import * as fs from 'node:fs';
import Ajv from 'ajv';
import { CacheableLocalUser, ILocalUser } from '@/models/entities/user.js';
import { Schema, SchemaType } from '@/misc/schema.js';
import { AccessToken } from '@/models/entities/access-token.js';
import { IEndpointMeta } from './endpoints.js';
import { ApiError } from './error.js';

export type Response = Record<string, any> | void;

// TODO: paramsの型をT['params']のスキーマ定義から推論する
type executor<T extends IEndpointMeta, Ps extends Schema> =
	(params: SchemaType<Ps>, user: T['requireCredential'] extends true ? CacheableLocalUser : CacheableLocalUser | null, token: AccessToken | null, file?: any, cleanup?: () => any, ip?: string | null, headers?: Record<string, string> | null) =>
		Promise<T['res'] extends undefined ? Response : SchemaType<NonNullable<T['res']>>>;

const ajv = new Ajv({
	useDefaults: true,
});

ajv.addFormat('misskey:id', /^[a-zA-Z0-9]+$/);

export default function <T extends IEndpointMeta, Ps extends Schema>(meta: T, paramDef: Ps, cb: executor<T, Ps>)
		: (params: any, user: T['requireCredential'] extends true ? CacheableLocalUser : CacheableLocalUser | null, token: AccessToken | null, file?: any, ip?: string | null, headers?: Record<string, string> | null) => Promise<any> {
	const validate = ajv.compile(paramDef);

	return (params: any, user: T['requireCredential'] extends true ? CacheableLocalUser : CacheableLocalUser | null, token: AccessToken | null, file?: any, ip?: string | null, headers?: Record<string, string> | null) => {
		let cleanup: undefined | (() => void) = undefined;

		if (meta.requireFile) {
			cleanup = () => {
				fs.unlink(file.path, () => {});
			};

			if (file == null) return Promise.reject(new ApiError({
				message: 'File required.',
				code: 'FILE_REQUIRED',
				id: '4267801e-70d1-416a-b011-4ee502885d8b',
			}));
		}

		const valid = validate(params);
		if (!valid) {
			if (file) cleanup!();

			const errors = validate.errors!;
			const err = new ApiError({
				message: 'Invalid param.',
				code: 'INVALID_PARAM',
				id: '3d81ceae-475f-4600-b2a8-2bc116157532',
			}, {
				param: errors[0].schemaPath,
				reason: errors[0].message,
			});
			return Promise.reject(err);
		}

		return cb(params as SchemaType<Ps>, user, token, file, cleanup, ip, headers);
	};
}