# World factory "production lines" (conveyors) — where to find them

The game has **fixed single-recipe world structures** — item conveyors that run *one*
recipe (e.g. **1 Raw Aurogen Crystal → 10 Energy Rods**). These are a separate mechanic
from the player **workbench** recipes (which live in `extracted/crafting_recipes.json`,
sourced from `CraftingRecipeBundle` assets). This note records **where they live** so the
data can be re-derived after a game update.

## The mechanic

In code it's a *"Factory Production Line"*. It's an Entitas ECS feature, namespace
`Hologryph.Sand.Shared.Game.Features.Crafting` (see `il2cpp/dump.cs`):

| Class | Holds |
|---|---|
| `ProductionLineComponent` | `int inputEntityIndex`, `int outputEntityIndex` |
| `ProductionLineRecipeComponent` | `CraftingRecipe recipe`  ← the recipe |
| `ProductionLineInputDataComponent` / `…OutputDataComponent` | `bool isLargeItem{Input,Output}` |
| `CraftingRecipe` | `CraftingIngredient[] inputIngredients`, `CraftingIngredient[] outputIngredients`, `float craftingTimeSeconds` |
| `CraftingIngredient` | `string itemId`, `int amount` |

Note `CraftingRecipe` / `CraftingIngredient` are the **same types** the workbench uses —
only the container differs (a workbench holds `List<CraftingRecipeBundle> recipeBundles`;
a production line holds a single `CraftingRecipe` on the entity).

## Where the data lives

- **Bundle:** `epb_assets_all.bundle` (reachable via the `bundles/` symlink).
- **Prefabs:** `game_conveyor_*_epb.prefab`, under
  `Assets/Content/Game/game_conveyor/...`. 14 carry a recipe; 4 of them are named
  `game_conveyor_base*` (large/small in→out variants) — what distinguishes them from
  the product-named ones beyond the name is not established here.
- **Serialization:** each prefab GameObject (`m_Name = game_conveyor_<x>_epb`) has two
  components — a `Transform` and a `MonoBehaviour` whose script is **`EntityBlueprint`**.
  `EntityBlueprint : SerializedMonoBehaviour` (Sirenix Odin), so the component data —
  including the `CraftingRecipe` — is in its **Odin-serialized
  `serializationData.SerializedBytes`**, not in plain typetree fields. (Same situation as
  the loot tables — see [TASK.md](TASK.md) / `extract_loot.py`.)

### Extraction path (how to read it)

`UnityPy` (with an IL2CPP `TypeTreeGenerator` over `GameAssembly.dll` +
`global-metadata.dat`) reads the `EntityBlueprint` MonoBehaviour → pull
`serializationData.SerializedBytes` → `bundle/odin_read.py` parses the Odin binary →
walk the tree for the node with `inputIngredients` / `outputIngredients`.

```bash
venv/bin/python bundle/extract_production_lines.py   # -> extracted/production_lines.json
```

Key item ids seen here: `item_crystalHandles` = *Raw Aurogen Crystal*,
`item_energyBar` = *NZ Mk2 Energy Rod*, `item_blackBox` = *Black Box*,
`item_resourceCoralPiece` = *Coral Chunk*. Resolve any id → display name via
`extracted/items_registry.json` / `extracted/item_names.json` (built from
`CheatItemDefinitionsData`).

## Island placement — open lead

Which factory/island runs which conveyor is grouped by the
`energy_grid_*_epb.prefab` blueprints in the same bundle:
`Wunderinsel`, `Kaiserplatz`, `DeusExMachine`, `Factorio`, `LittleFactory1-3`,
`LittleFactoryArmory1-3`, `TestFactory`. The **`…Armory`** groups are the likely
**Sprengstofffabrik** (explosives factory) host for the explosive / grenade / rocket /
cannon conveyors.

**Not yet resolved:** an `energy_grid_*` blueprint's Odin data references its conveyors by
**entity reference, not item-id string** (a string scan of its serialized bytes finds no
`game_conveyor_*` / `item_*` ids). So mapping recipe → specific island needs the **island
prefab placements** in `islands_assets_all.bundle` (the `island_*` / fort / `loc_event_*`
prefabs, where `Sprengstofffabrik` is an i2 `Toponyms/` name), not the conveyor or
energy_grid EPBs alone. That linkage is the next step if island attribution is wanted.