benckx / lego-compare-inventory-vs-wanted

Compare Bricklinks XML parts list in order to filter out the ones you already own

About

When viewing Lego models on BrickLink, it is possible to add all the necessary parts to a "Wanted List" (and then use this list to purchase the parts). However, it doesn't seem possible to automatically filter out the parts you already own (from the sets you already own) from those "Wanted List".

So I wrote a script that updates the "Wanted List" XML file by taking into account the parts you already own (based on the inventory generated from Rebrickable). You can then upload the updated XML on BrickLink to create a new "Wanted List" and purchase the parts from this list instead.

Maybe there's already a more simple solution directly on BrickLink, but I could not find it (if you know the solution, feel free to open an issue). There are options on BrickLink to add and part out sets, but it doesn't seem to be taken into account while making a "Wanted List". But maybe I'm missing something obvious.

In any case I'll be able to do more custom things with my parts lists this way.

How To

on Rebrickable

First add all the sets you own: go to "My LEGO" -> "My Sets Lists". Create a list and add your sets. This will allow Rebrickable to create an inventory of all the parts you own. You can also add individual parts.

You can then export your inventory from Rebrickable in the BrickLink format (go to "My LEGO" -> "All my parts" -> " Export Parts" -> "BrickLink XML") and replace data/inventory.xml by the export result.

on BrickLink

Go to your "Wanted List" and click "Download". Move the file under the data folder.

In Code

Replace the "Wanted List" XML file accordingly:

fun main() {
    val filterer = InventoryFilterer("data/razor-crest-75331.xml")
    filterer.execute()
}

The script will output 2 files:

• data/razor-crest-75331-updated.xml where the parts you own have been subtracted
• data/razor-crest-75331-output-report.csv CSV report in the following format, so you can double-check the modifications:

modification type	part id	color code	color	qty needed	qty inventory	qty missing
sufficient	18649	86	Light Bluish Gray	4	4	0
sufficient	22484	85	Dark Bluish Gray	1	2	0
...	...	...	...	...	...	...
insufficient	10247	11	Black	6	2	4

Ideas for future iterations

• Implement some kind of rules engine that allow for color substitution (e.g. "use dark grey if I don't have the part in black") or part substitution (e.g. "use two 2x2 brick if I don't have one 2x4 brick") (something like that already exists in the Studio app of BrickLink)
• Maybe a UI and an executable, so it's user-friendly for everyone