//服务端地址


import {server} from "./api";

export enum Method {
    PUT="PUT",
    POST="POST",
    GET="GET"
}

export enum Result {
    OK="OK",
    FAIL="FAIL"
}


/**
 * 响应数据
 */
export class JSONResponse<Q> {
    result?:Result
    customResult?:Q
}

/**
 * 数据类型转换
 */
export abstract class TransformData<Q,T extends JSONResponse<Q>> {
    protected target: T

    constructor() {
        this.target = this.newObject();
    }

    protected abstract newObject(): T

    public transform(data:any){
        this.transformResult(data)
        this.transformBody(data)
        return this.target
    }

    protected  transformBody(data:any){

    }

    private transformResult(data:any){
        if("result" in data ) {
            this.target.result = data.result
        }
        if("customResult" in data){
            this.target.customResult = data.customResult
        }
    }
}

//发送请求
export function request<Q,E extends JSONResponse<Q>,T extends TransformData<Q,E>>(api:string,method:Method,formParams: {[propName:string]: string | Blob|Array<string>},transform:T,callback:Function) {
    let formData
    let queryParams=''
    if(method===Method.GET) {
        for(let formParam in formParams){
            let params=formParams[formParam]
            if(params instanceof Array) {
                for(let value in params){
                    queryParams+='&'+formParam+'='+params[value]
                }
            }else{
                queryParams += '&' + formParam + '=' + params
            }
        }
        queryParams='?'+queryParams.substr(1)
    }else{
        formData=new FormData()
        for (let formParam in formParams) {
            let params= formParams[formParam]
            if(params instanceof  Array){
                for(let value in params){
                    if(params.hasOwnProperty(value)) {
                        formData.append(formParam + '[]', params[value])
                    }
                }
            }else if(params instanceof Blob||typeof params==="string"){
                formData.append(formParam,params)
            }

        }

    }
    fetch(server+api+queryParams,{
        method:method,
        body:formData,
        credentials: 'include',
    })
        .then(
            response=>{if(response.status===200){
                return response.json()
            }else{
                throw new Error("遇到无法处理的错误，请联系管理员")

            }}
        )
        .catch(
            error =>console.error('Error:', error)
        )
        .then((response:JSONResponse<Q>)=>{
            callback(transform.transform(response))
        })
}