import { getSafeJson } from '@openpanel/json';
import { getRedisCache } from '@openpanel/redis';
import { ch } from '../clickhouse/client';
import { BaseBuffer } from './base-buffer';

export interface IClickhouseLog {
  id?: string;
  project_id: string;
  device_id: string;
  profile_id: string;
  session_id: string;
  timestamp: string;
  observed_at: string;
  severity_number: number;
  severity_text: string;
  body: string;
  trace_id: string;
  span_id: string;
  trace_flags: number;
  logger_name: string;
  attributes: Record<string, string>;
  resource: Record<string, string>;
  sdk_name: string;
  sdk_version: string;
  country: string;
  city: string;
  region: string;
  os: string;
  os_version: string;
  browser: string;
  browser_version: string;
  device: string;
  brand: string;
  model: string;
}

export class LogBuffer extends BaseBuffer {
  private batchSize = process.env.LOG_BUFFER_BATCH_SIZE
    ? Number.parseInt(process.env.LOG_BUFFER_BATCH_SIZE, 10)
    : 4000;
  private chunkSize = process.env.LOG_BUFFER_CHUNK_SIZE
    ? Number.parseInt(process.env.LOG_BUFFER_CHUNK_SIZE, 10)
    : 1000;
  private microBatchIntervalMs = process.env.LOG_BUFFER_MICRO_BATCH_MS
    ? Number.parseInt(process.env.LOG_BUFFER_MICRO_BATCH_MS, 10)
    : 10;
  private microBatchMaxSize = process.env.LOG_BUFFER_MICRO_BATCH_SIZE
    ? Number.parseInt(process.env.LOG_BUFFER_MICRO_BATCH_SIZE, 10)
    : 100;

  private pendingLogs: IClickhouseLog[] = [];
  private flushTimer: ReturnType<typeof setTimeout> | null = null;
  private isFlushing = false;
  private flushRetryCount = 0;

  private queueKey = 'log_buffer:queue';
  protected bufferCounterKey = 'log_buffer:total_count';

  constructor() {
    super({
      name: 'log',
      onFlush: async () => {
        await this.processBuffer();
      },
    });
  }

  add(log: IClickhouseLog) {
    this.pendingLogs.push(log);

    if (this.pendingLogs.length >= this.microBatchMaxSize) {
      this.flushLocalBuffer();
      return;
    }

    if (!this.flushTimer) {
      this.flushTimer = setTimeout(() => {
        this.flushTimer = null;
        this.flushLocalBuffer();
      }, this.microBatchIntervalMs);
    }
  }

  public async flush() {
    if (this.flushTimer) {
      clearTimeout(this.flushTimer);
      this.flushTimer = null;
    }
    await this.flushLocalBuffer();
  }

  private async flushLocalBuffer() {
    if (this.isFlushing || this.pendingLogs.length === 0) {
      return;
    }

    this.isFlushing = true;
    const logsToFlush = this.pendingLogs;
    this.pendingLogs = [];

    try {
      // Push to Redis queue for processing
      const pipeline = getRedisCache().pipeline();
      for (const log of logsToFlush) {
        pipeline.lpush(this.queueKey, JSON.stringify(log));
      }
      await pipeline.exec();

      // Increment counter
      await getRedisCache().incrby(this.bufferCounterKey, logsToFlush.length);

      this.flushRetryCount = 0;
    } catch (error) {
      this.logger.error('Failed to push logs to Redis queue', { error });
      // Re-queue locally on failure
      this.pendingLogs = logsToFlush.concat(this.pendingLogs);
      this.flushRetryCount++;

      // If max retries exceeded, log and drop
      if (this.flushRetryCount >= 3) {
        this.logger.error('Max retries exceeded, dropping logs', {
          droppedCount: this.pendingLogs.length,
        });
        this.pendingLogs = [];
        this.flushRetryCount = 0;
      }
    } finally {
      this.isFlushing = false;
    }
  }

  private async processBuffer() {
    const startTime = Date.now();
    const redis = getRedisCache();

    try {
      // Get batch of logs from Redis
      const batch: string[] = [];
      const pipeline = redis.pipeline();

      for (let i = 0; i < this.batchSize; i++) {
        pipeline.rpop(this.queueKey);
      }

      const results = await pipeline.exec();
      if (!results) {
        return;
      }

      for (const result of results) {
        if (result[1]) {
          batch.push(result[1] as string);
        }
      }

      if (batch.length === 0) {
        return;
      }

      this.logger.info(`Processing ${batch.length} logs`);

      // Parse logs
      const logs: IClickhouseLog[] = [];
      for (const item of batch) {
        try {
          const parsed = getSafeJson<IClickhouseLog>(item);
          if (parsed) {
            logs.push(parsed);
          }
        } catch (error) {
          this.logger.error('Failed to parse log', { error, item });
        }
      }

      if (logs.length === 0) {
        return;
      }

      // Insert into ClickHouse in chunks
      const chunks = this.chunks(logs, this.chunkSize);
      for (const chunk of chunks) {
        await this.insertChunk(chunk);
      }

      // Decrement counter
      await redis.decrby(this.bufferCounterKey, batch.length);

      this.logger.info('Logs processed successfully', {
        count: logs.length,
        elapsed: Date.now() - startTime,
      });
    } catch (error) {
      this.logger.error('Failed to process logs', { error });
      throw error;
    }
  }

  private async insertChunk(logs: IClickhouseLog[]) {
    const query = `
      INSERT INTO logs (
        id, project_id, device_id, profile_id, session_id,
        timestamp, observed_at, severity_number, severity_text, body,
        trace_id, span_id, trace_flags, logger_name, attributes, resource,
        sdk_name, sdk_version, country, city, region,
        os, os_version, browser, browser_version, device, brand, model
      )
      VALUES
    `;

    const values = logs
      .map((log) => {
        return `(
          generateUUIDv4(),
          ${escape(log.project_id)},
          ${escape(log.device_id)},
          ${escape(log.profile_id)},
          ${escape(log.session_id)},
          ${escape(log.timestamp)},
          ${escape(log.observed_at)},
          ${log.severity_number},
          ${escape(log.severity_text)},
          ${escape(log.body)},
          ${escape(log.trace_id)},
          ${escape(log.span_id)},
          ${log.trace_flags},
          ${escape(log.logger_name)},
          ${mapToSql(log.attributes)},
          ${mapToSql(log.resource)},
          ${escape(log.sdk_name)},
          ${escape(log.sdk_version)},
          ${escape(log.country)},
          ${escape(log.city)},
          ${escape(log.region)},
          ${escape(log.os)},
          ${escape(log.os_version)},
          ${escape(log.browser)},
          ${escape(log.browser_version)},
          ${escape(log.device)},
          ${escape(log.brand)},
          ${escape(log.model)}
        )`;
      })
      .join(',');

    await ch.query({
      query: `${query} ${values}`,
      clickhouse_settings: {
        wait_end_of_query: 1,
      },
    });
  }
}

function escape(value: string): string {
  if (value === null || value === undefined) {
    return "''";
  }
  return `'${value.replace(/'/g, "\\'").replace(/\\/g, '\\\\')}'`;
}

function mapToSql(map: Record<string, string>): string {
  if (!map || Object.keys(map).length === 0) {
    return '{}';
  }
  const entries = Object.entries(map)
    .map(([k, v]) => `${escape(k)}: ${escape(v)}`)
    .join(', ');
  return `{${entries}}`;
}