package core

import (
	"context"
	"crypto/x509"
	"encoding/json"
	"encoding/pem"
	"errors"
	"io"
	"net/http"
	"net/url"
	"strings"
	"time"

	"repositories.action2quare.com/ayo/gocommon/logger"

	"github.com/golang-jwt/jwt"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo/options"
)

type Apple_WebValidationTokenRequest struct {
	ClientID     string
	ClientSecret string
	Code         string
	RedirectURI  string
}

type Apple_WebRefreshTokenRequest struct {
	ClientID     string
	ClientSecret string
	RefreshToken string
}

type Apple_ValidationResponse struct {
	AccessToken      string `json:"access_token"`
	TokenType        string `json:"token_type"`
	ExpiresIn        int    `json:"expires_in"`
	RefreshToken     string `json:"refresh_token"`
	IDToken          string `json:"id_token"`
	Error            string `json:"error"`
	ErrorDescription string `json:"error_description"`
}

func (mg *Maingate) platform_apple_get_login_url(w http.ResponseWriter, r *http.Request) {

	browserinfo, err := mg.GetUserBrowserInfo(r)

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		logger.Error(err)
		return
	}

	existid := r.URL.Query().Get("existid")
	//fmt.Println("existid =>", existid)
	if existid != "" {
		// 기존 계정이 있는 경우에는 그 계정 부터 조회한다.
		info, err := mg.getUserTokenWithCheck(AuthPlatformApple, existid, browserinfo)
		if err == nil {
			if info.token != "" {
				params := url.Values{}
				params.Add("id", existid)
				params.Add("authtype", AuthPlatformApple)
				http.Redirect(w, r, "actionsquare://login?"+params.Encode(), http.StatusSeeOther)
				return
			}
		}
	}

	sessionkey := mg.GeneratePlatformLoginNonceKey()
	nonce := mg.GeneratePlatformLoginNonceKey()

	mg.mongoClient.Delete(CollectionPlatformLoginToken, bson.M{
		"platform": AuthPlatformApple,
		"key":      sessionkey,
	})

	_, _, err = mg.mongoClient.Update(CollectionPlatformLoginToken, bson.M{
		"_id": primitive.NewObjectID(),
	}, bson.M{
		"$setOnInsert": bson.M{
			"platform": AuthPlatformApple,
			"key":      sessionkey,
			"nonce":    nonce,
			"brinfo":   browserinfo,
		},
	}, options.Update().SetUpsert(true))

	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		logger.Error(err)
		return
	}

	params := url.Values{}
	params.Add("client_id", config.AppleCientId)
	params.Add("redirect_uri", config.RedirectBaseUrl+"/authorize/"+AuthPlatformApple)

	params.Add("response_type", "code id_token")
	params.Add("scope", "name email")
	params.Add("nonce", nonce)
	params.Add("response_mode", "form_post")

	// set cookie for storing token
	cookie := http.Cookie{
		Name:    "LoginFlowContext_SessionKey",
		Value:   sessionkey,
		Expires: time.Now().Add(1 * time.Hour),
		//SameSite: http.SameSiteStrictMode,
		SameSite: http.SameSiteLaxMode,
		//		HttpOnly: false,
		Secure: true,
		Path:   "/",
	}
	http.SetCookie(w, &cookie)
	//Set-Cookie

	http.Redirect(w, r, "https://appleid.apple.com/auth/authorize?"+params.Encode(), http.StatusSeeOther)
}

func (mg *Maingate) platform_apple_authorize(w http.ResponseWriter, r *http.Request) {

	defer r.Body.Close()
	body, _ := io.ReadAll(r.Body)
	bodyString := string(body)
	code := ""
	for _, params := range strings.Split(bodyString, "&") {
		args := strings.Split(params, "=")
		if len(args) == 2 {
			if args[0] == "code" {
				code = args[1]
			}
		}
	}

