/**
 * Hydration Worker
 *
 * Processes raw payloads and hydrates them to canonical tables.
 * Features:
 * - Distributed locking to prevent double-processing
 * - Batch processing for efficiency
 * - Automatic retry with backoff
 * - Dry-run mode for testing
 */

import { Pool } from 'pg';
import { v4 as uuidv4 } from 'uuid';
import {
  RawPayload,
  HydrationOptions,
  HydrationResult,
  HydrationBatchResult,
} from './types';
import { getNormalizer } from './normalizers';
import {
  getUnprocessedPayloads,
  markPayloadProcessed,
  markPayloadFailed,
} from './payload-store';
import { HydrationLockManager, LOCK_NAMES } from './locking';
import { hydrateToCanonical } from './canonical-upsert';

const DEFAULT_BATCH_SIZE = 50;
const DEFAULT_MAX_RETRIES = 3;
const DEFAULT_LOCK_TIMEOUT_MS = 10 * 60 * 1000; // 10 minutes

// ============================================================
// HYDRATION WORKER CLASS
// ============================================================

export class HydrationWorker {
  private pool: Pool;
  private lockManager: HydrationLockManager;
  private workerId: string;
  private options: HydrationOptions;
  private isRunning: boolean = false;

  constructor(pool: Pool, options: HydrationOptions = {}) {
    this.pool = pool;
    this.workerId = `hydration-${uuidv4().slice(0, 8)}`;
    this.lockManager = new HydrationLockManager(pool, this.workerId);
    this.options = {
      dryRun: false,
      batchSize: DEFAULT_BATCH_SIZE,
      maxRetries: DEFAULT_MAX_RETRIES,
      lockTimeoutMs: DEFAULT_LOCK_TIMEOUT_MS,
      ...options,
    };
  }

  /**
   * Process a single payload
   */
  async processPayload(payload: RawPayload): Promise<HydrationResult> {
    const startedAt = new Date();
    const errors: string[] = [];

    try {
      // Get normalizer for this platform
      const normalizer = getNormalizer(payload.platform);
      if (!normalizer) {
        throw new Error(`No normalizer found for platform: ${payload.platform}`);
      }

      // Validate payload
      const validation = normalizer.validatePayload(payload.raw_json);
      if (!validation.valid) {
        errors.push(...validation.errors);
        if (errors.length > 0 && !payload.raw_json) {
          throw new Error(`Invalid payload: ${errors.join(', ')}`);
        }
      }

      // Normalize
      const normResult = normalizer.normalize(payload);

      if (normResult.errors.length > 0) {
        errors.push(...normResult.errors.map((e) => `${e.field}: ${e.message}`));
      }

      if (normResult.products.length === 0) {
        console.warn(`[HydrationWorker] No products in payload ${payload.id}`);
      }

      // Hydrate to canonical tables
      const hydrateResult = await hydrateToCanonical(
        this.pool,
        payload.dispensary_id,
        normResult,
        payload.crawl_run_id,
        { dryRun: this.options.dryRun }
      );

      // Mark as processed
      if (!this.options.dryRun) {
        await markPayloadProcessed(this.pool, payload.id);
      }

      const finishedAt = new Date();

      console.log(
        `[HydrationWorker] ${this.options.dryRun ? '[DryRun] ' : ''}Processed payload ${payload.id}: ` +
        `${hydrateResult.productsNew} new, ${hydrateResult.productsUpdated} updated, ` +
        `${hydrateResult.productsDiscontinued} discontinued, ${hydrateResult.snapshotsCreated} snapshots, ` +
        `${hydrateResult.variantsUpserted} variants (${hydrateResult.variantSnapshotsCreated} variant snapshots)`
      );

      return {
        success: true,
        payloadId: payload.id,
        dispensaryId: payload.dispensary_id,
        productsUpserted: hydrateResult.productsUpserted,
        productsNew: hydrateResult.productsNew,
        productsUpdated: hydrateResult.productsUpdated,
        productsDiscontinued: hydrateResult.productsDiscontinued,
        snapshotsCreated: hydrateResult.snapshotsCreated,
        brandsCreated: hydrateResult.brandsCreated,
        categoriesCreated: 0,
        errors,
        startedAt,
        finishedAt,
        durationMs: finishedAt.getTime() - startedAt.getTime(),
      };
    } catch (error: any) {
      const finishedAt = new Date();
      errors.push(error.message);

      // Mark as failed
      if (!this.options.dryRun) {
        await markPayloadFailed(this.pool, payload.id, error.message);
      }

      console.error(`[HydrationWorker] Failed to process payload ${payload.id}:`, error.message);

      return {
        success: false,
        payloadId: payload.id,
        dispensaryId: payload.dispensary_id,
        productsUpserted: 0,
        productsNew: 0,
        productsUpdated: 0,
        productsDiscontinued: 0,
        snapshotsCreated: 0,
        brandsCreated: 0,
        categoriesCreated: 0,
        errors,
        startedAt,
        finishedAt,
        durationMs: finishedAt.getTime() - startedAt.getTime(),
      };
    }
  }

  /**
   * Process a batch of payloads
   */
  async processBatch(
    platform?: string
  ): Promise<HydrationBatchResult> {
    const startTime = Date.now();
    const errors: Array<{ payloadId: string; error: string }> = [];
    let payloadsProcessed = 0;
    let payloadsFailed = 0;
    let totalProductsUpserted = 0;
    let totalSnapshotsCreated = 0;
    let totalBrandsCreated = 0;

