project-inter-server/src/repositories/RedisParkingRepository.ts

import { createClient, RedisClientType } from 'redis';
import { ParkingGetterSetterRepository } from "./ParkingGetterSetterRepository";
import { IParkingStructure, IParkingStructureTimestampRecord } from "../entities/ParkingRepositoryEntities";
import { HistoricalParkingAverageQueryResult, ParkingStructureCountOptions } from "./ParkingGetterRepository";

export type ParkingStructureID = string;

// Every 10 minutes
export const PARKING_LOGGING_INTERVAL_MS = 600000;

export class RedisParkingRepository implements ParkingGetterSetterRepository {
  private dataLastAdded: Map<ParkingStructureID, Date> = new Map();

  constructor(
    private redisClient = createClient({
      url: process.env.REDIS_URL,
      socket: {
        tls: (process.env.REDIS_URL?.match(/rediss:/) != null),
        rejectUnauthorized: false,
      }
    }),
  ) {
  }

  get isReady() {
    return this.redisClient.isReady;
  }

  public async connect() {
    await this.redisClient.connect();
  }

  public async disconnect() {
    await this.redisClient.disconnect();
  }

  public async clearAllData() {
    await this.redisClient.flushAll();
    this.dataLastAdded.clear();
  }

  addOrUpdateParkingStructure = async (structure: IParkingStructure): Promise<void> => {
    // Store current structure data
    await this.redisClient.hSet(`parking:structure:${structure.id}`, {
      id: structure.id,
      name: structure.name,
      address: structure.address,
      capacity: structure.capacity.toString(),
      spotsAvailable: structure.spotsAvailable.toString(),
      latitude: structure.coordinates.latitude.toString(),
      longitude: structure.coordinates.longitude.toString(),
      updatedTime: structure.updatedTime.toISOString()
    });

    // Add to historical data if needed
    await this.addHistoricalDataForStructure(structure);
  };

  private addHistoricalDataForStructure = async (structure: IParkingStructure): Promise<void> => {
    const now = Date.now();
    const lastAdded = this.dataLastAdded.get(structure.id);

    const parkingLoggingIntervalExceeded = () => {
      return !lastAdded || (now - lastAdded.getTime()) >= PARKING_LOGGING_INTERVAL_MS;
    };

    if (parkingLoggingIntervalExceeded()) {
      // Use Redis Time Series to store historical data
      const timeSeriesKey = `parking:timeseries:${structure.id}`;

      try {
        // Try to add the time series data point
        await this.redisClient.sendCommand([
          'TS.ADD',
          timeSeriesKey,
          now.toString(),
          structure.spotsAvailable.toString(),
          'LABELS',
          'structureId',
          structure.id
        ]);
      } catch (error) {
        // If time series doesn't exist, create it first
        try {
          await this.redisClient.sendCommand([
            'TS.CREATE',
            timeSeriesKey,
            'LABELS',
            'structureId',
            structure.id
          ]);
          // Now add the data point
          await this.redisClient.sendCommand([
            'TS.ADD',
            timeSeriesKey,
            now.toString(),
            structure.spotsAvailable.toString()
          ]);
        } catch (createError) {
          // If still fails, it might be because time series already exists, try adding again
          await this.redisClient.sendCommand([
            'TS.ADD',
            timeSeriesKey,
            now.toString(),
            structure.spotsAvailable.toString()
          ]);
        }
      }

      this.dataLastAdded.set(structure.id, new Date(now));
    }
  };

  clearParkingStructureData = async (): Promise<void> => {
    // Get all parking structure keys
    const structureKeys = await this.redisClient.keys('parking:structure:*');
    const timeSeriesKeys = await this.redisClient.keys('parking:timeseries:*');

