import { getItem } from "./storage";

export function compatibleFetch(endpoint, options) {
    if (window.fetch && typeof window.fetch === "function") {
        return fetch(endpoint, options);
    } else {
        return new Promise((resolve, reject) => {
            const req = new XMLHttpRequest();
            req.addEventListener("load", () => {
                resolve({
                    status: req.status,
                    ok: [200, 201, 204].includes(req.status),
                    json() {
                        return JSON.parse(req.responseText);
                    }
                });
            });
            req.addEventListener("error", (e) => {
                reject(e);
            });
    
            req.open(options.method || "GET", endpoint);
            if (options.headers) {
                for (const [header, value] of Object.entries(options.headers)) {
                    req.setRequestHeader(header, value);
                }
            }
            req.send(options.body);
        });
    }
}

export default async function(method, endpoint, auth=true, body=null) {
    const options = {
        method,  
    };

    if (body) {
        options.body = JSON.stringify(body);
        options.headers = {
            ...options.headers || {},
            "Content-Type": "application/json"
        };
    }

    if (auth) {
        const token = getItem("auth:token");
        if (token) {
            options.headers = {
                ...options.headers || {},
                "Authorization": `Bearer ${token}`
            };
        }
    }

    try {
        const res = await compatibleFetch(endpoint, options);
        return {
            success: true,
            json: res.status === 204 ? null : await res.json(),
            ok: res.ok,
            status: res.status
        }
    } catch (e) {
        return {
            success: false,
            json: null,
            ok: false,
            status: null
        }
    }
}