const portal = require('/lib/xp/portal');

const initServiceUrlRoot = (serviceName, label) => {
    const url = portal.serviceUrl({service: serviceName}) + '/';
    //log.info("Init " + label + ": " + JSON.stringify(url, null, 2));
    return url;
};

let ASSET_ROOT_URL;
const getAssetRoot = () => {
    if (ASSET_ROOT_URL === undefined) {
        ASSET_ROOT_URL = initServiceUrlRoot('react4xp', 'ASSET_ROOT_URL');
    }
    return ASSET_ROOT_URL;
};

let CLIENT_ROOT_URL;
const getClientRoot = () => {
    if (CLIENT_ROOT_URL === undefined) {
        CLIENT_ROOT_URL = initServiceUrlRoot('react4xp-client', 'CLIENT_ROOT_URL');
    }
    return CLIENT_ROOT_URL;
};


let DEPENDENCIES_ROOT_URL
const getDependenciesRoot = () => {
    if (DEPENDENCIES_ROOT_URL === undefined) {
        DEPENDENCIES_ROOT_URL = initServiceUrlRoot('react4xp-dependencies', 'DEPENDENCIES_ROOT_URL');
    }
    return DEPENDENCIES_ROOT_URL;
};


let SERVICE_ROOT_URL;
const getServiceRoot = () => {
    if (SERVICE_ROOT_URL === undefined) {
        SERVICE_ROOT_URL = initServiceUrlRoot('', 'SERVICE_ROOT_URL');
    }
    return SERVICE_ROOT_URL;
};

const stripSlashes = suffix => {
    while (suffix.startsWith('/')) {
        suffix = suffix.substring(1);
    }
    while (suffix.endsWith('/')) {
        suffix = suffix.substring(0, suffix.length - 1);
    }
    return suffix;
};

// Strips away the beginning of a service URL - the root path of the service - and returns everything after that,
// to pick up path variations not picked up in req.params, e.g. asset names after a slash.
//
// Why? For now (6.15.x), lib-router doesn't work properly in service controllers. And since portal.serviceUrl is not
// entirely consistent across calling contexts, the incoming core service path may not necessarily match the above
// constants. Hence, the workaround.
//
// Returns empty string if there is no suffix. Strips slashes from both ends.
// Throws an error if the path doesn't match any known variation of the service path.
// Logs a warning when the fallback is used.
const SERVICE_ROOTS = {};
let LOGGEDWARNING = false;
const getSuffix = (path, serviceName) => {
    const standardRoot = SERVICE_ROOTS[serviceName] = (
        SERVICE_ROOTS[serviceName] ||
        (portal.serviceUrl({service: serviceName}))
    );

    let location = path.indexOf(standardRoot);
    if (location !== -1) {
        return stripSlashes(path.substring(location + standardRoot.length));
    }

    const fallbackRoot = `/_/service/${app.name}/${serviceName}`;
    location = path.indexOf(fallbackRoot);
    if (location !== -1) {
        if (!LOGGEDWARNING) {
            log.warning(`Fallback: matched path '${path}' with service name '${serviceName}', returning suffix after service name. This will not be logged again.`);
            LOGGEDWARNING = true;
        }
        return stripSlashes(path.substring(location + fallbackRoot.length));
    }

    throw Error(`Unexpected service suffix lookup: requested path ('${path}') doesn't seem to belong to the service '${serviceName}'.`);
};

module.exports = {
    getAssetRoot, getClientRoot, getDependenciesRoot, getServiceRoot, getSuffix
};