type Options = {
  /** The time before the copied status is reset. */
  delay: number;
};

/** Use this hook to copy text to the clipboard and show a copied state.
 *
 * ## Usage
 * ```svelte
 * <script lang="ts">
 * 		import { UseClipboard } from "$lib/hooks/use-clipboard.svelte";
 *
 * 		const clipboard = new UseClipboard();
 * </script>
 *
 * <button onclick={() => clipboard.copy('Hello, World!')}>
 *     {#if clipboard.copied === 'success'}
 *         Copied!
 *     {:else if clipboard.copied === 'failure'}
 *         Failed to copy!
 *     {:else}
 *         Copy
 *     {/if}
 * </button>
 * ```
 *
 */
export class UseClipboard {
  #copiedStatus = $state<'success' | 'failure'>();
  private delay: number;
  private timeout: ReturnType<typeof setTimeout> | undefined = undefined;

  constructor({ delay = 500 }: Partial<Options> = {}) {
    this.delay = delay;
  }

  /** Copies the given text to the users clipboard.
   *
   * ## Usage
   * ```ts
   * clipboard.copy('Hello, World!');
   * ```
   *
   * @param text
   * @returns
   */
  async copy(text: string) {
    if (this.timeout) {
      this.#copiedStatus = undefined;
      clearTimeout(this.timeout);
    }

    this.#copiedStatus = await copyText(text);

    this.timeout = setTimeout(() => {
      this.#copiedStatus = undefined;
    }, this.delay);

    return this.#copiedStatus;
  }

  /** true when the user has just copied to the clipboard. */
  get copied() {
    return this.#copiedStatus === 'success';
  }

  /**	Indicates whether a copy has occurred
   * and gives a status of either `success` or `failure`. */
  get status() {
    return this.#copiedStatus;
  }
}

export async function copyText(text: string): Promise<'success' | 'failure'> {
  try {
    if (navigator.clipboard && window.isSecureContext) {
      await navigator.clipboard.writeText(text);
      return 'success';
    }

    // when navigator.clipboard is unavailable we fallback to this for wider browser compatibility
    const textArea = document.createElement('textarea');
    textArea.value = text;
    textArea.style.position = 'fixed';
    textArea.style.top = '0';
    textArea.style.left = '0';
    document.body.appendChild(textArea);
    textArea.focus();
    textArea.select();

    const successful = document.execCommand('copy');

    document.body.removeChild(textArea);

    return successful ? 'success' : 'failure';
  } catch {
    return 'failure';
  }
}