/*
 * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
 * SPDX-License-Identifier: AGPL-3.0-only
 */

import { Inject, Injectable } from '@nestjs/common';
import { IsNull } from 'typeorm';
import { DI } from '@/di-symbols.js';
import { QueryService } from '@/core/QueryService.js';
import type { MiChannel, MiNote, NotesRepository } from '@/models/_.js';
import type { MiLocalUser, MiUser } from '@/models/User.js';
import { ApiError } from '../error.js';

/**
 * Utility service for accessing data with Mastodon semantics
 */
@Injectable()
export class MastodonDataService {
	constructor(
		@Inject(DI.notesRepository)
		private readonly notesRepository: NotesRepository,

		@Inject(QueryService)
		private readonly queryService: QueryService,
	) {}

	/**
	 * Fetches a note in the context of the current user, and throws an exception if not found.
	 */
	public async requireNote<Rel extends NoteRelations = NoteRelations>(noteId: string, me: MiLocalUser | null | undefined, relations?: Rel): Promise<NoteWithRelations<Rel>> {
		const note = await this.getNote(noteId, me, relations);

		if (!note) {
			throw new ApiError({
				message: 'No such note.',
				code: 'NO_SUCH_NOTE',
				id: '24fcbfc6-2e37-42b6-8388-c29b3861a08d',
				kind: 'client',
				httpStatusCode: 404,
			});
		}

		return note;
	}

	/**
	 * Fetches a note in the context of the current user.
	 */
	public async getNote<Rel extends NoteRelations = NoteRelations>(noteId: string, me: MiLocalUser | null | undefined, relations?: Rel): Promise<NoteWithRelations<Rel> | null> {
		// Root query: note + required dependencies
		const query = this.notesRepository
			.createQueryBuilder('note')
			.where('note.id = :noteId', { noteId });

		// Load relations
		if (relations) {
			if (relations.reply) {
				query.leftJoinAndSelect('note.reply', 'reply');
				if (typeof(relations.reply) === 'object') {
					if (relations.reply.reply) query.leftJoinAndSelect('note.reply.reply', 'replyReply');
					if (relations.reply.renote) query.leftJoinAndSelect('note.reply.renote', 'replyRenote');
					if (relations.reply.user) query.innerJoinAndSelect('note.reply.user', 'replyUser');
					if (relations.reply.channel) query.leftJoinAndSelect('note.reply.channel', 'replyChannel');
				}
			}
			if (relations.renote) {
				query.leftJoinAndSelect('note.renote', 'renote');
				if (typeof(relations.renote) === 'object') {
					if (relations.renote.reply) query.leftJoinAndSelect('note.renote.reply', 'renoteReply');
					if (relations.renote.renote) query.leftJoinAndSelect('note.renote.renote', 'renoteRenote');
					if (relations.renote.user) query.innerJoinAndSelect('note.renote.user', 'renoteUser');
					if (relations.renote.channel) query.leftJoinAndSelect('note.renote.channel', 'renoteChannel');
				}
			}
			if (relations.user) {
				query.innerJoinAndSelect('note.user', 'user');
			}
			if (relations.channel) {
				query.leftJoinAndSelect('note.channel', 'channel');
			}
		}

		// Restrict visibility
		this.queryService.generateVisibilityQuery(query, me);
		if (me) {
			this.queryService.generateBlockedUserQueryForNotes(query, me);
		}

		return await query.getOne() as NoteWithRelations<Rel> | null;
	}

	/**
	 * Checks where the current user has made a reblog / boost / pure renote of a given target note.
	 */
	public async hasReblog(noteId: string, me: MiLocalUser | null | undefined): Promise<boolean> {
		if (!me) return false;

		return await this.notesRepository.existsBy({
			// Reblog of the target note by me
			userId: me.id,
			renoteId: noteId,

			// That is pure (not a quote)
			text: IsNull(),
			cw: IsNull(),
			replyId: IsNull(),
			hasPoll: false,
			fileIds: '{}',
		});
	}
}

interface NoteRelations {
	reply?: boolean | {
		reply?: boolean;
		renote?: boolean;
		user?: boolean;
		channel?: boolean;
	};
	renote?: boolean | {
		reply?: boolean;
		renote?: boolean;
		user?: boolean;
		channel?: boolean;
	};
	user?: boolean;
	channel?: boolean;
}

type NoteWithRelations<Rel extends NoteRelations> = MiNote & {
	reply: Rel extends { reply: false }
		? null
		: null | (MiNote & {
			reply: Rel['reply'] extends { reply: true } ? MiNote | null : null;
			renote: Rel['reply'] extends { renote: true } ? MiNote | null : null;
			user: Rel['reply'] extends { user: true } ? MiUser : null;
			channel: Rel['reply'] extends { channel: true } ? MiChannel | null : null;
		});
	renote: Rel extends { renote: false }
		? null
		: null | (MiNote & {
			reply: Rel['renote'] extends { reply: true } ? MiNote | null : null;
			renote: Rel['renote'] extends { renote: true } ? MiNote | null : null;
			user: Rel['renote'] extends { user: true } ? MiUser : null;
			channel: Rel['renote'] extends { channel: true } ? MiChannel | null : null;
		});
	user: Rel extends { user: true } ? MiUser : null;
	channel: Rel extends { channel: true } ? MiChannel | null : null;
};