import cron from 'node-cron';
import { config } from './config/config.js';
import dbManager from './db/databaseManager.js';
import dbInitializer from './db/initializer.js';
import partitionManager from './db/partitionManager.js';
import { createKafkaConsumers } from './kafka/consumer.js';
import { parseMessageToRows } from './processor/index.js';
import { createRedisClient } from './redis/redisClient.js';
import { RedisIntegration } from './redis/redisIntegration.js';
import { buildErrorQueueKey, enqueueError, startErrorRetryWorker } from './redis/errorQueue.js';
import { MetricCollector } from './utils/metricCollector.js';
import { logger } from './utils/logger.js';

const bootstrap = async () => {
  // Log startup config (masked)
  logger.info('Starting application with config', {
    env: process.env.NODE_ENV,
    db: {
      host: config.db.host,
      port: config.db.port,
      user: config.db.user,
      database: config.db.database,
      schema: config.db.schema
    },
    kafka: {
      brokers: config.kafka.brokers,
      topic: config.kafka.topic,
      groupId: config.kafka.groupId
    },
    redis: {
      host: config.redis.host,
      port: config.redis.port
    }
  });

  // 0. Initialize Database (Create DB, Schema, Table, Partitions)
  await dbInitializer.initialize();

  // Metric Collector
  const metricCollector = new MetricCollector();

  // 1. Setup Partition Maintenance Cron Job (Every day at 00:00)
  cron.schedule('0 0 * * *', async () => {
    logger.info('Running scheduled partition maintenance...');
    try {
      await partitionManager.ensurePartitions(30);
    } catch (err) {
      logger.error('Scheduled partition maintenance failed', err);
    }
  });

  // 1.1 Setup Metric Reporting Cron Job (Every minute)
  // Moved after redisIntegration initialization


  // DatabaseManager is now a singleton exported instance, but let's keep consistency if possible
  // In databaseManager.js it exports `dbManager` instance by default.
  // The original code was `const dbManager = new DatabaseManager(config.db);` which implies it might have been a class export.
  // Let's check `databaseManager.js` content. 
  // Wait, I imported `dbManager` from `./db/databaseManager.js`.
  // If `databaseManager.js` exports an instance as default, I should use that.
  // If it exports a class, I should instantiate it.
  
  // Let's assume the previous code `new DatabaseManager` was correct if it was a class.
  // BUT I used `dbManager.pool` in `partitionManager.js` assuming it's an instance.
  // I need to verify `databaseManager.js`.

  const redisClient = await createRedisClient(config.redis);
  const redisIntegration = new RedisIntegration(
    redisClient,
    config.redis.projectName,
    config.redis.apiBaseUrl
  );
  redisIntegration.startHeartbeat();

  // 1.1 Setup Metric Reporting Cron Job (Every minute)
  cron.schedule('* * * * *', async () => {
    const metrics = metricCollector.getAndReset();
    const flushAvgMs = metrics.batch_flush_count > 0 ? (metrics.batch_flush_ms_sum / metrics.batch_flush_count).toFixed(1) : '0.0';
    const dbAvgMs = metrics.db_insert_count > 0 ? (metrics.db_insert_ms_sum / metrics.db_insert_count).toFixed(1) : '0.0';
    const report = `[Minute Metrics] Pulled: ${metrics.kafka_pulled}, Parse Error: ${metrics.parse_error}, Inserted: ${metrics.db_inserted}, Failed: ${metrics.db_failed}, FlushAvgMs: ${flushAvgMs}, DbAvgMs: ${dbAvgMs}, PulledByPartition: ${JSON.stringify(metrics.keyed?.kafka_pulled_by_partition || {})}, InsertedByPartition: ${JSON.stringify(metrics.keyed?.db_inserted_by_partition || {})}, FailedByPartition: ${JSON.stringify(metrics.keyed?.db_failed_by_partition || {})}, InsertedByDay: ${JSON.stringify(metrics.keyed?.db_inserted_by_day || {})}, DbMsByDay: ${JSON.stringify(metrics.keyed?.db_insert_ms_sum_by_day || {})}`;
    console.log(report);
    logger.info(report, metrics);
    
    try {
      await redisIntegration.info('Minute Metrics', metrics);
    } catch (err) {
      logger.error('Failed to report metrics to Redis', { error: err?.message });
    }
  });

  const errorQueueKey = buildErrorQueueKey(config.redis.projectName);

