What smartphone should I buy???

I've been researching for a new smartphone, here are my requirements:

1. 13 MP or higher rear camera capable of 4K video

2. 5 MP or higher front-facing camera

3. Android 4.4 KitKat, doesn't need to be Stock Android or Google Android

4. Quad-core 2.2 GHz or higher

5. 5 inch or bigger display

6. 1920 x 1080p Full HD display

7. A budget of $800

Optional:

1. Water resistant or proof

2. Not really that thick and heavy, 170 grams is good enough

Please leave a comment for suggestions. Thanks :)