// Libraries
import _ from 'lodash';

// Services & Utils
import store from 'app/core/store';
import { getDatasourceSrv } from 'app/features/plugins/datasource_srv';
import { Emitter } from 'app/core/core';
import {
  LAST_USED_DATASOURCE_KEY,
  ensureQueries,
  generateEmptyQuery,
  parseUrlState,
  getTimeRange,
  getTimeRangeFromUrl,
  generateNewKeyAndAddRefIdIfMissing,
} from 'app/core/utils/explore';

// Types
import { ThunkResult } from 'app/types';
import {
  RawTimeRange,
  DataSourceApi,
  DataQuery,
  DataSourceSelectItem,
  QueryFixAction,
  LogsDedupStrategy,
  AbsoluteTimeRange,
} from '@grafana/ui';
import { ExploreId, RangeScanner, ExploreUIState, QueryTransaction, ExploreMode } from 'app/types/explore';
import {
  updateDatasourceInstanceAction,
  changeQueryAction,
  changeRefreshIntervalAction,
  ChangeRefreshIntervalPayload,
  changeSizeAction,
  ChangeSizePayload,
  clearQueriesAction,
  initializeExploreAction,
  loadDatasourceMissingAction,
  loadDatasourcePendingAction,
  queriesImportedAction,
  LoadDatasourceReadyPayload,
  loadDatasourceReadyAction,
  modifyQueriesAction,
  scanStartAction,
  setQueriesAction,
  splitCloseAction,
  splitOpenAction,
  addQueryRowAction,
  toggleGraphAction,
  toggleTableAction,
  ToggleGraphPayload,
  ToggleTablePayload,
  updateUIStateAction,
  testDataSourcePendingAction,
  testDataSourceSuccessAction,
  testDataSourceFailureAction,
  loadExploreDatasources,
  changeModeAction,
  scanStopAction,
  scanRangeAction,
  runQueriesAction,
  stateSaveAction,
  updateTimeRangeAction,
} from './actionTypes';
import { ActionOf, ActionCreator } from 'app/core/redux/actionCreatorFactory';
import { getTimeZone } from 'app/features/profile/state/selectors';
import { offOption } from '@grafana/ui/src/components/RefreshPicker/RefreshPicker';

/**
 * Updates UI state and save it to the URL
 */
const updateExploreUIState = (exploreId: ExploreId, uiStateFragment: Partial<ExploreUIState>): ThunkResult<void> => {
  return dispatch => {
    dispatch(updateUIStateAction({ exploreId, ...uiStateFragment }));
    dispatch(stateSaveAction());
  };
};

/**
 * Adds a query row after the row with the given index.
 */
export function addQueryRow(exploreId: ExploreId, index: number): ThunkResult<void> {
  return (dispatch, getState) => {
    const queries = getState().explore[exploreId].queries;
    const query = generateEmptyQuery(queries, index);

    dispatch(addQueryRowAction({ exploreId, index, query }));
  };
}

/**
 * Loads a new datasource identified by the given name.
 */
export function changeDatasource(exploreId: ExploreId, datasource: string): ThunkResult<void> {
  return async (dispatch, getState) => {
    let newDataSourceInstance: DataSourceApi = null;

    if (!datasource) {
      newDataSourceInstance = await getDatasourceSrv().get();
    } else {
      newDataSourceInstance = await getDatasourceSrv().get(datasource);
    }

    const currentDataSourceInstance = getState().explore[exploreId].datasourceInstance;
    const queries = getState().explore[exploreId].queries;

    await dispatch(importQueries(exploreId, queries, currentDataSourceInstance, newDataSourceInstance));

    dispatch(updateDatasourceInstanceAction({ exploreId, datasourceInstance: newDataSourceInstance }));

    if (getState().explore[exploreId].isLive) {
      dispatch(changeRefreshInterval(exploreId, offOption.value));
    }

    await dispatch(loadDatasource(exploreId, newDataSourceInstance));
    dispatch(runQueries(exploreId));
  };
}

/**
 * Change the display mode in Explore.
 */
export function changeMode(exploreId: ExploreId, mode: ExploreMode): ThunkResult<void> {
  return dispatch => {
    dispatch(clearQueries(exploreId));
    dispatch(changeModeAction({ exploreId, mode }));
    dispatch(runQueries(exploreId));
  };
}

