@clduab11/gemini-flow/src/streaming/buffer-sync-manager.ts

Revolutionary AI agent swarm coordination platform with Google Services integration, multimedia processing, and production-ready monitoring. Features 8 Google AI services, quantum computing capabilities, and enterprise-grade security.

/**
 * Buffer and Synchronization Manager
 *
 * Advanced buffering and synchronization strategies for multimedia streams:
 * - Adaptive buffering with predictive algorithms
 * - Multi-stream synchronization with sub-frame accuracy
 * - Jitter buffer management
 * - Clock synchronization across agents
 * - Quality-aware buffer management
 */

import { EventEmitter } from "events";
import { Logger } from "../utils/logger.js";
import {
  MultiModalChunk,
  BufferingStrategy,
  SynchronizationConfig,
  NetworkConditions,
  StreamingSession,
} from "../types/streaming.js";

export interface BufferMetrics {
  currentLevel: number; // Current buffer fill level (0-1)
  targetLevel: number; // Target buffer level (0-1)
  underrunCount: number; // Number of buffer underruns
  overrunCount: number; // Number of buffer overruns
  averageLatency: number; // Average end-to-end latency (ms)
  jitter: number; // Network jitter (ms)
  throughput: number; // Current throughput (bytes/s)
  efficiency: number; // Buffer efficiency score (0-1)
}

export interface SyncPoint {
  timestamp: number; // Presentation timestamp
  streamId: string; // Associated stream ID
  chunkId: string; // Chunk identifier
  priority: number; // Sync priority (0-10)
  tolerance: number; // Acceptable deviation (ms)
  dependencies: string[]; // Dependent chunks/streams
}

export interface BufferPool {
  id: string;
  type: "audio" | "video" | "data";
  capacity: number; // Maximum buffer size (bytes)
  chunks: MultiModalChunk[];
  watermarks: {
    low: number; // Low watermark (bytes)
    high: number; // High watermark (bytes)
    critical: number; // Critical level (bytes)
  };
  strategy: BufferingStrategy;
  metrics: BufferMetrics;
}

export interface ClockReference {
  id: string;
  type: "local" | "network" | "master";
  frequency: number; // Clock frequency (Hz)
  drift: number; // Clock drift (ppm)
  offset: number; // Offset from reference (ms)
  accuracy: number; // Clock accuracy (ms)
  lastSync: number; // Last synchronization time
}

export class BufferSyncManager extends EventEmitter {
  private logger: Logger;
  private bufferPools = new Map<string, BufferPool>();
  private syncPoints = new Map<number, SyncPoint[]>();
  private clockReferences = new Map<string, ClockReference>();
  private masterClock: ClockReference;
  private syncConfig: SynchronizationConfig;
  private adaptiveAlgorithm: AdaptiveBufferingAlgorithm;
  private jitterBuffer: JitterBuffer;
  private performanceMonitor: BufferPerformanceMonitor;

  constructor(syncConfig: SynchronizationConfig) {
    super();
    this.logger = new Logger("BufferSyncManager");
    this.syncConfig = syncConfig;
    this.adaptiveAlgorithm = new AdaptiveBufferingAlgorithm();
    this.jitterBuffer = new JitterBuffer();
    this.performanceMonitor = new BufferPerformanceMonitor();

    this.initializeMasterClock();
    this.startSynchronizationLoop();
  }

  /**
   * Create a new buffer pool for a stream
   */
  createBufferPool(
    streamId: string,
    type: "audio" | "video" | "data",
    strategy: BufferingStrategy,
  ): BufferPool {
    const pool: BufferPool = {
      id: streamId,
      type,
      capacity: this.calculateOptimalCapacity(type, strategy),
      chunks: [],
      watermarks: this.calculateWatermarks(type, strategy),
      strategy,
      metrics: {
        currentLevel: 0,
        targetLevel: strategy.type === "adaptive" ? 0.5 : 0.3,
        underrunCount: 0,
        overrunCount: 0,
        averageLatency: 0,
        jitter: 0,
        throughput: 0,
        efficiency: 1.0,
      },
    };

    this.bufferPools.set(streamId, pool);
    this.logger.info("Buffer pool created", {
      streamId,
      type,
      capacity: pool.capacity,
      strategy: strategy.type,
    });

    return pool;
  }

  /**
   * Add chunk to buffer with intelligent positioning
   */
  async addChunk(streamId: string, chunk: MultiModalChunk): Promise<boolean> {
    const pool = this.bufferPools.get(streamId);
    if (!pool) {
      this.logger.warn("Buffer pool not found", { streamId });
      return false;
    }