  const handleError = async (error, message) => {
    logger.error('Kafka processing error', {
      error: error?.message,
      type: error?.type,
      stack: error?.stack
    });
    try {
      await redisIntegration.error('Kafka processing error', {
        module: 'kafka',
        stack: error?.stack || error?.message
      });
    } catch (redisError) {
      logger.error('Redis error log failed', { error: redisError?.message });
    }
    if (message) {
      const messageValue = Buffer.isBuffer(message.value)
        ? message.value.toString('utf8')
        : message.value;
      try {
        await enqueueError(redisClient, errorQueueKey, {
          attempts: 0,
          value: messageValue,
          meta: {
            topic: message.topic,
            partition: message.partition,
            offset: message.offset,
            key: message.key
          },
          timestamp: Date.now()
        });
      } catch (enqueueError) {
        logger.error('Enqueue error payload failed', { error: enqueueError?.message });
      }
    }
  };

  const configuredBatchSize = Number.isFinite(config.kafka.batchSize) ? config.kafka.batchSize : 1000;
  const configuredBatchTimeoutMs = Number.isFinite(config.kafka.batchTimeoutMs) ? config.kafka.batchTimeoutMs : 20;
  const configuredMaxInFlight = Number.isFinite(config.kafka.maxInFlight) ? config.kafka.maxInFlight : 5000;

  const BATCH_SIZE = Math.max(10, Math.min(configuredBatchSize, configuredMaxInFlight));
  const BATCH_TIMEOUT_MS = Math.max(1, configuredBatchTimeoutMs);
  const commitOnAttempt = config.kafka.commitOnAttempt === true;
  
  const batchStates = new Map();

  const partitionKeyFromMessage = (message) => {
    if (message?.topic !== undefined && message?.partition !== undefined) {
      return `${message.topic}-${message.partition}`;
    }
    return 'retry';
  };

  const dayKeyFromTsMs = (tsMs) => {
    const numeric = typeof tsMs === 'string' ? Number(tsMs) : tsMs;
    if (!Number.isFinite(numeric)) return null;
    const d = new Date(numeric);
    if (Number.isNaN(d.getTime())) return null;
    const yyyy = d.getFullYear();
    const mm = String(d.getMonth() + 1).padStart(2, '0');
    const dd = String(d.getDate()).padStart(2, '0');
    return `${yyyy}${mm}${dd}`;
  };

  const getBatchState = (key) => {
    if (!batchStates.has(key)) {
      batchStates.set(key, { items: [], timer: null, flushing: null });
    }
    return batchStates.get(key);
  };

  const isDbConnectionError = (err) => {
    const code = err?.code;
    if (typeof code === 'string') {
      const networkCodes = new Set([
        'ECONNREFUSED',
        'ECONNRESET',
        'EPIPE',
        'ETIMEDOUT',
        'ENOTFOUND',
        'EHOSTUNREACH',
        'ENETUNREACH',
        '57P03',
        '08006',
        '08001',
        '08000',
        '08003'
      ]);
      if (networkCodes.has(code)) return true;
    }

    const message = typeof err?.message === 'string' ? err.message : '';
    if (!message) return false;
    const lower = message.toLowerCase();
    return (
      lower.includes('connection timeout') ||
      lower.includes('connection terminated') ||
      lower.includes('connection refused') ||
      lower.includes('terminating connection') ||
      lower.includes('econnrefused') ||
      lower.includes('econnreset') ||
      lower.includes('etimedout') ||
      lower.includes('could not connect') ||
      lower.includes('the database system is starting up') ||
      lower.includes('no pg_hba.conf entry')
    );
  };

  const isMissingPartitionError = (err) =>
    err?.code === '23514' ||
    (typeof err?.message === 'string' && err.message.includes('no partition of relation'));

