-- Migration 046: Crawler Reliability & Stabilization
-- Phase 1: Add fields for error taxonomy, retry management, and self-healing

-- ============================================================
-- PART 1: Error Taxonomy - Standardized error codes
-- ============================================================

-- Create enum for standardized error codes
DO $$
BEGIN
  IF NOT EXISTS (SELECT 1 FROM pg_type WHERE typname = 'crawl_error_code') THEN
    CREATE TYPE crawl_error_code AS ENUM (
      'SUCCESS',
      'RATE_LIMITED',
      'BLOCKED_PROXY',
      'HTML_CHANGED',
      'TIMEOUT',
      'AUTH_FAILED',
      'NETWORK_ERROR',
      'PARSE_ERROR',
      'NO_PRODUCTS',
      'UNKNOWN_ERROR'
    );
  END IF;
END;
$$ LANGUAGE plpgsql;

-- ============================================================
-- PART 2: Dispensary Crawl Configuration
-- ============================================================

-- Add crawl config columns to dispensaries
DO $$
BEGIN
  -- Crawl frequency (minutes between crawls)
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'crawl_frequency_minutes'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN crawl_frequency_minutes INTEGER DEFAULT 240;
  END IF;

  -- Max retries per crawl
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'max_retries'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN max_retries INTEGER DEFAULT 3;
  END IF;

  -- Current proxy ID
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'current_proxy_id'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN current_proxy_id INTEGER NULL;
  END IF;

  -- Current user agent
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'current_user_agent'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN current_user_agent TEXT NULL;
  END IF;

  -- Next scheduled run
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'next_crawl_at'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN next_crawl_at TIMESTAMPTZ NULL;
  END IF;

  -- Last successful crawl
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'last_success_at'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN last_success_at TIMESTAMPTZ NULL;
  END IF;

  -- Last error code (using text for flexibility, validated in app)
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'last_error_code'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN last_error_code TEXT NULL;
  END IF;

  -- Crawl status: active, degraded, paused, failed
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'crawl_status'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN crawl_status TEXT DEFAULT 'active';
  END IF;

  -- Backoff multiplier (increases with failures)
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'backoff_multiplier'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN backoff_multiplier NUMERIC(4,2) DEFAULT 1.0;
  END IF;

  -- Total attempt count (lifetime)
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'total_attempts'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN total_attempts INTEGER DEFAULT 0;
  END IF;

  -- Total success count (lifetime)
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensaries' AND column_name = 'total_successes'
  ) THEN
    ALTER TABLE dispensaries ADD COLUMN total_successes INTEGER DEFAULT 0;
  END IF;
END;
$$ LANGUAGE plpgsql;

-- ============================================================
-- PART 3: Enhanced Job Tracking
-- ============================================================

-- Add columns to dispensary_crawl_jobs
DO $$
BEGIN
  -- Error code
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensary_crawl_jobs' AND column_name = 'error_code'
  ) THEN
    ALTER TABLE dispensary_crawl_jobs ADD COLUMN error_code TEXT NULL;
  END IF;

  -- Proxy used for this job
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensary_crawl_jobs' AND column_name = 'proxy_used'
  ) THEN
    ALTER TABLE dispensary_crawl_jobs ADD COLUMN proxy_used TEXT NULL;
  END IF;

  -- User agent used for this job
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensary_crawl_jobs' AND column_name = 'user_agent_used'
  ) THEN
    ALTER TABLE dispensary_crawl_jobs ADD COLUMN user_agent_used TEXT NULL;
  END IF;

  -- Attempt number for this job
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensary_crawl_jobs' AND column_name = 'attempt_number'
  ) THEN
    ALTER TABLE dispensary_crawl_jobs ADD COLUMN attempt_number INTEGER DEFAULT 1;
  END IF;

  -- Backoff delay applied (ms)
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensary_crawl_jobs' AND column_name = 'backoff_delay_ms'
  ) THEN
    ALTER TABLE dispensary_crawl_jobs ADD COLUMN backoff_delay_ms INTEGER DEFAULT 0;
  END IF;

  -- HTTP status code received
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensary_crawl_jobs' AND column_name = 'http_status'
  ) THEN
    ALTER TABLE dispensary_crawl_jobs ADD COLUMN http_status INTEGER NULL;
  END IF;

  -- Response time (ms)
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.columns
    WHERE table_name = 'dispensary_crawl_jobs' AND column_name = 'response_time_ms'
  ) THEN
    ALTER TABLE dispensary_crawl_jobs ADD COLUMN response_time_ms INTEGER NULL;
  END IF;
END;
$$ LANGUAGE plpgsql;

-- ============================================================
-- PART 4: Crawl History Table (for detailed tracking)
-- ============================================================

CREATE TABLE IF NOT EXISTS crawl_attempts (
  id SERIAL PRIMARY KEY,
  dispensary_id INTEGER NOT NULL REFERENCES dispensaries(id),
  job_id INTEGER REFERENCES dispensary_crawl_jobs(id),

  -- Timing
  started_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
  finished_at TIMESTAMPTZ,
  duration_ms INTEGER,

  -- Result
  error_code TEXT NOT NULL DEFAULT 'UNKNOWN_ERROR',
  error_message TEXT,
  http_status INTEGER,

  -- Context
  attempt_number INTEGER NOT NULL DEFAULT 1,
  proxy_used TEXT,
  user_agent_used TEXT,

  -- Metrics
  products_found INTEGER DEFAULT 0,
  products_upserted INTEGER DEFAULT 0,
  snapshots_created INTEGER DEFAULT 0,

