Implementing Vampiric Bite and Regeneration

I am in the midst of trying to migrate my Curse of Strahd game from Roll20 to Foundry. I am using Midi QOL to automate damage applications so that I don't lose function from what Roll20 did for me. A bunch of things has gone very smoothly, but I am a bit stuck on two of the vampiric abilities:

Vampiric Bite -- On hit: 6 (1d6 + 3) piercing damage plus 7 (2d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampire regains hit points equal to that amount. The reduction lasts until the target finishes a long rest -- I'd like to automate the self-heal component and maybe even the mac hit point reduction, though, I'm totally ready to accept just the self-heal portion.  

Regeneration -- The vampire regains 10 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight or running water. If the vampire takes radiant damage or damage from holy water, this trait doesn't function at the start of the vampire's next turn -- The conditions seem a bit convoluted for automation, so my current goal is just to create a simple action that does self-healing. 

Foundry Macros - Writing My First (with some understanding)

I've been fiddling with macros and javascript relative to Foundry VTT for a few days now.  It seems a good time to write my own.  By that I mean go through the steps following closely in spacemandev's footsteps in his YouTube video, FoundryVTT Macros 101.

 I'll try to note the interesting bits as I go through the process. 

Foundry Macros -- Getting a Start

The task I've taken on, migrating an existing Curse of Strahd campaign that has been running in Roll20 for about a year with a lot of amazing automation that Jon engineered for us places a fairly high bar.  

I need Foundry to pretty much be as good as our Roll20 environment across the board.  Foundry Macros appear to be much more powerful and robust than those offered in Roll20...but we have a couple of years of patching over warts and automating our game system.  

This posting focuses on my learning the Foundry macro ropes, largely indexing resources that I expect will make my journey easier. 

Installing and Initial Learnings with Foundry VTT

I received Foundry VTT for my birthday.  So, of course, I just have to mess with it.  I am in the process of installing it on my Mac and will be taking notes into this posting of things that I encounter that peak my interest.  No overarching organization, just things as I learn them.

Before getting into the process, I'll take a stab at why I am looking at transitioning from Roll20 to a different VTT.  Following are my major issues that I hope Foundry will alleviate without introducing a new set of issues:

• Speed - Roll20 is not fast, changing maps is a significant delay.
• Search - The ability to search inside the journal is just bizarre.  It helpfully most of the tabs that don't contain matches, leaving me with a bunch of folders that may or may not contain hits.  This results in exploration of the file tree by the Colombus method (blindly clicking things until I happen upon something)
• UI Consistency - The click an ability displays it to the player while clicking a spell displays in chat (or maybe the other way around).  This and similar features make learning Roll20 difficult.
• Text Formatting - OMG there are multiple ways to do this, with location of the text changing the method.  Making it all worse, the formatting tools work sometimes and rarely in the way that I would predict.
• Monthly subscription - I don't like paying a sub fee for this service
• Speed - Did I mention that the game can be slooooooow?

Ok, so on with the show...