  const insertRowsWithRetry = async (rows) => {
    const startedAt = Date.now();
    let attemptedPartitionFix = false;
    while (true) {
      try {
        await dbManager.insertRows({ schema: config.db.schema, table: config.db.table, rows });
        metricCollector.increment('db_insert_count', 1);
        metricCollector.increment('db_insert_ms_sum', Date.now() - startedAt);
        return;
      } catch (err) {
        if (isDbConnectionError(err)) {
          logger.error('Database offline during batch insert. Retrying in 5s...', { error: err.message });
          await new Promise(r => setTimeout(r, 5000));
          while (!(await dbManager.checkConnection())) {
            logger.warn('Database still offline. Waiting 5s...');
            await new Promise(r => setTimeout(r, 5000));
          }
          continue;
        }
        if (isMissingPartitionError(err) && !attemptedPartitionFix) {
          attemptedPartitionFix = true;
          try {
            await partitionManager.ensurePartitionsForTimestamps(rows.map(r => r.ts_ms));
          } catch (partitionErr) {
            if (isDbConnectionError(partitionErr)) {
              logger.error('Database offline during partition ensure. Retrying in 5s...', { error: partitionErr.message });
              await new Promise(r => setTimeout(r, 5000));
              while (!(await dbManager.checkConnection())) {
                logger.warn('Database still offline. Waiting 5s...');
                await new Promise(r => setTimeout(r, 5000));
              }
              continue;
            }
            throw partitionErr;
          }
          continue;
        }
        throw err;
      }
    }
  };

  const insertRowsOnce = async (rows) => {
    const startedAt = Date.now();
    await dbManager.insertRows({ schema: config.db.schema, table: config.db.table, rows });
    metricCollector.increment('db_insert_count', 1);
    metricCollector.increment('db_insert_ms_sum', Date.now() - startedAt);
  };

  const resolveInsertedItems = (partitionKey, items) => {
    let insertedRows = 0;
    for (const p of items) {
      insertedRows += p.rows.length;
      const dayKey = dayKeyFromTsMs(p.rows?.[0]?.ts_ms);
      if (dayKey) {
        metricCollector.incrementKeyed('db_inserted_by_day', dayKey, p.rows.length);
      }
      p.item.resolve();
    }
    metricCollector.increment('db_inserted', insertedRows);
    metricCollector.incrementKeyed('db_inserted_by_partition', partitionKey, insertedRows);
  };

  const handleFailedItem = async (partitionKey, p, err) => {
    metricCollector.increment('db_failed');
    metricCollector.incrementKeyed('db_failed_by_partition', partitionKey, 1);
    const dayKey = dayKeyFromTsMs(p.rows?.[0]?.ts_ms);
    if (dayKey) {
      metricCollector.incrementKeyed('db_failed_by_day', dayKey, 1);
    }
    await handleError(err, p.item.message);
    p.item.resolve();
  };

  const insertItemsDegraded = async (partitionKey, items) => {
    if (items.length === 0) return;
    const rows = items.flatMap(p => p.rows);
    if (commitOnAttempt) {
      try {
        await insertRowsOnce(rows);
        resolveInsertedItems(partitionKey, items);
      } catch (err) {
        for (const item of items) {
          await handleFailedItem(partitionKey, item, err);
        }
      }
      return;
    }
    try {
      await insertRowsWithRetry(rows);
      resolveInsertedItems(partitionKey, items);
      return;
    } catch (err) {
      if (items.length === 1) {
        try {
          await insertRowsWithRetry(items[0].rows);
          resolveInsertedItems(partitionKey, items);
        } catch (innerErr) {
          await handleFailedItem(partitionKey, items[0], innerErr);
        }
        return;
      }
      const mid = Math.floor(items.length / 2);
      await insertItemsDegraded(partitionKey, items.slice(0, mid));
      await insertItemsDegraded(partitionKey, items.slice(mid));
    }
  };

  const flushBatchForKey = async (partitionKey) => {
    const state = getBatchState(partitionKey);
    if (state.flushing) return state.flushing;

    state.flushing = (async () => {
      if (state.timer) {
        clearTimeout(state.timer);
        state.timer = null;
      }

      if (state.items.length === 0) return;

      const startedAt = Date.now();
      const currentBatch = state.items;
      state.items = [];

      const pendingDbItems = [];
      const unresolvedItems = [];

      try {
        for (const item of currentBatch) {
          try {
            const rows = parseMessageToRows(item.message);
            pendingDbItems.push({ item, rows });
            unresolvedItems.push(item);
          } catch (err) {
            metricCollector.increment('parse_error');
            metricCollector.incrementKeyed('parse_error_by_partition', partitionKey, 1);
            logger.error('Message processing failed (Parse/Validation)', { error: err.message });
            await handleError(err, item.message);
            item.resolve();
          }
        }

        if (pendingDbItems.length > 0) {
          const firstTs = pendingDbItems[0]?.rows?.[0]?.ts_ms;
          const dayKey = dayKeyFromTsMs(firstTs);
          if (dayKey) {
            const dayStartMs = Date.now();
            await insertItemsDegraded(partitionKey, pendingDbItems);
            metricCollector.incrementKeyed('db_insert_ms_sum_by_day', dayKey, Date.now() - dayStartMs);
          } else {
            await insertItemsDegraded(partitionKey, pendingDbItems);
          }
        }

