@RestController
@RequestMapping("/favorites")
class FavoriteController(private val applicationUserRepository: ApplicationUserRepository,
                         val lineService: LineService,
                         val stationService: StationService,
                         private var currentUser: ApplicationUser?) {

    private fun provideCurrentUser() : ApplicationUser? {
        if(this.currentUser == null) {
            val currentUsername: String = SecurityContextHolder.getContext().authentication.principal.toString()
            this.currentUser = this.applicationUserRepository.findByUsername(currentUsername)
        }
        return this.currentUser
    }


    @PostMapping
    fun addFavorite(@RequestParam(value = "type", required = true)type: FavoriteType?,
                    @RequestParam(value = "id", required = true)id: Long?) : ResponseEntity<String> {
        return if(provideCurrentUser() == null || type == null || id == null) {
            ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).body("You have to be logged and provide the type " +
                    "and the id of the desired entity in order to add it to your favorites list")
        } else {
            when(type) {
                FavoriteType.STATION -> {provideCurrentUser()?.addToFavorites(this.stationService.findById(id) as Station)
                    this.applicationUserRepository.save(provideCurrentUser() ?: throw Exception("User Not found"))}
                FavoriteType.LINE -> {provideCurrentUser()?.addToFavorites(this.lineService.findById(id) as Line)
                    this.applicationUserRepository.save(provideCurrentUser() ?: throw Exception("User Not found")) }
                FavoriteType.UNKNOWN -> return ResponseEntity.status(HttpStatus.UNPROCESSABLE_ENTITY).body("Unknown entity type")
            }
            ResponseEntity.status(HttpStatus.CREATED).body("The $type with id $id has been successfully added to your favorites")
        }
    }

@Entity
class ApplicationUser(
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        @Column(unique = true, nullable = false)
        val id: Long? = null,
        val username: String = "",
        var password: String = "",
        @ManyToMany(cascade= [CascadeType.DETACH, CascadeType.PERSIST, CascadeType.REFRESH, CascadeType.REMOVE], fetch = FetchType.EAGER)
        @JoinTable(name="user_favstation", joinColumns= [JoinColumn(name="user_id")], inverseJoinColumns=[JoinColumn(name="station_id")])
        var favoriteStations: MutableSet<Station> = mutableSetOf(),
        @ManyToMany(cascade= [CascadeType.DETACH, CascadeType.PERSIST, CascadeType.REFRESH, CascadeType.REMOVE] , fetch = FetchType.EAGER)
        @JoinTable(name="user_favline", joinColumns= [JoinColumn(name="user_id")], inverseJoinColumns=[JoinColumn(name="line_id")])
        var favoriteLines: MutableSet<Line> = mutableSetOf()) {

    fun addToFavorites(station: Station): Boolean {
        return this.favoriteStations.add(station)
    }

    fun addToFavorites(line: Line): Boolean {
        return this.favoriteLines.add(line)
    }

    fun deleteFavorite(station: Station): Boolean {
        return this.favoriteStations.remove(station)
    }

    fun deleteFavorite(line: Line): Boolean {
        return this.favoriteLines.remove(line)
    }
}