    // Check if buffer has capacity
    if (!this.hasCapacity(pool, chunk)) {
      const evicted = await this.evictChunks(pool, chunk.metadata.size);
      if (!evicted) {
        this.logger.warn("Buffer overflow, chunk dropped", {
          streamId,
          chunkId: chunk.id,
        });
        pool.metrics.overrunCount++;
        return false;
      }
    }

    // Insert chunk in correct temporal position
    const insertIndex = this.findInsertPosition(pool, chunk);
    pool.chunks.splice(insertIndex, 0, chunk);

    // Update buffer metrics
    this.updateBufferMetrics(pool);

    // Check for synchronization requirements
    if (chunk.sync) {
      this.addSyncPoint({
        timestamp: chunk.sync.presentationTimestamp,
        streamId,
        chunkId: chunk.id,
        priority: chunk.metadata.priority === "critical" ? 10 : 5,
        tolerance: this.syncConfig.tolerance,
        dependencies: chunk.sync.dependencies,
      });
    }

    // Trigger adaptive algorithm update
    this.adaptiveAlgorithm.onChunkAdded(pool, chunk);

    this.emit("chunk_buffered", {
      streamId,
      chunk,
      bufferLevel: pool.metrics.currentLevel,
    });
    return true;
  }

  /**
   * Retrieve next chunk for playback
   */
  getNextChunk(streamId: string, currentTime: number): MultiModalChunk | null {
    const pool = this.bufferPools.get(streamId);
    if (!pool || pool.chunks.length === 0) {
      return null;
    }

    // Find the chunk that should be played at current time
    const tolerance = this.syncConfig.tolerance;
    const chunkIndex = pool.chunks.findIndex((chunk) => {
      const playTime = chunk.sync?.presentationTimestamp || chunk.timestamp;
      return Math.abs(playTime - currentTime) <= tolerance;
    });

    if (chunkIndex === -1) {
      // No chunk ready for playback
      this.checkForUnderrun(pool, currentTime);
      return null;
    }

    // Remove and return the chunk
    const chunk = pool.chunks.splice(chunkIndex, 1)[0];
    this.updateBufferMetrics(pool);

    this.emit("chunk_consumed", {
      streamId,
      chunk,
      bufferLevel: pool.metrics.currentLevel,
    });
    return chunk;
  }

  /**
   * Synchronize multiple streams to a common timeline
   */
  async synchronizeStreams(
    streamIds: string[],
    referenceTime: number,
  ): Promise<boolean> {
    try {
      const pools = streamIds
        .map((id) => this.bufferPools.get(id))
        .filter(Boolean) as BufferPool[];

      if (pools.length === 0) {
        return false;
      }

      // Calculate synchronization adjustments
      const adjustments = this.calculateSyncAdjustments(pools, referenceTime);

      // Apply adjustments to each stream
      for (const [streamId, adjustment] of adjustments) {
        await this.applySyncAdjustment(streamId, adjustment);
      }

      // Verify synchronization accuracy
      const syncAccuracy = this.verifySynchronization(pools, referenceTime);

      this.emit("streams_synchronized", {
        streamIds,
        referenceTime,
        accuracy: syncAccuracy,
        adjustments: Object.fromEntries(adjustments),
      });

      return syncAccuracy <= this.syncConfig.tolerance;
    } catch (error) {
      this.logger.error("Stream synchronization failed", {
        streamIds,
        error: (error as Error).message,
      });
      return false;
    }
  }

