import IEvent from "../intefaces/IEvent";
import ATSEvent from "./ATSEvent";

// ClickFix landing pages: the element that copies the command the fake
// CAPTCHA asks the person to run. The attribute's value is the command; when
// it is empty the element's own text is (a command box that copies itself).
export const COPY_COMMAND_ATTRIBUTE = "data-ats-copy-command";

const findCopyElement = (event?: Event): HTMLElement | null => {
	if (!(event?.target instanceof Element)) {
		return null;
	}

	return event.target.closest<HTMLElement>(`[${COPY_COMMAND_ATTRIBUTE}]`);
};

const commandOf = (element: HTMLElement): string => {
	const command = (element.getAttribute(COPY_COMMAND_ATTRIBUTE) || "").trim();
	return command || (element.textContent || "").trim();
};

/**
 * Puts the text on the clipboard. The Clipboard API needs a secure context;
 * plain-http landing pages fall back to the legacy copy command, which only
 * works while the click is still being handled.
 */
const copyToClipboard = (text: string): void => {
	if (navigator.clipboard?.writeText) {
		navigator.clipboard.writeText(text).catch(() => undefined);
		return;
	}

	const field = document.createElement("textarea");
	field.value = text;
	field.setAttribute("readonly", "");
	field.style.position = "fixed";
	field.style.opacity = "0";
	document.body.appendChild(field);
	try {
		field.select();
		if (typeof document.execCommand === "function") {
			document.execCommand("copy");
		}
	} finally {
		field.remove();
	}
};

export default class CommandCopied extends ATSEvent implements IEvent {
	get trigger(): string {
		return "click";
	}
	get source(): Window {
		return window;
	}
	get name(): string {
		return "command_copied";
	}
	get hasTypes(): boolean {
		return false;
	}
	get redirectOnFinish(): boolean {
		return true;
	}
	get isBlocking(): boolean {
		return true;
	}
	get allowMultiple(): boolean {
		return false;
	}

	isValid(event: Event): boolean {
		const element = findCopyElement(event);
		return !!element && this.basicValidation(element);
	}

	typeOf(): string {
		return "command";
	}

	perform(event?: Event): void {
		const element = findCopyElement(event);
		if (element) {
			copyToClipboard(commandOf(element));
		}
	}
}