/**
 * Query change handler for the query row with the given index.
 * If `override` is reset the query modifications and run the queries. Use this to set queries via a link.
 */
export function changeQuery(
  exploreId: ExploreId,
  query: DataQuery,
  index: number,
  override: boolean
): ThunkResult<void> {
  return (dispatch, getState) => {
    // Null query means reset
    if (query === null) {
      const queries = getState().explore[exploreId].queries;
      const { refId, key } = queries[index];
      query = generateNewKeyAndAddRefIdIfMissing({ refId, key }, queries, index);
    }

    dispatch(changeQueryAction({ exploreId, query, index, override }));
    if (override) {
      dispatch(runQueries(exploreId));
    }
  };
}

/**
 * Keep track of the Explore container size, in particular the width.
 * The width will be used to calculate graph intervals (number of datapoints).
 */
export function changeSize(
  exploreId: ExploreId,
  { height, width }: { height: number; width: number }
): ActionOf<ChangeSizePayload> {
  return changeSizeAction({ exploreId, height, width });
}

export const updateTimeRange = (options: {
  exploreId: ExploreId;
  rawRange?: RawTimeRange;
  absoluteRange?: AbsoluteTimeRange;
}): ThunkResult<void> => {
  return dispatch => {
    dispatch(updateTimeRangeAction({ ...options }));
    dispatch(runQueries(options.exploreId));
  };
};

/**
 * Change the refresh interval of Explore. Called from the Refresh picker.
 */
export function changeRefreshInterval(
  exploreId: ExploreId,
  refreshInterval: string
): ActionOf<ChangeRefreshIntervalPayload> {
  return changeRefreshIntervalAction({ exploreId, refreshInterval });
}

/**
 * Clear all queries and results.
 */
export function clearQueries(exploreId: ExploreId): ThunkResult<void> {
  return dispatch => {
    dispatch(scanStopAction({ exploreId }));
    dispatch(clearQueriesAction({ exploreId }));
    dispatch(stateSaveAction());
  };
}

/**
 * Loads all explore data sources and sets the chosen datasource.
 * If there are no datasources a missing datasource action is dispatched.
 */
export function loadExploreDatasourcesAndSetDatasource(
  exploreId: ExploreId,
  datasourceName: string
): ThunkResult<void> {
  return dispatch => {
    const exploreDatasources: DataSourceSelectItem[] = getDatasourceSrv()
      .getExternal()
      .map(
        (ds: any) =>
          ({
            value: ds.name,
            name: ds.name,
            meta: ds.meta,
          } as DataSourceSelectItem)
      );

    dispatch(loadExploreDatasources({ exploreId, exploreDatasources }));

    if (exploreDatasources.length >= 1) {
      dispatch(changeDatasource(exploreId, datasourceName));
    } else {
      dispatch(loadDatasourceMissingAction({ exploreId }));
    }
  };
}

/**
 * Initialize Explore state with state from the URL and the React component.
 * Call this only on components for with the Explore state has not been initialized.
 */
export function initializeExplore(
  exploreId: ExploreId,
  datasourceName: string,
  queries: DataQuery[],
  rawRange: RawTimeRange,
  containerWidth: number,
  eventBridge: Emitter,
  ui: ExploreUIState
): ThunkResult<void> {
  return async (dispatch, getState) => {
    const timeZone = getTimeZone(getState().user);
    const range = getTimeRange(timeZone, rawRange);
    dispatch(loadExploreDatasourcesAndSetDatasource(exploreId, datasourceName));
    dispatch(
      initializeExploreAction({
        exploreId,
        containerWidth,
        eventBridge,
        queries,
        range,
        ui,
      })
    );
  };
}

/**
 * Datasource loading was successfully completed.
 */
export const loadDatasourceReady = (
  exploreId: ExploreId,
  instance: DataSourceApi
): ActionOf<LoadDatasourceReadyPayload> => {
  const historyKey = `grafana.explore.history.${instance.meta.id}`;
  const history = store.getObject(historyKey, []);
  // Save last-used datasource
  store.set(LAST_USED_DATASOURCE_KEY, instance.name);

  return loadDatasourceReadyAction({
    exploreId,
    history,
  });
};

export function importQueries(
  exploreId: ExploreId,
  queries: DataQuery[],
  sourceDataSource: DataSourceApi,
  targetDataSource: DataSourceApi
): ThunkResult<void> {
  return async dispatch => {
    if (!sourceDataSource) {
      // explore not initialized
      dispatch(queriesImportedAction({ exploreId, queries }));
      return;
    }

