import * as Bull from 'bull';
import * as httpSignature from 'http-signature';
import parseAcct from '../../misc/acct/parse';
import { IRemoteUser } from '../../models/entities/user';
import perform from '../../remote/activitypub/perform';
import { resolvePerson, updatePerson } from '../../remote/activitypub/models/person';
import { URL } from 'url';
import { publishApLogStream } from '../../services/stream';
import Logger from '../../services/logger';
import { registerOrFetchInstanceDoc } from '../../services/register-or-fetch-instance-doc';
import { Instances, Users, UserPublickeys } from '../../models';
import { instanceChart } from '../../services/chart';
import { UserPublickey } from '../../models/entities/user-publickey';
import fetchMeta from '../../misc/fetch-meta';
import { toPuny } from '../../misc/convert-host';
import { validActor } from '../../remote/activitypub/type';
import { ensure } from '../../prelude/ensure';

const logger = new Logger('inbox');

// ユーザーのinboxにアクティビティが届いた時の処理
export default async (job: Bull.Job): Promise<void> => {
	const signature = job.data.signature;
	const activity = job.data.activity;

	//#region Log
	const info = Object.assign({}, activity);
	delete info['@context'];
	delete info['signature'];
	logger.debug(JSON.stringify(info, null, 2));
	//#endregion

	const keyIdLower = signature.keyId.toLowerCase();
	let user: IRemoteUser;
	let key: UserPublickey;

	if (keyIdLower.startsWith('acct:')) {
		const acct = parseAcct(keyIdLower.slice('acct:'.length));
		const host = acct.host ? toPuny(acct.host) : null;
		const username = toPuny(acct.username);

		if (host === null) {
			logger.warn(`request was made by local user: @${username}`);
			return;
		}

		// アクティビティ内のホストの検証
		try {
			ValidateActivity(activity, host);
		} catch (e) {
			logger.warn(e.message);
			return;
		}

		// ブロックしてたら中断
		// TODO: いちいちデータベースにアクセスするのはコスト高そうなのでどっかにキャッシュしておく
		const meta = await fetchMeta();
		if (meta.blockedHosts.includes(host)) {
			logger.info(`Blocked request: ${host}`);
			return;
		}

		user = await Users.findOne({
			usernameLower: username.toLowerCase(),
			host: host
		}) as IRemoteUser;

		key = await UserPublickeys.findOne(user.id).then(ensure);
	} else {
		// アクティビティ内のホストの検証
		const host = toPuny(new URL(signature.keyId).hostname);
		try {
			ValidateActivity(activity, host);
		} catch (e) {
			logger.warn(e.message);
			return;
		}

		// ブロックしてたら中断
		// TODO: いちいちデータベースにアクセスするのはコスト高そうなのでどっかにキャッシュしておく
		const meta = await fetchMeta();
		if (meta.blockedHosts.includes(host)) {
			logger.info(`Blocked request: ${host}`);
			return;
		}

		key = await UserPublickeys.findOne({
			keyId: signature.keyId
		}).then(ensure);

		user = await Users.findOne(key.userId) as IRemoteUser;
	}

	// Update Person activityの場合は、ここで署名検証/更新処理まで実施して終了
	if (activity.type === 'Update') {
		if (activity.object && validActor.includes(activity.object.type)) {
			if (user == null) {
				logger.warn('Update activity received, but user not registed.');
			} else if (!httpSignature.verifySignature(signature, key.keyPem)) {
				logger.warn('Update activity received, but signature verification failed.');
			} else {
				updatePerson(activity.actor, null, activity.object);
			}
			return;
		}
	}

	// アクティビティを送信してきたユーザーがまだMisskeyサーバーに登録されていなかったら登録する
	if (user == null) {
		user = await resolvePerson(activity.actor) as IRemoteUser;
	}

	if (user == null) {
		throw new Error('failed to resolve user');
	}

	if (!httpSignature.verifySignature(signature, key.keyPem)) {
		logger.error('signature verification failed');
		return;
	}

	//#region Log
	publishApLogStream({
		direction: 'in',
		activity: activity.type,
		host: user.host,
		actor: user.username
	});
	//#endregion

	// Update stats
	registerOrFetchInstanceDoc(user.host).then(i => {
		Instances.update(i.id, {
			latestRequestReceivedAt: new Date(),
			lastCommunicatedAt: new Date(),
			isNotResponding: false
		});

		instanceChart.requestReceived(i.host);
	});

	// アクティビティを処理
	await perform(user, activity);
};

/**
 * Validate host in activity
 * @param activity Activity
 * @param host Expect host
 */
function ValidateActivity(activity: any, host: string) {
	// id (if exists)
	if (typeof activity.id === 'string') {
		const uriHost = toPuny(new URL(activity.id).hostname);
		if (host !== uriHost) {
			const diag = activity.signature ? '. Has LD-Signature. Forwarded?' : '';
			throw new Error(`activity.id(${activity.id}) has different host(${host})${diag}`);
		}
	}

	// actor (if exists)
	if (typeof activity.actor === 'string') {
		const uriHost = toPuny(new URL(activity.actor).hostname);
		if (host !== uriHost) throw new Error('activity.actor has different host');
	}

	// For Create activity
	if (activity.type === 'Create' && activity.object) {
		// object.id (if exists)
		if (typeof activity.object.id === 'string') {
			const uriHost = toPuny(new URL(activity.object.id).hostname);
			if (host !== uriHost) throw new Error('activity.object.id has different host');
		}

		// object.attributedTo (if exists)
		if (typeof activity.object.attributedTo === 'string') {
			const uriHost = toPuny(new URL(activity.object.attributedTo).hostname);
			if (host !== uriHost) throw new Error('activity.object.attributedTo has different host');
		}
	}
}