const {sendActionToService} = require('@truss/comm');

const debug = require('debug')('truss:gateway:actions');

module.exports = (serviceMap) => ({
  'truss/hook-services': ({payload: {hook, args}}) => {
    if (!(hook in serviceMap.hooks)) { return []; }
    return serviceMap.hooks[hook];
  },
  'truss/invoke': ({payload: {hook, args}}) => {
    if (!(hook in serviceMap.hooks)) { return {}; }
    return invokeHook(serviceMap.hooks[hook], hook, args);
  },
  'truss/invoke-flat': ({payload: {hook, args}}) => {
    if (!(hook in serviceMap.hooks)) { return []; }
    return invokeHookFlat(serviceMap.hooks[hook], hook, args);
  },
});

function invokeHookFlat(services, hook, args) {
  debug(`invoking hookFlat(${hook}(${JSON.stringify(args, null, '  ')}))...`);
  return invokeHookFlatInternal(services, hook, args);
}

function invokeHookFlatInternal(services, hook, args) {
  const action = {type: 'truss/hook', payload: {hook, args}};
  return Promise.all(services.map((service) => {
    return sendActionToService(action, service);
  }));
}

function invokeHook(services, hook, args) {
  debug(`invoking hook ${hook}(${JSON.stringify(args, null, '  ')})...`);
  return invokeHookFlatInternal(services, hook, args).then((result) => {
    return result.reduce((l, r, i) => (l[services[i]] = r, l), {});
  });
}