  -- Metadata
  metadata JSONB,
  created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
);

-- Index for quick lookups
CREATE INDEX IF NOT EXISTS idx_crawl_attempts_dispensary_id ON crawl_attempts(dispensary_id);
CREATE INDEX IF NOT EXISTS idx_crawl_attempts_error_code ON crawl_attempts(error_code);
CREATE INDEX IF NOT EXISTS idx_crawl_attempts_started_at ON crawl_attempts(started_at DESC);

-- ============================================================
-- PART 5: Views for Monitoring
-- ============================================================

-- Drop existing view if exists
DROP VIEW IF EXISTS v_crawler_status;

-- Crawler status view with all reliability fields
CREATE VIEW v_crawler_status AS
SELECT
  d.id,
  d.name,
  d.slug,
  d.menu_type,
  d.platform_dispensary_id,
  d.crawl_status,
  d.consecutive_failures,
  d.last_crawl_at,
  d.last_success_at,
  d.last_failure_at,
  d.last_error_code,
  d.next_crawl_at,
  d.crawl_frequency_minutes,
  d.max_retries,
  d.current_proxy_id,
  d.current_user_agent,
  d.backoff_multiplier,
  d.total_attempts,
  d.total_successes,
  d.product_count,
  CASE
    WHEN d.total_attempts > 0
    THEN ROUND(d.total_successes::NUMERIC / d.total_attempts * 100, 1)
    ELSE 0
  END AS success_rate,
  CASE
    WHEN d.crawl_status = 'failed' THEN 'FAILED'
    WHEN d.crawl_status = 'paused' THEN 'PAUSED'
    WHEN d.crawl_status = 'degraded' THEN 'DEGRADED'
    WHEN d.menu_type IS NULL OR d.menu_type = 'unknown' THEN 'NEEDS_DETECTION'
    WHEN d.platform_dispensary_id IS NULL THEN 'NEEDS_PLATFORM_ID'
    WHEN d.next_crawl_at IS NULL THEN 'NOT_SCHEDULED'
    WHEN d.next_crawl_at <= NOW() THEN 'DUE'
    ELSE 'SCHEDULED'
  END AS schedule_status,
  d.failed_at,
  d.failure_notes
FROM dispensaries d
WHERE d.state = 'AZ';

-- Drop existing view if exists
DROP VIEW IF EXISTS v_crawl_error_summary;

-- Error summary view
CREATE VIEW v_crawl_error_summary AS
SELECT
  error_code,
  COUNT(*) as total_occurrences,
  COUNT(DISTINCT dispensary_id) as affected_stores,
  MAX(started_at) as last_occurrence,
  AVG(duration_ms)::INTEGER as avg_duration_ms
FROM crawl_attempts
WHERE started_at > NOW() - INTERVAL '7 days'
GROUP BY error_code
ORDER BY total_occurrences DESC;

-- Drop existing view if exists
DROP VIEW IF EXISTS v_crawl_health;

-- Overall crawl health view
CREATE VIEW v_crawl_health AS
SELECT
  COUNT(*) FILTER (WHERE crawl_status = 'active') as active_crawlers,
  COUNT(*) FILTER (WHERE crawl_status = 'degraded') as degraded_crawlers,
  COUNT(*) FILTER (WHERE crawl_status = 'paused') as paused_crawlers,
  COUNT(*) FILTER (WHERE crawl_status = 'failed') as failed_crawlers,
  COUNT(*) FILTER (WHERE next_crawl_at <= NOW()) as due_now,
  COUNT(*) FILTER (WHERE consecutive_failures > 0) as stores_with_failures,
  AVG(consecutive_failures)::NUMERIC(4,2) as avg_consecutive_failures,
  COUNT(*) FILTER (WHERE last_success_at > NOW() - INTERVAL '24 hours') as successful_last_24h
FROM dispensaries
WHERE state = 'AZ' AND menu_type = 'dutchie';

-- ============================================================
-- PART 6: Constraint for minimum crawl gap
-- ============================================================

-- Function to check minimum crawl gap (2 minutes)
CREATE OR REPLACE FUNCTION check_minimum_crawl_gap()
RETURNS TRIGGER AS $$
BEGIN
  -- Only check for new pending jobs
  IF NEW.status = 'pending' AND NEW.dispensary_id IS NOT NULL THEN
    -- Check if there's a recent job for same dispensary
    IF EXISTS (
      SELECT 1 FROM dispensary_crawl_jobs
      WHERE dispensary_id = NEW.dispensary_id
        AND id != NEW.id
        AND status IN ('pending', 'running')
        AND created_at > NOW() - INTERVAL '2 minutes'
    ) THEN
      RAISE EXCEPTION 'Minimum 2-minute gap required between crawls for same dispensary';
    END IF;
  END IF;
  RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- Create trigger (drop first if exists)
DROP TRIGGER IF EXISTS enforce_minimum_crawl_gap ON dispensary_crawl_jobs;
CREATE TRIGGER enforce_minimum_crawl_gap
  BEFORE INSERT ON dispensary_crawl_jobs
  FOR EACH ROW
  EXECUTE FUNCTION check_minimum_crawl_gap();

-- ============================================================
-- PART 7: Comments
-- ============================================================

COMMENT ON TABLE crawl_attempts IS 'Detailed history of every crawl attempt for analytics and debugging';
COMMENT ON VIEW v_crawler_status IS 'Current status of all crawlers with reliability metrics';
COMMENT ON VIEW v_crawl_error_summary IS 'Summary of errors by type over last 7 days';
COMMENT ON VIEW v_crawl_health IS 'Overall health metrics for the crawling system';