/*
 * SPDX-FileCopyrightText: syuilo and misskey-project
 * SPDX-License-Identifier: AGPL-3.0-only
 */

import { randomUUID } from 'node:crypto';
import * as fs from 'node:fs';
import * as stream from 'node:stream/promises';
import { Inject, Injectable } from '@nestjs/common';
import * as Sentry from '@sentry/node';
import { DI } from '@/di-symbols.js';
import { getIpHash } from '@/misc/get-ip-hash.js';
import type { MiLocalUser, MiUser } from '@/models/User.js';
import type { MiAccessToken } from '@/models/AccessToken.js';
import type Logger from '@/logger.js';
import type { UserIpsRepository } from '@/models/_.js';
import { MetaService } from '@/core/MetaService.js';
import { createTemp } from '@/misc/create-temp.js';
import { bindThis } from '@/decorators.js';
import { RoleService } from '@/core/RoleService.js';
import type { Config } from '@/config.js';
import { ApiError } from './error.js';
import { RateLimiterService } from './RateLimiterService.js';
import { ApiLoggerService } from './ApiLoggerService.js';
import { AuthenticateService, AuthenticationError } from './AuthenticateService.js';
import type { FastifyRequest, FastifyReply } from 'fastify';
import type { OnApplicationShutdown } from '@nestjs/common';
import type { IEndpointMeta, IEndpoint } from './endpoints.js';

const accessDenied = {
	message: 'Access denied.',
	code: 'ACCESS_DENIED',
	id: '56f35758-7dd5-468b-8439-5d6fb8ec9b8e',
};

@Injectable()
export class ApiCallService implements OnApplicationShutdown {
	private logger: Logger;
	private userIpHistories: Map<MiUser['id'], Set<string>>;
	private userIpHistoriesClearIntervalId: NodeJS.Timeout;

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

		@Inject(DI.userIpsRepository)
		private userIpsRepository: UserIpsRepository,

		private metaService: MetaService,
		private authenticateService: AuthenticateService,
		private rateLimiterService: RateLimiterService,
		private roleService: RoleService,
		private apiLoggerService: ApiLoggerService,
	) {
		this.logger = this.apiLoggerService.logger;
		this.userIpHistories = new Map<MiUser['id'], Set<string>>();

		this.userIpHistoriesClearIntervalId = setInterval(() => {
			this.userIpHistories.clear();
		}, 1000 * 60 * 60);
	}

	#sendApiError(reply: FastifyReply, err: ApiError): void {
		let statusCode = err.httpStatusCode;
		if (err.httpStatusCode === 401) {
			reply.header('WWW-Authenticate', 'Bearer realm="Misskey"');
		} else if (err.code === 'RATE_LIMIT_EXCEEDED') {
			const info: unknown = err.info;
			const unixEpochInSeconds = Date.now();
			if (typeof(info) === 'object' && info && 'resetMs' in info && typeof(info.resetMs) === 'number') {
				const cooldownInSeconds = Math.ceil((info.resetMs - unixEpochInSeconds) / 1000);
				// もしかするとマイナスになる可能性がなくはないのでマイナスだったら0にしておく
				reply.header('Retry-After', Math.max(cooldownInSeconds, 0).toString(10));
			} else {
				this.logger.warn(`rate limit information has unexpected type ${typeof(err.info?.reset)}`);
			}
		} else if (err.kind === 'client') {
			reply.header('WWW-Authenticate', `Bearer realm="Misskey", error="invalid_request", error_description="${err.message}"`);
			statusCode = statusCode ?? 400;
		} else if (err.kind === 'permission') {
			// (ROLE_PERMISSION_DENIEDは関係ない)
			if (err.code === 'PERMISSION_DENIED') {
				reply.header('WWW-Authenticate', `Bearer realm="Misskey", error="insufficient_scope", error_description="${err.message}"`);
			}
			statusCode = statusCode ?? 403;
		} else if (!statusCode) {
			statusCode = 500;
		}
		this.send(reply, statusCode, err);
	}

