package controllers

import (
	"encoding/json"
	"log"
	"net/http"
	"strconv"
	"time"

	"git.aiterp.net/lucifer/lucifer/internal/respond"
	"git.aiterp.net/lucifer/lucifer/models"
	"github.com/gorilla/mux"
)

// The UserController is a controller for all users.
type UserController struct {
	users    models.UserRepository
	sessions models.SessionRepository
}

// getUsers (`GET /`): List users
func (c *UserController) getUsers(w http.ResponseWriter, r *http.Request) {
	if session := models.SessionFromContext(r.Context()); session == nil {
		respond.Error(w, http.StatusForbidden, "permission_denied", "You must log in")
		return
	}

	// TODO: Only admin should be allowed to do this?

	users, err := c.users.List(r.Context())
	if err != nil {
		respond.Error(w, 500, "db_error", err.Error())
		return
	}

	respond.Data(w, users)
}

// getUser (`GET /:id`): Get user by id
func (c *UserController) getUser(w http.ResponseWriter, r *http.Request) {
	session := models.SessionFromContext(r.Context())
	if session == nil {
		respond.Error(w, http.StatusForbidden, "permission_denied", "You must log in")
		return
	}

	// TODO: Only admin should be allowed to do this?

	var user models.User

	id, err := strconv.Atoi(mux.Vars(r)["id"])
	if err == nil {
		user, err = c.users.FindByID(r.Context(), id)
		if err != nil {
			respond.Error(w, 404, "not_found", err.Error())
			return
		}
	} else {
		user, err = c.users.FindByName(r.Context(), mux.Vars(r)["id"])
		if err != nil {
			respond.Error(w, 404, "not_found", err.Error())
			return
		}
	}

	respond.Data(w, user)
}

func (c *UserController) session(w http.ResponseWriter, r *http.Request) {
	type response struct {
		LoggedIn bool         `json:"loggedIn"`
		User     *models.User `json:"user"`
	}

	session := models.SessionFromContext(r.Context())
	if session == nil {
		respond.Data(w, response{})
		return
	}

	user, err := c.users.FindByID(r.Context(), session.UserID)
	if err != nil {
		respond.Data(w, response{})
		return
	}

	respond.Data(w, response{
		LoggedIn: true,
		User:     &user,
	})
}

// login (`POST /login`): Log in as user
func (c *UserController) login(w http.ResponseWriter, r *http.Request) {
	loginData := struct {
		Username string `json:"username"`
		Password string `json:"password"`
	}{}

	err := json.NewDecoder(r.Body).Decode(&loginData)
	if err != nil {
		respond.Error(w, 400, "invalid_json", "Input is not valid JSON.")
		return
	}

	user, err := c.users.FindByName(r.Context(), loginData.Username)
	if err != nil {
		respond.Error(w, http.StatusUnauthorized, "login_failed", "Login failed.")
		return
	}

	if err := user.CheckPassword(loginData.Password); err != nil {
		respond.Error(w, http.StatusUnauthorized, "login_failed", "Login failed.")
		return
	}

	session := models.Session{
		Expires: time.Now().Add(7 * 24 * time.Hour),
		UserID:  user.ID,
	}
	session.GenerateID()

	if err := c.sessions.Insert(r.Context(), session); err != nil {
		log.Printf("Session create for user %s (%d) failed: %s", user.Name, user.ID, err)
		respond.Error(w, http.StatusInternalServerError, "internal_error", "Failed to open session.")
		return
	}

	http.SetCookie(w, session.Cookie())

	log.Printf("User %s logged in", user.Name)

	respond.Data(w, user)
}

func (c *UserController) register(w http.ResponseWriter, r *http.Request) {
	registerData := struct {
		Username string `json:"username"`
		Password string `json:"password"`
	}{}

	if err := json.NewDecoder(r.Body).Decode(&registerData); err != nil {
		respond.Error(w, http.StatusBadRequest, "invalid_json", "Input is not valid JSON.")
		return
	}

	if len(registerData.Username) < 1 {
		respond.Error(w, http.StatusBadRequest, "invalid_username", "The username cannot be empty.")
		return
	}
	if _, err := strconv.Atoi(registerData.Username); err == nil {
		respond.Error(w, http.StatusBadRequest, "invalid_username", "The username cannot start with a number.")
		return
	}

	user := models.User{Name: registerData.Username}

	if err := user.SetPassword(registerData.Password); err != nil {
		respond.Error(w, http.StatusBadRequest, "invalid_password", "The password is not valid: "+err.Error())
		return
	}

	user, err := c.users.Insert(r.Context(), user)
	if err != nil {
		respond.Error(w, http.StatusBadRequest, "invalid_password", "The password is not valid: "+err.Error())
		return
	}

	log.Printf("User %s registered", user.Name)

	respond.Data(w, user)
}

// login (`POST /logout`): Log in as user
func (c *UserController) logout(w http.ResponseWriter, r *http.Request) {
	logoutData := struct {
		ClearAll bool `json:"clearAll"`
	}{}

	session := models.SessionFromContext(r.Context())
	if session == nil {
		respond.Error(w, http.StatusUnauthorized, "permission_denied", "You are not logged in (that's what you wanted anyway, wasn't it?)")
		return
	}

	json.NewDecoder(r.Body).Decode(&logoutData)

	user, err := c.users.FindByID(r.Context(), session.UserID)
	if err != nil {
		respond.Error(w, http.StatusNotFound, "not_found", "You user was not found")
		return
	}

	if logoutData.ClearAll {
		err := c.sessions.Clear(r.Context(), user)
		if err != nil {
			log.Printf("Session clear for user %s (%d) failed: %s", user.Name, user.ID, err)
			respond.Error(w, http.StatusInternalServerError, "clear_failed", "Sesison clear failed")
			return
		}
	} else {
		err := c.sessions.Remove(r.Context(), *session)
		if err != nil {
			log.Printf("Session remove for user %s (%d) with id %s failed: %s", user.Name, user.ID, session.ID, err)
			respond.Error(w, http.StatusInternalServerError, "remove_failed", "Session remove failed")
			return
		}
	}

	cookie := session.Cookie()
	cookie.Expires = time.Unix(0, 0)
	http.SetCookie(w, cookie)

	log.Printf("User %s logged out (clearAll: %t)", user.Name, logoutData.ClearAll)

	respond.Data(w, logoutData)
}

// Mount mounts the controller
func (c *UserController) Mount(router *mux.Router, prefix string) {
	sub := router.PathPrefix(prefix).Subrouter()

	sub.HandleFunc("/", c.getUsers).Methods("GET")
	sub.HandleFunc("/session", c.session).Methods("GET")
	sub.HandleFunc("/{id}", c.getUser).Methods("GET")
	sub.HandleFunc("/login", c.login).Methods("POST")
	sub.HandleFunc("/logout", c.logout).Methods("POST")
	sub.HandleFunc("/register", c.register).Methods("POST")
}

// NewUserController creates a new UserController.
func NewUserController(users models.UserRepository, sessions models.SessionRepository) *UserController {
	return &UserController{users: users, sessions: sessions}
}