        metricCollector.increment('batch_flush_count', 1);
        metricCollector.increment('batch_flush_ms_sum', Date.now() - startedAt);
      } catch (err) {
        if (!commitOnAttempt && isDbConnectionError(err)) {
          state.items = unresolvedItems.concat(state.items);
          if (!state.timer) {
            state.timer = setTimeout(() => {
              state.timer = null;
              flushBatchForKey(partitionKey);
            }, 5000);
          }
          return;
        }

        logger.error('Batch flush failed (non-network). Marking as consumed', {
          error: err?.message,
          partitionKey,
          batchSize: currentBatch.length
        });

        for (const item of unresolvedItems) {
          try {
            await handleError(err, item.message);
          } catch {}
          item.resolve();
        }
      }
    })().finally(() => {
      state.flushing = null;
      if (state.items.length > 0) {
        if (state.items.length >= BATCH_SIZE) {
          flushBatchForKey(partitionKey);
        } else if (!state.timer) {
          state.timer = setTimeout(() => {
            state.timer = null;
            flushBatchForKey(partitionKey);
          }, BATCH_TIMEOUT_MS);
        }
      }
    });

    return state.flushing;
  };

  const handleMessage = (message) => {
    if (message.topic) {
      metricCollector.increment('kafka_pulled');
      metricCollector.incrementKeyed('kafka_pulled_by_partition', `${message.topic}-${message.partition}`, 1);
    }
    
    // const messageValue = Buffer.isBuffer(message.value)
    //   ? message.value.toString('utf8')
    //   : message.value;
    // const messageKey = Buffer.isBuffer(message.key)
    //   ? message.key.toString('utf8')
    //   : message.key;

    // const logDetails = {
    //   topic: message.topic,
    //   partition: message.partition,
    //   offset: message.offset,
    //   key: messageKey,
    //   value: config.kafka.logMessages ? messageValue : undefined,
    //   valueLength: !config.kafka.logMessages && typeof messageValue === 'string' ? messageValue.length : null
    // };
    
    // logger.info('Kafka message received', logDetails);

    const partitionKey = partitionKeyFromMessage(message);
    const state = getBatchState(partitionKey);

    return new Promise((resolve, reject) => {
      state.items.push({ message, resolve, reject });
      if (state.items.length >= BATCH_SIZE) {
        flushBatchForKey(partitionKey);
      } else if (!state.timer) {
        state.timer = setTimeout(() => {
          state.timer = null;
          flushBatchForKey(partitionKey);
        }, BATCH_TIMEOUT_MS);
      }
    });
  };

  const consumers = createKafkaConsumers({
    kafkaConfig: config.kafka,
    onMessage: handleMessage,
    onError: handleError
  });

  // Start retry worker (non-blocking)
  startErrorRetryWorker({
    client: redisClient,
    queueKey: errorQueueKey,
    redisIntegration,
    handler: async (item) => {
      if (!item?.value) {
        throw new Error('Missing value in retry payload');
      }
      await handleMessage({ value: item.value });
    }
  }).catch(err => {
    logger.error('Retry worker failed', { error: err?.message });
  });

  // Graceful Shutdown Logic
  const shutdown = async (signal) => {
    logger.info(`Received ${signal}, shutting down...`);
    
    try {
      // 1. Close Kafka Consumer
      if (consumers && consumers.length > 0) {
        await Promise.all(consumers.map(c => new Promise((resolve) => c.close(true, resolve))));
        logger.info('Kafka consumer closed', { count: consumers.length });
      }

      // 2. Stop Redis Heartbeat (if method exists, otherwise just close client)
      // redisIntegration.stopHeartbeat(); // Assuming implementation or just rely on client close

      // 3. Close Redis Client
      await redisClient.quit();
      logger.info('Redis client closed');

      // 4. Close Database Pool
      await dbManager.close();
      logger.info('Database connection closed');

      process.exit(0);
    } catch (err) {
      logger.error('Error during shutdown', { error: err?.message });
      process.exit(1);
    }
  };

  process.on('SIGTERM', () => shutdown('SIGTERM'));
  process.on('SIGINT', () => shutdown('SIGINT'));
};

bootstrap().catch((error) => {
  logger.error('Service bootstrap failed', { error: error?.message });
  process.exit(1);
});