import type { Request, Response } from 'express';

export interface ValidResponse {
    result: true;
}

export type recoveryMethod = 'refreshEntirePage' | 'retryAPI' | 'gameLogin' | 'gatewayLogin' | 'gatewayPIN';

export interface InvalidResponse {
    result: false;
    reason: string;
    recovery?: recoveryMethod;
}

export const treatedSpecial = Symbol('treatedSpecial');
export type HttpMethod = 'get' | 'post' | 'put' | 'delete' | 'patch' | 'head';
export type RawArgType = Record<string, unknown> | Record<string, unknown>[] | undefined;

export type APINamespace = {
    [key: string]: APINamespace
    | GET<any, any, any>
    | POST<any, any, any>
    | PUT<any, any, any>
    | DELETE<any, any, any>
    | PATCH<any, any, any>
    | HEAD<any, any, any>
    ;
}

export abstract class APIExecuter<Q extends object, R extends ValidResponse, E extends InvalidResponse>{
    readonly reqType: HttpMethod | HttpMethod[];
    protected abstract parseQuery(expressReq: Request): Promise<Q>;
    protected abstract api(query: Q, expressReq: Request, expressRes: Response): Promise<R | E | typeof treatedSpecial>;
    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 === treatedSpecial) {
            return;
        }
        expressRes.json(result);
    }
}

export abstract class APIBodyParseExecuter<Q extends object, R extends ValidResponse, E extends InvalidResponse> extends APIExecuter<Q, R, E>{
    protected async parseQuery(expressReq: Request): Promise<Q> {
        throw new Error('Not implemented');
        return expressReq.body;
    }
}

export abstract class GET<Q extends object, R extends ValidResponse, E extends InvalidResponse> extends APIExecuter<Q, R, E>{
    readonly reqType = 'get';
    protected async parseQuery(expressReq: Request): Promise<Q> {
        expressReq.query;
        throw new Error('Not implemented');
        return expressReq.query as unknown as Q;
    }
}

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

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

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

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

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