  /**
   * Adapt buffering strategy based on network conditions
   */
  adaptToConditions(streamId: string, conditions: NetworkConditions): void {
    const pool = this.bufferPools.get(streamId);
    if (!pool) return;

    const newStrategy = this.adaptiveAlgorithm.calculateOptimalStrategy(
      pool.strategy,
      conditions,
      pool.metrics,
    );

    if (this.shouldUpdateStrategy(pool.strategy, newStrategy)) {
      this.updateBufferingStrategy(pool, newStrategy);

      this.emit("strategy_adapted", {
        streamId,
        oldStrategy: pool.strategy,
        newStrategy,
        conditions,
      });
    }
  }

  /**
   * Get comprehensive buffer statistics
   */
  getBufferStatistics(streamId?: string): Map<string, BufferMetrics> {
    const stats = new Map<string, BufferMetrics>();

    if (streamId) {
      const pool = this.bufferPools.get(streamId);
      if (pool) {
        stats.set(streamId, { ...pool.metrics });
      }
    } else {
      for (const [id, pool] of this.bufferPools) {
        stats.set(id, { ...pool.metrics });
      }
    }

    return stats;
  }

  /**
   * Predict optimal buffer size based on conditions
   */
  predictOptimalBufferSize(
    type: "audio" | "video" | "data",
    conditions: NetworkConditions,
    qualityLevel: string,
  ): number {
    return this.adaptiveAlgorithm.predictOptimalSize(
      type,
      conditions,
      qualityLevel,
    );
  }

  /**
   * Flush buffer pool
   */
  flushBuffer(streamId: string): number {
    const pool = this.bufferPools.get(streamId);
    if (!pool) return 0;

    const flushedCount = pool.chunks.length;
    pool.chunks = [];
    this.updateBufferMetrics(pool);

    this.emit("buffer_flushed", { streamId, flushedCount });
    return flushedCount;
  }

  /**
   * Calculate optimal buffer capacity based on stream type and strategy
   */
  private calculateOptimalCapacity(
    type: "audio" | "video" | "data",
    strategy: BufferingStrategy,
  ): number {
    const baseCapacities = {
      audio: 1024 * 1024, // 1 MB for audio
      video: 10 * 1024 * 1024, // 10 MB for video
      data: 512 * 1024, // 512 KB for data
    };

    let capacity = baseCapacities[type];

    // Adjust based on strategy
    switch (strategy.type) {
      case "adaptive":
        capacity *= 1.5; // More space for adaptation
        break;
      case "predictive":
        capacity *= 2.0; // More space for prediction
        break;
      case "fixed":
        capacity *= 1.0; // Standard size
        break;
    }

    // Adjust based on target latency
    if (strategy.targetLatency < 100) {
      capacity *= 0.5; // Smaller buffer for low latency
    } else if (strategy.targetLatency > 500) {
      capacity *= 2.0; // Larger buffer for high latency tolerance
    }

    return Math.floor(capacity);
  }

  /**
   * Calculate buffer watermarks
   */
  private calculateWatermarks(
    type: "audio" | "video" | "data",
    strategy: BufferingStrategy,
  ): any {
    const capacity = this.calculateOptimalCapacity(type, strategy);

    return {
      low: Math.floor(capacity * 0.2), // 20% for low watermark
      high: Math.floor(capacity * 0.8), // 80% for high watermark
      critical: Math.floor(capacity * 0.95), // 95% for critical level
    };
  }

  /**
   * Check if buffer has capacity for new chunk
   */
  private hasCapacity(pool: BufferPool, chunk: MultiModalChunk): boolean {
    const currentSize = pool.chunks.reduce(
      (sum, c) => sum + c.metadata.size,
      0,
    );
    return currentSize + chunk.metadata.size <= pool.capacity;
  }

  /**
   * Evict chunks to make space
   */
  private async evictChunks(
    pool: BufferPool,
    neededSpace: number,
  ): Promise<boolean> {
    let freedSpace = 0;
    const toEvict: MultiModalChunk[] = [];

    // Use LRU strategy for eviction
    const sortedChunks = [...pool.chunks].sort(
      (a, b) => a.timestamp - b.timestamp,
    );

    for (const chunk of sortedChunks) {
      if (freedSpace >= neededSpace) break;

