Fluid Cap breakdown

breakdown.txt

Personal notes for fluid cap and general fluid grokking since this seems really unintuitive to me.

I have not worked with fluids before and the fluid cap seems very baggage-laden to me. 

It feels held back by the previous implementation of Fluids, 
and is not consistent with the interface of `IItemHandler`, the inventory cap. 
Oh well. Here goes.

Classes:
- `IFluidHandler`: The Capability Interface for the fluid cap.
    - Generally something that has this cap has one or more "tanks" inside of it, that can hold Fluids.
    - You can fill and drain out of this handler, letting it decide which tank to use internally
    - Can also query it for an `IFluidTankProperties[]`
    - Why can this not directly get a list of `IFluidTanks`, instead opting for gimped out state snapshots?
- `IFluidTank`: Interface for some sort of "tank"
    - Can get the `FluidStack`, get the amount, get the capacity
    - Can fill and drain
    - Can get a `FluidTankInfo`: Immutable snapshot of a tank's state: contains `FluidStack` and `Capacity`
    - `FluidTank`: Straightforward implementation of the interface
        - Also a `IFluidHandler` itself - simply the only tank in the handler
- `IFluidTankProperties`: Abstract read-only representation of a tank's state
    - Can get the tank's contents, max capacity, and whether you can drain specific Fluids in or out of it
    - `FluidTankPropertiesWrapper`: Implementation that draws from an actual `FluidTank` object
        - Why is this not on the `FluidTank` itself??
    - `FluidTankProperties`: Immutable POJO implementation of the interface.
        - Seems to be a duplicate of `FluidTankInfo`, yet `FluidTankInfo` is not deprecated?! 
        - Even contains a factory to convert from `FluidTankInfo` to `FluidTankProperties`
- `IFluidHandler` impls:
    - `FluidHandlerItemStack`: Designed to wrap around an ItemStack and use NBT to track the Fluids. 
        - Also implements `ICapabilityProvider` for maximum convenience
        - Assumes the stack only has one tank.
        - subclass `Consumable`: Destroys the stack when fluid exhausted
        - subclass `SwapEmpty`: Switches the stack to another when fluid exhausted
    - `FluidHandlerItemStackSimply`: Designed to wrap aroudn an ItemStack and use NBT to track the Fluids.
        - Also implements `ICapabilityProvider` for maximum convenience
        - Assumes the stack only has one tank.
        - Only allows the handler/tank to be in two states: full, or empty.
        - subclass `Consumable`: Destroys the stack when fluid exhausted
        - subclass `SwapEmpty`: Switches the stack to another when fluid exhausted
    - `EmptyFluidHandler`: Straightforward. Immutable.
    - `FluidHandlerFluidMap`: Handler that delegates each Fluid to another internal handler. 
        - e.g. Milk will to one `IFluidHandler`, water to another `IFluidHandler`, etc.
    - `FluidHandlerConcatenate`: Handler that joins a bunch of other handlers into one object. Similar to `CombinedInvWrapper` for items.
- `ItemFluidContainer`: Demo of an Item with an `IFluidHandler` attached. Defaults to a single `FluidHandlerItemStack`
- `TileFluidHandler`: Demo of a TE with an `IFluidHandler` attached. Defaults to a `FluidTank` with a bucket's capacity.

DO NOT USE Classes:
- The *other* `IFluidHandler`: Old one. Don't use.
- The *other* `ItemFluidContainer`: Old one. Don't use.
- The *other* `TileFluidHandler`: Old one. Don't use.
- `IFluidContainer`: Completely obsoleted by caps.
- `FluidContainerRegistry`: Completely obsoleted by caps.