core_ng/server/api/defs.ts

import type { Request, Response } from 'express';
import type { Callable, DefAPINamespace, DeleteAPICallT, GetAPICallT, HeadAPICallT, HttpMethod, InvalidResponse, PatchAPICallT, PostAPICallT, PutAPICallT, RawArgType, ValidResponse, recoveryMethod } from '../apiStructure/defs';
import {
    validate,
    type ValidatorOptions,
} from "class-validator";
import { type ClassTransformOptions, plainToInstance } from "class-transformer";

export type APINamespace = {
    [key: string]: APINamespace
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    | ClassType<GET<any, any, any>>
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    | ClassType<POST<any, any, any>>
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    | ClassType<PUT<any, any, any>>
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    | ClassType<DELETE<any, any, any>>
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    | ClassType<PATCH<any, any, any>>
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    | ClassType<HEAD<any, any, any>>
    ;
}

type ValidatorType<T> = T extends undefined ? undefined : ClassType<T>;

// eslint-disable-next-line @typescript-eslint/no-explicit-any
export type AnyAPIExecuter = APIExecuter<any, any, any>;

export abstract class APIExecuter<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType>{
    readonly abstract reqType: HttpMethod;
    readonly abstract argValidator?: ValidatorType<Q>;
    protected abstract parseQuery(expressReq: Request): Promise<Q>;
    protected abstract api(query: Q, expressReq: Request, expressRes: Response): Promise<R | E | true>;
    public async run(expressReq: Request, expressRes: Response): Promise<void> {
        const query = await this.parseQuery(expressReq);
        //TODO: middleware (인증, 요구사항, 아마도 decorator)
        const result = await this.api(query, expressReq, expressRes);
        if (result === true) {
            return;
        }
        expressRes.json(result);
    }
}

export abstract class APIBodyParseExecuter<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType> extends APIExecuter<R, E, Q>{
    protected async parseQuery(expressReq: Request): Promise<Q> {

        if (!this.argValidator) {
            return expressReq.body as Q;
        }

        const query = expressReq.body;
        const classObject = plainToInstance(this.argValidator, query);
        const errors = await validate(classObject);
        if (errors.length) {
            throw errors;
        }

        return classObject as Q;
    }
}

export abstract class GET<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType> extends APIExecuter<R, E, Q>{
    override readonly reqType = 'get';
    protected async parseQuery(expressReq: Request): Promise<Q> {
        if (!this.argValidator) {
            return expressReq.query as Q;
        }

        const query = expressReq.query;
        const classObject = plainToInstance(this.argValidator, query);
        const errors = await validate(classObject);
        if (errors.length) {
            throw errors;
        }

        return classObject as Q;
    }
}

export abstract class POST<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType> extends APIBodyParseExecuter<R, E, Q>{
    readonly reqType = 'post';
}

export abstract class PUT<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType> extends APIBodyParseExecuter<R, E, Q>{
    readonly reqType = 'put';
}

export abstract class DELETE<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType> extends APIBodyParseExecuter<R, E, Q>{
    readonly reqType = 'delete';
}

export abstract class PATCH<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType> extends APIBodyParseExecuter<R, E, Q>{
    readonly reqType = 'patch';
}

export abstract class HEAD<R extends ValidResponse, E extends InvalidResponse, Q extends RawArgType> extends APIBodyParseExecuter<R, E, Q>{
    readonly reqType = 'head';
}

export function raiseError(reason: string, recovery?: recoveryMethod): InvalidResponse {
    if (recovery) {
        return {
            result: false,
            reason,
            recovery,
        };
    }
    return {
        result: false,
        reason,
    };
}


// eslint-disable-next-line @typescript-eslint/no-explicit-any
export type ClassType<T> = new (...args: any[]) => T;

export type APIServerType<T extends Callable> =
    T extends GetAPICallT<infer Q, infer R, infer E> ? ClassType<GET<R, E, Q>> :
    T extends PostAPICallT<infer Q, infer R, infer E> ? ClassType<POST<R, E, Q>> :
    T extends PutAPICallT<infer Q, infer R, infer E> ? ClassType<PUT<R, E, Q>> :
    T extends DeleteAPICallT<infer Q, infer R, infer E> ? ClassType<DELETE<R, E, Q>> :
    T extends PatchAPICallT<infer Q, infer R, infer E> ? ClassType<PATCH<R, E, Q>> :
    T extends HeadAPICallT<infer Q, infer R, infer E> ? ClassType<HEAD<R, E, Q>> :
    never;
export type APINamespaceType<T extends DefAPINamespace> = {
    [K in keyof T]:
    T[K] extends Callable ? APIServerType<T[K]> :
    T[K] extends DefAPINamespace ? APINamespaceType<T[K]> :
    never;
};