import { flatMap } from 'lodash';
import { NOT_IN_DB_PREFIX } from '../constants';

const metricsIdsInPanel = panel =>
  panel.metrics.filter(metric => metric.metricId && metric.result).map(metric => metric.metricId);

/**
 * Returns a reference to the currently selected dashboard
 * from the list of dashboards.
 *
 * @param {Object} state
 */
export const selectedDashboard = state => {
  const { allDashboards } = state;
  return (
    allDashboards.find(d => d.path === state.currentDashboard) ||
    allDashboards.find(d => d.default) ||
    null
  );
};

/**
 * Get all state for metric in the dashboard or a group. The
 * states are not repeated so the dashboard or group can show
 * a global state.
 *
 * @param {Object} state
 * @returns {Function} A function that returns an array of
 * states in all the metric in the dashboard or group.
 */
export const getMetricStates = state => groupKey => {
  let groups = state.dashboard.panelGroups;
  if (groupKey) {
    groups = groups.filter(group => group.key === groupKey);
  }

  const metricStates = groups.reduce((acc, group) => {
    group.panels.forEach(panel => {
      panel.metrics.forEach(metric => {
        if (metric.state) {
          acc.push(metric.state);
        }
      });
    });
    return acc;
  }, []);

  // Deduplicate and sort array
  return Array.from(new Set(metricStates)).sort();
};

/**
 * Getter to obtain the list of metric ids that have data
 *
 * Useful to understand which parts of the dashboard should
 * be displayed. It is a Vuex Method-Style Access getter.
 *
 * @param {Object} state
 * @returns {Function} A function that returns an array of
 * metrics in the dashboard that contain results, optionally
 * filtered by group key.
 */
export const metricsWithData = state => groupKey => {
  let groups = state.dashboard.panelGroups;
  if (groupKey) {
    groups = groups.filter(group => group.key === groupKey);
  }

  const res = [];
  groups.forEach(group => {
    group.panels.forEach(panel => {
      res.push(...metricsIdsInPanel(panel));
    });
  });

  return res;
};

/**
 * Metrics loaded from project-defined dashboards do not have a metric_id.
 * This getter checks which metrics are stored in the db (have a metric id)
 * This is hopefully a temporary solution until BE processes metrics before passing to FE
 *
 * Related:
 * https://gitlab.com/gitlab-org/gitlab/-/issues/28241
 * https://gitlab.com/gitlab-org/gitlab/-/merge_requests/27447
 */
export const metricsSavedToDb = state => {
  const metricIds = [];
  state.dashboard.panelGroups.forEach(({ panels }) => {
    panels.forEach(({ metrics }) => {
      const metricIdsInDb = metrics
        .filter(({ metricId }) => !metricId.startsWith(NOT_IN_DB_PREFIX))
        .map(({ metricId }) => metricId);

      metricIds.push(...metricIdsInDb);
    });
  });
  return metricIds;
};

/**
 * Filter environments by names.
 *
 * This is used in the environments dropdown with searchable input.
 *
 * @param {Object} state
 * @returns {Array} List of environments
 */
export const filteredEnvironments = state =>
  state.environments.filter(env =>
    env.name.toLowerCase().includes((state.environmentsSearchTerm || '').trim().toLowerCase()),
  );

/**
 * Maps an variables object to an array along with stripping
 * the variable prefix.
 *
 * @param {Object} variables - Custom variables provided by the user
 * @returns {Array} The custom variables array to be send to the API
 * in the format of [variable1, variable1_value]
 */

export const getCustomVariablesArray = state =>
  flatMap(state.promVariables, (variable, key) => [key, variable.value]);

// prevent babel-plugin-rewire from generating an invalid default during karma tests
export default () => {};
