import * as fs from 'node:fs';
import { Inject, Injectable } from '@nestjs/common';
import { MoreThan } from 'typeorm';
import { format as dateFormat } from 'date-fns';
import { DI } from '@/di-symbols.js';
import type { NotesRepository, PollsRepository, UsersRepository } from '@/models/index.js';
import type { Config } from '@/config.js';
import type Logger from '@/logger.js';
import { DriveService } from '@/core/DriveService.js';
import { createTemp } from '@/misc/create-temp.js';
import type { Poll } from '@/models/entities/Poll.js';
import type { Note } from '@/models/entities/Note.js';
import { QueueLoggerService } from '../QueueLoggerService.js';
import type Bull from 'bull';
import type { DbUserJobData } from '../types.js';
import { bindThis } from '@/decorators.js';

@Injectable()
export class ExportNotesProcessorService {
	private logger: Logger;

	constructor(
		@Inject(DI.config)
		private config: Config,

		@Inject(DI.usersRepository)
		private usersRepository: UsersRepository,

		@Inject(DI.pollsRepository)
		private pollsRepository: PollsRepository,

		@Inject(DI.notesRepository)
		private notesRepository: NotesRepository,

		private driveService: DriveService,
		private queueLoggerService: QueueLoggerService,
	) {
		this.logger = this.queueLoggerService.logger.createSubLogger('export-notes');
	}

	@bindThis
	public async process(job: Bull.Job<DbUserJobData>, done: () => void): Promise<void> {
		this.logger.info(`Exporting notes of ${job.data.user.id} ...`);

		const user = await this.usersRepository.findOneBy({ id: job.data.user.id });
		if (user == null) {
			done();
			return;
		}

		// Create temp file
		const [path, cleanup] = await createTemp();

		this.logger.info(`Temp file is ${path}`);

		try {
			const stream = fs.createWriteStream(path, { flags: 'a' });

			const write = (text: string): Promise<void> => {
				return new Promise<void>((res, rej) => {
					stream.write(text, err => {
						if (err) {
							this.logger.error(err);
							rej(err);
						} else {
							res();
						}
					});
				});
			};

			await write('[');

			let exportedNotesCount = 0;
			let cursor: Note['id'] | null = null;

			while (true) {
				const notes = await this.notesRepository.find({
					where: {
						userId: user.id,
						...(cursor ? { id: MoreThan(cursor) } : {}),
					},
					take: 100,
					order: {
						id: 1,
					},
				}) as Note[];

				if (notes.length === 0) {
					job.progress(100);
					break;
				}

				cursor = notes[notes.length - 1].id;

				for (const note of notes) {
					let poll: Poll | undefined;
					if (note.hasPoll) {
						poll = await this.pollsRepository.findOneByOrFail({ noteId: note.id });
					}
					const content = JSON.stringify(serialize(note, poll));
					const isFirst = exportedNotesCount === 0;
					await write(isFirst ? content : ',\n' + content);
					exportedNotesCount++;
				}

				const total = await this.notesRepository.countBy({
					userId: user.id,
				});

				job.progress(exportedNotesCount / total);
			}

			await write(']');

			stream.end();
			this.logger.succ(`Exported to: ${path}`);

			const fileName = 'notes-' + dateFormat(new Date(), 'yyyy-MM-dd-HH-mm-ss') + '.json';
			const driveFile = await this.driveService.addFile({ user, path, name: fileName, force: true });

			this.logger.succ(`Exported to: ${driveFile.id}`);
		} finally {
			cleanup();
		}

		done();
	}
}

function serialize(note: Note, poll: Poll | null = null): Record<string, unknown> {
	return {
		id: note.id,
		text: note.text,
		createdAt: note.createdAt,
		fileIds: note.fileIds,
		replyId: note.replyId,
		renoteId: note.renoteId,
		poll: poll,
		cw: note.cw,
		visibility: note.visibility,
		visibleUserIds: note.visibleUserIds,
		localOnly: note.localOnly,
	};
}