# Input File

InputFile allows users to upload a file, or multiple files by dragging and
dropping them into an area on the page or by clicking a button.

## Design & usage guidelines

When contributing to, or consuming the InputFile component, consider the
following:

* Provide feedback once the file(s) have been dropped and uploading begins.


## Configuration

### getUploadParams

`getUploadParams` is a necessary callback that tells InputFile where and how to
upload files that are passed to it. It must return an object conforming to the
`UploadParams` interface. `getUploadParams` can be async, allowing for a network
request to fetch any extra fields.

```ts
interface UploadParams {
  /**
   * Url to POST file to.
   */
  readonly url: string;

  /**
   * Key to identify file.
   * If unspecified a random `uuid` will be used.
   */
  readonly key?: string;

  /**
   * Any extra fields to send with the upload POST.
   * If unspecified only the file will be included.
   */
  readonly fields?: { [field: string]: string };
}
```

### updateFiles helper

InputFile also exports an `updateFiles` method. This method allows for easily
updating an array of `FileUpload`s based on their `key` as uploads progress.

```ts
/**
 * Upsert a given `FileUpload` into an array of `FileUpload`s.
 * `key` is used to uniquely identify files.
 *
 * @param updatedFile FileUpload File that was updated.
 * @param files Existing array of FileUploads.
 * @returns FileUpload[] updated set of files.
 */
export function updateFiles(updatedFile: FileUpload, files: FileUpload[]);
```

### validator

InputFile can accept a `validator` function as a prop. This will allow you to
reject or accept file uploads based on your needs. The value of the function
must accept a File and return `null` when it is accepted or an error object when
rejected.

For example, the code below only accepts files that are less than 2MB in size.
Take a look at the
[File Size Validator](/storybook/web/?path=/story/components-forms-and-inputs-inputfile--file-size-validator)
story for expected behavior.

```ts
function fileSizeValidator(file: File) {
  if (file.size > 2000000) {
    return {
      code: "file-too-big",
      message: "The file is too big. Try using a smaller image",
    };
  }

  return null;
}
```

### maxFiles

The `maxFiles` property in the InputFile component is used to specify the
maximum number of files that can be uploaded via the dropzone. This property is
part of the `maxFilesValidation` object, which also includes the
`numberOfCurrentFiles` property to track the number of files that have already
been uploaded. When the total number of uploaded files exceeds the `maxFiles`
limit, the component will display a validation message and prevent additional
files from being uploaded.

The
[Max Files Limit](/storybook/web/?path=/story/components-forms-and-inputs-inputfile--max-files-limit)
example demonstrates the behaviour of uploading more than `maxFiles`.

```ts
 <InputFile
    ...
    onUploadComplete={handleUpload}
    maxFilesValidation={{ maxFiles: 3, numberOfCurrentFiles: files.length }}
  />
```

`maxFiles` is directly mapped to `react-dropzone`'s `maxFiles` prop, documented
[here](https://react-dropzone.js.org/#!/Accepting%20specific%20number%20of%20files).

### description

The `description` prop is a string that can be used to provide additional
information to the user. A common use case is to provide the accepted file types
and maximum size for each file. With a helpful `description`, users are more
aware of the limitations and requirements of the file upload.

### hintText

The hint text provides instructions for file upload and automatically adjusts
based on context. For single files it shows "Select or drag a file here to
upload", while for multiple files it shows "Select or drag files here to
upload". When `allowedTypes` is set to "images", it uses "image" instead of
"file". You can override the default text using the `hintText` prop.

### allowedTypes

The `allowedTypes` prop determines the types of files that can be uploaded.
`allowedTypes` accepts `images`, `basicImages` or an array of customized file
types. If the `allowedTypes` prop is not provided, all types will be accepted.

Using the `FileTypes` enum, you can customize the types of files that are
allowed to be uploaded.

```ts
<InputFile
  ...
  allowedTypes={["JPEG", "PNG", "HEIC", "PDF", "DOCX"]}
/>
```

## Basic usage

```tsx
<InputFile
  getUploadParams={file => ({
    url: "https://upload.example.com",
    key: file.name,
  })}
/>
```

## Default content structure

When no children are provided, InputFile renders different default content based
on the `variation` and `size` props:

### Dropzone variation (default)

```tsx
// size="base" (default)
<InputFile getUploadParams={getUploadParams}>
  <InputFile.DropzoneWrapper>
    <Content spacing="small">
      <InputFile.Button size="small" fullWidth={false} />
      <InputFile.HintText />
      <InputFile.Description />
    </Content>
  </InputFile.DropzoneWrapper>
</InputFile>

// size="small"
<InputFile size="small" getUploadParams={getUploadParams}>
  <InputFile.DropzoneWrapper>
    <Content spacing="small">
      <InputFile.Button size="small" fullWidth={false} />
      {/* In the default InputFile, HintText and Description are omitted in small size */}
    </Content>
  </InputFile.DropzoneWrapper>
</InputFile>
```