    let importedQueries = queries;
    // Check if queries can be imported from previously selected datasource
    if (sourceDataSource.meta.id === targetDataSource.meta.id) {
      // Keep same queries if same type of datasource
      importedQueries = [...queries];
    } else if (targetDataSource.importQueries) {
      // Datasource-specific importers
      importedQueries = await targetDataSource.importQueries(queries, sourceDataSource.meta);
    } else {
      // Default is blank queries
      importedQueries = ensureQueries();
    }

    const nextQueries = ensureQueries(importedQueries);

    dispatch(queriesImportedAction({ exploreId, queries: nextQueries }));
  };
}

/**
 * Tests datasource.
 */
export const testDatasource = (exploreId: ExploreId, instance: DataSourceApi): ThunkResult<void> => {
  return async dispatch => {
    let datasourceError = null;

    dispatch(testDataSourcePendingAction({ exploreId }));

    try {
      const testResult = await instance.testDatasource();
      datasourceError = testResult.status === 'success' ? null : testResult.message;
    } catch (error) {
      datasourceError = (error && error.statusText) || 'Network error';
    }

    if (datasourceError) {
      dispatch(testDataSourceFailureAction({ exploreId, error: datasourceError }));
      return;
    }

    dispatch(testDataSourceSuccessAction({ exploreId }));
  };
};

/**
 * Reconnects datasource when there is a connection failure.
 */
export const reconnectDatasource = (exploreId: ExploreId): ThunkResult<void> => {
  return async (dispatch, getState) => {
    const instance = getState().explore[exploreId].datasourceInstance;
    dispatch(changeDatasource(exploreId, instance.name));
  };
};

/**
 * Main action to asynchronously load a datasource. Dispatches lots of smaller actions for feedback.
 */
export function loadDatasource(exploreId: ExploreId, instance: DataSourceApi): ThunkResult<void> {
  return async (dispatch, getState) => {
    const datasourceName = instance.name;

    // Keep ID to track selection
    dispatch(loadDatasourcePendingAction({ exploreId, requestedDatasourceName: datasourceName }));

    await dispatch(testDatasource(exploreId, instance));

    if (datasourceName !== getState().explore[exploreId].requestedDatasourceName) {
      // User already changed datasource again, discard results
      return;
    }

    if (instance.init) {
      try {
        instance.init();
      } catch (err) {
        console.log(err);
      }
    }

    if (datasourceName !== getState().explore[exploreId].requestedDatasourceName) {
      // User already changed datasource again, discard results
      return;
    }

    dispatch(loadDatasourceReady(exploreId, instance));
  };
}

/**
 * Action to modify a query given a datasource-specific modifier action.
 * @param exploreId Explore area
 * @param modification Action object with a type, e.g., ADD_FILTER
 * @param index Optional query row index. If omitted, the modification is applied to all query rows.
 * @param modifier Function that executes the modification, typically `datasourceInstance.modifyQueries`.
 */
export function modifyQueries(
  exploreId: ExploreId,
  modification: QueryFixAction,
  index: number,
  modifier: any
): ThunkResult<void> {
  return dispatch => {
    dispatch(modifyQueriesAction({ exploreId, modification, index, modifier }));
    if (!modification.preventSubmit) {
      dispatch(runQueries(exploreId));
    }
  };
}

/**
 * Main action to run queries and dispatches sub-actions based on which result viewers are active
 */
export function runQueries(exploreId: ExploreId): ThunkResult<void> {
  return (dispatch, getState) => {
    dispatch(updateTimeRangeAction({ exploreId }));
    dispatch(runQueriesAction({ exploreId }));
  };
}

/**
 * Start a scan for more results using the given scanner.
 * @param exploreId Explore area
 * @param scanner Function that a) returns a new time range and b) triggers a query run for the new range
 */
export function scanStart(exploreId: ExploreId, scanner: RangeScanner): ThunkResult<void> {
  return dispatch => {
    // Register the scanner
    dispatch(scanStartAction({ exploreId, scanner }));
    // Scanning must trigger query run, and return the new range
    const range = scanner();
    // Set the new range to be displayed
    dispatch(scanRangeAction({ exploreId, range }));
  };
}

/**
 * Reset queries to the given queries. Any modifications will be discarded.
 * Use this action for clicks on query examples. Triggers a query run.
 */
export function setQueries(exploreId: ExploreId, rawQueries: DataQuery[]): ThunkResult<void> {
  return (dispatch, getState) => {
    // Inject react keys into query objects
    const queries = getState().explore[exploreId].queries;
    const nextQueries = rawQueries.map((query, index) => generateNewKeyAndAddRefIdIfMissing(query, queries, index));
    dispatch(setQueriesAction({ exploreId, queries: nextQueries }));
    dispatch(runQueries(exploreId));
  };
}

