Trying to make an actual "EXP" and "Level Up" system for your farmer

[StardewNick672]

So I am new to modding, and my first mod is wanting to make an "Experience" and "Level Up" system for your entire character. I know that there are EXP and Level system for your skills, but I am trying to make a EXP and Level system for your Farmer. Experience is gained for doing various things, like harvesting crops, or catching fish, and not only (in the skill ones) you get skill XP, but farmer XP as well. Once you reach a certain amount your farmer will level up and it's maximum HP and Energy will increase, much like the Rune Factory series of games. I also will make a system that allows further increase of vanilla stats once you reach level 5, 15, 25, etc., and a major "Special Bonus" that lets you pick one of five different ones at level 10, 30, 50, 70, and 90, and eventually after level 90, you will have all five of them.

How do I locate code for the various skills so I can add EXP awards to my farmer in this mod?

Kind of an update: I am trying to make it so the farmer's EXP points are added based on the skill. Like when you harvest a crop, you will get EXP as a formula of the base sell price of the crop divided by 2, multiplied by a value depending on the quality of the crop (1x for normal quality, 2x for silver quality, 3x for gold quality, and 5x for iridium quality), which is rounded. Another one is for catching a fish, which goes through a various amount of things such as the difficulty of the fish caught, your fishing rod type, if it was a perfect or the treasure box was caught, and how many fish were caught in a row without the line breaking. How am I going to do such a thing?

 

[StardewNick672]

There's also more things in this mod I am making, such as a "Farm Point" system contributing to a "Stardew Rank", an upgradeable bulletin board that adds more Help Wanted quests at a time as well as variable difficulty (from Rank D ~ Rank S) with bigger deadlines and rewards, and a shipping bin upgrade that increases the amount of XP gotten for shipping.