# Item
An item is the base concept for CDB. Everything is an Item. An Item describes a general product or object.

## Defining an Item
An Item is defined within a markdown file with frontmatter. Items are the root dataset of CDB. One can use [this](https://git.hydrar.de/red/itemdb) as a starting point or create their own items.

For example, we define a "Water" Item:
```markdown
---
name: "Water"
variants:
  common:
    name: "Common Water"
---

# Water
This is a Water Item
```

The file consist of the frontmatter, containing values for the item, and the rest of the markdown file containing a description.

## Variants
Variants are different version of the same item. Each variant can have their own values. Each item needs at least one variant.

For our water example:
```yml
name: "Water"
variant:
  regular:
    name: "Regular Water"
  sparkling:
    name: "Sparkling Water"
  destilled:
    name: "Destilled Water"
```

Here we have defined three "Water" item variants.

## Inventory
With the items defined, you can start tracking their inventory. See [Transaction](Transaction.md).

### Min
You can set a minimum required inventory for an item variant. This will trigger events when an item reaches a low inventory threshold.

```yml
name: "Water"
variants:
  regular:
    name: "Regular Water"
    min: 2
```

This will ensure that at least two units of the "Regular Water" item variant are in inventory.

### Expiry
You can set a default expiry time for an Item Variant. This value is defined as days until expiry.

```yml
name: "Water"
variants:
  regular:
    name: "Regular Water"
    expiry: 30
```

This will mark any item variant as expired if it's older than 30 days.

### Barcodes
You can associate barcodes with your item variants. This is useful for Quick Adding Items.

```yml
name: "Water"
variants:
  regular:
    name: "Regular Water"
    barcodes: [12345678]
```

### Need Conditions
Some items prefer or need to be stored under some conditions. These conditions can be configured and warn you when locations dont match the required conditions.

```yml
name: "Water"
variants:
  regular:
    name: "Regular Water"
    needs:
      temperature: [5.0, 10.0]
```

### Quantization
Sometimes items are homogenous and can be subdivided.
This can be defined via the `unit` of an Item Variant.
You define the base unit (the smallest possible instance) of an Item Variant. In this case `ml`.
Optionally you can define various `conversions` to bigger units by specifiying the units name and how many of the base unit this unit is.
In this case we define `liter` to be 1000 `ml`.

```yml
name: "Water"
variants:
  regular:
    name: "Regular Water"
    unit:
      by: "ml"
      conversions:
        liter: 1000
```

### Properties
Some items might be more or less the same thing but come in various configurations.
To address such items you can define custom properties on Item Variants.
You can then use these properties to save and filter on metadata about your items.
This can be done by defining custom properties in a JSON schema like format in `properties`:

```yml
name: "iPhone"
variants:
  iphone:
    name: "iPhone"
    properties:
      color:
        enum: ["Black", "White", "Red"]
        description: "The Phone Color"
      ram:
        type: integer
        description: "The amount of RAM"
```