-- Migration: Auto-retry failed proxies after cooldown period
-- Proxies that fail will be retried after a configurable interval

-- Add last_failed_at column to track when proxy last failed
ALTER TABLE proxies ADD COLUMN IF NOT EXISTS last_failed_at TIMESTAMP;

-- Add retry settings
INSERT INTO settings (key, value, description)
VALUES
  ('proxy_retry_interval_hours', '4', 'Hours to wait before retrying a failed proxy'),
  ('proxy_max_failures_before_permanent', '10', 'Max failures before proxy is permanently disabled')
ON CONFLICT (key) DO NOTHING;

-- Create function to get eligible proxies (active OR failed but past retry interval)
CREATE OR REPLACE FUNCTION get_eligible_proxy_ids()
RETURNS TABLE(proxy_id INT) AS $$
DECLARE
  retry_hours INT;
BEGIN
  -- Get retry interval from settings (default 4 hours)
  SELECT COALESCE(value::int, 4) INTO retry_hours
  FROM settings WHERE key = 'proxy_retry_interval_hours';

  RETURN QUERY
  SELECT p.id
  FROM proxies p
  WHERE p.active = true
     OR (
       p.active = false
       AND p.last_failed_at IS NOT NULL
       AND p.last_failed_at < NOW() - (retry_hours || ' hours')::interval
       AND p.failure_count < 10  -- Don't retry if too many failures
     )
  ORDER BY
    p.active DESC,  -- Prefer active proxies
    p.failure_count ASC,  -- Then prefer proxies with fewer failures
    RANDOM();
END;
$$ LANGUAGE plpgsql;

-- Create scheduled job to periodically re-enable proxies past their retry window
-- This runs every hour and marks proxies as active if they're past retry interval
CREATE OR REPLACE FUNCTION auto_reenable_proxies()
RETURNS INT AS $$
DECLARE
  retry_hours INT;
  max_failures INT;
  reenabled_count INT;
BEGIN
  -- Get settings
  SELECT COALESCE(value::int, 4) INTO retry_hours
  FROM settings WHERE key = 'proxy_retry_interval_hours';

  SELECT COALESCE(value::int, 10) INTO max_failures
  FROM settings WHERE key = 'proxy_max_failures_before_permanent';

  -- Re-enable proxies that have cooled down
  UPDATE proxies
  SET active = true,
      updated_at = NOW()
  WHERE active = false
    AND last_failed_at IS NOT NULL
    AND last_failed_at < NOW() - (retry_hours || ' hours')::interval
    AND failure_count < max_failures;

  GET DIAGNOSTICS reenabled_count = ROW_COUNT;

  IF reenabled_count > 0 THEN
    RAISE NOTICE 'Auto-reenabled % proxies after % hour cooldown', reenabled_count, retry_hours;
  END IF;

  RETURN reenabled_count;
END;
$$ LANGUAGE plpgsql;

-- Add index for efficient querying
CREATE INDEX IF NOT EXISTS idx_proxies_retry
ON proxies(active, last_failed_at, failure_count);

COMMENT ON COLUMN proxies.last_failed_at IS 'Timestamp of last failure - used for auto-retry logic';
COMMENT ON FUNCTION auto_reenable_proxies() IS 'Call periodically to re-enable failed proxies that have cooled down';