import * as redirect from "./redirect";

async function sendRequest(endpoint, body) {
    const formData = new FormData();

    for (var key in body) {
        formData.append(key, body[key]);
    }

    const request = {
        method: "POST",
        // headers: {
        //     "Content-Type": "application/x-www-form-urlencoded",
        // },

        body: formData,
    };

    let response;

    try {
        response = await fetch(endpoint, request);
        if (!response.ok) {
            throw new Error(response.statusText);
        }
    } catch (err) {
        console.error(err);
        return null;
    }

    return await response.json();
}

/**
 * @param {string} code the authorization code received from the OIDC
 * provider
 * @returns {Promise<boolean>} true if the token was fetched, false otherwise
 */
async function getToken(code) {
    const auth_url = import.meta.env.VITE_URL;
    const endpoint = `${auth_url}/auth-api/token`;
    const formData = {
        grant_type: "authorization_code",
        code: code,
        redirect_uri: `${auth_url}/complete/epita/`,
        client_id: import.meta.env.VITE_CLIENT_ID,
    };
    const response = await sendRequest(endpoint, formData);

    if (response === null) {
        console.error("Failed to retrieve OIDC token");
        alert("Failed to retrieve OIDC token");

        localStorage.clear();
        redirect.redirectToLoginPage();
        return false;
    }

    localStorage.setItem("token", response.id_token);
    localStorage.setItem("refresh_token", response.refresh_token);
    console.debug("Saved token and refresh tokens");

    return true;
}

/**
 * @param {string} refreshToken the refresh token (optional)
 * @returns {Promise<boolean>} whether the token has been refreshed or not
 */
async function refreshToken(refreshToken) {
    refreshToken = refreshToken || localStorage.getItem("refresh_token");
    if (!refreshToken) {
        console.error("Unable to retrieve refresh token");
        return false;
    }

    const auth_url = import.meta.env.VITE_URL;
    const endpoint = `${auth_url}/auth-api/token`;
    const formData = {
        client_id: import.meta.env.VITE_CLIENT_ID,
        // client_secret: "",
        grant_type: "authorization_code",
        refresh_token: refreshToken,
        scope: "epita profile picture",
    };
    const response = await sendRequest(endpoint, formData);

    if (response === null) {
        console.error("Failed to retrieve OIDC token");
        alert("Failed to retrieve OIDC token");

        localStorage.clear();
        redirect.redirectToLoginPage();
        return false;
    }

    localStorage.setItem("token", response.id_token);
    localStorage.setItem("refresh_token", response.refresh_token);
    console.debug("Saved token and refresh tokens");

    return true;
}

/**
 * @returns {Promise<boolean>} true if the user is authenticated, false otherwise
 */
async function authenticate() {
    const token = localStorage.getItem("token");

    if (token !== null) {
        return true;
    }

    const refresh_token = localStorage.getItem("refresh_token");

    if (refresh_token !== null) {
        return await refreshToken(refresh_token);
    }

    localStorage.clear();
    redirect.redirectToLoginPage();
    return false;
}

/**
 * @param {string} endpoint
 * @param {object} options this object should at least contain the method.
 * @returns {Promise<Response>} the response or null
 * We want a {Promise<Response>} so we can read the headers as well as the
 * body, rather than just the body
 */
async function authedAPIRequest(endpoint, options) {
    if (!(await authenticate())) {
        return null;
    }

    // if (!options.method) {
    //     console.error("Invalid parameter: options (missing method)");
    //     return null;
    // }

    // Deep copy req
    const request = JSON.parse(JSON.stringify(options));

    if (!request.headers) {
        request.headers = {};
    }

    // Pcq ce PUTAIN de js est pas foutu de faire ce qu'on lui demande
    request.headers.Authorization = "Bearer " + localStorage.getItem("token");

    const full_endpoint = import.meta.env.VITE_URL + "/api" + endpoint;

    const response = await fetch(full_endpoint, request);

    if (response.status === 401) {
        const response_err = await response.text();

        if (response_err.includes("Token expired")) {
            if (await refreshToken(null)) {
                return await authedAPIRequest(endpoint, options);
            }
        }

        localStorage.clear();
        alert("Redirecting to logging page");
        redirect.redirectToLoginPage();
        return null;
    }

    return response;
}

export { getToken, refreshToken, authenticate, authedAPIRequest };