	// set cookie for storing token
	cookie := http.Cookie{
		Name:     "LoginFlowContext_code",
		Value:    code,
		Expires:  time.Now().Add(1 * time.Minute),
		SameSite: http.SameSiteLaxMode,
		Secure:   true,
		Path:     "/",
	}
	http.SetCookie(w, &cookie)

	http.Redirect(w, r, config.RedirectBaseUrl+"/authorize_result/"+AuthPlatformApple, http.StatusSeeOther) //-- 바로 받으니까 쿠키 안와서 한번 더 Redirect 시킨다.
}

func (mg *Maingate) platform_apple_authorize_result(w http.ResponseWriter, r *http.Request) {

	brinfo, err := mg.GetUserBrowserInfo(r)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		logger.Error(err)
		return
	}

	cookie, err := r.Cookie("LoginFlowContext_SessionKey")
	if err != nil {
		logger.Println("Session not found", err)
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	cookiecode, err := r.Cookie("LoginFlowContext_code")
	if err != nil {
		logger.Println("code not found", err)
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	code := cookiecode.Value

	found, err := mg.mongoClient.FindOne(CollectionPlatformLoginToken, bson.M{
		"key":      cookie.Value,
		"platform": AuthPlatformApple,
	})

	if err != nil {
		logger.Println("LoginFlowContext_SessionKey find key :", err)
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	if found == nil {
		logger.Println("LoginFlowContext_SessionKey not found")
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	if cookie.Value != found["key"] {
		logger.Println("LoginFlowContext_SessionKey key not match")
		logger.Println(cookie.Value)
		logger.Println(found["key"])
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	if brinfo != found["brinfo"] { //-- 로그인 시작점과 인증점의 브라우저 혹은 접속지 정보가 다르다?
		logger.Println("LoginFlowContext_SessionKey brinfo not match ")
		logger.Println(brinfo)
		logger.Println(found["brinfo"])
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	// Generate the client secret used to authenticate with Apple's validation servers
	secret, err := generateClientSecret(config.ApplePrivateKey, config.AppleTeamId, config.AppleServiceId, config.AppleKeyId)
	if err != nil {
		logger.Error("error generating secret: ", err)
		return
	}

	vReq := Apple_WebValidationTokenRequest{
		ClientID:     config.AppleServiceId,
		ClientSecret: secret,
		Code:         code,
		RedirectURI:  config.RedirectBaseUrl + "/authorize/" + AuthPlatformApple, // This URL must be validated with apple in your service
	}

	var resp Apple_ValidationResponse

	err = verifyWebToken(context.Background(), vReq, &resp)
	if err != nil {
		logger.Error("error verifying: ", err)
		return
	}

	if resp.Error != "" {
		logger.Errorf("apple returned an error: %s - %s\n", resp.Error, resp.ErrorDescription)
		return
	}

	// fmt.Println("==============================")
	// fmt.Println("IDToken:", resp.IDToken)
	// fmt.Println("AccessToken:", resp.AccessToken)
	// fmt.Println("ExpiresIn:", resp.ExpiresIn)
	// fmt.Println("RefreshToken:", resp.RefreshToken)
	// fmt.Println("TokenType:", resp.TokenType)
	// fmt.Println("==============================")

	userid, email, nonce := JWTparseCode("https://appleid.apple.com/auth/keys", resp.IDToken)

	if nonce == "" || nonce != found["nonce"] {
		logger.Errorf("nonce not match")
		return
	}

	if userid != "" && email != "" {
		var info usertokeninfo
		info.platform = AuthPlatformApple
		info.userid = userid
		info.token = resp.RefreshToken
		info.brinfo = brinfo
		info.email = email

		mg.setUserToken(info)
		params := url.Values{}
		params.Add("id", userid)
		params.Add("authtype", AuthPlatformApple)
		http.Redirect(w, r, "actionsquare://login?"+params.Encode(), http.StatusSeeOther)
	} else {
		http.Redirect(w, r, "actionsquare://error", http.StatusSeeOther)
	}
}

func (mg *Maingate) platform_apple_getuserinfo(refreshToken string) (bool, string, string) {
	//=================================RefreshToken을 사용해서 정보 가져 온다. 이미 인증된 사용자의 업데이트 목적
	secret, err := generateClientSecret(config.ApplePrivateKey, config.AppleTeamId, config.AppleServiceId, config.AppleKeyId)
	if err != nil {
		logger.Error("error generating secret: ", err)
		return false, "", ""
	}

	vReqRefreshToken := Apple_WebRefreshTokenRequest{
		ClientID:     config.AppleServiceId,
		ClientSecret: secret,
		RefreshToken: refreshToken,
	}

	var respReferesh Apple_ValidationResponse

	err = verifyRefreshToken(context.Background(), vReqRefreshToken, &respReferesh)
	if err != nil {
		logger.Error("error verifying: " + err.Error())
		return false, "", ""
	}

	if respReferesh.Error != "" {
		logger.Errorf("apple returned an error: %s - %s\n", respReferesh.Error, respReferesh.ErrorDescription)
		return false, "", ""
	}

	userid, email, _ := JWTparseCode("https://appleid.apple.com/auth/keys", respReferesh.IDToken)