### Button variation

```tsx
<InputFile variation="button" getUploadParams={getUploadParams}>
  <InputFile.Button fullWidth={true} />
</InputFile>
```

## Customization

### Using props

Basic customization can be achieved through props:

```tsx
<InputFile
  getUploadParams={getUploadParams}
  buttonLabel="Choose Images"
  allowMultiple={true}
  allowedTypes="images"
  hintText="Drop your images here"
  description="Supported formats: JPG, PNG"
/>
```

### Using children

For complete control over the layout, you can provide custom children:

```tsx
<InputFile getUploadParams={getUploadParams}>
  <InputFile.DropzoneWrapper>
    <Content spacing="small">
      <InputFile.Button size="small" fullWidth={false} />
      <InputFile.HintText />
      <InputFile.Description />
    </Content>
  </InputFile.DropzoneWrapper>
</InputFile>
```

### Available subcomponents

1. `InputFile.Button`: Upload button

   ```tsx
   <InputFile.Button size="large" fullWidth={false} variation="work" />
   ```

2. `InputFile.HintText`: Helper text for the dropzone

   ```tsx
   <InputFile.HintText size="small" />
   ```

3. `InputFile.Description`: Additional description text

   ```tsx
   <InputFile.Description size="small" variation="subdued" />
   ```

4. `InputFile.DropzoneWrapper`: Wrapper for dropzone content
   ```tsx
   <InputFile.DropzoneWrapper>{/* Your content */}</InputFile.DropzoneWrapper>
   ```

### Using context

Subcomponents automatically access the InputFile context. The context includes:

```tsx
interface InputFileContentContextValue {
  fileType: string; // Type of file being uploaded
  allowMultiple: boolean; // Multiple files allowed
  description?: string; // Description text
  hintText?: string; // Hint text
  buttonLabel?: string; // Button label
  size: "small" | "base"; // Component size
}
```

You can also access this context in custom components:

```tsx
import { useInputFileContentContext } from "./InputFileContentContext";

function CustomUploadContent() {
  const { fileType, allowMultiple, size } = useInputFileContentContext();

  return (
    <div>
      <h3>Upload {allowMultiple ? `${fileType}s` : fileType}</h3>
      <InputFile.Button size={size} />
    </div>
  );
}

<InputFile getUploadParams={getUploadParams}>
  <CustomUploadContent />
</InputFile>;
```

## Examples

### Basic dropzone

```tsx
<InputFile getUploadParams={getUploadParams} />
```

### Image upload with validation

```tsx
<InputFile
  getUploadParams={getUploadParams}
  allowedTypes="images"
  maxFilesValidation={{ maxFiles: 5, numberOfCurrentFiles: 0 }}
  validator={file => {
    if (file.size > 5000000) {
      return { code: "file-too-large", message: "File is too large" };
    }
    return null;
  }}
/>
```

### Custom dropzone layout

```tsx
<InputFile getUploadParams={getUploadParams}>
  <InputFile.DropzoneWrapper>
    <div className="custom-layout">
      <Heading level={2}>Upload Documents</Heading>
      <div className="upload-section">
        <InputFile.Button size="large" />
        <InputFile.HintText />
      </div>
      <div className="info-section">
        <InputFile.Description />
      </div>
    </div>
  </InputFile.DropzoneWrapper>
</InputFile>
```

### Custom button

```tsx
<InputFile variation="button" getUploadParams={getUploadParams}>
  <InputFile.Button
    ariaLabel="Upload image"
    label="Upload image"
    icon="image"
    type="tertiary"
    fullWidth={true}
  />
</InputFile>
```

## Developer notes

* Always provide clear feedback during the upload process
* Consider using size="small" in compact layouts or forms
* Include descriptive text to help users understand file requirements
* If you would like to restrict specific file types, it is advised that you use
  the `allowedTypes` property instead of the `validator` property.
* For image uploads, use `allowedTypes="basicImages"` to restrict to common
  formats


