import React, { FC, useEffect, useMemo, useState } from 'react';
import { useDispatch } from 'react-redux';

import { LoadingPlaceholder } from '@grafana/ui';
import {
  AlertManagerCortexConfig,
  GrafanaManagedReceiverConfig,
  Receiver,
  TestReceiversAlert,
} from 'app/plugins/datasource/alertmanager/types';

import { useUnifiedAlertingSelector } from '../../../hooks/useUnifiedAlertingSelector';
import {
  fetchGrafanaNotifiersAction,
  testReceiversAction,
  updateAlertManagerConfigAction,
} from '../../../state/actions';
import { GrafanaChannelValues, ReceiverFormValues } from '../../../types/receiver-form';
import { GRAFANA_RULES_SOURCE_NAME } from '../../../utils/datasource';
import {
  formChannelValuesToGrafanaChannelConfig,
  formValuesToGrafanaReceiver,
  grafanaReceiverToFormValues,
  updateConfigWithReceiver,
} from '../../../utils/receiver-form';

import { GrafanaCommonChannelSettings } from './GrafanaCommonChannelSettings';
import { ReceiverForm } from './ReceiverForm';
import { TestContactPointModal } from './TestContactPointModal';

interface Props {
  alertManagerSourceName: string;
  config: AlertManagerCortexConfig;
  existing?: Receiver;
}

const defaultChannelValues: GrafanaChannelValues = Object.freeze({
  __id: '',
  secureSettings: {},
  settings: {},
  secureFields: {},
  disableResolveMessage: false,
  type: 'email',
});

export const GrafanaReceiverForm: FC<Props> = ({ existing, alertManagerSourceName, config }) => {
  const grafanaNotifiers = useUnifiedAlertingSelector((state) => state.grafanaNotifiers);
  const [testChannelValues, setTestChannelValues] = useState<GrafanaChannelValues>();

  const dispatch = useDispatch();

  useEffect(() => {
    if (!(grafanaNotifiers.result || grafanaNotifiers.loading)) {
      dispatch(fetchGrafanaNotifiersAction());
    }
  }, [grafanaNotifiers, dispatch]);

  // transform receiver DTO to form values
  const [existingValue, id2original] = useMemo((): [
    ReceiverFormValues<GrafanaChannelValues> | undefined,
    Record<string, GrafanaManagedReceiverConfig>
  ] => {
    if (!existing || !grafanaNotifiers.result) {
      return [undefined, {}];
    }
    return grafanaReceiverToFormValues(existing, grafanaNotifiers.result!);
  }, [existing, grafanaNotifiers.result]);

  const onSubmit = (values: ReceiverFormValues<GrafanaChannelValues>) => {
    const newReceiver = formValuesToGrafanaReceiver(values, id2original, defaultChannelValues);
    dispatch(
      updateAlertManagerConfigAction({
        newConfig: updateConfigWithReceiver(config, newReceiver, existing?.name),
        oldConfig: config,
        alertManagerSourceName: GRAFANA_RULES_SOURCE_NAME,
        successMessage: existing ? 'Contact point updated.' : 'Contact point created',
        redirectPath: '/alerting/notifications',
      })
    );
  };

  const onTestChannel = (values: GrafanaChannelValues) => {
    setTestChannelValues(values);
  };

  const testNotification = (alert?: TestReceiversAlert) => {
    if (testChannelValues) {
      const existing: GrafanaManagedReceiverConfig | undefined = id2original[testChannelValues.__id];
      const chan = formChannelValuesToGrafanaChannelConfig(testChannelValues, defaultChannelValues, 'test', existing);

      const payload = {
        alertManagerSourceName,
        receivers: [
          {
            name: 'test',
            grafana_managed_receiver_configs: [chan],
          },
        ],
        alert,
      };

      dispatch(testReceiversAction(payload));
    }
  };

  const takenReceiverNames = useMemo(
    () => config.alertmanager_config.receivers?.map(({ name }) => name).filter((name) => name !== existing?.name) ?? [],
    [config, existing]
  );

  if (grafanaNotifiers.result) {
    return (
      <>
        <ReceiverForm<GrafanaChannelValues>
          config={config}
          onSubmit={onSubmit}
          initialValues={existingValue}
          onTestChannel={onTestChannel}
          notifiers={grafanaNotifiers.result}
          alertManagerSourceName={alertManagerSourceName}
          defaultItem={defaultChannelValues}
          takenReceiverNames={takenReceiverNames}
          commonSettingsComponent={GrafanaCommonChannelSettings}
        />
        <TestContactPointModal
          onDismiss={() => setTestChannelValues(undefined)}
          isOpen={!!testChannelValues}
          onTest={(alert) => testNotification(alert)}
        />
      </>
    );
  } else {
    return <LoadingPlaceholder text="Loading notifiers..." />;
  }
};