    // Delete all structure and time series data
    if (structureKeys.length > 0) {
      await this.redisClient.del(structureKeys);
    }
    if (timeSeriesKeys.length > 0) {
      await this.redisClient.del(timeSeriesKeys);
    }

    this.dataLastAdded.clear();
  };

  getParkingStructureById = async (id: string): Promise<IParkingStructure | null> => {
    const data = await this.redisClient.hGetAll(`parking:structure:${id}`);

    if (Object.keys(data).length === 0) {
      return null;
    }

    return {
      id: data.id,
      name: data.name,
      address: data.address,
      capacity: parseInt(data.capacity),
      spotsAvailable: parseInt(data.spotsAvailable),
      coordinates: {
        latitude: parseFloat(data.latitude),
        longitude: parseFloat(data.longitude)
      },
      updatedTime: new Date(data.updatedTime)
    };
  };

  getParkingStructures = async (): Promise<IParkingStructure[]> => {
    const keys = await this.redisClient.keys('parking:structure:*');
    const structures: IParkingStructure[] = [];

    for (const key of keys) {
      const data = await this.redisClient.hGetAll(key);
      if (Object.keys(data).length > 0) {
        structures.push({
          id: data.id,
          name: data.name,
          address: data.address,
          capacity: parseInt(data.capacity),
          spotsAvailable: parseInt(data.spotsAvailable),
          coordinates: {
            latitude: parseFloat(data.latitude),
            longitude: parseFloat(data.longitude)
          },
          updatedTime: new Date(data.updatedTime)
        });
      }
    }

    return structures;
  };

  removeParkingStructureIfExists = async (id: string): Promise<IParkingStructure | null> => {
    const structure = await this.getParkingStructureById(id);
    if (structure) {
      await this.redisClient.del(`parking:structure:${id}`);
      await this.redisClient.del(`parking:timeseries:${id}`);
      this.dataLastAdded.delete(id);
      return structure;
    }
    return null;
  };

  getHistoricalAveragesOfParkingStructureCounts = async (id: string, options: ParkingStructureCountOptions): Promise<HistoricalParkingAverageQueryResult[]> => {
    const timeSeriesKey = `parking:timeseries:${id}`;

    try {
      // Get time series data for the specified range
      const timeSeriesData = await this.redisClient.sendCommand([
        'TS.RANGE',
        timeSeriesKey,
        options.startUnixEpochMs.toString(),
        options.endUnixEpochMs.toString()
      ]) as [string, string][];

      if (!timeSeriesData || timeSeriesData.length === 0) {
        return [];
      }

      // Convert Redis time series data to our record format
      const records: IParkingStructureTimestampRecord[] = timeSeriesData.map(([timestamp, value]) => ({
        id,
        timestampMs: parseInt(timestamp),
        spotsAvailable: parseInt(value)
      }));

      return this.calculateAveragesFromRecords(records, options);
    } catch (error) {
      // Time series might not exist
      return [];
    }
  };

  private calculateAveragesFromRecords = (
    records: IParkingStructureTimestampRecord[],
    options: ParkingStructureCountOptions
  ): HistoricalParkingAverageQueryResult[] => {
    const results: HistoricalParkingAverageQueryResult[] = [];
    const { startUnixEpochMs, endUnixEpochMs, intervalMs } = options;

    let currentIntervalStart = startUnixEpochMs;

    while (currentIntervalStart < endUnixEpochMs) {
      const currentIntervalEnd = Math.min(currentIntervalStart + intervalMs, endUnixEpochMs);
      const recordsInInterval = this.getRecordsInTimeRange(records, currentIntervalStart, currentIntervalEnd);

      if (recordsInInterval.length > 0) {
        const averageResult = this.calculateAverageForInterval(currentIntervalStart, currentIntervalEnd, recordsInInterval);
        results.push(averageResult);
      }

      currentIntervalStart = currentIntervalEnd;
    }

    return results;
  };

  private getRecordsInTimeRange = (
    records: IParkingStructureTimestampRecord[],
    startMs: number,
    endMs: number
  ): IParkingStructureTimestampRecord[] => {
    return records.filter(record =>
      record.timestampMs >= startMs && record.timestampMs < endMs
    );
  };

  private calculateAverageForInterval = (
    fromMs: number,
    toMs: number,
    records: IParkingStructureTimestampRecord[]
  ): HistoricalParkingAverageQueryResult => {
    const totalSpotsAvailable = records.reduce((sum, record) => sum + record.spotsAvailable, 0);
    const averageSpotsAvailable = totalSpotsAvailable / records.length;

    return {
      fromUnixEpochMs: fromMs,
      toUnixEpochMs: toMs,
      averageSpotsAvailable
    };
  };
}