import { DataSourceInstanceSettings, DataSourceJsonData } from '@grafana/data';
import { config, getBackendSrv, getDataSourceSrv } from '@grafana/runtime';
import {
  CustomVariable,
  PanelBuilders,
  SceneFlexItem,
  SceneFlexLayout,
  sceneGraph,
  SceneObject,
  SceneObjectBase,
  SceneQueryRunner,
  SceneVariableSet,
  VariableDependencyConfig,
  VariableValueSelectors,
  type SceneComponentProps,
  type SceneObjectState,
  type SceneVariable,
} from '@grafana/scenes';
import { Stack, LinkButton } from '@grafana/ui';
import { Trans } from 'app/core/internationalization';

import { MetricsLogsConnector } from '../Integrations/logs/base';
import { createLabelsCrossReferenceConnector } from '../Integrations/logs/labelsCrossReference';
import { lokiRecordingRulesConnector } from '../Integrations/logs/lokiRecordingRules';
import { reportExploreMetrics } from '../interactions';
import { VAR_FILTERS, VAR_LOGS_DATASOURCE, VAR_LOGS_DATASOURCE_EXPR, VAR_METRIC, VAR_METRIC_EXPR } from '../shared';
import { isConstantVariable, isCustomVariable } from '../utils';

import { NoRelatedLogsScene } from './NoRelatedLogsFoundScene';

export interface RelatedLogsSceneState extends SceneObjectState {
  controls: SceneObject[];
  body: SceneFlexLayout;
  connectors: MetricsLogsConnector[];
}

const LOGS_PANEL_CONTAINER_KEY = 'related_logs/logs_panel_container';
const RELATED_LOGS_QUERY_KEY = 'related_logs/logs_query';

export class RelatedLogsScene extends SceneObjectBase<RelatedLogsSceneState> {
  constructor(state: Partial<RelatedLogsSceneState>) {
    super({
      controls: [],
      body: new SceneFlexLayout({
        direction: 'column',
        height: '400px',
        children: [
          new SceneFlexItem({
            key: LOGS_PANEL_CONTAINER_KEY,
            body: undefined,
          }),
        ],
      }),
      connectors: [],
      ...state,
    });

    this.addActivationHandler(this.onActivate.bind(this));
  }

  private onActivate() {
    this.setState({
      connectors: [lokiRecordingRulesConnector, createLabelsCrossReferenceConnector(this)],
    });
    this.setLogsDataSourceVar();
  }

  private setLogsDataSourceVar(): Promise<void> {
    const selectedMetric = sceneGraph.interpolate(this, VAR_METRIC_EXPR);
    return Promise.all(this.state.connectors.map((connector) => connector.getDataSources(selectedMetric))).then(
      (results) => {
        const lokiDataSources = results.flat().slice(0, 10); // limit to the first ten matching Loki data sources
        const logsPanelContainer = sceneGraph.findByKeyAndType(this, LOGS_PANEL_CONTAINER_KEY, SceneFlexItem);

        if (!lokiDataSources?.length) {
          logsPanelContainer.setState({
            body: new NoRelatedLogsScene({}),
          });
          this.setState({ $variables: undefined, controls: undefined });
        } else {
          logsPanelContainer.setState({
            body: PanelBuilders.logs()
              .setTitle('Logs')
              .setData(
                new SceneQueryRunner({
                  datasource: { uid: VAR_LOGS_DATASOURCE_EXPR },
                  queries: [],
                  key: RELATED_LOGS_QUERY_KEY,
                })
              )
              .build(),
          });
          this.setState({
            $variables: new SceneVariableSet({
              variables: [
                new CustomVariable({
                  name: VAR_LOGS_DATASOURCE,
                  label: 'Logs data source',
                  query: lokiDataSources?.map((ds) => `${ds.name} : ${ds.uid}`).join(','),
                }),
              ],
            }),
            controls: [new VariableValueSelectors({ layout: 'vertical' })],
          });
        }
      }
    );
  }

  private updateLokiQuery() {
    const selectedDatasourceVar = sceneGraph.lookupVariable(VAR_LOGS_DATASOURCE, this);
    const selectedMetricVar = sceneGraph.lookupVariable(VAR_METRIC, this);