## Props

### Web

#### InputFile

| Prop | Type | Required | Default | Description |
|------|------|----------|---------|-------------|
| `getUploadParams` | `(file: File) => UploadParams | Promise<UploadParams>` | Yes | — | A callback that receives a file object and returns a `UploadParams` needed to upload the file.  More info is availabl... |
| `allowedTypes` | `"all" | string[] | "images" | "basicImages"` | No | `all` | Allowed File types. @param  "images" - only accepts all types of image @param  "basicImages" - only accepts png, jpg ... |
| `allowMultiple` | `boolean` | No | `false` | Allow for multiple files to be selected for upload. |
| `buttonLabel` | `string` | No | `Automatic` | Label for the InputFile's button. |
| `children` | `ReactNode` | No | — | Children will be rendered instead of the default content |
| `description` | `string` | No | — | Further description of the input. |
| `hintText` | `string` | No | — | Override the default hint text with a custom value. |
| `maxFilesValidation` | `{ readonly maxFiles: number; readonly numberOfCurrentFiles: number; }` | No | — | An object which helps control and validate the number of files being uploaded via the dropzone. `maxFilesValidation={... |
| `name` | `string` | No | — | Sets the `name` attribute on the underlying `<input>` element. |
| `onUploadComplete` | `(file: FileUpload) => void` | No | — | Upload event handler. Triggered on upload completion. |
| `onUploadError` | `(error: Error) => void` | No | — | Upload event handler. Triggered on upload error. |
| `onUploadProgress` | `(file: FileUpload) => void` | No | — | Upload event handler. Triggered as upload progresses. |
| `onUploadStart` | `(file: FileUpload) => void` | No | — | Upload event handler. Triggered on upload start. |
| `size` | `"small" | "base"` | No | `base` | Size of the InputFile |
| `validator` | `<T extends File>(file: T) => FileError | FileError[]` | No | — | Pass a custom validator function that will be called when a file is dropped. |
| `variation` | `"button" | "dropzone"` | No | `dropzone` | Display variation. |

#### InputFile.Button

| Prop | Type | Required | Default | Description |
|------|------|----------|---------|-------------|
| `ariaControls` | `string` | No | — | Used for screen readers. Will override label on screen reader if present. |
| `ariaExpanded` | `boolean` | No | — |  |
| `ariaHaspopup` | `boolean` | No | — |  |
| `ariaLabel` | `string` | No | — |  |
| `disabled` | `boolean` | No | — |  |
| `external` | `boolean` | No | — |  |
| `fullWidth` | `boolean` | No | `false` |  |
| `icon` | `IconNames` | No | — |  |
| `iconOnRight` | `boolean` | No | — |  |
| `id` | `string` | No | — |  |
| `label` | `string` | No | — |  |
| `loading` | `boolean` | No | — |  |
| `onClick` | `(event: MouseEvent<HTMLAnchorElement | HTMLButtonElement, MouseEvent>) => void` | No | — |  |
| `onMouseDown` | `(event: MouseEvent<HTMLAnchorElement | HTMLButtonElement, MouseEvent>) => void` | No | — |  |
| `role` | `string` | No | — | Used to override the default button role. |
| `size` | `ButtonSize` | No | — |  |
| `type` | `ButtonType` | No | — |  |
| `UNSAFE_className` | `{ container?: string; buttonLabel?: { textStyle?: string; }; buttonIcon?: { svg?: string; path?: string; }; }` | No | — | **Use at your own risk:** Custom class names for specific elements. This should only be used as a **last resort**. Us... |
| `UNSAFE_style` | `{ container?: CSSProperties; buttonLabel?: { textStyle?: CSSProperties; }; buttonIcon?: { svg?: CSSProperties; path?: CSSProperties; }; }` | No | — | **Use at your own risk:** Custom style for specific elements. This should only be used as a **last resort**. Using th... |
| `variation` | `ButtonVariation` | No | — |  |

#### InputFile.Description

| Prop | Type | Required | Default | Description |
|------|------|----------|---------|-------------|
| `align` | `"center" | "end" | "start"` | No | — |  |
| `element` | `TextElement` | No | `"p"` | The HTML element to render the text as. |
| `maxLines` | `"small" | "large" | "base" | "larger" | "single" | "unlimited"` | No | — |  |
| `size` | `"small" | "large" | "base"` | No | `small` |  |
| `UNSAFE_className` | `{ textStyle?: string; }` | No | — | **Use at your own risk:** Custom classNames for specific elements. This should only be used as a **last resort**. Usi... |
| `UNSAFE_style` | `{ textStyle?: CSSProperties; }` | No | — | **Use at your own risk:** Custom style for specific elements. This should only be used as a **last resort**. Using th... |
| `variation` | `"info" | "disabled" | "success" | "error" | "default" | "subdued" | "warn"` | No | `subdued` |  |

#### InputFile.HintText

| Prop | Type | Required | Default | Description |
|------|------|----------|---------|-------------|
| `align` | `"center" | "end" | "start"` | No | — |  |
| `element` | `TextElement` | No | `"p"` | The HTML element to render the text as. |
| `maxLines` | `"small" | "large" | "base" | "larger" | "single" | "unlimited"` | No | — |  |
| `size` | `"small" | "large" | "base"` | No | `small` |  |
| `UNSAFE_className` | `{ textStyle?: string; }` | No | — | **Use at your own risk:** Custom classNames for specific elements. This should only be used as a **last resort**. Usi... |
| `UNSAFE_style` | `{ textStyle?: CSSProperties; }` | No | — | **Use at your own risk:** Custom style for specific elements. This should only be used as a **last resort**. Using th... |
| `variation` | `"info" | "disabled" | "success" | "error" | "default" | "subdued" | "warn"` | No | — |  |
