BMCbreed Mod Notes

What was built

Server-only Cobblemon extension providing breeding eggs, pasture automation, and administrative commands under the mod id bmcbreed.
Adds two items: breeding_egg (hidden Pokémon eggs) and pasture_token (places a pasture block that breeds nearby Pokémon).
Adds a pasture block & block entity that periodically scans a 10-block radius for compatible Pokémon and produces encrypted eggs.

Configuration lives at config/BMCbreed/config.json with toggles for egg encryption, encryption key, breeding scan rate, shiny logic, hopper output, and neuter cost.
Eggs store Pokémon data in a CustomData tag; when encryptEggs is true the data is AES-128 encrypted into BMCData using the configured key.
Breeding eggs tick while a player is walking; every 20 ticks the internal cycles counter decreases until hatching, then the Pokémon is added to the player’s party (or dropped if full).
Pasture blocks check every eggCheckTicks for two compatible Pokémon (gender/egg groups, ignoring neutered or baby Pokémon). If found, they clone a child, apply shiny chances (supports disabled/masuda/crystal with multiplier), and create a breeding egg using the species’ egg cycles.
If allowHoppers is true the pasture tries to insert eggs into a hopper beneath; otherwise it spawns the egg above the block.

/eggInfo – Inspect held egg; shows "§kSecret" when encrypted, otherwise displays IVs.
/forceHatch – Sets held egg cycles to 0 so it hatches on next tick.
/neuter <slot> – Marks the Pokémon in the given party slot as unbreedable and charges neuterCost experience levels (rounded up).
/checkBreedable <slot> – Reports whether the party Pokémon is breedable.
/giveEgg <player> <specs> – Creates an egg from Cobblemon specs and gives it to the player.
/bmcbreed reload – Reloads the config and reinitializes encryption.

Encryption uses AES/ECB/PKCS5Padding with the key truncated/padded to 16 bytes; encrypted data is stored as Base64 string BMCData.
Eggs use Mojang 1.21.1 data components (CustomData) rather than legacy NBT wrappers.
Neutering adds breedable=false to Pokémon persistent data; pasture breeding ignores Pokémon with this flag.

Permissions API calls use a lightweight fallback stub; integrate a full permissions provider if stricter controls are needed.
Pasture breeding stops after creating one egg per scan interval; expanding throughput would require queueing or multiple blocks.
Eggs are consumed only when successfully added to a party; full parties will leave the egg intact after a warning message.