      // Don't evict high-priority chunks
      if (chunk.metadata.priority === "critical") continue;

      toEvict.push(chunk);
      freedSpace += chunk.metadata.size;
    }

    // Remove evicted chunks
    for (const chunk of toEvict) {
      const index = pool.chunks.indexOf(chunk);
      if (index !== -1) {
        pool.chunks.splice(index, 1);
      }
    }

    this.emit("chunks_evicted", {
      poolId: pool.id,
      evictedCount: toEvict.length,
      freedSpace,
    });

    return freedSpace >= neededSpace;
  }

  /**
   * Find correct insertion position for chunk
   */
  private findInsertPosition(pool: BufferPool, chunk: MultiModalChunk): number {
    const timestamp = chunk.sync?.presentationTimestamp || chunk.timestamp;

    for (let i = 0; i < pool.chunks.length; i++) {
      const existingTimestamp =
        pool.chunks[i].sync?.presentationTimestamp || pool.chunks[i].timestamp;
      if (timestamp < existingTimestamp) {
        return i;
      }
    }

    return pool.chunks.length;
  }

  /**
   * Update buffer metrics
   */
  private updateBufferMetrics(pool: BufferPool): void {
    const currentSize = pool.chunks.reduce(
      (sum, c) => sum + c.metadata.size,
      0,
    );
    pool.metrics.currentLevel = currentSize / pool.capacity;

    // Update other metrics based on recent performance
    this.performanceMonitor.updateMetrics(pool);
  }

  /**
   * Add synchronization point
   */
  private addSyncPoint(syncPoint: SyncPoint): void {
    const bucket = Math.floor(syncPoint.timestamp / 1000) * 1000; // 1-second buckets

    if (!this.syncPoints.has(bucket)) {
      this.syncPoints.set(bucket, []);
    }

    this.syncPoints.get(bucket)!.push(syncPoint);
  }

  /**
   * Check for buffer underrun
   */
  private checkForUnderrun(pool: BufferPool, currentTime: number): void {
    if (pool.metrics.currentLevel < pool.watermarks.low / pool.capacity) {
      pool.metrics.underrunCount++;

      this.emit("buffer_underrun", {
        poolId: pool.id,
        currentLevel: pool.metrics.currentLevel,
        currentTime,
        underrunCount: pool.metrics.underrunCount,
      });
    }
  }

  /**
   * Calculate synchronization adjustments
   */
  private calculateSyncAdjustments(
    pools: BufferPool[],
    referenceTime: number,
  ): Map<string, number> {
    const adjustments = new Map<string, number>();

    for (const pool of pools) {
      if (pool.chunks.length === 0) continue;

      const nextChunk = pool.chunks[0];
      const chunkTime =
        nextChunk.sync?.presentationTimestamp || nextChunk.timestamp;
      const adjustment = referenceTime - chunkTime;

      adjustments.set(pool.id, adjustment);
    }

    return adjustments;
  }

  /**
   * Apply synchronization adjustment to stream
   */
  private async applySyncAdjustment(
    streamId: string,
    adjustment: number,
  ): Promise<void> {
    const pool = this.bufferPools.get(streamId);
    if (!pool) return;

    // Adjust timestamps of all chunks in buffer
    for (const chunk of pool.chunks) {
      if (chunk.sync?.presentationTimestamp) {
        chunk.sync.presentationTimestamp += adjustment;
      } else {
        chunk.timestamp += adjustment;
      }
    }
  }

  /**
   * Verify synchronization accuracy
   */
  private verifySynchronization(
    pools: BufferPool[],
    referenceTime: number,
  ): number {
    let maxDeviation = 0;

    for (const pool of pools) {
      if (pool.chunks.length === 0) continue;

      const nextChunk = pool.chunks[0];
      const chunkTime =
        nextChunk.sync?.presentationTimestamp || nextChunk.timestamp;
      const deviation = Math.abs(chunkTime - referenceTime);

