package middlewares

import (
	"context"
	"errors"
	"fmt"
	"github.com/emvi/logbuch"
	conf "github.com/muety/wakapi/config"
	"github.com/muety/wakapi/models"
	"github.com/muety/wakapi/services"
	"github.com/muety/wakapi/utils"
	"net/http"
	"strings"
)

type AuthenticateMiddleware struct {
	config         *conf.Config
	userSrvc       services.IUserService
	whitelistPaths []string
}

func NewAuthenticateMiddleware(userService services.IUserService, whitelistPaths []string) *AuthenticateMiddleware {
	return &AuthenticateMiddleware{
		config:         conf.Get(),
		userSrvc:       userService,
		whitelistPaths: whitelistPaths,
	}
}

func (m *AuthenticateMiddleware) Handler(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		m.ServeHTTP(w, r, h.ServeHTTP)
	})
}

func (m *AuthenticateMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
	for _, p := range m.whitelistPaths {
		if strings.HasPrefix(r.URL.Path, p) || r.URL.Path == p {
			next(w, r)
			return
		}
	}

	var user *models.User
	user, err := m.tryGetUserByCookie(r)

	if err != nil {
		user, err = m.tryGetUserByApiKey(r)
	}

	if err != nil {
		if strings.HasPrefix(r.URL.Path, "/api") {
			w.WriteHeader(http.StatusUnauthorized)
		} else {
			http.SetCookie(w, m.config.GetClearCookie(models.AuthCookieKey, "/"))
			http.Redirect(w, r, fmt.Sprintf("%s/?error=unauthorized", m.config.Server.BasePath), http.StatusFound)
		}
		return
	}

	ctx := context.WithValue(r.Context(), models.UserKey, user)
	next(w, r.WithContext(ctx))
}

func (m *AuthenticateMiddleware) tryGetUserByApiKey(r *http.Request) (*models.User, error) {
	key, err := utils.ExtractBearerAuth(r)
	if err != nil {
		return nil, err
	}

	var user *models.User
	userKey := strings.TrimSpace(key)
	user, err = m.userSrvc.GetUserByKey(userKey)
	if err != nil {
		return nil, err
	}
	return user, nil
}

func (m *AuthenticateMiddleware) tryGetUserByCookie(r *http.Request) (*models.User, error) {
	login, err := utils.ExtractCookieAuth(r, m.config)
	if err != nil {
		return nil, err
	}

	user, err := m.userSrvc.GetUserById(login.Username)
	if err != nil {
		return nil, err
	}

	if !CheckAndMigratePassword(user, login, m.config.Security.PasswordSalt, &m.userSrvc) {
		return nil, errors.New("invalid password")
	}

	return user, nil
}

// migrate old md5-hashed passwords to new salted bcrypt hashes for backwards compatibility
func CheckAndMigratePassword(user *models.User, login *models.Login, salt string, userServiceRef *services.IUserService) bool {
	if utils.IsMd5(user.Password) {
		if utils.CompareMd5(user.Password, login.Password, "") {
			logbuch.Info("migrating old md5 password to new bcrypt format for user '%s'", user.ID)
			(*userServiceRef).MigrateMd5Password(user, login)
			return true
		}
		return false
	}
	return utils.CompareBcrypt(user.Password, login.Password, salt)
}