package main

import (
	"fmt"
	"os"
	"net/http"
	"syscall"
	"os/signal"
	"time"
	"context"
	//"encoding/json"
	"strings"

	"github.com/ProtonMail/go-crypto/openpgp"
	//"github.com/ProtonMail/go-crypto/openpgp/packet"
)

type Server struct {
	PublicKeys openpgp.EntityList
	PrivateKeys openpgp.EntityList

	KeyMap map[string]*openpgp.Entity

	//PubkeyGroups []*openpgp.Entity
}

func NewServer(publicKeys, privateKeys []string) (*Server, error) {
	s := &Server{KeyMap: make(map[string]*openpgp.Entity)}

	pub, err := s.loadKeysFromFiles(publicKeys)
	if err != nil {
		return nil, err
	}

	s.PublicKeys = pub

	fmt.Println("Public keys:")
	for _, k := range pub {
		for name, _ := range k.Identities {
			fmt.Println("\t"+name)
		}

		fmt.Printf("\t%X\n", k.PrimaryKey.KeyId)
		if len(k.Subkeys) == 0 {
			continue
		}

		fmt.Println("\tSubkeys:")
		for _, sub := range k.Subkeys {
			str := []string{}
			if sub.PublicKey != nil {
				str = append(str, fmt.Sprintf("public: %X", sub.PublicKey.KeyId))
			}
			if sub.PrivateKey != nil {
				str = append(str, fmt.Sprintf("private: %X", sub.PrivateKey.KeyId))
			}

			fmt.Println("\t\t"+strings.Join(str, " / "))
		}
	}

	priv, err := s.loadKeysFromFiles(privateKeys)
	if err != nil {
		return nil, err
	}

	s.PrivateKeys = priv

	fmt.Println("Private keys:")
	for _, k := range priv {
		for name, _ := range k.Identities {
			fmt.Println("\t"+name)
		}

		fmt.Printf("\t%X\n", k.PrimaryKey.KeyId)
		if len(k.Subkeys) == 0 {
			continue
		}

		fmt.Println("\tSubkeys:")
		for _, sub := range k.Subkeys {
			str := []string{}
			if sub.PublicKey != nil {
				str = append(str, fmt.Sprintf("public: %X", sub.PublicKey.KeyId))
			}
			if sub.PrivateKey != nil {
				str = append(str, fmt.Sprintf("private: %X", sub.PrivateKey.KeyId))
			}

			fmt.Println("\t\t"+strings.Join(str, " / "))
		}
	}

	return s, nil
}

func (s *Server) loadKeysFromFiles(filenames []string) (openpgp.EntityList, error) {
	var keyring openpgp.EntityList

	for _, f := range filenames {
		file, err := os.Open(f)
		if err != nil {
			return nil, err
		}

		keys, err := openpgp.ReadArmoredKeyRing(file)
		if err != nil {
			file.Close()
			return nil, err
		}
		file.Close()

		for _, key := range keys {
			keyring = append(keyring, key)
			s.KeyMap[fmt.Sprintf("%x", key.PrimaryKey.KeyId)] = key

			for _, sub := range key.Subkeys {
				if sub.PublicKey != nil {
					s.KeyMap[fmt.Sprintf("%x", sub.PublicKey.KeyId)] = key
				}

				if sub.PrivateKey != nil {
					s.KeyMap[fmt.Sprintf("%x", sub.PrivateKey.KeyId)] = key
				}
			}
		}
	}

	return keyring, nil
}

func (s *Server) handler_publickey(w http.ResponseWriter, r *http.Request) {
	path := strings.Split(strings.Trim(r.URL.Path, "/"), "/")
	if len(path) < 2 {
		fmt.Fprintln(w, "missing path stuff")
		return
	}
	fmt.Println(r.URL.Path)

	search := strings.ToLower(path[1])
	fmt.Println("searching for", search)

	key := s.findPubKey(search)
	if key == nil {
		http.Error(w, fmt.Sprintf("Key not found; searched for %q", search), 500)
		return
	}

	err := key.Serialize(w)
	if err != nil {
		fmt.Printf("Serialization error: %s\n", err)
	}
}

func (s *Server) findPubKey(search string) *openpgp.Entity {
	if k, found := s.KeyMap[search]; found {
		for _, sub := range k.Subkeys {
			if sub.PublicKey != nil && fmt.Sprintf("%x", sub.PublicKey.KeyId) == search {
				return k
			}
		}
	}

