < 1 {
		return errors.New("no keys in key ring")
	}

	pgpEntity = entitylist[0]

	passphrase := []byte(config.PGP.Passphrase)

	if err := pgpEntity.PrivateKey.Decrypt(passphrase); err != nil {
		return err
	}

	for _, subkey := range pgpEntity.Subkeys {
		err := subkey.PrivateKey.Decrypt(passphrase)

		if err != nil {
			return err
		}
	}

	return nil
}

func createDirs(config Conf) error {
	for _, distro := range config.Repo.DistroNames() {
		for _, arch := range config.Repo.ArchitectureNames() {
			if _, err := fs.Stat(config.ArchPath(distro, arch)); err != nil {
				if os.IsNotExist(err) {
					log.Debugf("Directory for %s (%s) does not exist, creating", distro, arch)
					if err := fs.MkdirAll(config.ArchPath(distro, arch), 0755); err != nil {
						return fmt.Errorf("error creating directory for %s (%s): %s", distro, arch, err)
					}
				} else {
					return fmt.Errorf("error inspecting %s (%s): %s", distro, arch, err)
				}
			}
			if _, err := fs.Stat(config.PoolPath(distro, arch)); err != nil {
				if os.IsNotExist(err) {
					log.Debugf("Directory for %s (%s) does not exist, creating", distro, arch)
					if err := fs.MkdirAll(config.PoolPath(distro, arch), 0755); err != nil {
						return fmt.Errorf("error creating directory for %s (%s): %s", distro, arch, err)
					}
				} else {
					return fmt.Errorf("error inspecting %s (%s): %s", distro, arch, err)
				}
			}
		}
	}
	return nil
}

func copyFile(sourceFs afero.Fs, oldPath string, destFs afero.Fs, newPath string) error {
	old, err := sourceFs.Open(oldPath)

	if err != nil {
		return err
	}

	defer old.Close()

	n, err := destFs.Create(newPath)

	if err != nil {
		return err
	}

	defer n.Close()

	_, err = io.Copy(n, old)

	return err
}