	#sendAuthenticationError(reply: FastifyReply, err: unknown): void {
		if (err instanceof AuthenticationError) {
			const message = 'Authentication failed. Please ensure your token is correct.';
			reply.header('WWW-Authenticate', `Bearer realm="Misskey", error="invalid_token", error_description="${message}"`);
			this.send(reply, 401, new ApiError({
				message: 'Authentication failed. Please ensure your token is correct.',
				code: 'AUTHENTICATION_FAILED',
				id: 'b0a7f5f8-dc2f-4171-b91f-de88ad238e14',
			}));
		} else {
			this.send(reply, 500, new ApiError());
		}
	}

	#onExecError(ep: IEndpoint, data: any, err: Error, userId?: MiUser['id']): void {
		if (err instanceof ApiError || err instanceof AuthenticationError) {
			throw err;
		} else {
			const errId = randomUUID();
			this.logger.error(`Internal error occurred in ${ep.name}: ${err.message}`, {
				ep: ep.name,
				ps: data,
				e: {
					message: err.message,
					code: err.name,
					stack: err.stack,
					id: errId,
				},
			});

			if (this.config.sentryForBackend) {
				Sentry.captureMessage(`Internal error occurred in ${ep.name}: ${err.message}`, {
					level: 'error',
					user: {
						id: userId,
					},
					extra: {
						ep: ep.name,
						ps: data,
						e: {
							message: err.message,
							code: err.name,
							stack: err.stack,
							id: errId,
						},
					},
				});
			}

			throw new ApiError(null, {
				e: {
					message: err.message,
					code: err.name,
					id: errId,
				},
			});
		}
	}

	@bindThis
	public handleRequest(
		endpoint: IEndpoint & { exec: any },
		request: FastifyRequest<{ Body: Record<string, unknown> | undefined, Querystring: Record<string, unknown> }>,
		reply: FastifyReply,
	): void {
		const body = request.method === 'GET'
			? request.query
			: request.body;

		// https://datatracker.ietf.org/doc/html/rfc6750.html#section-2.1 (case sensitive)
		const token = request.headers.authorization?.startsWith('Bearer ')
			? request.headers.authorization.slice(7)
			: body?.['i'];
		if (token != null && typeof token !== 'string') {
			reply.code(400);
			return;
		}
		this.authenticateService.authenticate(token).then(([user, app]) => {
			this.call(endpoint, user, app, body, null, request).then((res) => {
				if (request.method === 'GET' && endpoint.meta.cacheSec && !token && !user) {
					reply.header('Cache-Control', `public, max-age=${endpoint.meta.cacheSec}`);
				}
				this.send(reply, res);
			}).catch((err: ApiError) => {
				this.#sendApiError(reply, err);
			});

			if (user) {
				this.logIp(request, user);
			}
		}).catch(err => {
			this.#sendAuthenticationError(reply, err);
		});
	}

	@bindThis
	public async handleMultipartRequest(
		endpoint: IEndpoint & { exec: any },
		request: FastifyRequest<{ Body: Record<string, unknown>, Querystring: Record<string, unknown> }>,
		reply: FastifyReply,
	): Promise<void> {
		const multipartData = await request.file().catch(() => {
			/* Fastify throws if the remote didn't send multipart data. Return 400 below. */
		});
		if (multipartData == null) {
			reply.code(400);
			reply.send();
			return;
		}

		const [path] = await createTemp();
		await stream.pipeline(multipartData.file, fs.createWriteStream(path));

		const fields = {} as Record<string, unknown>;
		for (const [k, v] of Object.entries(multipartData.fields)) {
			fields[k] = typeof v === 'object' && 'value' in v ? v.value : undefined;
		}