	for _, k := range s.PublicKeys {
		for _, id := range k.Identities {
			if strings.ToLower(id.UserId.Name) == search {
				return k
			}

			if strings.ToLower(id.UserId.Email) == search {
				return k
			}
		}
	}

	return nil
}

func (s *Server) handler_privatekey(w http.ResponseWriter, r *http.Request) {
	path := strings.Split(strings.Trim(r.URL.Path, "/"), "/")
	if len(path) < 2 {
		fmt.Fprintln(w, "missing path stuff")
		return
	}
	fmt.Println(r.URL.Path)

	search := strings.ToLower(path[1])
	fmt.Println("searching for", search)

	key := s.findPrivKey(search)
	if key == nil {
		http.Error(w, "Key not found", 500)
		return
	}

	err := key.SerializePrivate(w, nil)
	if err != nil {
		fmt.Printf("Serialization error: %s\n", err)
	}
}

func (s *Server) findPrivKey(search string) *openpgp.Entity {
	if k, found := s.KeyMap[search]; found {
		if k.PrivateKey != nil && fmt.Sprintf("%x", k.PrivateKey.KeyId) == search {
			return k
		}

		for _, sub := range k.Subkeys {
			if sub.PrivateKey != nil && fmt.Sprintf("%x", sub.PrivateKey.KeyId) == search {
				return k
			}
		}
	}

	for _, k := range s.PrivateKeys {
		fmt.Printf("%X\n", k.PrimaryKey.KeyId)
		for _, id := range k.Identities {
			if strings.ToLower(id.UserId.Name) == search {
				return k
			}

			if strings.ToLower(id.UserId.Email) == search {
				return k
			}
		}
	}

	return nil
}

func (s *Server) handler_debug(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintln(w, "Public Keys:")
	for _, key := range s.PublicKeys {
		//fmt.Fprintf(w, "%#v\n", key.PrimaryIdentity())
		fmt.Fprintf(w,"%s\n\t%X\n\t%X\n",
			key.PrimaryIdentity().Name,
			key.PrimaryKey.Fingerprint,
			key.PrimaryKey.KeyId,
		)

		//j, err := json.Marshal(key)
		//if err != nil {
		//	fmt.Fprintf(w, "ERROR: %s", err)
		//	return
		//}

		//fmt.Fprintf(w,"\t\t%s\n", j)
	}

	fmt.Fprintln(w, "\nPrivate Keys:")
	for _, key := range s.PrivateKeys {
		//fmt.Fprintf(w, "%#v\n", key.PrimaryIdentity())
		fmt.Fprintf(w,"%s\n\t%X\n\t%X\n",
			key.PrimaryIdentity().Name,
			key.PrimaryKey.Fingerprint,
			key.PrivateKey.KeyId,
		)

		for _, sub := range key.Subkeys {
			fmt.Fprintf(w, "\t>%X\n\t>%X\n",
				sub.PublicKey.KeyId,
				sub.PrivateKey.KeyId,
			)
		}
	}
}

func handler_default(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintln(w, "henlo")
}

func run() error {
	sv, err := NewServer(
		[]string{
			//"keys/gpg-generated/cust-a.pub",
			//"keys/gpg-generated/cust-b.pub",
			//"keys/gpg-generated/internal-public.asc",
			"keys/public/Customer.asc",
			"keys/public/Company.asc",
		},
		[]string{
			//"keys/gpg-generated/internal-private.asc",
			"keys/private/Company.asc",
		},
	)
	if err != nil {
		return err
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/pubkey/", sv.handler_publickey)
	mux.HandleFunc("/privkey/", sv.handler_privatekey)
	mux.HandleFunc("/debug/", sv.handler_debug)
	mux.HandleFunc("/", handler_default)

	server := &http.Server{
		Addr:           ":8080",
		Handler:        mux,
		ReadTimeout:    10 * time.Second,
		WriteTimeout:   10 * time.Second,
		MaxHeaderBytes: 1 << 20,
	}

	done := make(chan os.Signal, 1)
	signal.Notify(done, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)

	go func() {
		fmt.Println("listening on", server.Addr)
		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			fmt.Println("Listen: ", err)
		}
	}()

	<-done
	fmt.Println("stopping")

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()

	if err := server.Shutdown(ctx); err != nil {
		fmt.Println("Clean shutdown failed: ", err)
	}
	fmt.Println("goodbye")

	return nil
}

func main() {
	err := run()
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}