import { SettingStatusEnum, status } from "../utils/SettingStatus.mjs";
import { __ID__ } from "../consts.mjs";
import { Logger } from "../utils/Logger.mjs";
import { preventTweakRegistration } from "../utils/preRegisterTweak.mjs";

const key = `chatImageLinks`;
const IMAGE_TYPES = [
	`png`,
	`jpg`,
	`jpeg`,
	`webp`,
	`svg`,
];

export function chatImageLinks() {
	status[key] = SettingStatusEnum.Unknown;
	if (preventTweakRegistration(key)) { return };

	/** @type {number|null} */
	let hookID = null;

	// #region Registration
	Logger.log(`Registering setting: ${key}`);
	game.settings.register(__ID__, key, {
		name: `OFT.setting.${key}.name`,
		hint: `OFT.setting.${key}.hint`,
		scope: `user`,
		type: Boolean,
		default: true,
		config: true,
		requiresReload: false,
		onChange: (newValue) => {
			if (newValue) {
				hookID = Hooks.on(`chatMessage`, chatMessageHandler);
			} else if (hookID != null) {
				Hooks.off(`chatMessage`, hookID);
			};
		},
	});
	// #endregion Registration

	// #region Implementation
	if (game.settings.get(__ID__, key)) {
		Logger.log(`setting:${key} | Adding chat message listener`);
		Hooks.on(`chatMessage`, chatMessageHandler);
	};
	// #endregion Implementation

	status[key] = SettingStatusEnum.Registered;
};

// #region Helpers
const pattern = new RegExp(
	`https?:\\/\\/\\S*\\.(?:${IMAGE_TYPES.join(`|`)})`,
	`gi`,
);

// MARK: Mutate & Resend
const handled = new Set();
async function mutateAndResendMessage(chatLog, message, options) {
	const validMatches = new Set();

	const matches = message.match(pattern);
	for (const match of matches) {
		if (await isAcceptableImage(match)) {
			validMatches.add(match);
		};
	};

	message = message.replaceAll(
		pattern,
		(url) => {
			if (!validMatches.has(url)) {
				return url;
			};
			return `<img src="${url}" alt="${url}">`;
		},
	);

	handled.add(message);
	chatLog.processMessage(message, options);
};

// MARK: Chat Message
/**
 * Must be synchronous since it is a hook handler, but the mutation +
 * resending can be done asynchronously since it doesn't matter how
 * long it takes.
 */
function chatMessageHandler(chatLog, message, options) {
	if (!game.settings.get(__ID__, key)) { return };

	// Don't re-process the same message
	if (handled.has(message)) { return };

	// Prevent cancellation for non-matching messages
	const match = message.match(pattern);
	if (!match) { return };

	mutateAndResendMessage(chatLog, message, options);
	return false;
};

// MARK: isAcceptableImage
async function isAcceptableImage(url) {
	if (!URL.canParse(url)) { return false };

	try {
		const response = await fetch(url, { method: `HEAD` });
		const contentType = response.headers.get(`Content-Type`);
		Logger.debug(`Image data:`, { url, contentType });

		let [ superType, subtype ] = contentType.split(`/`);
		if (superType !== `image`) {
			return false;
		};
		if (subtype.includes(`+`)) {
			subtype = subtype.split(`+`, 2).at(0);
		};
		return IMAGE_TYPES.includes(subtype);
	} catch {
		return false;
	};
};
// #endregion Helpers