	// fmt.Println("==============================")
	// fmt.Println("RefreshToken")
	// fmt.Println("==============================")
	// fmt.Println("IDToken:", respReferesh.IDToken)
	// fmt.Println("AccessToken:", respReferesh.AccessToken)
	// fmt.Println("ExpiresIn:", respReferesh.ExpiresIn)
	// fmt.Println("RefreshToken:", respReferesh.RefreshToken)
	// fmt.Println("TokenType:", respReferesh.TokenType)
	// fmt.Println("==============================")
	// fmt.Println("Parse:")
	// fmt.Println("userid:", userid)
	// fmt.Println("email:", email)
	// fmt.Println("nonce:", nonce)

	return true, userid, email

}

func generateClientSecret(signingKey, teamID, clientID, keyID string) (string, error) {
	block, _ := pem.Decode([]byte(signingKey))
	if block == nil {
		return "", errors.New("empty block after decoding")
	}

	privKey, err := x509.ParsePKCS8PrivateKey(block.Bytes)
	if err != nil {
		return "", err
	}

	// Create the Claims
	now := time.Now()
	claims := &jwt.StandardClaims{
		Issuer:    teamID,
		IssuedAt:  now.Unix(),
		ExpiresAt: now.Add(time.Hour*24*180 - time.Second).Unix(), // 180 days
		Audience:  "https://appleid.apple.com",
		Subject:   clientID,
	}

	token := jwt.NewWithClaims(jwt.SigningMethodES256, claims)
	token.Header["alg"] = "ES256"
	token.Header["kid"] = keyID

	return token.SignedString(privKey)
}

func verifyWebToken(ctx context.Context, reqBody Apple_WebValidationTokenRequest, result interface{}) error {
	data := url.Values{}
	data.Set("client_id", reqBody.ClientID)
	data.Set("client_secret", reqBody.ClientSecret)
	data.Set("code", reqBody.Code)
	data.Set("redirect_uri", reqBody.RedirectURI)
	data.Set("grant_type", "authorization_code")

	req, err := http.NewRequestWithContext(ctx, "POST", "https://appleid.apple.com/auth/token", strings.NewReader(data.Encode()))
	if err != nil {
		return err
	}

	req.Header.Add("content-type", "application/x-www-form-urlencoded")
	req.Header.Add("accept", "application/json")
	req.Header.Add("user-agent", "go-signin-with-apple") // apple requires a user agent

	client := &http.Client{}
	res, err := client.Do(req)
	if err != nil {
		return err
	}

	defer res.Body.Close()

	return json.NewDecoder(res.Body).Decode(result)
}

func verifyRefreshToken(ctx context.Context, reqBody Apple_WebRefreshTokenRequest, result interface{}) error {
	data := url.Values{}
	data.Set("client_id", reqBody.ClientID)
	data.Set("client_secret", reqBody.ClientSecret)
	data.Set("grant_type", "refresh_token")
	data.Set("refresh_token", reqBody.RefreshToken)

	//return doRequest(ctx, c.client, &result, c.validationURL, data)

	req, err := http.NewRequestWithContext(ctx, "POST", "https://appleid.apple.com/auth/token", strings.NewReader(data.Encode()))
	if err != nil {
		return err
	}

	req.Header.Add("content-type", "application/x-www-form-urlencoded")
	req.Header.Add("accept", "application/json")
	req.Header.Add("user-agent", "go-signin-with-apple") // apple requires a user agent

	client := &http.Client{}
	res, err := client.Do(req)
	if err != nil {
		return err
	}

	defer res.Body.Close()

	return json.NewDecoder(res.Body).Decode(result)
}