import {toast} from "../components/message";

export type HttpMethod = 'get' | 'post' | 'delete' | 'put'

export enum RequestDataContentType {
    JSON = 'application/json;charset=UTF-8',
    FORM = 'application/x-www-form-urlencoded;charset=UTF-8',
    FORM_DATA = 'multipart/form-data;charset=UTF-8',
}

export const httpConfig = {
    baseURL: '',
    globalErrorHandler: {
        1201: '请求参数不合法'
    }
}
export type ResponseModel<T> = {
    code: number
    message: string
    data: T
    trace?: string
}

class Http {
    post<T>(url, data) {
        return this.request<T>(url, data)
    }

    get<T>(url, data = null) {
        return this.request<T>(url, data, 'get')
    }

    /**
     * GET /xxxx?a=1&b=2
     * NAME: value
     * NAME2: value
     * ....
     *
     * POSTDATA
     *
     *
     * @param url
     * @param method
     * @param data
     */
    request<T>(url: string, data: any = null, method: HttpMethod = 'post', type: 'normal' | 'form' = 'normal') {
        return new Promise<T>((resolve, reject) => {
            let contentType = RequestDataContentType.FORM;
            if (data) {
                if (type === 'form') {
                    const form = new FormData();
                    for (const key in data) {
                        form.append(key, data[key]);
                    }
                    data = form; // 将data有{} => formData
                    contentType = RequestDataContentType.FORM_DATA; // 由于使用formData
                    method = 'post';
                } else if (method == 'post') {
                    // 将数据对象 转成json
                    data = JSON.stringify(data);
                    contentType = RequestDataContentType.JSON;
                } else {
                    // 装对象转成 key=value&key=value
                    const params = [];
                    for (const key in data) {
                        params.push(`${key}=${data[key]}`);
                    }
                    data = params.join('&')
                }
            }

            fetch(httpConfig.baseURL + url, {
                method,
                body: data,
                headers: {
                    'Content-Type': contentType
                }
            })
                .then(res => res.json()) // 只要json的响应数据
                .then((res: ResponseModel<T>) => {
                    const {code, data, message} = res;
                    if (code !== 0) {
                        const err = httpConfig.globalErrorHandler[code]
                        // 需要统一处理数据
                        if (code === 403) {
                            toast("登录凭证无效或者已过期")
                            return;
                        } else if (err) {
                            toast(httpConfig.globalErrorHandler[code])
                            return;
                        }
                        reject(Error(res.message))
                        return;
                    }
                    resolve(res.data)
                })
                .catch(() => {

                })
        });
    }
}

const http = new Http();
export default http