import { NextApiHandler, NextApiRequest, NextApiResponse } from "next"

// checkout NextJS 'NextApiResponse' generic,
// TL;DR 
// calling response.send & response.json can be type, NextApiResponse<your_interface_or_type>
interface API_Response {
  ok: boolean,
  status?: number,
  data?: any
}
  

interface ControllerConstructor {
    new (req: NextApiRequest, res: NextApiResponse<API_Response>): IController
}
// instance 
interface IController {
    req: NextApiRequest,
    res: NextApiResponse,
    controls: IControlTypes,
    exec(): Promise<any>,
    setControls(controls: IControlTypes): void
}

// to execute
export type IControlFunction = NextApiHandler<API_Response>

// supported http verbs 
type IControlMethods = 'GET' | 'POST' | 'UPDATE' | 'DELETE' | 'PUT' | 'PATCH' | 'OPTIONS'  

// available controls 
type IControlTypes = {
    [methods in IControlMethods]?: IControlFunction;
}


export const Controller: ControllerConstructor = class Controller implements IController {
    controls: IControlTypes = {};
    // constructor 
    constructor(public req: NextApiRequest, public res: NextApiResponse<API_Response>){}
    
    // run single controller, [e.g. GET /api/users ]
    async exec() {
        try{
            const { method } = this.req
  
            // get the controller according to http verb | method
            const control = this.controls[method as IControlMethods]
            if(!control){
                // method not supported, end the request
                return this.res.status(405).end()
            }
            // execute the target control
            return await control(this.req,this.res)
        }catch(e){
            // reject the request
            return this.res.status(500).json({
                ok: false,
                status: 500,
                data: {}
            })
        }
    }
  
    // set controllers,
    // controllers must be set before calling `await this.exec()`
    setControls(controls: IControlTypes){
        this.controls = controls
    }
    
}