package device

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"net/http"
	"time"

	"git.nutfactory.org/hoernschen/Matrix/config"
	"git.nutfactory.org/hoernschen/Matrix/utils"
)

func InitServerSigningKey() (err error) {
	publicKey, privateKey, err := utils.GenerateKeyPair()
	if err != nil {
		return
	}
	config.PublicKey = publicKey
	config.PrivateKey = privateKey
	config.KeyId = "ed25519:1"
	return
}

func GetServerSigningKeyHandler(w http.ResponseWriter, r *http.Request) {
	if config.PublicKey == nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: "Server Signing Key Missing"}); err != nil {
			panic(err)
		}
		return
	}
	response := ServerKeys{
		ServerName: config.Homeserver,
		VerifyKeys: make(map[string]verifyKey),
	}
	response.VerifyKeys[config.KeyId] = verifyKey{Key: base64.RawStdEncoding.EncodeToString(config.PublicKey)}
	content, err := json.Marshal(response)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		if err := json.NewEncoder(w).Encode(utils.ErrorResponse{ErrorMessage: fmt.Sprintf("Error creating Signatures: %s", err)}); err != nil {
			panic(err)
		}
		return
	}

	response.Signatures = utils.SignContent(content)

	w.WriteHeader(http.StatusOK)
	if err := json.NewEncoder(w).Encode(response); err != nil {
		panic(err)
	}
}

func GetVerifyKey(server string, id string) (key []byte, err error) {
	if val, ok := config.VerifyKeys[server][id]; ok {
		key = val
	} else {
		requestUrl := fmt.Sprintf("%s://%s/_matrix/key/v2/server", config.HttpString, server)
		client := &http.Client{Timeout: 2 * time.Second}
		var req *http.Request
		req, err = http.NewRequest(http.MethodGet, requestUrl, bytes.NewBuffer(nil))
		if err != nil {
			return
		}
		var res *http.Response
		res, err = client.Do(req)
		if err != nil {
			return
		}
		if res.StatusCode != http.StatusOK {
			utils.HandleHTTPError(res)
		}
		serverKeyRes := ServerKeys{}
		decoder := json.NewDecoder(res.Body)
		err = decoder.Decode(&serverKeyRes)
		config.VerifyKeys[server] = make(map[string][]byte)
		for keyId, verifyKey := range serverKeyRes.VerifyKeys {
			verifyKeyBytes, err := base64.RawStdEncoding.DecodeString(verifyKey.Key)
			if err == nil {
				config.VerifyKeys[server][keyId] = verifyKeyBytes
				if id == keyId {
					key = verifyKeyBytes
				}
			}
		}
	}
	return
}