Over medium heat, add oil to a large pan. Once the oil starts to sizzle, toss the garlic and chili in and stir so that it's fragrant.
Add the pork and let it cook for a few minutes before adding the eggplant and mushrooms. When the pan gets dry, add water to help cook the ingredients.
Once everything's cooked, season with oyster sauce, fish sauce and sugar.
Stir fry until everything is well-mixed and remove from heat to serve hot with rice.
Notes
If you have low tolerance to spicy food, you might want to go easy on the chili first and keep adding until you reach your preferred level of heat.