package handler

import (
	"me-fit/service"
	"me-fit/template"
	"me-fit/template/auth"
	"me-fit/types"
	"me-fit/utils"

	"database/sql"
	"errors"
	"net/http"
	"time"
)

type HandlerAuth interface {
	handle(router *http.ServeMux)
}

type HandlerAuthImpl struct {
	db             *sql.DB
	service        service.AuthService
	serverSettings *types.ServerSettings
}

func NewHandlerAuth(db *sql.DB, service service.AuthService, serverSettings *types.ServerSettings) HandlerAuth {
	return HandlerAuthImpl{
		db:             db,
		service:        service,
		serverSettings: serverSettings,
	}
}

func (handler HandlerAuthImpl) handle(router *http.ServeMux) {
	// Don't use auth middleware for these routes, as it makes redirecting very difficult, if the mail is not yet verified
	router.Handle("/auth/signin", handler.handleSignInPage())
	router.Handle("/auth/signup", handler.handleSignUpPage())
	router.Handle("/auth/verify", handler.handleSignUpVerifyPage()) // Hint for the user to verify their email
	router.Handle("/auth/delete-account", handler.handleDeleteAccountPage())
	router.Handle("/auth/verify-email", service.HandleSignUpVerifyResponsePage(handler.db)) // The link contained in the email
	router.Handle("/auth/change-password", handler.handleChangePasswordPage())
	router.Handle("/auth/reset-password", handler.handleResetPasswordPage())
	router.Handle("/api/auth/signup", handler.handleSignUp())
	router.Handle("/api/auth/signin", handler.handleSignIn())
	router.Handle("/api/auth/signout", handler.handleSignOut())
	router.Handle("/api/auth/delete-account", handler.HandleDeleteAccountComp())
	router.Handle("/api/auth/verify-resend", handler.HandleVerifyResendComp())
	router.Handle("/api/auth/change-password", handler.HandleChangePasswordComp())
	router.Handle("/api/auth/reset-password", service.HandleResetPasswordComp(handler.db, handler.serverSettings))
	router.Handle("/api/auth/reset-password-actual", service.HandleActualResetPasswordComp(handler.db))
}

var (
	securityWaitDuration = 250 * time.Millisecond
)

func (handler HandlerAuthImpl) handleSignInPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			userComp := service.UserInfoComp(nil)
			signIn := auth.SignInOrUpComp(true)
			err := template.Layout(signIn, userComp, handler.serverSettings.Environment).Render(r.Context(), w)

			if err != nil {
				utils.LogError("Failed to render sign in page", err)
				http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			}
		}

		if !user.EmailVerified {
			utils.DoRedirect(w, r, "/auth/verify")
		} else {
			utils.DoRedirect(w, r, "/")
		}
	}
}

func (handler HandlerAuthImpl) handleSignIn() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, err := utils.WaitMinimumTime(securityWaitDuration, func() (*service.User, error) {
			var email = r.FormValue("email")
			var password = r.FormValue("password")

			session, err := handler.service.SignIn(email, password)
			if err != nil {
				return nil, err
			}

			cookie := http.Cookie{
				Name:     "id",
				Value:    session.Id,
				MaxAge:   60 * 60 * 8, // 8 hours
				Secure:   true,
				HttpOnly: true,
				SameSite: http.SameSiteStrictMode,
				Path:     "/",
			}

			http.SetCookie(w, &cookie)

			return session.User, nil
		})

		if err != nil {
			if err == service.ErrInvaidCredentials {
				utils.TriggerToast(w, r, "error", "Invalid email or password")
				http.Error(w, "Invalid email or password", http.StatusUnauthorized)
			} else {
				utils.LogError("Error signing in", err)
				http.Error(w, "An error occurred", http.StatusInternalServerError)
			}
			return
		}

		if user.EmailVerified {
			utils.DoRedirect(w, r, "/")
		} else {
			utils.DoRedirect(w, r, "/auth/verify")
		}
	}
}

func (handler HandlerAuthImpl) handleSignUpPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			userComp := service.UserInfoComp(nil)
			signUpComp := auth.SignInOrUpComp(false)
			err := template.Layout(signUpComp, userComp, handler.serverSettings.Environment).Render(r.Context(), w)

			if err != nil {
				utils.LogError("Failed to render sign up page", err)
				http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			}
		}

		if !user.EmailVerified {
			utils.DoRedirect(w, r, "/auth/verify")
		} else {
			utils.DoRedirect(w, r, "/")
		}
	}
}

func (handler HandlerAuthImpl) handleSignUp() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var email = r.FormValue("email")
		var password = r.FormValue("password")