    // Acquire lock
    const lockAcquired = await this.lockManager.acquireLock(
      LOCK_NAMES.HYDRATION_BATCH,
      this.options.lockTimeoutMs
    );

    if (!lockAcquired) {
      console.log('[HydrationWorker] Could not acquire batch lock, skipping');
      return {
        payloadsProcessed: 0,
        payloadsFailed: 0,
        totalProductsUpserted: 0,
        totalSnapshotsCreated: 0,
        totalBrandsCreated: 0,
        errors: [],
        durationMs: Date.now() - startTime,
      };
    }

    try {
      // Create hydration run record
      let runId: number | null = null;
      if (!this.options.dryRun) {
        const result = await this.pool.query(
          `INSERT INTO hydration_runs (worker_id, started_at, status)
           VALUES ($1, NOW(), 'running')
           RETURNING id`,
          [this.workerId]
        );
        runId = result.rows[0].id;
      }

      // Get unprocessed payloads
      const payloads = await getUnprocessedPayloads(this.pool, {
        limit: this.options.batchSize,
        platform,
        maxAttempts: this.options.maxRetries,
      });

      console.log(`[HydrationWorker] Processing ${payloads.length} payloads`);

      // Process each payload
      for (const payload of payloads) {
        const result = await this.processPayload(payload);

        if (result.success) {
          payloadsProcessed++;
          totalProductsUpserted += result.productsUpserted;
          totalSnapshotsCreated += result.snapshotsCreated;
          totalBrandsCreated += result.brandsCreated;
        } else {
          payloadsFailed++;
          if (result.errors.length > 0) {
            errors.push({
              payloadId: payload.id,
              error: result.errors.join('; '),
            });
          }
        }
      }

      // Update hydration run record
      if (!this.options.dryRun && runId) {
        await this.pool.query(
          `UPDATE hydration_runs SET
            finished_at = NOW(),
            status = $2,
            payloads_processed = $3,
            products_upserted = $4,
            snapshots_created = $5,
            brands_created = $6,
            errors_count = $7
           WHERE id = $1`,
          [
            runId,
            payloadsFailed > 0 ? 'completed_with_errors' : 'completed',
            payloadsProcessed,
            totalProductsUpserted,
            totalSnapshotsCreated,
            totalBrandsCreated,
            payloadsFailed,
          ]
        );
      }

      console.log(
        `[HydrationWorker] Batch complete: ${payloadsProcessed} processed, ${payloadsFailed} failed`
      );

      return {
        payloadsProcessed,
        payloadsFailed,
        totalProductsUpserted,
        totalSnapshotsCreated,
        totalBrandsCreated,
        errors,
        durationMs: Date.now() - startTime,
      };
    } finally {
      await this.lockManager.releaseLock(LOCK_NAMES.HYDRATION_BATCH);
    }
  }

  /**
   * Run continuous hydration loop
   */
  async runLoop(intervalMs: number = 30000): Promise<void> {
    this.isRunning = true;
    console.log(`[HydrationWorker] Starting loop (interval: ${intervalMs}ms)`);

    while (this.isRunning) {
      try {
        const result = await this.processBatch();

        if (result.payloadsProcessed === 0) {
          // No work to do, wait before checking again
          await new Promise((resolve) => setTimeout(resolve, intervalMs));
        }
      } catch (error: any) {
        console.error('[HydrationWorker] Loop error:', error.message);
        await new Promise((resolve) => setTimeout(resolve, intervalMs));
      }
    }

    await this.lockManager.releaseAllLocks();
    console.log('[HydrationWorker] Loop stopped');
  }

  /**
   * Stop the hydration loop
   */
  stop(): void {
    this.isRunning = false;
  }

  /**
   * Get worker ID
   */
  getWorkerId(): string {
    return this.workerId;
  }
}

// ============================================================
// STANDALONE FUNCTIONS
// ============================================================

/**
 * Run a single hydration batch (for cron jobs)
 */
export async function runHydrationBatch(
  pool: Pool,
  options: HydrationOptions = {}
): Promise<HydrationBatchResult> {
  const worker = new HydrationWorker(pool, options);
  return worker.processBatch();
}

/**
 * Process a specific payload by ID
 */
export async function processPayloadById(
  pool: Pool,
  payloadId: string,
  options: HydrationOptions = {}
): Promise<HydrationResult> {
  const result = await pool.query(
    `SELECT * FROM raw_payloads WHERE id = $1`,
    [payloadId]
  );

  if (result.rows.length === 0) {
    throw new Error(`Payload not found: ${payloadId}`);
  }

  const worker = new HydrationWorker(pool, options);
  return worker.processPayload(result.rows[0]);
}

/**
 * Reprocess failed payloads
 */
export async function reprocessFailedPayloads(
  pool: Pool,
  options: HydrationOptions = {}
): Promise<HydrationBatchResult> {
  // Reset failed payloads for reprocessing
  await pool.query(
    `UPDATE raw_payloads
     SET hydration_attempts = 0,
         hydration_error = NULL
     WHERE processed = FALSE
       AND hydration_error IS NOT NULL`
  );

  const worker = new HydrationWorker(pool, options);
  return worker.processBatch();
}