		// https://datatracker.ietf.org/doc/html/rfc6750.html#section-2.1 (case sensitive)
		const token = request.headers.authorization?.startsWith('Bearer ')
			? request.headers.authorization.slice(7)
			: fields['i'];
		if (token != null && typeof token !== 'string') {
			reply.code(400);
			return;
		}
		this.authenticateService.authenticate(token).then(([user, app]) => {
			this.call(endpoint, user, app, fields, {
				name: multipartData.filename,
				path: path,
			}, request).then((res) => {
				this.send(reply, res);
			}).catch((err: ApiError) => {
				this.#sendApiError(reply, err);
			});

			if (user) {
				this.logIp(request, user);
			}
		}).catch(err => {
			this.#sendAuthenticationError(reply, err);
		});
	}

	@bindThis
	private send(reply: FastifyReply, x?: any, y?: ApiError) {
		if (x == null) {
			reply.code(204);
			reply.send();
		} else if (typeof x === 'number' && y) {
			reply.code(x);
			reply.send({
				error: {
					message: y!.message,
					code: y!.code,
					id: y!.id,
					kind: y!.kind,
					...(y!.info ? { info: y!.info } : {}),
				},
			});
		} else {
			// 文字列を返す場合は、JSON.stringify通さないとJSONと認識されない
			reply.send(typeof x === 'string' ? JSON.stringify(x) : x);
		}
	}

	@bindThis
	private async logIp(request: FastifyRequest, user: MiLocalUser) {
		const meta = await this.metaService.fetch();
		if (!meta.enableIpLogging) return;
		const ip = request.ip;
		const ips = this.userIpHistories.get(user.id);
		if (ips == null || !ips.has(ip)) {
			if (ips == null) {
				this.userIpHistories.set(user.id, new Set([ip]));
			} else {
				ips.add(ip);
			}

			try {
				this.userIpsRepository.createQueryBuilder().insert().values({
					createdAt: new Date(),
					userId: user.id,
					ip: ip,
				}).orIgnore(true).execute();
			} catch {
			}
		}
	}

	@bindThis
	private async call(
		ep: IEndpoint & { exec: any },
		user: MiLocalUser | null | undefined,
		token: MiAccessToken | null | undefined,
		data: any,
		file: {
			name: string;
			path: string;
		} | null,
		request: FastifyRequest<{ Body: Record<string, unknown> | undefined, Querystring: Record<string, unknown> }>,
	) {
		const isSecure = user != null && token == null;

		if (ep.meta.secure && !isSecure) {
			throw new ApiError(accessDenied);
		}

		if (ep.meta.limit) {
			// koa will automatically load the `X-Forwarded-For` header if `proxy: true` is configured in the app.
			let limitActor: string;
			if (user) {
				limitActor = user.id;
			} else {
				limitActor = getIpHash(request.ip);
			}

			const limit = Object.assign({}, ep.meta.limit);

			if (limit.key == null) {
				(limit as any).key = ep.name;
			}

			// TODO: 毎リクエスト計算するのもあれだしキャッシュしたい
			const factor = user ? (await this.roleService.getUserPolicies(user.id)).rateLimitFactor : 1;

			if (factor > 0) {
				// Rate limit
				await this.rateLimiterService.limit(limit as IEndpointMeta['limit'] & { key: NonNullable<string> }, limitActor, factor).catch(err => {
					if ('info' in err) {
						// errはLimiter.LimiterInfoであることが期待される
						throw new ApiError({
							message: 'Rate limit exceeded. Please try again later.',
							code: 'RATE_LIMIT_EXCEEDED',
							id: 'd5826d14-3982-4d2e-8011-b9e9f02499ef',
							httpStatusCode: 429,
						}, err.info);
					} else {
						throw new TypeError('information must be a rate-limiter information.');
					}
				});
			}
		}

		if (ep.meta.requireCredential || ep.meta.requireModerator || ep.meta.requireAdmin) {
			if (user == null) {
				throw new ApiError({
					message: 'Credential required.',
					code: 'CREDENTIAL_REQUIRED',
					id: '1384574d-a912-4b81-8601-c7b1c4085df1',
					httpStatusCode: 401,
				});
			} else if (user!.isSuspended) {
				throw new ApiError({
					message: 'Your account has been suspended.',
					code: 'YOUR_ACCOUNT_SUSPENDED',
					kind: 'permission',
					id: 'a8c724b3-6e9c-4b46-b1a8-bc3ed6258370',
				});
			}
		}

