package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"sync"
	"strings"
	"golang.org/x/crypto/openpgp"
	"runtime"
	"errors"
)

var VERSION string = "1.1.0"

type Conf struct {
	ListenPort    string   `json:"listenPort"`
	RootRepoPath  string   `json:"rootRepoPath"`
	SupportArch   []string `json:"supportedArch"`
	DistroNames   []string `json:"distroNames"`
	PGPSecretKey  string   `json:"pgpSecretKey"`
	PGPPassphrase string   `json:"pgpPassphrase"`
	EnableSSL     bool     `json:"enableSSL"`
	SSLCert       string   `json:"SSLcert"`
	SSLKey        string   `json:"SSLkey"`
	Key           string   `json:"key"`
}

func (c Conf) DistPath(distro string) string {
	return filepath.Join(c.RootRepoPath, "dists", distro)
}

func (c Conf) ArchPath(distro, arch string) string {
	return filepath.Join(c.RootRepoPath, "dists", distro, "main/binary-"+arch)
}

func (c Conf) PoolPath(distro, arch string) string {
	return filepath.Join(c.RootRepoPath, "pool/main", distro, arch)
}

func (c Conf) PoolPackagePath(distro, arch, name string) string {
	name = packageName(name)
	return filepath.Join(c.RootRepoPath, "pool/main", distro, arch, name[0:1], name)
}

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.Mutex
	configFile   = flag.String("c", "conf.json", "config file location")
	flagShowVersion = flag.Bool("version", false, "Show dnsconfig version")
	parsedConfig = Conf{}
	pgpEntity *openpgp.Entity
)

func main() {
	flag.Parse()

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

	file, err := ioutil.ReadFile(*configFile)
	if err != nil {
		log.Fatalln("unable to read config file, exiting...")
	}
	if err := json.Unmarshal(file, &parsedConfig); err != nil {
		log.Fatalln("unable to marshal config file, exiting...")
	}

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

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

	http.Handle("/", http.StripPrefix("/", http.FileServer(http.Dir(parsedConfig.RootRepoPath))))
	http.Handle("/upload", uploadHandler(parsedConfig))
	http.Handle("/delete", deleteHandler(parsedConfig))

	if parsedConfig.EnableSSL {
		log.Println("running with SSL enabled")
		log.Fatalln(http.ListenAndServeTLS(":"+parsedConfig.ListenPort, parsedConfig.SSLCert, parsedConfig.SSLKey, nil))
	} else {
		log.Println("running without SSL enabled")
		log.Fatalln(http.ListenAndServe(":"+parsedConfig.ListenPort, nil))
	}
}

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

	secretKey, err := os.Open(config.PGPSecretKey)
	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.PGPPassphrase)

	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.DistroNames {
		for _, arch := range config.SupportArch {
			if _, err := os.Stat(config.ArchPath(distro, arch)); err != nil {
				if os.IsNotExist(err) {
					log.Printf("Directory for %s (%s) does not exist, creating", distro, arch)
					if err := os.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 := os.Stat(config.PoolPath(distro, arch)); err != nil {
				if os.IsNotExist(err) {
					log.Printf("Directory for %s (%s) does not exist, creating", distro, arch)
					if err := os.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
}