      maxDeviation = Math.max(maxDeviation, deviation);
    }

    return maxDeviation;
  }

  /**
   * Check if buffering strategy should be updated
   */
  private shouldUpdateStrategy(
    current: BufferingStrategy,
    proposed: BufferingStrategy,
  ): boolean {
    // Only update if the change is significant
    const bufferSizeDiff =
      Math.abs(proposed.bufferSize - current.bufferSize) / current.bufferSize;
    const latencyDiff =
      Math.abs(proposed.targetLatency - current.targetLatency) /
      current.targetLatency;

    return bufferSizeDiff > 0.1 || latencyDiff > 0.1; // 10% threshold
  }

  /**
   * Update buffering strategy for pool
   */
  private updateBufferingStrategy(
    pool: BufferPool,
    newStrategy: BufferingStrategy,
  ): void {
    pool.strategy = newStrategy;
    pool.watermarks = this.calculateWatermarks(pool.type, newStrategy);

    // Adjust buffer capacity if needed
    const newCapacity = this.calculateOptimalCapacity(pool.type, newStrategy);
    if (newCapacity !== pool.capacity) {
      pool.capacity = newCapacity;

      // Evict chunks if new capacity is smaller
      if (newCapacity < pool.capacity) {
        const currentSize = pool.chunks.reduce(
          (sum, c) => sum + c.metadata.size,
          0,
        );
        if (currentSize > newCapacity) {
          this.evictChunks(pool, currentSize - newCapacity);
        }
      }
    }
  }

  /**
   * Initialize master clock reference
   */
  private initializeMasterClock(): void {
    this.masterClock = {
      id: "master",
      type: "local",
      frequency: 1000, // 1 kHz
      drift: 0,
      offset: 0,
      accuracy: 1, // 1ms accuracy
      lastSync: Date.now(),
    };

    this.clockReferences.set("master", this.masterClock);
  }

  /**
   * Start synchronization loop
   */
  private startSynchronizationLoop(): void {
    setInterval(() => {
      this.performSynchronizationCycle();
    }, 100); // 100ms sync cycle
  }

  /**
   * Perform synchronization cycle
   */
  private performSynchronizationCycle(): void {
    const currentTime = Date.now();

    // Update clock references
    for (const [, clock] of this.clockReferences) {
      if (clock.type === "network") {
        this.updateNetworkClock(clock, currentTime);
      }
    }

    // Process synchronization points
    this.processSyncPoints(currentTime);
  }

  /**
   * Update network clock
   */
  private updateNetworkClock(clock: ClockReference, currentTime: number): void {
    // Network clock synchronization logic would go here
    clock.lastSync = currentTime;
  }

  /**
   * Process synchronization points
   */
  private processSyncPoints(currentTime: number): void {
    const bucket = Math.floor(currentTime / 1000) * 1000;
    const syncPoints = this.syncPoints.get(bucket);

    if (syncPoints) {
      // Process sync points for current time bucket
      for (const syncPoint of syncPoints) {
        this.processSyncPoint(syncPoint, currentTime);
      }

      // Clean up processed sync points
      this.syncPoints.delete(bucket);
    }
  }

  /**
   * Process individual sync point
   */
  private processSyncPoint(syncPoint: SyncPoint, currentTime: number): void {
    const deviation = Math.abs(syncPoint.timestamp - currentTime);

    if (deviation > syncPoint.tolerance) {
      this.emit("sync_deviation_detected", {
        syncPoint,
        deviation,
        currentTime,
      });
    }
  }

  /**
   * Clean up resources
   */
  cleanup(): void {
    this.bufferPools.clear();
    this.syncPoints.clear();
    this.clockReferences.clear();
    this.removeAllListeners();

    this.logger.info("Buffer sync manager cleaned up");
  }
}

/**
 * Adaptive buffering algorithm implementation
 */
class AdaptiveBufferingAlgorithm {
  private history: Map<string, any[]> = new Map();

  calculateOptimalStrategy(
    current: BufferingStrategy,
    conditions: NetworkConditions,
    metrics: BufferMetrics,
  ): BufferingStrategy {
    // Analyze current performance
    const performanceScore = this.calculatePerformanceScore(metrics);

