import { publishNoteStream } from '../stream';
import renderDelete from '../../remote/activitypub/renderer/delete';
import renderAnnounce from '../../remote/activitypub/renderer/announce';
import renderUndo from '../../remote/activitypub/renderer/undo';
import { renderActivity } from '../../remote/activitypub/renderer';
import renderTombstone from '../../remote/activitypub/renderer/tombstone';
import config from '../../config';
import { registerOrFetchInstanceDoc } from '../register-or-fetch-instance-doc';
import { User } from '../../models/entities/user';
import { Note } from '../../models/entities/note';
import { Notes, Users, Instances } from '../../models';
import { notesChart, perUserNotesChart, instanceChart } from '../chart';
import { deliverToFollowers } from '../../remote/activitypub/deliver-manager';

/**
 * 投稿を削除します。
 * @param user 投稿者
 * @param note 投稿
 */
export default async function(user: User, note: Note, quiet = false) {
	const deletedAt = new Date();

	if (note.renoteId) {
		Notes.decrement({ id: note.renoteId }, 'renoteCount', 1);
		Notes.decrement({ id: note.renoteId }, 'score', 1);
	}

	if (!quiet) {
		publishNoteStream(note.id, 'deleted', {
			deletedAt: deletedAt
		});

		//#region ローカルの投稿なら削除アクティビティを配送
		if (Users.isLocalUser(user)) {
			let renote: Note | undefined;

			// if deletd note is renote
			if (note.renoteId && note.text == null && !note.hasPoll && (note.fileIds == null || note.fileIds.length == 0)) {
				renote = await Notes.findOne({
					id: note.renoteId
				});
			}

			const content = renderActivity(renote
				? renderUndo(renderAnnounce(renote.uri || `${config.url}/notes/${renote.id}`, note), user)
				: renderDelete(renderTombstone(`${config.url}/notes/${note.id}`), user));

			deliverToFollowers(user, content);
		}

		// also deliever delete activity to cascaded notes
		const cascadingNotes = (await findCascadingNotes(note)).filter(note => !note.localOnly); // filter out local-only notes
		for (const cascadingNote of cascadingNotes) {
			if (!cascadingNote.user) continue;
			if (!Users.isLocalUser(cascadingNote.user)) continue;
			const content = renderActivity(renderDelete(renderTombstone(`${config.url}/notes/${cascadingNote.id}`), cascadingNote.user));
			deliverToFollowers(cascadingNote.user, content);
		}
		//#endregion

		// 統計を更新
		notesChart.update(note, false);
		perUserNotesChart.update(user, note, false);

		if (Users.isRemoteUser(user)) {
			registerOrFetchInstanceDoc(user.host).then(i => {
				Instances.decrement({ id: i.id }, 'notesCount', 1);
				instanceChart.updateNote(i.host, note, false);
			});
		}
	}

	await Notes.delete({
		id: note.id,
		userId: user.id
	});
}

async function findCascadingNotes(note: Note) {
	const cascadingNotes: Note[] = [];

	const recursive = async (noteId: string) => {
		const query = Notes.createQueryBuilder('note')
			.where('note.replyId = :noteId', { noteId })
			.leftJoinAndSelect('note.user', 'user');
		const replies = await query.getMany();
		for (const reply of replies) {
			cascadingNotes.push(reply);
			await recursive(reply.id);
		}
	};
	await recursive(note.id);

	return cascadingNotes.filter(note => note.userHost === null); // filter out non-local users
}
