Hi, so I am trying to make something like (but not exactly) a custom furnace, in which players can put certain items in. The catch here being that the furnace only has one output. In order to get the output, an empty "container" item must be inserted, and based on the value of the item they put in the other slot, it will make the output a "charged" version of the empty container. How the catch here is that I want different items to have different values, and as a result charge the container to different values. Then I want to be able to use the custom "charged" item as a furnace fuel with a variable burn time based on a number assigned to the "charged" item. So EX:

 

Empty Item has an empty texture, and has a value of "0 out of 1000 fuel points"

Then you put that and say, wheat, into this custom furnace interface. The wheat dissapears, and the texture changes to a "partially full" container with a value of "25 out of 1000 fuel points"

Then someone puts a piece of coal into it, and that adds say 200 points. Then you have the same partially full container with a value of "225 out of 1000 fuel points".

Then someone can take the item and put it in a custom furnace along with something that needs smelted, say iron ore for example.

So lets say it takes 200 fuel points to smelt the iron ore, so then the furnace spits out an iron ingot and a "partially full" container with a value of "25 out of 1000 fuel points".

 

How complicated would this be? And where should I even start. I have 0 experience with custom interfaces/guis, or even making a block that is clickable. Any good examples/tutorial mods that would be useful to get a look at for pointers anyone knows of?

You might be interested in my sifter, then:

 

https://github.com/Draco18s/ReasonableRealism/blob/1.12.1/src/main/java/com/draco18s/ores/recipes/OreProcessingRecipes.java

 

(Note: I haven't converted my machines to JSON "recipe" format yet because I'm lazy)