    // Adjust strategy based on conditions
    const newStrategy = { ...current };

    if (conditions.quality.packetLoss > 0.05) {
      // High packet loss - increase buffer size
      newStrategy.bufferSize = Math.min(
        current.bufferSize * 1.5,
        current.bufferSize * 3,
      );
    }

    if (conditions.latency.rtt > 200) {
      // High latency - adjust target latency
      newStrategy.targetLatency = Math.max(current.targetLatency * 1.2, 500);
    }

    if (metrics.underrunCount > 5) {
      // Frequent underruns - increase buffer size
      newStrategy.bufferSize = Math.min(
        current.bufferSize * 1.3,
        current.bufferSize * 2,
      );
    }

    return newStrategy;
  }

  onChunkAdded(pool: BufferPool, chunk: MultiModalChunk): void {
    // Record chunk addition for learning
    const history = this.history.get(pool.id) || [];
    history.push({
      timestamp: Date.now(),
      chunkSize: chunk.metadata.size,
      bufferLevel: pool.metrics.currentLevel,
      priority: chunk.metadata.priority,
    });

    // Keep only recent history
    if (history.length > 100) {
      history.splice(0, history.length - 100);
    }

    this.history.set(pool.id, history);
  }

  predictOptimalSize(
    type: "audio" | "video" | "data",
    conditions: NetworkConditions,
    qualityLevel: string,
  ): number {
    // Predictive algorithm implementation
    const baseSize = type === "video" ? 10 * 1024 * 1024 : 1024 * 1024;

    // Adjust based on conditions
    let multiplier = 1.0;

    if (conditions.bandwidth.available < 1000000) {
      // < 1 Mbps
      multiplier *= 0.5;
    } else if (conditions.bandwidth.available > 10000000) {
      // > 10 Mbps
      multiplier *= 1.5;
    }

    if (qualityLevel === "high" || qualityLevel === "ultra") {
      multiplier *= 1.5;
    } else if (qualityLevel === "low") {
      multiplier *= 0.7;
    }

    return Math.floor(baseSize * multiplier);
  }

  private calculatePerformanceScore(metrics: BufferMetrics): number {
    // Calculate performance score based on multiple factors
    let score = 1.0;

    // Penalize underruns and overruns
    score -= (metrics.underrunCount + metrics.overrunCount) * 0.1;

    // Reward efficiency
    score *= metrics.efficiency;

    // Penalize high jitter
    if (metrics.jitter > 50) {
      score *= 0.8;
    }

    return Math.max(0, Math.min(1, score));
  }
}

/**
 * Jitter buffer implementation
 */
class JitterBuffer {
  private buffers = new Map<string, any[]>();

  addPacket(streamId: string, packet: any): void {
    // Jitter buffer implementation
  }

  getPacket(streamId: string): any {
    // Retrieve packet from jitter buffer
    return null;
  }
}

/**
 * Buffer performance monitor
 */
class BufferPerformanceMonitor {
  updateMetrics(pool: BufferPool): void {
    // Update performance metrics based on buffer state
    const chunks = pool.chunks;

    if (chunks.length > 0) {
      // Calculate average latency
      const latencies = chunks
        .filter((c) => c.metadata.synchronized)
        .map((c) => Date.now() - c.timestamp);

      if (latencies.length > 0) {
        pool.metrics.averageLatency =
          latencies.reduce((sum, l) => sum + l, 0) / latencies.length;
      }

      // Calculate throughput
      const recentChunks = chunks.filter(
        (c) => Date.now() - c.timestamp < 5000,
      ); // Last 5 seconds
      const totalBytes = recentChunks.reduce(
        (sum, c) => sum + c.metadata.size,
        0,
      );
      pool.metrics.throughput = totalBytes / 5; // Bytes per second
    }

    // Calculate efficiency
    pool.metrics.efficiency = this.calculateEfficiency(pool);
  }

  private calculateEfficiency(pool: BufferPool): number {
    // Buffer efficiency calculation
    const idealLevel = pool.metrics.targetLevel;
    const actualLevel = pool.metrics.currentLevel;
    const deviation = Math.abs(idealLevel - actualLevel);

    return Math.max(0, 1 - deviation);
  }
}