package com.example.app.tests;

import android.support.test.espresso.IdlingResource;
import android.support.test.espresso.ViewFinder;
import android.support.test.espresso.ViewInteraction;
import android.util.Log;
import android.view.View;

import java.lang.reflect.Field;

import static android.support.test.espresso.Espresso.onView;
import static android.support.test.espresso.matcher.ViewMatchers.withId;

/**
 * An implementation of {@link IdlingResource} that is idle until view (provided by viewId) is visible.
 */
public class IdleUntilVisibleIdlingResource implements IdlingResource {
    private static final String TAG = IdleUntilVisibleIdlingResource.class.getSimpleName();

    private ResourceCallback resourceCallback;
    private final int viewId;

    public IdleUntilVisibleIdlingResource(int viewId) {
        this.viewId = viewId;
    }

    @Override
    public String getName() {
        return TAG;
    }

    @Override
    public boolean isIdleNow() {
        // i don't know what activity is current, so I can't just call findViewById()
        View viewOfInterest;
        try {
            Field field = ViewInteraction.class.getDeclaredField("viewFinder");
            field.setAccessible(true);
            ViewInteraction viewInteraction = onView(withId(viewId));
            ViewFinder viewFinder = (ViewFinder) field.get(viewInteraction);
            viewOfInterest = viewFinder.getView();
        } catch (IllegalAccessException | NoSuchFieldException e) {
            Log.e(TAG, "Reflection failed", e);
            // if reflection fails, just return false and eventually we'll hit our IdlingPolicy timeout
            return false;
        }

        boolean isIdle = viewOfInterest != null && viewOfInterest.getVisibility() == View.VISIBLE;
        if (isIdle) {
            resourceCallback.onTransitionToIdle();
        }
        return isIdle;
    }

    @Override
    public void registerIdleTransitionCallback(ResourceCallback callback) {
        resourceCallback = callback;
    }
}