FacebookHelper.kt

package com.wellaapp.presentation.screens.authorization.view

import android.app.Activity
import android.content.Intent
import com.facebook.CallbackManager
import com.facebook.FacebookCallback
import com.facebook.FacebookException
import com.facebook.login.LoginManager
import com.facebook.login.LoginResult
import com.wellaapp.presentation.screens.authorization.presenter.AuthorizationMVP

/**
 * @author Denis_Zinkovskiy at 2/16/17.
 */
class FacebookHelper(view: AuthorizationMVP.View) {

    private var defaultPermissions: MutableList<String> = mutableListOf("public_profile", "email")
    private val loginManager: LoginManager = LoginManager.getInstance()
    private var callbackManager: CallbackManager = CallbackManager.Factory.create()

    init {
        loginManager.registerCallback(callbackManager, object : FacebookCallback<LoginResult?> {
            override fun onError(error: FacebookException?) {
                view.onError<Unit>(error?.message!!, null)
            }

            override fun onSuccess(result: LoginResult?) {
                view.facebookLogin(result?.accessToken!!)
            }

            override fun onCancel() {
            }
        })
    }

    fun login(activity: Activity, permissions: MutableList<String> = defaultPermissions) {
        loginManager.logInWithReadPermissions(activity, permissions)
    }

    fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        callbackManager.onActivityResult(requestCode, resultCode, data)
    }
}