/**
 * Close the split view and save URL state.
 */
export function splitClose(itemId: ExploreId): ThunkResult<void> {
  return dispatch => {
    dispatch(splitCloseAction({ itemId }));
    dispatch(stateSaveAction());
  };
}

/**
 * Open the split view and copy the left state to be the right state.
 * The right state is automatically initialized.
 * The copy keeps all query modifications but wipes the query results.
 */
export function splitOpen(): ThunkResult<void> {
  return (dispatch, getState) => {
    // Clone left state to become the right state
    const leftState = getState().explore[ExploreId.left];
    const queryState = getState().location.query[ExploreId.left] as string;
    const urlState = parseUrlState(queryState);
    const queryTransactions: QueryTransaction[] = [];
    const itemState = {
      ...leftState,
      queryTransactions,
      queries: leftState.queries.slice(),
      exploreId: ExploreId.right,
      urlState,
    };
    dispatch(splitOpenAction({ itemState }));
    dispatch(stateSaveAction());
  };
}

/**
 * Creates action to collapse graph/logs/table panel. When panel is collapsed,
 * queries won't be run
 */
const togglePanelActionCreator = (
  actionCreator: ActionCreator<ToggleGraphPayload> | ActionCreator<ToggleTablePayload>
) => (exploreId: ExploreId, isPanelVisible: boolean): ThunkResult<void> => {
  return dispatch => {
    let uiFragmentStateUpdate: Partial<ExploreUIState>;
    const shouldRunQueries = !isPanelVisible;

    switch (actionCreator.type) {
      case toggleGraphAction.type:
        uiFragmentStateUpdate = { showingGraph: !isPanelVisible };
        break;
      case toggleTableAction.type:
        uiFragmentStateUpdate = { showingTable: !isPanelVisible };
        break;
    }

    dispatch(actionCreator({ exploreId }));
    dispatch(updateExploreUIState(exploreId, uiFragmentStateUpdate));

    if (shouldRunQueries) {
      dispatch(runQueries(exploreId));
    }
  };
};

/**
 * Expand/collapse the graph result viewer. When collapsed, graph queries won't be run.
 */
export const toggleGraph = togglePanelActionCreator(toggleGraphAction);

/**
 * Expand/collapse the table result viewer. When collapsed, table queries won't be run.
 */
export const toggleTable = togglePanelActionCreator(toggleTableAction);

/**
 * Change logs deduplication strategy and update URL.
 */
export const changeDedupStrategy = (exploreId: ExploreId, dedupStrategy: LogsDedupStrategy): ThunkResult<void> => {
  return dispatch => {
    dispatch(updateExploreUIState(exploreId, { dedupStrategy }));
  };
};

export function refreshExplore(exploreId: ExploreId): ThunkResult<void> {
  return (dispatch, getState) => {
    const itemState = getState().explore[exploreId];
    if (!itemState.initialized) {
      return;
    }

    const { urlState, update, containerWidth, eventBridge } = itemState;
    const { datasource, queries, range: urlRange, ui } = urlState;
    const refreshQueries: DataQuery[] = [];
    for (let index = 0; index < queries.length; index++) {
      const query = queries[index];
      refreshQueries.push(generateNewKeyAndAddRefIdIfMissing(query, refreshQueries, index));
    }
    const timeZone = getTimeZone(getState().user);
    const range = getTimeRangeFromUrl(urlRange, timeZone);

    // need to refresh datasource
    if (update.datasource) {
      const initialQueries = ensureQueries(queries);
      dispatch(initializeExplore(exploreId, datasource, initialQueries, range, containerWidth, eventBridge, ui));
      return;
    }

    if (update.range) {
      dispatch(updateTimeRangeAction({ exploreId, rawRange: range.raw }));
    }

    // need to refresh ui state
    if (update.ui) {
      dispatch(updateUIStateAction({ ...ui, exploreId }));
    }

    // need to refresh queries
    if (update.queries) {
      dispatch(setQueriesAction({ exploreId, queries: refreshQueries }));
    }

    // always run queries when refresh is needed
    if (update.queries || update.ui || update.range) {
      dispatch(runQueries(exploreId));
    }
  };
}