    if (!isCustomVariable(selectedDatasourceVar) || !isConstantVariable(selectedMetricVar)) {
      return;
    }

    const selectedMetric = selectedMetricVar.getValue();
    const selectedDatasourceUid = selectedDatasourceVar.getValue();

    if (typeof selectedMetric !== 'string' || typeof selectedDatasourceUid !== 'string') {
      return;
    }

    const lokiQueries = this.state.connectors.reduce<Record<string, string>>((acc, connector, idx) => {
      const lokiExpr = connector.getLokiQueryExpr(selectedMetric, selectedDatasourceUid);

      if (lokiExpr) {
        acc[connector.name ?? `connector-${idx}`] = lokiExpr;
      }

      return acc;
    }, {});
    const relatedLogsQuery = sceneGraph.findByKeyAndType(this, RELATED_LOGS_QUERY_KEY, SceneQueryRunner);
    relatedLogsQuery.setState({
      queries: Object.keys(lokiQueries).map((connectorName) => ({
        refId: `RelatedLogs-${connectorName}`,
        expr: lokiQueries[connectorName],
        maxLines: 100,
      })),
    });
  }

  protected _variableDependency = new VariableDependencyConfig(this, {
    variableNames: [VAR_LOGS_DATASOURCE, VAR_FILTERS],
    onReferencedVariableValueChanged: (variable: SceneVariable) => {
      const { name } = variable.state;

      if (name === VAR_LOGS_DATASOURCE) {
        this.updateLokiQuery();
      }

      if (name === VAR_FILTERS) {
        this.setLogsDataSourceVar().then(() => this.updateLokiQuery());
      }
    },
  });

  static readonly Component = ({ model }: SceneComponentProps<RelatedLogsScene>) => {
    const { controls, body } = model.useState();

    return (
      <div>
        <Stack gap={1} direction={'column'} grow={1}>
          <Stack gap={1} direction={'row'} grow={1} justifyContent={'space-between'} alignItems={'start'}>
            <Stack gap={1}>
              {controls?.map((control) => <control.Component key={control.state.key} model={control} />)}
            </Stack>

            <LinkButton
              href={`${config.appSubUrl}/a/grafana-lokiexplore-app`} // We prefix with the appSubUrl for environments that don't host grafana at the root.
              target="_blank"
              tooltip="Navigate to the Explore Logs app"
              variant="secondary"
              size="sm"
              onClick={() => reportExploreMetrics('related_logs_action_clicked', { action: 'open_explore_logs' })}
            >
              <Trans i18nKey="explore-metrics.related-logs.openExploreLogs">Open Explore Logs</Trans>
            </LinkButton>
          </Stack>
          <body.Component model={body} />
        </Stack>
      </div>
    );
  };
}

export function buildRelatedLogsScene() {
  return new RelatedLogsScene({});
}

export async function findHealthyLokiDataSources() {
  const lokiDataSources = getDataSourceSrv().getList({
    logs: true,
    type: 'loki',
    filter: (ds) => ds.uid !== 'grafana',
  });
  const healthyLokiDataSources: Array<DataSourceInstanceSettings<DataSourceJsonData>> = [];
  const unhealthyLokiDataSources: Array<DataSourceInstanceSettings<DataSourceJsonData>> = [];

  await Promise.all(
    lokiDataSources.map((ds) =>
      getBackendSrv()
        .get(`/api/datasources/${ds.id}/health`, undefined, undefined, {
          showSuccessAlert: false,
          showErrorAlert: false,
        })
        .then((health) =>
          health?.status === 'OK' ? healthyLokiDataSources.push(ds) : unhealthyLokiDataSources.push(ds)
        )
        .catch(() => unhealthyLokiDataSources.push(ds))
    )
  );

  if (unhealthyLokiDataSources.length) {
    console.warn(
      `Found ${unhealthyLokiDataSources.length} unhealthy Loki data sources: ${unhealthyLokiDataSources.map((ds) => ds.name).join(', ')}`
    );
  }

  return healthyLokiDataSources;
}