<script>
  /**
   * @event {ReadonlyArray<File>} add
   * @event {ReadonlyArray<File>} change
   */

  /**
   * Specify the accepted file types
   * @type {ReadonlyArray<string>}
   */
  export let accept = [];

  /**
   * Obtain a reference to the uploaded files
   * @type {ReadonlyArray<File>}
   */
  export let files = [];

  /** Set to `true` to allow multiple files */
  export let multiple = false;

  /**
   * Override the default behavior of validating uploaded files.
   * By default, files are not validated
   * @type {(files: ReadonlyArray<File>) => ReadonlyArray<File>}
   */
  export let validateFiles = (files) => files;

  /** Specify the label text */
  export let labelText = "Add file";

  /** Specify the `role` attribute of the drop container */
  export let role = "button";

  /** Set to `true` to disable the input */
  export let disabled = false;

  /** Specify `tabindex` attribute */
  export let tabindex = "0";

  /** Set an id for the input element */
  export let id = "ccs-" + Math.random().toString(36);

  /** Specify a name attribute for the input */
  export let name = "";

  /** Obtain a reference to the input HTML element */
  export let ref = null;

  import { createEventDispatcher } from "svelte";

  const dispatch = createEventDispatcher();

  let over = false;
</script>

<div
  class:bx--file="{true}"
  {...$$restProps}
  on:dragover
  on:dragover|preventDefault|stopPropagation="{({ dataTransfer }) => {
    if (!disabled) {
      over = true;
      dataTransfer.dropEffect = 'copy';
    }
  }}"
  on:dragleave
  on:dragleave|preventDefault|stopPropagation="{({ dataTransfer }) => {
    if (!disabled) {
      over = false;
      dataTransfer.dropEffect = 'move';
    }
  }}"
  on:drop
  on:drop|preventDefault|stopPropagation="{({ dataTransfer }) => {
    if (!disabled) {
      over = false;
      files = validateFiles([...dataTransfer.files]);
      dispatch('add', files);
      dispatch('change', files);
    }
  }}"
>
  <label
    for="{id}"
    tabindex="{tabindex}"
    class:bx--file-browse-btn="{true}"
    class:bx--file-browse-btn--disabled="{disabled}"
    on:keydown
    on:keydown="{({ key }) => {
      if (key === ' ' || key === 'Enter') {
        ref.click();
      }
    }}"
  >
    <div
      role="{role}"
      class:bx--file__drop-container="{true}"
      class:bx--file__drop-container--drag-over="{over}"
    >
      <slot name="labelText">
        {labelText}
      </slot>
    </div>
  </label>
  <input
    bind:this="{ref}"
    type="file"
    tabindex="-1"
    id="{id}"
    disabled="{disabled}"
    accept="{accept}"
    name="{name}"
    multiple="{multiple}"
    class:bx--file-input="{true}"
    on:change="{({ target }) => {
      files = validateFiles([...target.files]);
      dispatch('add', files);
      dispatch('change', files);
    }}"
    on:click
    on:click="{({ target }) => {
      target.value = null;
    }}"
  />
</div>
