import express from 'express';
import _ from 'lodash';

import { PluginProperty, PluginPropertyResponse } from '../../api/core/plugin/PluginPropertyInterface';
import { BasePlugin, PropertiesWrapper } from '../common/BasePlugin';
import {
  ActivityAnalyzer,
  ActivityAnalyzerPluginResponse,
  ActivityAnalyzerRequest,
  ActivityAnalyzerResponse,
} from './ActivityAnalyzerInterface';

export interface ActivityAnalyzerBaseInstanceContext {
  properties: PropertiesWrapper;
  activityAnalyzer: ActivityAnalyzer;
}

export abstract class ActivityAnalyzerPlugin extends BasePlugin<ActivityAnalyzerBaseInstanceContext> {
  constructor(enableThrottling = false) {
    super(enableThrottling);

    // We init the specific route to listen for activity analysis requests
    this.initActivityAnalysis();
    this.setErrorHandler();
  }

  // Helper to fetch the activity analyzer resource with caching
  async fetchActivityAnalyzer(activityAnalyzerId: string): Promise<ActivityAnalyzer> {
    const activityAnalyzerResponse = await super.requestGatewayHelper<ActivityAnalyzerResponse>(
      'GET',
      `${this.outboundPlatformUrl}/v1/activity_analyzers/${activityAnalyzerId}`,
    );

    this.logger.debug(
      `Fetched Activity Analyzer: ${activityAnalyzerId} - ${JSON.stringify(activityAnalyzerResponse.data)}`,
    );
    return activityAnalyzerResponse.data;
  }

  // Method to build an instance context
  // To be overriden to get a cutom behavior

  // Helper to fetch the activity analyzer resource with caching
  async fetchActivityAnalyzerProperties(activityAnalyzerId: string): Promise<PluginProperty[]> {
    const activityAnalyzerPropertyResponse = await super.requestGatewayHelper<PluginPropertyResponse>(
      'GET',
      `${this.outboundPlatformUrl}/v1/activity_analyzers/${activityAnalyzerId}/properties`,
    );
    this.logger.debug(
      `Fetched Activity Analyzer Properties: ${activityAnalyzerId} - ${JSON.stringify(
        activityAnalyzerPropertyResponse.data,
      )}`,
    );
    return activityAnalyzerPropertyResponse.data;
  }

  // Method to process an Activity Analysis

  // This is a default provided implementation
  protected async instanceContextBuilder(activityAnalyzerId: string): Promise<ActivityAnalyzerBaseInstanceContext> {
    const activityAnalyzerP = this.fetchActivityAnalyzer(activityAnalyzerId);
    const activityAnalyzerPropsP = this.fetchActivityAnalyzerProperties(activityAnalyzerId);

    const results = await Promise.all([activityAnalyzerP, activityAnalyzerPropsP]);

    const activityAnalyzer = results[0];
    const activityAnalyzerProps = results[1];

    return {
      properties: new PropertiesWrapper(activityAnalyzerProps),
      activityAnalyzer: activityAnalyzer,
    };
  }

  protected async getInstanceContext(activityAnalyzerId: string): Promise<ActivityAnalyzerBaseInstanceContext> {
    if (!this.pluginCache.get(activityAnalyzerId)) {
      void this.pluginCache.put(
        activityAnalyzerId,
        this.instanceContextBuilder(activityAnalyzerId).catch((err) => {
          this.logger.error(`Error while caching instance context: ${(err as Error).message}`);
          this.pluginCache.del(activityAnalyzerId);
          throw err;
        }),
        this.getInstanceContextCacheExpiration(),
      );
    }
    return this.pluginCache.get(activityAnalyzerId) as Promise<ActivityAnalyzerBaseInstanceContext>;
  }

  // To be overriden by the Plugin to get a custom behavior
  protected abstract onActivityAnalysis(
    request: ActivityAnalyzerRequest,
    instanceContext: ActivityAnalyzerBaseInstanceContext,
  ): Promise<ActivityAnalyzerPluginResponse>;

  private initActivityAnalysis(): void {
    this.app.post(
      '/v1/activity_analysis',
      this.asyncMiddleware(async (req: express.Request, res: express.Response) => {
        if (!this.httpIsReady()) {
          const msg = {
            error: 'Plugin not initialized',
          };
          this.logger.error('POST /v1/activity_analysis : %s', JSON.stringify(msg));
          return res.status(500).json(msg);
        } else if (!req.body || _.isEmpty(req.body)) {
          const msg = {
            error: 'Missing request body',
          };
          this.logger.error('POST /v1/activity_analysis : %s', JSON.stringify(msg));
          return res.status(500).json(msg);
        } else {
          this.logger.debug(`POST /v1/activity_analysis ${JSON.stringify(req.body)}`);

          const activityAnalyzerRequest = req.body as ActivityAnalyzerRequest;

          if (!this.onActivityAnalysis) {
            const errMsg = 'No Activity Analyzer listener registered!';
            this.logger.error(errMsg);
            return res.status(500).json({ error: errMsg });
          }

          const instanceContext: ActivityAnalyzerBaseInstanceContext = await this.getInstanceContext(
            activityAnalyzerRequest.activity_analyzer_id,
          );

          const pluginResponse = await this.onActivityAnalysis(activityAnalyzerRequest, instanceContext);

          this.logger.debug(`Returning: ${JSON.stringify(pluginResponse)}`);
          return res.status(200).send(JSON.stringify(pluginResponse));
        }
      }),
    );
  }
}