# Pegination

Implementation of cursor pagination. See the tests for details.

### Requirements

#### 1. Structure `SourceRequest`

Source request sent to API

```rust
#[derive(Debug, Clone)]
struct SourceRequest {}
```

#### 2. Structure `Filters`

Data source filters, excludes limit and offset

```rust
#[derive(Clone, Debug, Deserialize, PartialEq, Serialize)]
struct Filters {}
```

#### 3. Structure `Item`

Data source entity

```rust
#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
struct Item {}
```

#### 4. Entity `Error`

```rust
enum AppError {}
```

### Required implementations

#### 1. `SourceRequest` to `Request<Filters>` transormation

```rust
impl TryFrom<SourceRequest> for Request<Filters> {}
```

#### 2. `DataSource`

```rust
trait DataSource<Item, Filters: Clone + PartialEq, OffsetValue: Clone>
```

### Usage

Having all of the stuff described above, you can use `pagination` function this way:

```rust
const DEFAULT_LIMIT: u16 = 100;

let paginated_data = pagination::<Item, Filters, OffsetValue, AppError>(data_source, source_request, DEFAULT_LIMIT).await?;
// {
//   "last_cursor": null,
//   "has_next_page": false,
//   "data": [
//     ..items
//   ]
// }
```