		if (ep.meta.prohibitMoved) {
			if (user?.movedToUri) {
				throw new ApiError({
					message: 'You have moved your account.',
					code: 'YOUR_ACCOUNT_MOVED',
					kind: 'permission',
					id: '56f20ec9-fd06-4fa5-841b-edd6d7d4fa31',
				});
			}
		}

		if ((ep.meta.requireModerator || ep.meta.requireAdmin) && !user!.isRoot) {
			const myRoles = await this.roleService.getUserRoles(user!.id);
			if (ep.meta.requireModerator && !myRoles.some(r => r.isModerator || r.isAdministrator)) {
				throw new ApiError({
					message: 'You are not assigned to a moderator role.',
					code: 'ROLE_PERMISSION_DENIED',
					kind: 'permission',
					id: 'd33d5333-db36-423d-a8f9-1a2b9549da41',
				});
			}
			if (ep.meta.requireAdmin && !myRoles.some(r => r.isAdministrator)) {
				throw new ApiError({
					message: 'You are not assigned to an administrator role.',
					code: 'ROLE_PERMISSION_DENIED',
					kind: 'permission',
					id: 'c3d38592-54c0-429d-be96-5636b0431a61',
				});
			}
		}

		if (ep.meta.requireRolePolicy != null && !user!.isRoot) {
			const myRoles = await this.roleService.getUserRoles(user!.id);
			const policies = await this.roleService.getUserPolicies(user!.id);
			if (!policies[ep.meta.requireRolePolicy] && !myRoles.some(r => r.isAdministrator)) {
				throw new ApiError({
					message: 'You are not assigned to a required role.',
					code: 'ROLE_PERMISSION_DENIED',
					kind: 'permission',
					id: '7f86f06f-7e15-4057-8561-f4b6d4ac755a',
				});
			}
		}

		if (token && ((ep.meta.kind && !token.permission.some(p => p === ep.meta.kind))
			|| (!ep.meta.kind && (ep.meta.requireCredential || ep.meta.requireModerator || ep.meta.requireAdmin)))) {
			throw new ApiError({
				message: 'Your app does not have the necessary permissions to use this endpoint.',
				code: 'PERMISSION_DENIED',
				kind: 'permission',
				id: '1370e5b7-d4eb-4566-bb1d-7748ee6a1838',
			});
		}

		// Cast non JSON input
		if ((ep.meta.requireFile || request.method === 'GET') && ep.params.properties) {
			for (const k of Object.keys(ep.params.properties)) {
				const param = ep.params.properties![k];
				if (['boolean', 'number', 'integer'].includes(param.type ?? '') && typeof data[k] === 'string') {
					try {
						data[k] = JSON.parse(data[k]);
					} catch (e) {
						throw new ApiError({
							message: 'Invalid param.',
							code: 'INVALID_PARAM',
							id: '0b5f1631-7c1a-41a6-b399-cce335f34d85',
						}, {
							param: k,
							reason: `cannot cast to ${param.type}`,
						});
					}
				}
			}
		}

		// API invoking
		if (this.config.sentryForBackend) {
			return await Sentry.startSpan({
				name: 'API: ' + ep.name,
			}, () => ep.exec(data, user, token, file, request.ip, request.headers)
				.catch((err: Error) => this.#onExecError(ep, data, err, user?.id)));
		} else {
			return await ep.exec(data, user, token, file, request.ip, request.headers)
				.catch((err: Error) => this.#onExecError(ep, data, err, user?.id));
		}
	}

	@bindThis
	public dispose(): void {
		clearInterval(this.userIpHistoriesClearIntervalId);
	}

	@bindThis
	public onApplicationShutdown(signal?: string | undefined): void {
		this.dispose();
	}
}