		_, err := utils.WaitMinimumTime(securityWaitDuration, func() (interface{}, error) {
			user, err := handler.service.SignUp(email, password)
			if err != nil {
				return nil, err
			}

			go handler.service.SendVerificationMail(user.Id, user.Email)
			return nil, nil
		})

		if err != nil {
			if errors.Is(err, types.ErrInternal) {
				utils.TriggerToast(w, r, "error", "An error occurred")
				return
			} else if errors.Is(err, service.ErrInvalidEmail) {
				utils.TriggerToast(w, r, "error", "The email provided is invalid")
				return
			}
			// If the "service.ErrAccountExists", then just continue
		}

		utils.TriggerToast(w, r, "success", "A link to activate your account has been emailed to the address provided.")
	}
}

func (handler HandlerAuthImpl) handleSignOut() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		err := handler.service.SignOut(utils.GetSessionID(r))
		if err != nil {
			utils.TriggerToast(w, r, "error", "Internal Server Error")
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		c := http.Cookie{
			Name:     "id",
			Value:    "",
			MaxAge:   -1,
			Secure:   true,
			HttpOnly: true,
			SameSite: http.SameSiteStrictMode,
			Path:     "/",
		}

		http.SetCookie(w, &c)
		utils.DoRedirect(w, r, "/")
	}
}

func (handler HandlerAuthImpl) handleSignUpVerifyPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			utils.DoRedirect(w, r, "/auth/signin")
		}

		if user.EmailVerified {
			utils.DoRedirect(w, r, "/")
		} else {
			userComp := service.UserInfoComp(user)
			signIn := auth.VerifyComp()
			err := template.Layout(signIn, userComp, handler.serverSettings.Environment).Render(r.Context(), w)
			if err != nil {
				utils.LogError("Failed to render verify page", err)
				http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			}
		}
	}
}

func (handler HandlerAuthImpl) handleDeleteAccountPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		// An unverified email should be able to delete their account
		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			utils.DoRedirect(w, r, "/auth/signin")
		}

		userComp := service.UserInfoComp(user)
		comp := auth.DeleteAccountComp()
		err = template.Layout(comp, userComp, handler.serverSettings.Environment).Render(r.Context(), w)
		if err != nil {
			utils.LogError("Failed to render delete account page", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		}
	}
}

func (handler HandlerAuthImpl) handleChangePasswordPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {

		isPasswordReset := r.URL.Query().Has("token")

		user, _ := handler.service.GetUserFromSessionId(utils.GetSessionID(r))

		if user == nil && !isPasswordReset {
			utils.DoRedirect(w, r, "/auth/signin")
		} else {
			userComp := service.UserInfoComp(user)
			comp := auth.ChangePasswordComp(isPasswordReset)
			err := template.Layout(comp, userComp, handler.serverSettings.Environment).Render(r.Context(), w)
			if err != nil {
				utils.LogError("Failed to render change password page", err)
				http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			}
		}
	}
}

func (handler HandlerAuthImpl) handleResetPasswordPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {

		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			utils.DoRedirect(w, r, "/auth/signin")
		}

		userComp := service.UserInfoComp(user)
		comp := auth.ResetPasswordComp()
		err = template.Layout(comp, userComp, handler.serverSettings.Environment).Render(r.Context(), w)
		if err != nil {
			utils.LogError("Failed to render change password page", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		}
	}
}

func (handler HandlerAuthImpl) HandleResetPasswordPage() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {

		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		userComp := service.UserInfoComp(user)
		comp := auth.ResetPasswordComp()
		err = template.Layout(comp, userComp, handler.serverSettings.Environment).Render(r.Context(), w)
		if err != nil {
			utils.LogError("Failed to render change password page", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		}
	}
}

func (handler HandlerAuthImpl) HandleDeleteAccountComp() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		password := r.FormValue("password")

		_, err = handler.service.SignIn(user.Email, password)
		if err != nil {
			utils.TriggerToast(w, r, "error", "Password not correct")
			return
		}

		err = handler.service.DeleteAccount(user)
		if err != nil {
			utils.TriggerToast(w, r, "error", "Internal Server Error")
			return
		}

		utils.DoRedirect(w, r, "/")
	}
}

func (handler HandlerAuthImpl) HandleVerifyResendComp() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		go handler.service.SendVerificationMail(user.Id, user.Email)

		w.Write([]byte("<p class=\"mt-8\">Verification email sent</p>"))
	}
}

func (handler HandlerAuthImpl) HandleChangePasswordComp() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {

		user, err := handler.service.GetUserFromSessionId(utils.GetSessionID(r))
		if err != nil {
			utils.DoRedirect(w, r, "/auth/signin")
			return
		}

		currPass := r.FormValue("current-password")
		newPass := r.FormValue("new-password")

		err = handler.service.ChangePassword(user, currPass, newPass)
		if err != nil {
			utils.TriggerToast(w, r, "error", "Password not correct")
			return
		}

		utils.TriggerToast(w, r, "success", "Password changed")
	}
}