import { Loader } from '../fuse-loader';

const customizedHMRPlugin = {
    hmrUpdate: ({ type, path, content }) => {
        if (type === 'js' || type === 'css') {
            const isModuleStateful = (path) => statefulModuleCheck(path);

            /** If a stateful module has changed reload the window */
            if (isModuleStateful(path)) {
                window.location.reload();
            }

            /** Otherwise flush the other modules */
            Loader.flush(function (fileName) {
                return !isModuleStateful(fileName);
            });

            /** Patch the module at give path */
            Loader.dynamic(path, content);

            /** Re-import / run the mainFile */
            if (Loader.mainFile) {
                try {
                    Loader.import(Loader.mainFile);
                } catch (e) {
                    // in case if a package was not found
                    // It probably means that it's just not in the scope
                    if (typeof e === 'string') { // a better way but string?!
                        if (/not found/.test(e)) {
                            window.location.reload();
                        }
                    }
                    console.error(e);
                }

            }

            /** We don't want the default behavior */
            return true;
        }
    },
};

/** Only register the plugin once */
let alreadyRegistered = false;

/** Current names of stateful modules */
let statefulModuleCheck: (moduleName: string) => boolean = () => false;

/**
 * Registers given module names as being stateful
 * @param isStateful for a given moduleName returns true if the module is stateful
 */
export const setStatefulModules = (isStateful: (moduleName: string) => boolean) => {
    if (!alreadyRegistered) {
        alreadyRegistered = true;
        Loader.addPlugin(customizedHMRPlugin);
    }
    statefulModuleCheck = isStateful;
};